Bromine oxides are not as well-characterised as chlorine oxides or iodine oxides, as they are all fairly unstable: it was once thought that they could not exist at all. Dibromine monoxide is a dark-brown solid which, while reasonably stable at −60 °C, decomposes at its melting point of −17.5 °C; it is useful in bromination reactions[47] and may be made from the low-temperature decomposition of bromine dioxide in a vacuum. It oxidises iodine to iodine pentoxide and benzene to 1,4-benzoquinone; in alkaline solutions, it gives the hypobromite anion.[48]

Bromine is intermediate in reactivity between chlorine and iodine, and is one of the most reactive elements. Bond energies to bromine tend to be lower than those to chlorine but higher than those to iodine, and bromine is a weaker oxidising agent than chlorine but a stronger one than iodine. This can be seen from the standard electrode potentials of the X2/X− couples (F, +2.866 V; Cl, +1.395 V; Br, +1.087 V; I, +0.615 V; At, approximately +0.3 V). Bromination often leads to higher oxidation states than iodination but lower or equal oxidation states to chlorination. Bromine tends to react with compounds including M–M, M–H, or M–C bonds to form M–Br bonds.[36]

Bromine pentafluoride (BrF5) was first synthesised in 1930. It is produced on a large scale by direct reaction of bromine with excess fluorine at temperatures higher than 150 °C, and on a small scale by the fluorination of potassium bromide at 25 °C. It also reacts violently with water and is a very strong fluorinating agent, although chlorine trifluoride is still stronger.[44]

Bromine has two stable isotopes, 79Br and 81Br. These are its only two natural isotopes, with 79Br making up 51% of natural bromine and 81Br making up the remaining 49%. Both have nuclear spin 3/2− and thus may be used for nuclear magnetic resonance, although 81Br is more favourable. The relatively 1:1 distribution of the two isotopes in nature is helpful in identification of bromine containing compounds using mass spectroscopy. Other bromine isotopes are all radioactive, with half-lives too short to occur in nature. Of these, the most important are 80Br (t1/2 = 17.7 min), 80mBr (t1/2 = 4.421 h), and 82Br (t1/2 = 35.28 h), which may be produced from the neutron activation of natural bromine.[32] The most stable bromine radioisotope is 77Br (t1/2 = 57.04 h). The primary decay mode of isotopes lighter than 79Br is electron capture to isotopes of selenium; that of isotopes heavier than 81Br is beta decay to isotopes of krypton; and 80Br may decay by either mode to stable 80Se or 80Kr. Br isotopes from 87Br and heavier undergo beta decay with neutron emission and are of practical importance because they are fission products.[38]

Large amounts of bromide salts are toxic from the action of soluble bromide ions, causing bromism. However, bromine is beneficial for human eosinophils,[10] and is an essential trace element for collagen development in all animals.[11] Hundreds of known organobromine compounds are generated by terrestrial and marine plants and animals, and some serve important biological roles.[12] As a pharmaceutical, the simple bromide ion (Br−) has inhibitory effects on the central nervous system, and bromide salts were once a major medical sedative, before replacement by shorter-acting drugs. They retain niche uses as antiepileptics.

Understanding how radial loads are distributed within the bearing is vital for ensuring even wear and preventing premature failure. The design of radial bearings allows for uniform load distribution across the inner and outer rings, optimizing load-bearing capacity and minimizing stress on the bearing components.

A 2014 study suggests that bromine (in the form of bromide ion) is a necessary cofactor in the biosynthesis of collagen IV, making the element essential to basement membrane architecture and tissue development in animals.[11] Nevertheless, no clear deprivation symptoms or syndromes have been documented in mammals.[75] In other biological functions, bromine may be non-essential but still beneficial when it takes the place of chlorine. For example, in the presence of hydrogen peroxide, H2O2, formed by the eosinophil, and either chloride, iodide, thiocyanate, or bromide ions, eosinophil peroxidase provides a potent mechanism by which eosinophils kill multicellular parasites (such as the nematode worms involved in filariasis) and some bacteria (such as tuberculosis bacteria). Eosinophil peroxidase is a haloperoxidase that preferentially uses bromide over chloride for this purpose, generating hypobromite (hypobromous acid), although the use of chloride is possible.[10]

At standard conditions for temperature and pressure it is a liquid; the only other element that is liquid under these conditions is mercury. At high temperatures, organobromine compounds readily dissociate to yield free bromine atoms, a process that stops free radical chemical chain reactions. This effect makes organobromine compounds useful as fire retardants, and more than half the bromine produced worldwide each year is put to this purpose. The same property causes ultraviolet sunlight to dissociate volatile organobromine compounds in the atmosphere to yield free bromine atoms, causing ozone depletion. As a result, many organobromine compounds—such as the pesticide methyl bromide—are no longer used. Bromine compounds are still used in well drilling fluids, in photographic film, and as an intermediate in the manufacture of organic chemicals.

