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63-598: Buildings , aircraft , skeletons , anthills , beaver dams , bridges and salt domes are all examples of load -bearing structures. The results of construction are divided into buildings and non-building structures , and make up the infrastructure of a human society. Built structures are broadly divided by their varying design approaches and standards, into categories including building structures, architectural structures , civil engineering structures and mechanical structures. The effects of loads on physical structures are determined through structural analysis , which

126-456: A chemical compound is a graphic representation of the molecular structure (determined by structural chemistry methods), showing how the atoms are possibly arranged in the real three-dimensional space . The chemical bonding within the molecule is also shown, either explicitly or implicitly. Unlike other chemical formula types, which have a limited number of symbols and are capable of only limited descriptive power, structural formulas provide

189-486: A chemical reaction or synthesis using structural formulas rather than chemical names, because the structural formulas allow the chemist to visualize the molecules and the structural changes that occur in them during chemical reactions. ChemSketch and ChemDraw are popular downloads/websites that allow users to draw reactions and structural formulas, typically in the Lewis Structure style. Bonds are often shown as

252-411: A hierarchical organization , but hierarchy makes it easier for a listener to understand and remember the music. In analogy to linguistic terminology, motifs and phrases can be combined to make complete musical ideas such as sentences and phrases . A larger form is known as the period . One such form that was widely used between 1600 and 1900 has two phrases, an antecedent and a consequent , with

315-409: A pointer that links them together in a particular order. Out of these any number of other data structures can be created such as stacks , queues , trees and hash tables . In solving a problem, a data structure is generally an integral part of the algorithm . In modern programming style, algorithms and data structures are encapsulated together in an abstract data type . Software architecture

378-632: A 3-D molecule to 2-D, and therefore, there are limitations to changing the configuration of the chiral centers. Fischer projections are used to determine the R and S configuration on a chiral carbon and it is done using the Cahn Ingold Prelog rules . It is a convenient way to represent and distinguish between enantiomers and diastereomers . A structural formula is a simplified model that cannot represent certain aspects of chemical structures. For example, formalized bonding may not be applicable to dynamic systems such as delocalized bonds . Aromaticity

441-692: A Fischer Projection. Certain conformations of cyclohexane and other small-ring compounds can be shown using a standard convention. For example, the standard chair conformation of cyclohexane involves a perspective view from slightly above the average plane of the carbon atoms and indicates clearly which groups are axial (pointing vertically up or down) and which are equatorial (almost horizontal, slightly slanted up or down). Bonds in front may or may not be highlighted with stronger lines or wedges. The conformations progress as follows: chair to half-chair to twist-boat to boat to twist-boat to half-chair to chair. The cyclohexane conformations may also be used to show

504-606: A big part of the regular maintenance required. Systems for transport of people within buildings: Systems for transport of people between interconnected buildings: Buildings may be damaged during construction or during maintenance. They may be damaged by accidents involving storms, explosions, subsidence caused by mining, water withdrawal or poor foundations and landslides. Buildings may suffer fire damage and flooding. They may become dilapidated through lack of proper maintenance, or alteration work improperly carried out. Structural formula The structural formula of

567-403: A certain general amount of internal infrastructure to function, which includes such elements like heating / cooling, power and telecommunications, water and wastewater etc. Especially in commercial buildings (such as offices or factories), these can be extremely intricate systems taking up large amounts of space (sometimes located in separate areas or double floors / false ceilings) and constitute

630-504: A crystal have a structure that involves repetition of a basic unit called a unit cell . The atoms can be modeled as points on a lattice , and one can explore the effect of symmetry operations that include rotations about a point, reflections about a symmetry planes, and translations (movements of all the points by the same amount). Each crystal has a finite group, called the space group , of such operations that map it onto itself; there are 230 possible space groups. By Neumann's law ,

