Browse Topic: Chemicals

Items (6,683)
The design and analysis of the wave plate of the tank body of the low-temperature liquid nitrogen tank car are carried out. According to the design method of the empirical formula, the 0.43 MPa low-temperature mobile liquid nitrogen tank body wave plate with the working temperature of -196°C to -178°C is optimized. According to the analysis and design standards, the stress distribution law of the mobile liquid nitrogen tank body under the forward impact condition is analyzed by the method of numerical analysis. The results show that the stress value will gradually increase near the junction of the tank body and the support, and the parts such as the head, the pad, the angle steel ring, and the Z3848 glass steel pipe meet the requirements of the analysis and design standards. At the same time, the first six orders of the natural mode vibration frequency of the tank body are analyzed, which provides a reliable and effective data analysis for the optimization design of the low-temperature
Ding, XuqiangNi, YiweiGu, ChenYan, DongdongXu, ZhiquanWang, Qi
Polyimides are a class of polymers with imide rings in their main chains. They are renowned for their exceptional mechanical properties, high-temperature resistance, low-temperature endurance, and resistance to chemical solvents, which allow for long-term use under harsh medical operating conditions. Consequently, research on polyimide films has garnered widespread attention. In this study, a two-step method was employed to simplify and optimize the preparation process of polyimide. Initially, a polyamic acid (PAA) solution was prepared, and PAA films were fabricated using a spin coater. Subsequently, the films were imidized to obtain polyimide (PI) films. The impact of various parameters, such as spinning speed, layer number, and temperature, on the film-forming properties of polyimide was investigated using the method of controlling variables. The findings indicate that by setting the spin coater parameters to 700 revolutions per minute (r/min) for 90 seconds, followed by a
Huang, JiehaoXu, ZihuiZhao, KaihongLin, QitingHu, WenzhongWang, Liying
This SAE Standard specifies requirements for a gelled compound for cleaning the soiled exterior of service aircraft. The cleaning gel may be applied by pressure pump as a thixotropic liquid, by brushing or by swabbing. The surfaces to be cleaned may be unpainted metal or surfaces painted with glossy or matt schemes, including strippable acrylic paint complying with DTD 5599. This Standard includes tests to limit specific forms of corrosion that affect aircraft structural materials.
AMS J Aircraft Maintenance Chemicals and Materials Committee
This SAE Standard specifies requirements for a foaming liquid cleaning compound which, when diluted with water 1:9 v/v, is suitable for cleaning the soiled exterior of Service aircraft. The cleaning compound may be applied by spraying, either as foam or liquid, by brushing or by swabbing. The surfaces to be cleaned may be unpainted metal or surfaces painted with glossy or matt schemes, including strippable acrylic paint complying with DTD 5599. This Standard includes tests to limit specific forms of corrosion that affect aircraft structural materials.
AMS J Aircraft Maintenance Chemicals and Materials Committee
This specification covers a synthetic rubber in the form of sheet, strip, tubing, extrusions, and molded shapes. This specification should not be used for molded rings, compression seals, O-ring cords, and molded in place gaskets for aeronautical and aerospace applications without complete consideration of the end use prior to the selection this material.
AMS CE Elastomers Committee
This specification covers materials in the form of a liquid used to remove smut from aluminum surfaces treated with etch-type oxidation and corrosion removers.
AMS J Aircraft Maintenance Chemicals and Materials Committee
In the category of cast stainless steels, there are several variants per different level of addition of chromium, vanadium along with some minor elements, such as molybdenum, niobium, tungsten to meet the requirement of corrosion and oxidation resistance. However, the influence of chemical composition variations on the mechanical properties of cast SS continues to lack a clear understanding. In the present study, via machine learning, the effects of each element on the tensile properties of the selected cast stainless steel are studied. The machine learning model is then used to predict how variations in elements affect tensile behavior, with the predictions validated through physical testing.