α-Haloesters are generally thought of as highly reactive and consequently toxic intermediates in organic synthesis. Nevertheless, mammals, including humans, cats, and rats, appear to biosynthesize traces of an α-bromoester, 2-octyl 4-bromo-3-oxobutanoate, which is found in their cerebrospinal fluid and appears to play a yet unclarified role in inducing REM sleep.[12] Neutrophil myeloperoxidase can use H2O2 and Br− to brominate deoxycytidine, which could result in DNA mutations.[76] Marine organisms are the main source of organobromine compounds, and it is in these organisms that bromine is more firmly shown to be essential. More than 1600 such organobromine compounds were identified by 1999. The most abundant is methyl bromide (CH3Br), of which an estimated 56,000 tonnes is produced by marine algae each year.[12] The essential oil of the Hawaiian alga Asparagopsis taxiformis consists of 80% bromoform.[77] Most of such organobromine compounds in the sea are made by the action of a unique algal enzyme, vanadium bromoperoxidase.[78]

At room temperature, hydrogen bromide is a colourless gas, like all the hydrogen halides apart from hydrogen fluoride, since hydrogen cannot form strong hydrogen bonds to the large and only mildly electronegative bromine atom; however, weak hydrogen bonding is present in solid crystalline hydrogen bromide at low temperatures, similar to the hydrogen fluoride structure, before disorder begins to prevail as the temperature is raised.[39] Aqueous hydrogen bromide is known as hydrobromic acid, which is a strong acid (pKa = −9) because the hydrogen bonds to bromine are too weak to inhibit dissociation. The HBr/H2O system also involves many hydrates HBr·nH2O for n = 1, 2, 3, 4, and 6, which are essentially salts of bromine anions and hydronium cations. Hydrobromic acid forms an azeotrope with boiling point 124.3 °C at 47.63 g HBr per 100 g solution; thus hydrobromic acid cannot be concentrated beyond this point by distillation.[40]

Bromine is significantly less abundant in the crust than fluorine or chlorine, comprising only 2.5 parts per million of the Earth's crustal rocks, and then only as bromide salts. It is the 46th most abundant element in Earth's crust. It is significantly more abundant in the oceans, resulting from long-term leaching. There, it makes up 65 parts per million, corresponding to a ratio of about one bromine atom for every 660 chlorine atoms. Salt lakes and brine wells may have higher bromine concentrations: for example, the Dead Sea contains 0.4% bromide ions.[54] It is from these sources that bromine extraction is mostly economically feasible.[55][56][57] Bromine is the tenth most abundant element in seawater.[58]

To ensure bearings are not subjected to excessive radial loads, it’s essential to understand how to calculate these forces accurately. Proper calculations involve assessing the weight and forces acting on the bearing and determining how these forces are distributed. Precise calculations prevent overloading, a common cause of bearing failure.

Load analysis is a critical step in ensuring the reliable and efficient operation of machinery. It serves as a proactive measure to prevent premature bearing failure, reduce maintenance costs, and minimize downtime. Proper load analysis provides invaluable insights into how forces impact the bearings, allowing for informed decisions and optimized performance.

The bromide anion is not very toxic: a normal daily intake is 2 to 8 milligrams.[75] However, high levels of bromide chronically impair the membrane of neurons, which progressively impairs neuronal transmission, leading to toxicity, known as bromism. Bromide has an elimination half-life of 9 to 12 days, which can lead to excessive accumulation. Doses of 0.5 to 1 gram per day of bromide can lead to bromism. Historically, the therapeutic dose of bromide is about 3 to 5 grams of bromide, thus explaining why chronic toxicity (bromism) was once so common. While significant and sometimes serious disturbances occur to neurologic, psychiatric, dermatological, and gastrointestinal functions, death from bromism is rare.[79] Bromism is caused by a neurotoxic effect on the brain which results in somnolence, psychosis, seizures and delirium.[80]

In the realm of industrial machinery and equipment, the significance of bearings cannot be overstated. Bearings are the unsung heroes that ensure the smooth operation of a vast array of machines, from small household appliances to massive industrial engines. These critical components are designed to withstand a variety of forces, with two primary types of loads they must contend with: radial and axial loads. Understanding the distinctions between these load types and their implications is not only crucial for those in the bearing industry but also for anyone who relies on machinery and equipment powered by these versatile components. In this comprehensive exploration, we will delve into the world of radial loads and axial loads, shedding light on their fundamental differences and the pivotal role they play in various industries.

The aerospace industry places some of the most stringent demands on bearing performance and reliability. Bearings used in aircraft must handle extreme conditions and loads while ensuring safety and longevity. Delving into the specifics of aerospace bearings showcases the rigorous standards and quality requirements these components must meet.

The material from which a bearing is constructed plays a significant role in its load-carrying capacity. Different materials have varying load capacities, corrosion resistance, and suitability for particular environments. In load analysis, it’s essential to consider the bearing’s material in conjunction with the type of load it will bear. This ensures that the bearing can handle the expected forces and environmental conditions effectively.

Understanding the specific load conditions a bearing will encounter is crucial in making informed choices during the selection process. Load analysis takes into account factors such as load capacity, rotational speed, and environmental conditions, enabling professionals to choose the right bearing for the job. Selecting the ideal bearing for a given application is central to its performance and longevity.

Brominated vegetable oil (BVO), a complex mixture of plant-derived triglycerides that have been reacted to contain atoms of the element bromine bonded to the molecules, is used primarily to help emulsify citrus-flavored soft drinks, preventing them from separating during distribution.

By 1864, a 25% solution of liquid bromine in .75 molar aqueous potassium bromide[26] was widely used[27] to treat gangrene during the American Civil War, before the publications of Joseph Lister and Pasteur.[28] It was also used to exorcise spirits.[29]

Quality control and adherence to industry standards play a pivotal role in preventing bearing failures and minimizing costly downtime. By implementing proper quality assurance measures, manufacturers and users can enhance the reliability and longevity of bearings, contributing to smoother operations and cost savings.