693-416: A formal way and their structure analyzed. Two basic types of inference are deduction and induction . In a valid deduction, the conclusion necessarily follows from the premises, regardless of whether they are true or not. An invalid deduction contains some error in the analysis. An inductive argument claims that if the premises are true, the conclusion is likely. Building A building or edifice

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756-409: A group of inter-related (and possibly inter-connected) builds are referred to as a complex – for example a housing complex , educational complex, hospital complex, etc. The practice of designing, constructing, and operating buildings is most usually a collective effort of different groups of professionals and trades . Depending on the size, complexity, and purpose of a particular building project,

819-401: A half cadence in the middle and a full cadence at the end providing punctuation. On a larger scale are single-movement forms such as the sonata form and the contrapuntal form , and multi-movement forms such as the symphony . A social structure is a pattern of relationships. They are social organizations of individuals in various life situations. Structures are applicable to people in how

882-550: A large amount of land. According to the National Resources Inventory , approximately 107 million acres (430,000 km ) of land in the United States are developed. The International Energy Agency released a publication that estimated that existing buildings are responsible for more than 40% of the world's total primary energy consumption and for 24% of global carbon dioxide emissions. Any building requires

945-518: A line that connects one atom to another. One line indicates a single bond . Two lines indicate a double bond , and three lines indicate a triple bond . In some structures the atoms in between each bond are specified and shown. However, in some structures, the carbon molecules are not written out specifically. Instead, these carbons are indicated by a corner that forms when two lines connect. Additionally, Hydrogen atoms are implied and not usually drawn out. These can be inferred based on how many other atoms

1008-812: A more complete geometric representation of the molecular structure. For example, many chemical compounds exist in different isomeric forms, which have different enantiomeric structures but the same molecular formula . There are multiple types of ways to draw these structural formulas such as: Lewis structures , condensed formulas, skeletal formulas , Newman projections , Cyclohexane conformations , Haworth projections , and Fischer projections . Several systematic chemical naming formats, as in chemical databases , are used that are equivalent to, and as powerful as, geometric structures. These chemical nomenclature systems include SMILES , InChI and CML . These systematic chemical names can be converted to structural formulas and vice versa, but chemists nearly always describe

1071-454: A multilevel hierarchy of structures employing biominerals and proteins , at the bottom of which are collagen fibrils . In biology , one of the properties of life is its highly ordered structure, which can be observed at multiple levels such as in cells , tissues , organs , and organisms . In another context, structure can also observed in macromolecules , particularly proteins and nucleic acids . The function of these molecules

1134-453: A negative charge. In structural formulas, the positive charge is indicated by ⊕ , and the negative charge is indicated by ⊖ . Chirality in skeletal formulas is indicated by the Natta projection method. Stereochemistry is used to show the relative spatial arrangement of atoms in a molecule. Wedges are used to show this, and there are two types: dashed and filled. A filled wedge indicates that

1197-514: A redundant structure is needed so that if a component fails it has backups. A high redundancy is an essential part of the design of several systems in the Space Shuttle . As a branch of philosophy, logic is concerned with distinguishing good arguments from poor ones. A chief concern is with the structure of arguments. An argument consists of one or more premises from which a conclusion is inferred . The steps in this inference can be expressed in

1260-432: A society is as a system organized by a characteristic pattern of relationships. This is known as the social organization of the group. Sociologists have studied the changing structure of these groups. Structure and agency are two confronted theories about human behaviour. The debate surrounding the influence of structure and agency on human thought is one of the central issues in sociology. In this context, agency refers to

1323-468: A variety of diagrams called structural formulas . Lewis structures use a dot notation to represent the valence electrons for an atom; these are the electrons that determine the role of the atom in chemical reactions. Bonds between atoms can be represented by lines with one line for each pair of electrons that is shared. In a simplified version of such a diagram, called a skeletal formula , only carbon-carbon bonds and functional groups are shown. Atoms in