Mishra, NeelamBiswas, SurjayanV S, RajamanickamAluru, PhaniLiu, YiAkbari, MeysamCoryell, Jason
Viscoelastic behavior of polymeric materials serves as a critical indicator of their internal structure and chemical composition, offering valuable insights into energy absorption and dissipation mechanisms. This study focuses on the dynamic characterization of polymer foams through both experimental and numerical approaches, aiming to accurately capture their time and frequency dependent mechanical response. Experimental investigations include uniaxial tension and uniaxial compression, which characterize hyperelastic or instantaneous behavior of the material. Stress relaxation tests and Dynamic Mechanical Analysis (DMA) characterize the dependence on time and frequency. A combination of these tests is effectively utilized to create viscoelastic material models that can describe the material response as a function of time and frequency containing a viscous and an elastic part. This paper presents dynamic characterization of polymer foams in finite element simulations. Theoretical
M, Gokula KrishnanLin, ChunfuSavic, Vesna
This paper carried out the fire failure analysis of valve-regulated lead-acid battery in communication equipment room. Through disassembly and observation of the battery and iron frame of battery cabinet in the area of fire origin, we obtained the key residual traces and used the physical and chemical analysis methods such as macroscopic/microscopic morphology, EDS, X-ray and metallographic, it was finally judged that the leakage of the battery electrolyte lead to the connection of the battery electrode plate and the iron frame and subsequently the electric heating fault caused the fire accident. Furthermore, we put forward some suggestions according to the existing problems, which may contribute to the prevention of similar failures.
Guo, Yuhang
Dr. Mustafa Akbulut, Professor of Chemical engineering, has teamed up with Horticultural Science Professor Luis Cisneros-Zevallos to engineer longer-lasting, bacteria-free produce.
The article deals with the issue of identifying structural defects that contribute to the formation of a carbide net during thermochemical treatment of steel parts, which negatively affects the mechanical properties complex of finished products. Based on the available data, a theory has been put forward regarding the influence of the present non-metallic inclusions in the carburizing steels structure on carbide formation process in the hardened layer. As an experimentally the samples have been produced from the varying chemical composition alloy structure carburized steel (0.17-0.23 % C, 0.17-0.37 % Si, 0.80-1.10 % Mn, 1.00-1.30 % Cr, 0.03-0.09 % Ti). During microstructure analysis of the samples it has been establish that non-metallic inclusions, in particular sulfides, contribute to the formation of carbides and carbide net in steel due to their high chemical activity with carbon. Thus, contamination of the metal of carburizing steels with non-metallic inclusions is not only a defect
Runova, IuliiaChatkina, MariiaMusienko, Aleksandr
The automotive industry is advancing rapidly with the integration of cutting-edge technology, aesthetics, and performance. One area that has remained relatively underexplored in the pursuit of sleek, minimalistic interiors is the packaging of Sunshade in door trim system. Traditional sunshade design, often bulky and increasingly incompatible with the trend towards compact design and packaging. The car sunshade is a shield that is placed on a car side window and used for regulating the amount of light entering from the car window and helps improve the passenger comfort inside the cabin. Car Interior components, specifically plastic and seats are based on thermal stress properties. When we expose these parts to direct contact with sunlight, humidity and ambient temperature above threshold limit, the interior plastic parts can start to soften and melt. Due to this, they start emitting harmful chemicals which cause anemia and poor immune systems. So, the Sunshade, in addition to protecting
Palyal, NikitaD, GowthamBhaskararao, PathivadaBornare, HarshadRitesh, Kakade
Polymer compounds used in the manufacturing of automotive interiors are traditionally consist of polymer virgin material, elastomers, additives, pigments, fillers. These compounded polymers are prone to the emission of low molecular weight chemicals over a period of usage and exposure to the environment called volatile organic compounds (VOCs) and carbonyl compounds. These released VOCs and carbonyl compounds consist of chemicals like benzene, toluene, xylene, styrene, acetaldehyde, formaldehyde, acrolein etc. Short term or long-term exposure of these chemicals have adverse health effects like nausea, headache, vomiting, cancer, even death of personnel if found beyond the permissible limits. It has been observed that the majority of passenger have the above symptoms whenever travelled using passenger cars within few minutes of boarding and exchange the car cabin air. The study was planned to understand the reasons for the concerns and further resolution. This paper is focused on the