Bromide has been prescribed to exorcise demons by William A. Hammond, Surgeon General of the US Army, which he reports to be highly effective and evidence of a pathological explanation for demonic possession. John Nevius theorises though that bromide treatment could tone the nervous system and strengthen the will, allowing sufferers to emancipate themselves from demon spirits, whether pathological or supernatural.[29]

So-called "bromine dioxide", a pale yellow crystalline solid, may be better formulated as bromine perbromate, BrOBrO3. It is thermally unstable above −40 °C, violently decomposing to its elements at 0 °C. Dibromine trioxide, syn-BrOBrO2, is also known; it is the anhydride of hypobromous acid and bromic acid. It is an orange crystalline solid which decomposes above −40 °C; if heated too rapidly, it explodes around 0 °C. A few other unstable radical oxides are also known, as are some poorly characterised oxides, such as dibromine pentoxide, tribromine octoxide, and bromine trioxide.[48]

Load testing is a fundamental aspect of quality control in the bearing industry. This testing process simulates real-world load conditions to ensure that bearings can handle the forces they are designed for. Comprehensive load testing is essential in confirming that bearings meet their rated load capacities and perform reliably.

In complex mechanical systems, bearings often face the challenge of handling both radial and axial loads simultaneously. These mixed load scenarios require a comprehensive understanding of how these loads interact and impact the bearing’s performance. Engineers must develop strategies to manage these complex load conditions effectively.

Difference betweenradialandaxialrunout

Axial loads, sometimes referred to as thrust loads, are forces that act parallel to the bearing’s axis. Unlike radial loads, axial loads are generated when a force is applied in the direction of the shaft. This application of force creates a situation where bearings must handle axial movement. Imagine trying to push or pull the bearing along its axis, and you have a clear picture of axial loads.

In pharmacology, inorganic bromide compounds, especially potassium bromide, were frequently used as general sedatives in the 19th and early 20th century. Bromides in the form of simple salts are still used as anticonvulsants in both veterinary and human medicine, although the latter use varies from country to country. For example, the U.S. Food and Drug Administration (FDA) does not approve bromide for the treatment of any disease, and sodium bromide was removed from over-the-counter sedative products like Bromo-Seltzer, in 1975.[71] Commercially available organobromine pharmaceuticals include the vasodilator nicergoline, the sedative brotizolam, the anticancer agent pipobroman, and the antiseptic merbromin. Otherwise, organobromine compounds are rarely pharmaceutically useful, in contrast to the situation for organofluorine compounds. Several drugs are produced as the bromide (or equivalents, hydrobromide) salts, but in such cases bromide serves as an innocuous counterion of no biological significance.[51]

The main sources of bromine production are Israel and Jordan.[59] The element is liberated by halogen exchange, using chlorine gas to oxidise Br− to Br2. This is then removed with a blast of steam or air, and is then condensed and purified.[60] Today, bromine is transported in large-capacity metal drums or lead-lined tanks that can hold hundreds of kilograms or even tonnes of bromine. The bromine industry is about one-hundredth the size of the chlorine industry. Laboratory production is unnecessary because bromine is commercially available and has a long shelf life.[61]

When a lower bromide is wanted, either a higher halide may be reduced using hydrogen or a metal as a reducing agent, or thermal decomposition or disproportionation may be used, as follows:[41]

Brominated flame retardants represent a commodity of growing importance, and make up the largest commercial use of bromine. When the brominated material burns, the flame retardant produces hydrobromic acid which interferes in the radical chain reaction of the oxidation reaction of the fire. The mechanism is that the highly reactive hydrogen radicals, oxygen radicals, and hydroxyl radicals react with hydrobromic acid to form less reactive bromine radicals (i.e., free bromine atoms). Bromine atoms may also react directly with other radicals to help terminate the free radical chain-reactions that characterise combustion.[63][64]

Bromine is the third halogen, being a nonmetal in group 17 of the periodic table. Its properties are thus similar to those of fluorine, chlorine, and iodine, and tend to be intermediate between those of chlorine and iodine, the two neighbouring halogens. Bromine has the electron configuration [Ar]4s23d104p5, with the seven electrons in the fourth and outermost shell acting as its valence electrons. Like all halogens, it is thus one electron short of a full octet, and is hence a strong oxidising agent, reacting with many elements in order to complete its outer shell.[32] Corresponding to periodic trends, it is intermediate in electronegativity between chlorine and iodine (F: 3.98, Cl: 3.16, Br: 2.96, I: 2.66), and is less reactive than chlorine and more reactive than iodine. It is also a weaker oxidising agent than chlorine, but a stronger one than iodine. Conversely, the bromide ion is a weaker reducing agent than iodide, but a stronger one than chloride.[32] These similarities led to chlorine, bromine, and iodine together being classified as one of the original triads of Johann Wolfgang Döbereiner, whose work foreshadowed the periodic law for chemical elements.[33][34] It is intermediate in atomic radius between chlorine and iodine, and this leads to many of its atomic properties being similarly intermediate in value between chlorine and iodine, such as first ionisation energy, electron affinity, enthalpy of dissociation of the X2 molecule (X = Cl, Br, I), ionic radius, and X–X bond length.[32] The volatility of bromine accentuates its very penetrating, choking, and unpleasant odour.[35]