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1386-624: Is a matter of debate, but generally three stories or less is considered low-rise. There is clear evidence of homebuilding from around 18,000 BC. Buildings became common during the Neolithic period . Single-family residential buildings are most often called houses or homes . Multi-family residential buildings containing more than one dwelling unit are called duplexes or apartment buildings . Condominiums are apartments that occupants own rather than rent . Houses may be built in pairs ( semi-detached ) or in terraces, where all but two of

1449-421: Is an enclosed structure with a roof and walls , usually standing permanently in one place, such as a house or factory . Buildings come in a variety of sizes , shapes , and functions, and have been adapted throughout history for numerous factors, from building materials available, to weather conditions, land prices, ground conditions, specific uses, prestige , and aesthetic reasons. To better understand

1512-434: Is determined by their shape as well as their composition, and their structure has multiple levels. Protein structure has a four-level hierarchy. The primary structure is the sequence of amino acids that make it up. It has a peptide backbone made up of a repeated sequence of a nitrogen and two carbon atoms. The secondary structure consists of repeated patterns determined by hydrogen bonding . The two basic types are

1575-776: Is important to look to the left of the atom in the bracket to make sure what atom it is attached to. This is helpful when converting from condensed formula to another form of structural formula such as skeletal formula or Lewis structures . There are different ways to show the various functional groups in the condensed formulas such as aldehyde as CHO {\displaystyle {\ce {CHO}}} , Carboxylic acids as CO 2 H {\displaystyle {\ce {CO2H}}} or COOH {\displaystyle {\ce {COOH}}} , Esters as CO 2 R {\displaystyle {\ce {CO2R}}} or COOR {\displaystyle {\ce {COOR}}} . However,

1638-411: Is mostly used for small molecules. Each line represents the two electrons of a single bond . Two or three parallel lines between pairs of atoms represent double or triple bonds, respectively. Alternatively, pairs of dots may be used to represent bonding pairs. In addition, all non-bonded electrons (paired or unpaired) and any formal charges on atoms are indicated. Through the use of Lewis structures ,

1701-481: Is one in which at least one business is based and people do not live. Examples include stores , restaurant , and hotels . Industrial buildings are those in which heavy industry is done, such as manufacturing . These edifices include warehouses and factories . Agricultural buildings are the outbuildings , such as barns located on farms . Some buildings incorporate several or multiple different uses, most commonly commercial and residential. Sometimes

1764-418: Is one of the tasks of structural engineering . The structural elements can be classified as one-dimensional ( ropes , struts , beams , arches ), two-dimensional ( membranes , plates, slab , shells , vaults ), or three-dimensional (solid masses). Three-dimensional elements were the main option available to early structures such as Chichen Itza . A one-dimensional element has one dimension much larger than

1827-456: Is such a case and relies on convention to represent the bonding. Different styles of structural formulas may represent aromaticity in different ways, leading to different depictions of the same chemical compound. Another example is formal double bonds where the electron density is spread outside the formal bond, leading to partial double bond character and slow inter-conversion at room temperature. For all dynamic effects, temperature will affect

1890-487: Is the specific choices made between possible alternatives within a framework. For example, a framework might require a database and the architecture would specify the type and manufacturer of the database. The structure of software is the way in which it is partitioned into interrelated components. A key structural issue is minimizing dependencies between these components. This makes it possible to change one component without requiring changes in others. The purpose of structure

1953-419: Is to optimise for (brevity, readability, traceability, isolation and encapsulation, maintainability, extensibility, performance and efficiency), examples being: language choice , code , functions , libraries , builds , system evolution , or diagrams for flow logic and design . Structural elements reflect the requirements of the application: for example, if the system requires a high fault tolerance, then

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2016-426: Is used to indicate the front carbon. The sawhorse projection is very similar to a skeletal formula, and it can even use wedges instead of lines to indicate the stereochemistry of the molecule. The sawhorse projection is set apart from the skeletal formulas because the sawhorse projection is not a very good indicator of molecule geometry and molecular arrangement. Both a Newman and Sawhorse Projection can be used to create