Shukla, Sandeep KumarBalaji, K VVaratharajan, Senthilkumaran
Elastomeric materials are essential in advanced automotive engineering for mobility, isolation, damping, fluid transfer (cooling, steering, fuel, and brake), and sealing because of their unique physio mechanical properties. Elastomers are commonly used in both static and dynamic components, such as hoses, mounts, bushes, and tires. Engine emission standards and weight optimization have caused higher temperature exposure conditions for automotive components. The steering system uses special purpose elastomers like Chlorinated Polyethylene that can deteriorate under abnormal conditions during vehicle operation or manufacturing process due to the high temperature exposure. Therefore, it is crucial to understand the causes and consequences of thermal degradation of elastomers. Thermal degradation is a significant phenomenon that changes the physiochemical properties of elastomers, which results in a product not meeting functional requirements. This study investigates the thermal
Thiruppathi, AnandhiMishra, NitishKrishnamoorthy, Kunju
Polymer composites with the addition of natural fibers have gained prominence as a sustainable and technically viable alternative to conventional synthetic materials, especially in applications that require a balance between mechanical performance and environmental responsibility. This study evaluated the mechanical behavior of composites produced with plant fibers from banana (Musa sapientum) and sugarcane (Saccharum officinarum L.), both sourced from the northern region of Brazil. The fibers, used in their natural state without chemical treatment, were cut to a uniform length of 5 mm for standardization. The polymer matrix used was unsaturated terephthalic polyester resin, pre-accelerated and catalyzed with methyl ethyl ketone peroxide (MEKP). The molding of test samples was performed manually in silicone molds, according to ASTM D638 specifications, to ensure repeatability and comparability of results. The mechanical tests revealed that the composites made with sugarcane fibers had
Santos Borges, LarissaDias, Roberto Yuri CostaBrandao, Leonardo William MacedoMendonca Maia, Pedro VictorSilva de Mendonça, Alian GomesFujiyama, Roberto Tetsuo
This paper focuses on the performance of the high-pressure oxygen cylinder oxygen supplemental system in the lavatory of civil aircraft. Due to the potential safety hazards of chemical oxygen generators in the lavatory, high-pressure gaseous oxygen cylinders are used instead. Through theoretical and study, the influence of the orifice on the oxygen flow rate is thoroughly investigated. Based on relevant principles, the calculation method of the gas flow characteristics in the orifice is determined. Considering the high initial pressure of the oxygen cylinder, the supersonic flow condition within approximately 20 minutes is mainly considered. The Simulink is used to simulate the system flow rate under different temperatures during cabin depressurization. Experimental verification shows that the oxygen flow rate under different temperatures meets the minimum oxygen demand, and the simulation results are highly consistent with the experimental results, indicating that the simulation
Wan, ShutingLei, MingjunYu, Xiaoying
Nuclear microreactors could improve the performance of electric propulsion systems in spacecraft. University of Washington, Seattle, WA To develop spacecraft that can “maneuver without regret,” the U.S. Space Force is providing $35 million to a national research team, including engineers at the University of Washington. It will be the first to bring fast chemical rockets together with efficient electric propulsion powered by a nuclear microreactor. The newly formed Space Power and Propulsion for Agility, Responsiveness and Resilience (SPAR) Institute involves eight universities, and 14 industry partners and advisers in one of the nation's largest efforts to advance space power and propulsion.
Minimally invasive and interventional platforms increasingly demand smaller profiles, tighter tolerances, and components that maintain performance under thermal, chemical, and mechanical stress. Polyimide (PI) has emerged as a workhorse within these parameters because it combines high strength, thermal stability, chemical inertness, dielectric performance, and biocompatibility in thin-wall formats suitable for catheters, electrophysiology tools, and neurovascular systems. 1- 3
To develop spacecraft that can “maneuver without regret,” the U.S. Space Force is providing $35 million to a national research team, including engineers at the University of Washington. It will be the first to bring fast chemical rockets together with efficient electric propulsion powered by a nuclear microreactor.