The four oxoacids, hypobromous acid (HOBr), bromous acid (HOBrO), bromic acid (HOBrO2), and perbromic acid (HOBrO3), are better studied due to their greater stability, though they are only so in aqueous solution. When bromine dissolves in aqueous solution, the following reactions occur:[46]

There were many failed attempts to obtain perbromates and perbromic acid, leading to some rationalisations as to why they should not exist, until 1968 when the anion was first synthesised from the radioactive beta decay of unstable 83SeO2−4. Today, perbromates are produced by the oxidation of alkaline bromate solutions by fluorine gas. Excess bromate and fluoride are precipitated as silver bromate and calcium fluoride, and the perbromic acid solution may be purified. The perbromate ion is fairly inert at room temperature but is thermodynamically extremely oxidising, with extremely strong oxidising agents needed to produce it, such as fluorine or xenon difluoride. The Br–O bond in BrO−4 is fairly weak, which corresponds to the general reluctance of the 4p elements arsenic, selenium, and bromine to attain their group oxidation state, as they come after the scandide contraction characterised by the poor shielding afforded by the radial-nodeless 3d orbitals.[50]

Axialandradialload bearing

Preventing premature bearing failure due to load-related issues is a primary concern for engineers and maintenance personnel. Implementing proactive measures, such as proper lubrication, alignment, and load monitoring, can help extend bearing life and reduce the associated maintenance costs.

Axial load applications vary, and different scenarios may require specific types of thrust bearings. There are various varieties, including ball thrust bearings, roller thrust bearings, and magnetic thrust bearings, each tailored to specific applications. Understanding the differences between these varieties is essential for selecting the right bearing for the job.

Radial loads, also known as thrust loads, are forces that act perpendicular to the bearing’s axis. These loads occur when a force is applied at a right angle to the shaft, a common occurrence in many mechanical applications. It’s akin to pressing against the outer ring of the bearing, creating a force that tries to push or pull the bearing sideways.

Ethylene bromide was an additive in gasolines containing lead anti-engine knocking agents. It scavenges lead by forming volatile lead bromide, which is exhausted from the engine. This application accounted for 77% of the bromine use in 1966 in the US. This application has declined since the 1970s due to environmental regulations (see below).[67]

Load analysis enables engineers and maintenance professionals to select the appropriate bearings that can withstand the expected forces. By ensuring that bearings are not overloaded, it helps extend their lifespan, reducing wear and tear on the equipment. This, in turn, lowers maintenance and replacement costs while improving overall machine reliability.

Radial loads originate from a myriad of sources. They can result from the weight of rotating components, vibrations, misalignments, or even external forces applied to the equipment. These loads are often generated both by the machinery itself and by external factors. When you think of a wheel on a vehicle, the weight of the vehicle pressing down on the wheel hub is a prime example of a radial load.

A wide variety of organobromine compounds are used in industry. Some are prepared from bromine and others are prepared from hydrogen bromide, which is obtained by burning hydrogen in bromine.[62]

Organobromides are typically produced by additive or substitutive bromination of other organic precursors. Bromine itself can be used, but due to its toxicity and volatility, safer brominating reagents are normally used, such as N-bromosuccinimide. The principal reactions for organobromides include dehydrobromination, Grignard reactions, reductive coupling, and nucleophilic substitution.[51]

After the French chemists Louis Nicolas Vauquelin, Louis Jacques Thénard, and Joseph-Louis Gay-Lussac approved the experiments of the young pharmacist Balard, the results were presented at a lecture of the Académie des Sciences and published in Annales de Chimie et Physique.[14] In his publication, Balard stated that he changed the name from muride to brôme on the proposal of M. Anglada. The name brôme (bromine) derives from the Greek βρῶμος (brômos, "stench").[14][20][18][21] Other sources claim that the French chemist and physicist Joseph-Louis Gay-Lussac suggested the name brôme for the characteristic smell of the vapors.[22][23] Bromine was not produced in large quantities until 1858, when the discovery of salt deposits in Stassfurt enabled its production as a by-product of potash.[24]

Heavy machinery in construction and industrial settings often operates under challenging conditions, subjecting bearings to substantial loads. Understanding the vital role bearings play in these industries, along with the specific challenges they face, sheds light on the importance of load analysis and proper bearing selection.

Although dibromine is a strong oxidising agent with a high first ionisation energy, very strong oxidisers such as peroxydisulfuryl fluoride (S2O6F2) can oxidise it to form the cherry-red Br+2 cation. A few other bromine cations are known, namely the brown Br+3 and dark brown Br+5.[45] The tribromide anion, Br−3, has also been characterised; it is analogous to triiodide.[42]

To make brominated polymers and plastics, bromine-containing compounds can be incorporated into the polymer during polymerisation. One method is to include a relatively small amount of brominated monomer during the polymerisation process. For example, vinyl bromide can be used in the production of polyethylene, polyvinyl chloride or polypropylene. Specific highly brominated molecules can also be added that participate in the polymerisation process. For example, tetrabromobisphenol A can be added to polyesters or epoxy resins, where it becomes part of the polymer. Epoxies used in printed circuit boards are normally made from such flame retardant resins, indicated by the FR in the abbreviation of the products (FR-4 and FR-2). In some cases, the bromine-containing compound may be added after polymerisation. For example, decabromodiphenyl ether can be added to the final polymers.[65]