2079-1297: Is usually a response to high ground prices resulting from the desire of many people to live close to their places of employment or similar attractors. Terms for residential buildings reflect such characteristics as function (e.g., holiday cottage (vacation home) or timeshare if occupied seasonally); size ( cottage or great house ); value ( shack or mansion ); manner of construction ( log home or mobile home ); architectural style ( castle or Victorian ); and proximity to geographical features ( earth shelter , stilt house , houseboat , or floating home). For residents in need of special care, or those society considers dangerous enough to deprive of liberty , there are institutions ( nursing homes , orphanages , psychiatric hospitals , and prisons ) and group housing ( barracks and dormitories ). Historically, many people lived in communal buildings called longhouses , smaller dwellings called pit-houses , and houses combined with barns, sometimes called housebarns . Common building materials include brick, concrete, stone, and combinations thereof. Buildings are defined to be substantial, permanent structures. Such forms as yurts and motorhomes are therefore considered dwellings but not buildings . A commercial building

2142-413: The α-helix and the β-pleated sheet . The tertiary structure is a back and forth bending of the polypeptide chain, and the quaternary structure is the way that tertiary units come together and interact. Structural biology is concerned with biomolecular structure of macromolecules. Chemical structure refers to both molecular geometry and electronic structure. The structure can be represented by

2205-477: The 1,3, and 5 carbons. The Haworth projection is used for cyclic sugars . Axial and equatorial positions are not distinguished; instead, substituents are positioned directly above or below the ring atom to which they are connected. Hydrogen substituents are typically omitted. However, an important thing to keep in mind while reading an Haworth projection is that the ring structures are not flat. Therefore, Haworth does not provide 3-D shape. Sir Norman Haworth ,

2268-980: The United Nations estimate contributed to 33% of overall worldwide emissions. Including the manufacturing of building materials, the global CO 2 emissions were 39%. If new technologies in construction are not adopted during this time of rapid growth, emissions could double by 2050, according to the United Nations Environment Program . Glass buildings, especially all-glass skyscrapers, contribute significantly to climate change due to their energy inefficiency. While these structures are visually appealing and allow abundant natural light, they also trap heat, necessitating increased use of air conditioning systems, which contribute to higher carbon emissions. Experts advocate for design modifications and potential restrictions on all-glass edifices to mitigate their detrimental environmental impact. Buildings account for

2331-412: The atom is in the front of the molecule; it is pointing above the plane of the paper towards the front. A dashed wedge indicates that the atom is behind the molecule; it is pointing below the plane of the paper. When a straight, un-dashed line is used, the atom is in the plane of the paper. This spatial arrangement provides an idea of the molecule in a 3-dimensional space and there are constraints as to how

2394-544: The atom on the right when appearing at the start of a formula: In all cases, all atoms are shown, including hydrogen atoms. It is also helpful to show the carbonyls where the C = O {\displaystyle {\ce {C=O}}} is implied through the O {\displaystyle {\ce {O}}} being placed in the brackets. For example: CH 3 C ( O ) CH 3 {\displaystyle {\ce {CH3C(O)CH3}}} ( acetone ) Therefore, it

2457-467: The bond of interest, the sawhorse projection looking at the same bond but from a somewhat oblique vantage point. In the Newman projection, a circle is used to represent a plane perpendicular to the bond, distinguishing the substituents on the front carbon from the substituents on the back carbon. In the sawhorse projection, the front carbon is usually on the left and is always slightly lower. Sometimes, an arrow

2520-411: The carbon atoms are implied to be located at the vertices (corners) and ends of line segments rather than being indicated with the atomic symbol C. Hydrogen atoms attached to carbon atoms are not indicated: each carbon atom is understood to be associated with enough hydrogen atoms to give the carbon atom four bonds. The presence of a positive or negative charge at a carbon atom takes the place of one of