In an attempt to reduce CO2 release from alloy wheel production, we have developed an aluminum alloy for casting that satisfies necessary property requirements using recycled aluminum, but without heat treatment. The wheel is a critical safety feature of any vehicle, and it should have toughness and strength .In many wheels, virgin aluminum containing small amounts of impurities is used to maintain toughness, and heat treatment (T6), which is post-casting quick heating and quenching, is applied to provide strength. At the start of this project, we focused on two wheel-manufacturing processes, production of virgin aluminum and heat treatment, from which a large amount of CO2 is released. By switching to recycled aluminum, CO2 was reduced to one-ninth the original amount. The issue with recycled material is that impurities grow in the metal structures as intermetallic compounds and this reduces toughness. To deal with this issue, we have chosen high-pressure die casting (HPDC), in which
Suzuki, Noritaka
Nylon, Teflon, Kevlar. These are just a few familiar polymers — large-molecule chemical compounds — that have changed the world. From Teflon-coated frying pans to 3D printing, polymers are vital to creating the systems that make the world function better.
A noninvasive imaging system combines two advanced techniques to examine both the structure and chemical composition of skin cancers. This approach could improve how doctors diagnose and classify skin cancer and how they monitor treatment responses.
This specification covers an acrylonitrile-butadiene rubber in the form of molded rings, compression seals, O-ring cord, and molded-in-place gaskets for aeronautical and aerospace applications.
AMS CE Elastomers Committee
Hydrogen is a clean-burning fuel that could help to replace fossil fuels in transportation, the chemicals industry, and many other sectors. However, hydrogen is also an explosive gas, so it is essential to have safety systems that can reliably detect leaks in a variety of circumstances.
Although lithium is highly effective to treat bipolar disorder, the chemical has a narrow therapeutic window — too high a dose can be toxic to patients, causing kidney damage, thyroid damage, or even death, while too low a dose renders the treatment ineffective.
The increased functionality of today’s medical devices is astounding. Optical devices, for example, analyze chemicals, toxins, and biologic specimens. Semiconductor devices sense, analyze, and communicate. Microelectromechanical system (MEMS) devices utilize inertial methods to detect motion, direct light, and move components over short distances. Radiofrequency (RF) devices communicate wirelessly to other devices directly and remotely over the Internet. Handheld acoustic devices scan the body and build a virtual 3D model that shows conditions in the body. The innovation currently happening in the medical device industry is staggering, limited only by imagination and finding technical methods to implement the vision.
A wearable wristband could significantly improve diabetes management by continuously tracking not only glucose but also other chemical and cardiovascular signals that influence disease progression and overall health.
This standard establishes the recommended requirements for application of AMS3144 anodic electrodeposition primer to aerospace components. Adherence to these requirements will help facilitate satisfactory performance of the applied primer.
AMS G8 Aerospace Organic Coatings Committee
Engineers have developed a smart lactation pad that can quantify a wide range of chemicals in breast milk in real time. This work is pioneering the first wearable, rapid sensor for at-home measurement of chemicals in breast milk, addressing an important technology gap for improving the health of the mother and the baby.
This specification covers a corrosion-resistant steel in the form of sheet and strip over 0.005 inch (0.13 mm) in nominal thickness.
AMS F Corrosion and Heat Resistant Alloys Committee
This specification covers a corrosion-resistant steel in the form of cold-worked bars and wire up to 1.750 inches (44.45 mm), inclusive, in nominal diameter or least distance between parallel sides.
AMS F Corrosion and Heat Resistant Alloys Committee
This specification covers a corrosion-resistant steel in the form of sheet and strip 0.005 inch (0.13 mm) and over in nominal thickness.
AMS F Corrosion and Heat Resistant Alloys Committee
This specification covers a corrosion-resistant steel in the form of sheet and strip.
AMS F Corrosion and Heat Resistant Alloys Committee
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
This specification covers a biodegradable deodorant in the form of a liquid concentrate, solid, or gel.
AMS J Aircraft Maintenance Chemicals and Materials Committee
This specification establishes the requirements for chemical-film (conversion) coatings on aluminum alloys.