Radialandaxialalignment

Because it has similar antiseptic qualities to chlorine, bromine can be used in the same manner as chlorine as a disinfectant or antimicrobial in applications such as swimming pools. Bromine came into this use in the United States during World War II due to a predicted shortage of chlorine.[73] However, bromine is usually not used outside for these applications due to it being relatively more expensive than chlorine and the absence of a stabilizer to protect it from the sun. For indoor pools, it can be a good option as it is effective at a wider pH range. It is also more stable in a heated pool or hot tub.[74]

Löwig isolated bromine from a mineral water spring from his hometown Bad Kreuznach in 1825. Löwig used a solution of the mineral salt saturated with chlorine and extracted the bromine with diethyl ether. After evaporation of the ether, a brown liquid remained. With this liquid as a sample of his work he applied for a position in the laboratory of Leopold Gmelin in Heidelberg. The publication of the results was delayed and Balard published his results first.[17]

Axialvsradialplay

Thrust bearings, engineered to handle axial loads, are a fundamental part of many mechanical systems. These bearings are designed to support forces acting parallel to the bearing’s axis, making them an integral component in applications where controlled linear or rotational movement is required.

The simplest compound of bromine is hydrogen bromide, HBr. It is mainly used in the production of inorganic bromides and alkyl bromides, and as a catalyst for many reactions in organic chemistry. Industrially, it is mainly produced by the reaction of hydrogen gas with bromine gas at 200–400 °C with a platinum catalyst. However, reduction of bromine with red phosphorus is a more practical way to produce hydrogen bromide in the laboratory:[39]

Automotive applications demand precision and reliability. Bearings in the automotive industry must withstand both radial and axial loads while meeting stringent performance standards. Analyzing how bearings contribute to automotive safety, performance, and efficiency underscores their importance in this sector.

Unlike hydrogen fluoride, anhydrous liquid hydrogen bromide is difficult to work with as a solvent, because its boiling point is low, it has a small liquid range, its dielectric constant is low and it does not dissociate appreciably into H2Br+ and HBr−2 ions – the latter, in any case, are much less stable than the bifluoride ions (HF−2) due to the very weak hydrogen bonding between hydrogen and bromine, though its salts with very large and weakly polarising cations such as Cs+ and NR+4 (R = Me, Et, Bun) may still be isolated. Anhydrous hydrogen bromide is a poor solvent, only able to dissolve small molecular compounds such as nitrosyl chloride and phenol, or salts with very low lattice energies such as tetraalkylammonium halides.[40]

Elemental bromine (Br2) is toxic and causes chemical burns on human flesh. Inhaling bromine gas results in similar irritation of the respiratory tract, causing coughing, choking, shortness of breath, and death if inhaled in large enough amounts. Chronic exposure may lead to frequent bronchial infections and a general deterioration of health. As a strong oxidising agent, bromine is incompatible with most organic and inorganic compounds.[83] Caution is required when transporting bromine; it is commonly carried in steel tanks lined with lead, supported by strong metal frames.[61] The Occupational Safety and Health Administration (OSHA) of the United States has set a permissible exposure limit (PEL) for bromine at a time-weighted average (TWA) of 0.1 ppm. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of TWA 0.1 ppm and a short-term limit of 0.3 ppm. The exposure to bromine immediately dangerous to life and health (IDLH) is 3 ppm.[84] Bromine is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.[85]

Balard found bromine chemicals in the ash of seaweed from the salt marshes of Montpellier. The seaweed was used to produce iodine, but also contained bromine. Balard distilled the bromine from a solution of seaweed ash saturated with chlorine. The properties of the resulting substance were intermediate between those of chlorine and iodine; thus he tried to prove that the substance was iodine monochloride (ICl), but after failing to do so he was sure that he had found a new element and named it muride, derived from the Latin word muria ("brine").[15][18][19]

Elemental bromine is very reactive and thus does not occur as a free element in nature. Instead, it can be isolated from colourless soluble crystalline mineral halide salts analogous to table salt, a property it shares with the other halogens. While it is rather rare in the Earth's crust, the high solubility of the bromide ion (Br−) has caused its accumulation in the oceans. Commercially the element is easily extracted from brine evaporation ponds, mostly in the United States and Israel. The mass of bromine in the oceans is about one three-hundredth that of chlorine.

The direction of the load significantly affects how bearings respond and perform. Radial loads create radial stress on bearings, impacting their radial load capacity. This stress can lead to deformation and premature wear if not appropriately managed. In contrast, axial loads influence the axial load capacity of the bearing. Bearings need to be selected and designed to accommodate these different types of stressors effectively.

Dealing with radial loads effectively often requires implementing proper maintenance practices, ensuring proper alignment of the machinery, and ensuring that bearings are correctly lubricated. By addressing these challenges, businesses can significantly extend the lifespan of radial load bearings, reduce maintenance costs, and improve equipment reliability.

To better grasp the concept of radial loads, consider the conveyor system in a manufacturing facility. The pulleys in this system carry the weight of the items being conveyed, exerting radial loads on the bearings that support these pulleys. In essence, the bearings must withstand the sideways forces generated by the weight of the pulleys and the materials they transport.