2583-408: The carbon is attached to. For example, if Carbon A is attached to one other Carbon B, Carbon A will have three hydrogens in order to fill its octet. Electrons are usually shown as colored in circles. One circle indicates one electron. Two circles indicate a pair of electrons. Typically, a pair of electrons will also indicate a negative charge. By using the colored circles, the number of electrons in

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2646-429: The concept, see Nonbuilding structure for contrast. Buildings serve several societal needs – occupancy , primarily as shelter from weather, security, living space, privacy, to store belongings, and to comfortably live and work. A building as a shelter represents a physical separation of the human habitat (a place of comfort and safety) from the outside (a place that may be harsh and harmful at times). Ever since

2709-418: The first cave paintings , buildings have been objects or canvasses of much artistic expression . In recent years, interest in sustainable planning and building practices has become an intentional part of the design process of many new buildings and other structures, usually green buildings. A building is 'a structure that has a roof and walls and stands more or less permanently in one place'; "there

2772-585: The houses have others on either side. Apartments may be built round courtyards or as rectangular blocks surrounded by plots of ground. Houses built as single dwellings may later be divided into apartments or bedsitters , or converted to other uses (e.g., offices or shops). Hotels , especially of the extended-stay variety ( apartels ), can be classed as residential. Building types may range from huts to multimillion-dollar high-rise apartment blocks able to house thousands of people. Increasing settlement density in buildings (and smaller distances between buildings)

2835-407: The idea of excluding scientific or highly skilful treatment." Structural height in technical usage is the height to the highest architectural detail on the building from street level. Spires and masts may or may not be included in this height, depending on how they are classified. Spires and masts used as antennas are not generally included. The distinction between a low-rise and high-rise building

2898-436: The implied hydrogen atoms. Hydrogen atoms attached to atoms other than carbon must be written explicitly. An additional feature of skeletal formulas is that by adding certain structures the stereochemistry , that is the three-dimensional structure, of the compound can be determined. Often times, the skeletal formula can indicate stereochemistry through the use of wedges instead of lines. Solid wedges represent bonds pointing above

2961-660: The individual human capacity to act independently and make free choices. Structure here refers to factors such as social class , religion , gender , ethnicity , customs, etc. that seem to limit or influence individual opportunities. In computer science , a data structure is a way of organizing information in a computer so that it can be used efficiently. Data structures are built out of two basic types: An array has an index that can be used for immediate access to any data item (some programming languages require array size to be initialized ). A linked list can be reorganized, grown or shrunk, but its elements must be accessed with

3024-439: The molecule in real life. Lewis structure is best used to calculate formal charges or how atoms bond to each other as both electrons and bonds are shown. Lewis structures give an idea of the molecular and electronic geometry which varies based on the presence of bonds and lone pairs and through this one could determine the bond angles and hybridization as well. In early organic-chemistry publications, where use of graphics

3087-449: The observer, while horizontal lines are equivalent to wedges, pointing toward the observer. The projection is unrealistic, as a saccharide would never adopt this multiply eclipsed conformation. Nonetheless, the Fischer projection is a simple way of depicting multiple sequential stereocenters that does not require or imply any knowledge of actual conformation. A Fischer projection will restrict

3150-861: The other two, so the other dimensions can be neglected in calculations; however, the ratio of the smaller dimensions and the composition can determine the flexural and compressive stiffness of the element. Two-dimensional elements with a thin third dimension have little of either but can resist biaxial traction. The structure elements are combined in structural systems . The majority of everyday load-bearing structures are section-active structures like frames, which are primarily composed of one-dimensional (bending) structures. Other types are Vector-active structures such as trusses , surface-active structures such as shells and folded plates, form-active structures such as cable or membrane structures, and hybrid structures. Load-bearing biological structures such as bones, teeth, shells, and tendons derive their strength from