AMS B Finishes Processes and Fluids Committee
A Northwestern University-led team of researchers has developed a new fuel cell that harvests energy from microbes living in dirt. About the size of a standard paperback book, the completely soil-powered technology could fuel underground sensors used in precision agriculture and green infrastructure. This potentially could offer a sustainable, renewable alternative to batteries, which hold toxic, flammable chemicals that leach into the ground, are fraught with conflict-filled supply chains and contribute to the ever-growing problem of electronic waste.
The relation between the multiple auto-ignition in the premixed charge with fuel concentration distribution and associated pressure wave are numerically investigated. This study assumes that the auto-ignition phenomenon in the end-gas of PCCI combustion, a next-generation combustion method which is expected to achieve both low fuel consumption and low emissions at a high level. Detailed numerical analysis considering the elementary chemical reactions of the compressible reacting fluid flow described in the one-dimensional coordinate system with high spatial and time resolution was performed to clarify the detailed phenomena of the onset of the multiple auto-ignition and the pressure wave propagation in the gas.
Iizumi, KotaYoshida, Kenji
In response to the evolving landscape of exhaust gas regulations for small powertrains, reducing NOx emission is increasingly important. This study deeply investigated the feasibility of a NOx storage catalyst (NSC) containing cerium oxide (CeO2) and barium oxide (BaO) for reducing NOx emission. The key functions, NOx storage and reduction performances were evaluated, and deterioration mechanisms were explored through performance evaluations and physical property analyses. The findings revealed a strong correlation between the size of CeO2 crystals and NOx storage performance at low temperature, such as those encountered during city driving conditions. Conversely, at high temperature, such as those during highway driving conditions, NOx storage performance correlated well with sulfur deposition, suggesting that the formation of barium sulfate (BaSO4) contributes to the deactivation. This experiment also showed a strong correlation between NOx reduction performance and BaSO4 formation
Nakano, FumiyaKoito, Yusuke
This foundation specification (AMS1424T) and its associated category specifications (AMS1424/1 and AMS1424/2) cover a deicing/anti-icing material in the form of a fluid.
G-12ADF Aircraft Deicing Fluids
In recent years, researchers have increasingly focused on ammonia–diesel dual-fuel engines as a means of reducing CO2 emissions. Analyzing in-cylinder combustion processes is essential for optimizing the performance of ammonia–diesel dual-fuel engines. However, there is currently a lack of suitable reaction kinetics models for ammonia–diesel engine conditions. In this study, the ignition delay of ammonia/n-heptane mixtures was measured, and a reduced chemical mechanism was developed. Using rapid compression machine (RCM) experiments, the ignition delays of ammonia/n-heptane mixtures with different ammonia energy fractions (AEFs) (40%, 60%, and 80%) were measured. The test pressure ranged from 1.5 to 3.0 MPa, while the temperature ranged from 667 to 919 K, with an equivalence ratio of 1. The results showed that as the AEFs increased, the ignition delay of the premixed mixture also increased. When the AEF was 40%, the ammonia/n-heptane premixed mixture exhibited the negative temperature
Cai, KaiyuanLiu, YiChen, QingchuQi, YunliangLi, LiWang, Zhi
Composite materials are created by combining two or more different materials, such as a filler or fibrous reinforcement dispersed in a polymer matrix. The primary goal of developing composites is to improve properties while reducing weight, making them ideal for the sustainable development of the automotive industry. Poly(lactic acid) (PLA) has emerged as a promising polymer matrix for composites due to its ecological and biodegradable nature, as well as its good mechanical properties (tensile strength and modulus of elasticity), though it remains limited when compared to engineering polymers such as acrylonitrile butadiene styrene (ABS) and acrylonitrile styrene acrylate (ASA). Cotton fibers have gained visibility in recent years as reinforcement in various matrices due to their low cost, renewable origin, and relative abundance. Incorporating cotton fibers into PLA can improve its mechanical properties, enhancing attributes such as tensile strength and stiffness, which makes the
De Andrade, MarinaPolkowski, RodrigoHoriuchi, Lucas NaoGoncalves, Ana PaulaDe Oliveira, Vinícius