Apart from some minor medical applications, the first commercial use was the daguerreotype. In 1840, bromine was discovered to have some advantages over the previously used iodine vapor to create the light sensitive silver halide layer in daguerreotypy.[25]

Bromine is a chemical element; it has symbol Br and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between those of chlorine and iodine. Isolated independently by two chemists, Carl Jacob Löwig (in 1825) and Antoine Jérôme Balard (in 1826), its name was derived from Ancient Greek βρῶμος (bromos) 'stench', referring to its sharp and pungent smell.

Radialandaxialdirection

To gain a deeper understanding of axial loads, it’s essential to examine practical scenarios where they are prevalent. These applications, including automotive transmissions and ball screws, illustrate how axial loads are generated and how thrust bearings are used to manage these forces. A closer look at these typical applications helps to appreciate the role of axial load bearings in various industries.

The bearing industry maintains rigorous quality standards to ensure that bearings meet performance and reliability expectations. Understanding these standards and certifications is crucial for both manufacturers and end-users to guarantee the safety and functionality of the equipment.

For applications with axial loads, accurate calculations are equally vital. Engineers must determine the axial forces that the bearing will encounter and evaluate their distribution along the shaft. Accurate calculations help in the selection of the right thrust bearing capable of withstanding these forces. Without proper calculation, a bearing may become overloaded, leading to premature failure.

Lubrication is essential in preventing wear, reducing friction, and dissipating heat within a bearing. Properly lubricating a bearing is crucial for ensuring its longevity and optimal performance. The choice of lubricant and its quantity should be tailored to the specific load conditions the bearing will experience. In load analysis, lubrication requirements are carefully considered to minimize friction and heat generation, particularly in high-load applications.

Nearly all elements in the periodic table form binary bromides. The exceptions are decidedly in the minority and stem in each case from one of three causes: extreme inertness and reluctance to participate in chemical reactions (the noble gases, with the exception of xenon in the very unstable XeBr2); extreme nuclear instability hampering chemical investigation before decay and transmutation (many of the heaviest elements beyond bismuth); and having an electronegativity higher than bromine's (oxygen, nitrogen, fluorine, and chlorine), so that the resultant binary compounds are formally not bromides but rather oxides, nitrides, fluorides, or chlorides of bromine. (Nonetheless, nitrogen tribromide is named as a bromide as it is analogous to the other nitrogen trihalides.)[41]

Proper maintenance practices and load management are crucial for preventing bearing issues related to excessive loads. By implementing preventative measures, businesses can minimize the risk of bearing failure, resulting in increased machine reliability and cost savings over time.

The halogens form many binary, diamagnetic interhalogen compounds with stoichiometries XY, XY3, XY5, and XY7 (where X is heavier than Y), and bromine is no exception. Bromine forms a monofluoride and monochloride, as well as a trifluoride and pentafluoride. Some cationic and anionic derivatives are also characterised, such as BrF−2, BrCl−2, BrF+2, BrF+4, and BrF+6. Apart from these, some pseudohalides are also known, such as cyanogen bromide (BrCN), bromine thiocyanate (BrSCN), and bromine azide (BrN3).[42]

Hypobromous acid is unstable to disproportionation. The hypobromite ions thus formed disproportionate readily to give bromide and bromate:[46]

At room temperature, bromine trifluoride (BrF3) is a straw-coloured liquid. It may be formed by directly fluorinating bromine at room temperature and is purified through distillation. It reacts violently with water and explodes on contact with flammable materials, but is a less powerful fluorinating reagent than chlorine trifluoride. It reacts vigorously with boron, carbon, silicon, arsenic, antimony, iodine, and sulfur to give fluorides, and will also convert most metals and many metal compounds to fluorides; as such, it is used to oxidise uranium to uranium hexafluoride in the nuclear power industry. Refractory oxides tend to be only partially fluorinated, but here the derivatives KBrF4 and BrF2SbF6 remain reactive. Bromine trifluoride is a useful nonaqueous ionising solvent, since it readily dissociates to form BrF+2 and BrF−4 and thus conducts electricity.[43]

Radialvsaxialcontroller

The primary differentiation between radial and axial loads lies in the direction of the force. Radial loads exert their force perpendicular to the bearing’s axis, trying to push or pull the bearing sideways. In contrast, axial loads act in parallel to the bearing’s axis, attempting to move it along the shaft. This fundamental distinction has profound implications for bearing design and performance.

The role of bearings in machine manufacturing is pivotal, as these industries rely on precision and efficiency. Different types of machinery have unique load requirements, and bearing solutions must be tailored to meet those specific needs. Understanding the role of bearings in machine manufacturing helps engineers and manufacturers optimize performance.

Poisonous bromomethane was widely used as pesticide to fumigate soil and to fumigate housing, by the tenting method. Ethylene bromide was similarly used.[68] These volatile organobromine compounds are all now regulated as ozone depletion agents. The Montreal Protocol on Substances that Deplete the Ozone Layer scheduled the phase out for the ozone depleting chemical by 2005, and organobromide pesticides are no longer used (in housing fumigation they have been replaced by such compounds as sulfuryl fluoride, which contain neither the chlorine or bromine organics which harm ozone). Before the Montreal protocol in 1991 (for example) an estimated 35,000 tonnes of the chemical were used to control nematodes, fungi, weeds and other soil-borne diseases.[69][70]

Axialvsradialrotation

Axialvsradialmovement

Axial loads are particularly prevalent in applications where there’s a need for controlled linear or rotational movement. A classic example is found in automotive transmissions. Here, the gears apply axial forces to the bearings as they transfer power from the engine to the wheels, allowing the vehicle to move forward and backward.