The advance of regulatory emission standards for light-duty vehicles, trucks and motorcycles, coupled with rising sustainability concerns, particularly United Nations' Sustainable Development Goal 12 (responsible consumption and production), has created an urgent need for lighter, stronger, and more ecological materials. Polylactic acid (PLA), a biodegradable polymer derived from plant sources, offers promising mechanical tensile strength and processability. Nanocomposites, a solution that combines a base matrix with a nanoreinforcing filler, provides a path toward developing sustainable materials with new properties. Cellulose nanofibrils (CNF) are a valuable nanofiller obtained through industrial waste or vegetal fibers, offer a promising avenue for strengthening PLA-based materials. Additive manufacturing (AM) has gained popularity due to its ability to create complex parts, prototyping designs, and to evaluate new nanocomposite materials such as PLA/CNF, showing significant
de Oliveira, ViníciusHoriuchi, Lucas NaoGoncalves, Ana PaulaDe Andrade, MarinaPolkowski, Rodrigo
Automotive industry is growing rapidly with innovations leading to increase in new features and improving the Quality of vehicles. These new components are developed with the available design standards across global OEMs. This Quality research paper aims to address the need of revision of design standards due to environmental factors prevailing in India. With the increase towards autonomous mobility, the number of electronics is also increasing, and this involves hardware & software evaluation. The hardware testing is a point of concern due to increase in the failure rate from the markets. Environment changes are very much evident with the growing economies and OEMs are developing the components with innovation, but if the basic design standards are not revised in parallel with the changing environment, the issues will continue to trouble the end customers. The failed cases data received from across the country was analyzed and observed that the cases are majorly reported from urban
Marwah, RamnikPyasi, PraveenBindra, RiteshGarg, Vipin
Depletion of petroleum crude oil and its environmental impacts challenge future generations. Vegetable oils provide a sustainable alternative with benefits like anti-wear properties, biodegradability, and renewability. Kusum oil's ability to lower carbon emissions significantly and promote sustainable industrial practices highlights its potential as a viable green alternative. This research paper presents a comprehensive and comparative analysis of a sustainable, environmentally friendly bio-lubricant and nonedible vegetable oil like Kusum oil. Bio-lubricant is produced by transesterification followed by epoxidation, which is known as epoxidized kusum oil lubricant or dehydrated kusum oil (DKO). The process of epoxidation significantly enhances the properties of Kusum oil, making it a promising alternative to conventional lubricants. It is compared with a widely used conventional mineral oil lubricant like SAE10W40. DKO exhibits comparable density, viscosity index, pour point, and
Prabhakaran, JPali, Harveer SinghSingh, Nishant K.
Optical sensors serve as the backbone of numerous scientific and technological endeavors, from detecting gravitational waves to imaging biological tissues for medical diagnostics. These sensors use light to detect changes in properties of the environment they’re monitoring, including chemical biomarkers and physical properties like temperature. A persistent challenge in optical sensing has been enhancing sensitivity to detect faint signals amid noise.
This specification covers the requirements of uncoated aluminum alloy foil for core materials required for structural sandwich construction.
AMS D Nonferrous Alloys Committee
The chemical milling process used in the aerospace industry generates substantial metallic residue in the etching bath, referred to as chemical milling sludge (CMS). The direct disposal of CMS into the environment leads to ecological deterioration and economic losses. This study focused on the recovery of aluminum from the aerospace industry CMS, aiming to mitigate environmental harm and enhance resource efficiency. The energy-dispersive X-ray (EDX) analysis revealed that the aluminum content in extracted CMS increased significantly to 95.86%, compared to 28.98% in non-extracted sludge. The XRD analysis of the CMS extracted samples also revealed the presence of increased Al2O3. The surface morphology study suggested the irregularly shaped particles with large chunks, and fine granules were observed on CMS. The yield of Al2O3 was observed to be 35.9% (wt) prior to the calcination process followed by 12.1% (wt) after calcination. The phytotoxicity study indicated that the CMS inhibited
Prasad, JagSonwani, Ravi Kumar
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