At a pressure of 55 GPa (roughly 540,000 times atmospheric pressure) bromine undergoes an insulator-to-metal transition. At 75 GPa it changes to a face-centered orthorhombic structure. At 100 GPa it changes to a body centered orthorhombic monatomic form.[37]

Bromine was discovered independently by two chemists, Carl Jacob Löwig[13] and Antoine Balard,[14][15] in 1825 and 1826, respectively.[16]

Like solid chlorine and iodine, solid bromine crystallises in the orthorhombic crystal system, in a layered arrangement of Br2 molecules. The Br–Br distance is 227 pm (close to the gaseous Br–Br distance of 228 pm) and the Br···Br distance between molecules is 331 pm within a layer and 399 pm between layers (compare the van der Waals radius of bromine, 195 pm). This structure means that bromine is a very poor conductor of electricity, with a conductivity of around 5 × 10−13 Ω−1 cm−1 just below the melting point, although this is higher than the essentially undetectable conductivity of chlorine.[32]

Like the other carbon–halogen bonds, the C–Br bond is a common functional group that forms part of core organic chemistry. Formally, compounds with this functional group may be considered organic derivatives of the bromide anion. Due to the difference of electronegativity between bromine (2.96) and carbon (2.55), the carbon atom in a C–Br bond is electron-deficient and thus electrophilic. The reactivity of organobromine compounds resembles but is intermediate between the reactivity of organochlorine and organoiodine compounds. For many applications, organobromides represent a compromise of reactivity and cost.[51]

Specialized bearings are designed to excel in scenarios involving both radial and axial loads. These bearings are engineered to distribute forces in a way that optimally accommodates the combination of load types. Understanding the capabilities of these specialized bearings is crucial in applications where such complex load scenarios are prevalent.

An old qualitative test for the presence of the alkene functional group is that alkenes turn brown aqueous bromine solutions colourless, forming a bromohydrin with some of the dibromoalkane also produced. The reaction passes through a short-lived strongly electrophilic bromonium intermediate. This is an example of a halogen addition reaction.[53]

Other uses of organobromine compounds include high-density drilling fluids, dyes (such as Tyrian purple and the indicator bromothymol blue), and pharmaceuticals. Bromine itself, as well as some of its compounds, are used in water treatment, and is the precursor of a variety of inorganic compounds with an enormous number of applications (e.g. silver bromide for photography).[61] Zinc–bromine batteries are hybrid flow batteries used for stationary electrical power backup and storage; from household scale to industrial scale.

Bearing manufacturers engineer their products with different internal geometries and materials to withstand either radial or axial loads. Radial bearings, for instance, are designed to distribute the force evenly across the bearing’s inner and outer rings. In contrast, thrust bearings are built to withstand axial loads, with components that can resist the linear forces applied along the axis. Proper selection of the right bearing type for the specific application is pivotal in ensuring optimal performance and longevity.

In many real-world applications, bearings often experience both radial and axial loads simultaneously. Engineers must be well-versed in calculating and managing these combined loads effectively. Understanding how these loads interact with one another and impact the bearing is pivotal for successful load management. Proper selection and maintenance are essential in such complex scenarios.

In applications where axial loads are exceptionally high, such as heavy machinery and automotive transmissions, specialized bearings and load management techniques are required. Managing these high axial loads is critical for preventing premature bearing failure and ensuring the safe and efficient operation of the machinery.

Organobromides are the most common organohalides in nature, even though the concentration of bromide is only 0.3% of that for chloride in sea water, because of the easy oxidation of bromide to the equivalent of Br+, a potent electrophile. The enzyme bromoperoxidase catalyzes this reaction.[52] The oceans are estimated to release 1–2 million tons of bromoform and 56,000 tons of bromomethane annually.[12]

Potassium bromide and sodium bromide were used as anticonvulsants and sedatives in the late 19th and early 20th centuries, but were gradually superseded by chloral hydrate and then by the barbiturates.[30] In the early years of the First World War, bromine compounds such as xylyl bromide were used as poison gas.[31]

In some applications, off-the-shelf bearings may not suffice, necessitating the use of specialized bearings designed to handle unique load conditions. These specialized bearings are often customized to specific requirements, making them invaluable in industries where standard bearings may not perform optimally.

One of the fundamental considerations in bearing selection is matching the type of bearing to the type of load it will encounter. Bearings are designed to handle specific types of loads, and using the wrong bearing type can lead to premature failure and equipment damage. Professionals must evaluate the expected load conditions and choose the appropriate bearing to ensure optimal performance.

Exploring real-world applications of radial load bearings provides concrete examples of how these bearings function in different industries. These applications showcase the versatility of radial bearings, from their use in electric motors to conveyor systems and everything in between. Understanding these applications helps illustrate how radial loads impact bearing performance across various sectors.

Axial loads can be categorized into two primary types: thrust loads and moment loads. Thrust loads involve forces that are directly pushing or pulling along the axis of the bearing, while moment loads create a twisting effect, generating torque around the bearing’s axis. The distinction between these types is crucial for understanding the load distribution and the bearing’s response to each.

One of the primary tools in load analysis is the use of static and dynamic load ratings. These ratings indicate a bearing’s capacity to handle different types of loads. Static load ratings provide information about the maximum load a bearing can support without deformation, while dynamic load ratings are related to continuous use under varying loads. Engineers use these ratings to assess the bearing’s suitability for specific applications.

Bromous acids and bromites are very unstable, although the strontium and barium bromites are known.[49] More important are the bromates, which are prepared on a small scale by oxidation of bromide by aqueous hypochlorite, and are strong oxidising agents. Unlike chlorates, which very slowly disproportionate to chloride and perchlorate, the bromate anion is stable to disproportionation in both acidic and aqueous solutions. Bromic acid is a strong acid. Bromides and bromates may comproportionate to bromine as follows:[49]

A number of gaseous or highly volatile brominated halomethane compounds are non-toxic and make superior fire suppressant agents by this same mechanism, and are particularly effective in enclosed spaces such as submarines, airplanes, and spacecraft. However, they are expensive and their production and use has been greatly curtailed due to their effect as ozone-depleting agents. They are no longer used in routine fire extinguishers, but retain niche uses in aerospace and military automatic fire suppression applications. They include bromochloromethane (Halon 1011, CH2BrCl), bromochlorodifluoromethane (Halon 1211, CBrClF2), and bromotrifluoromethane (Halon 1301, CBrF3).[66]

Bromination of metals with Br2 tends to yield lower oxidation states than chlorination with Cl2 when a variety of oxidation states is available. Bromides can be made by reaction of an element or its oxide, hydroxide, or carbonate with hydrobromic acid, and then dehydrated by mildly high temperatures combined with either low pressure or anhydrous hydrogen bromide gas. These methods work best when the bromide product is stable to hydrolysis; otherwise, the possibilities include high-temperature oxidative bromination of the element with bromine or hydrogen bromide, high-temperature bromination of a metal oxide or other halide by bromine, a volatile metal bromide, carbon tetrabromide, or an organic bromide. For example, niobium(V) oxide reacts with carbon tetrabromide at 370 °C to form niobium(V) bromide.[41] Another method is halogen exchange in the presence of excess "halogenating reagent", for example:[41]

Bearings designed to handle radial loads, also known as radial bearings, are commonly found in various applications. They are engineered to efficiently support forces acting perpendicular to the bearing’s axis. These bearings come in numerous designs and sizes to suit a wide range of industrial applications.

Most metal bromides with the metal in low oxidation states (+1 to +3) are ionic. Nonmetals tend to form covalent molecular bromides, as do metals in high oxidation states from +3 and above. Both ionic and covalent bromides are known for metals in oxidation state +3 (e.g. scandium bromide is mostly ionic, but aluminium bromide is not). Silver bromide is very insoluble in water and is thus often used as a qualitative test for bromine.[41]

All four stable halogens experience intermolecular van der Waals forces of attraction, and their strength increases together with the number of electrons among all homonuclear diatomic halogen molecules. Thus, the melting and boiling points of bromine are intermediate between those of chlorine and iodine. As a result of the increasing molecular weight of the halogens down the group, the density and heats of fusion and vaporisation of bromine are again intermediate between those of chlorine and iodine, although all their heats of vaporisation are fairly low (leading to high volatility) thanks to their diatomic molecular structure.[32] The halogens darken in colour as the group is descended: fluorine is a very pale yellow gas, chlorine is greenish-yellow, and bromine is a reddish-brown volatile liquid that freezes at −7.2 °C and boils at 58.8 °C. (Iodine is a shiny black solid.) This trend occurs because the wavelengths of visible light absorbed by the halogens increase down the group.[32] Specifically, the colour of a halogen, such as bromine, results from the electron transition between the highest occupied antibonding πg molecular orbital and the lowest vacant antibonding σu molecular orbital.[36] The colour fades at low temperatures so that solid bromine at −195 °C is pale yellow.[32]

Silver bromide is used, either alone or in combination with silver chloride and silver iodide, as the light sensitive constituent of photographic emulsions.[61]

Bearing overload is a common issue that can lead to premature failure. Identifying the signs of an overloaded bearing, such as excessive heat and unusual noise, is essential in addressing the problem promptly.

The pale-brown bromine monofluoride (BrF) is unstable at room temperature, disproportionating quickly and irreversibly into bromine, bromine trifluoride, and bromine pentafluoride. It thus cannot be obtained pure. It may be synthesised by the direct reaction of the elements, or by the comproportionation of bromine and bromine trifluoride at high temperatures.[42] Bromine monochloride (BrCl), a red-brown gas, quite readily dissociates reversibly into bromine and chlorine at room temperature and thus also cannot be obtained pure, though it can be made by the reversible direct reaction of its elements in the gas phase or in carbon tetrachloride.[41] Bromine monofluoride in ethanol readily leads to the monobromination of the aromatic compounds PhX (para-bromination occurs for X = Me, But, OMe, Br; meta-bromination occurs for the deactivating X = –CO2Et, –CHO, –NO2); this is due to heterolytic fission of the Br–F bond, leading to rapid electrophilic bromination by Br+.[41]

Environmental conditions can have a substantial impact on bearing performance. Variables like temperature, humidity, and exposure to contaminants can affect how a bearing operates and its overall lifespan. When conducting load analysis, it’s essential to take these environmental factors into account. Selecting bearings with appropriate seals and coatings is necessary in situations where environmental conditions are challenging or corrosive. Properly assessing the bearing’s exposure to the environment helps in ensuring its long-term reliability and performance.

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