3213-543: The other. Skeletal formulas can depict cis and trans isomers of alkenes. Wavy single bonds are the standard way to represent unknown or unspecified stereochemistry or a mixture of isomers (as with tetrahedral stereocenters). A crossed double-bond has been used sometimes, but is no longer considered an acceptable style for general use. Lewis structures (or "Lewis dot structures") are flat graphical formulas that show atom connectivity and lone pair or unpaired electrons, but not three-dimensional structure. This notation

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3276-442: The placement of electrons, whether it is in a bond or in lone pairs , will allow for the identification of the formal charges of the atoms in the molecule to understand the stability and determine the most likely molecule (based on molecular geometry difference) that would be formed in a reaction. Lewis structures do give some thought to the geometry of the molecule as oftentimes, the bonds are drawn at certain angles to represent

3339-426: The plane of the paper, whereas dashed wedges represent bonds pointing below the plane. The Newman projection and the sawhorse projection are used to depict specific conformers or to distinguish vicinal stereochemistry. In both cases, two specific carbon atoms and their connecting bond are the center of attention. The only difference is a slightly different perspective: the Newman projection looking straight down

3402-491: The potential energy present at each stage as shown in the diagram. The chair conformations (A) have the lowest energy, whereas the half-chair conformations (D) have the highest energy. There is a peak/local maximum at the boat conformation (C), and there are valleys/local minimums at the twist-boat conformations (B). In addition, cyclohexane conformations can be used to indicate if the molecule has any 1,3 diaxial-interactions which are steric interactions between axial substituents on

3465-603: The project team may include: Regardless of their size or intended use, all buildings in the US must comply with zoning ordinances , building codes and other regulations such as fire codes , life safety codes and related standards. Vehicles—such as trailers , caravans , ships and passenger aircraft —are treated as "buildings" for life safety purposes. Buildings represent a large part of energy, electricity, water and materials consumption. As of 2020, they account for 37% of global energy use and energy-related CO 2 emissions, which

3528-534: The spatial arrangements can be arranged. Wavy single bonds represent unknown or unspecified stereochemistry or a mixture of isomers. For example, the adjacent diagram shows the fructose molecule with a wavy bond to the HOCH 2 - group at the left. In this case the two possible ring structures are in chemical equilibrium with each other and also with the open-chain structure. The ring automatically opens and closes, sometimes closing with one stereochemistry and sometimes with

3591-554: The symmetry of a crystal determines what physical properties, including piezoelectricity and ferromagnetism , the crystal can have. A large part of numerical analysis involves identifying and interpreting the structure of musical works. Structure can be found at the level of part of a work, the entire work, or a group of works. Elements of music such as pitch , duration and timbre combine into small elements like motifs and phrases , and these in turn combine in larger structures. Not all music (for example, that of John Cage ) has

3654-415: The upper center in a furanose sugar. The thinner bonds at the top of the ring refer to the bonds as being farther away and the thicker bonds at the bottom of the ring refer to the end of the ring that is closer to the viewer. The Fischer projection is mostly used for linear monosaccharides . At any given carbon center, vertical bond lines are equivalent to stereochemical hashed markings, directed away from

3717-456: The use of condensed formulas does not give an immediate idea of the molecular geometry of the compound or the number of bonds between the carbons, it needs to be recognized based on the number of atoms attached to the carbons and if there are any charges on the carbon. Skeletal formulas are the standard notation for more complex organic molecules. In this type of diagram, first used by the organic chemist Friedrich August Kekulé von Stradonitz ,

3780-426: The valence shell of each respective atom is indicated providing further descriptive information regarding the reactive capacity of that atom in the molecule. Oftentimes, atoms will have a positive or negative charge as their octet may not be complete. If the atom is missing a pair of electrons or has a proton, it will have a positive charge. If the atom has electrons that are not bonded to another atom, there will be

3843-424: Was a British Chemist, who won a Nobel Prize for his work on Carbohydrates and discovering the structure of Vitamin C. During his discovery, he also deducted different structural formulas which are now referred to as Haworth Projections. In a Haworth Projection a pyranose sugar is depicted as a hexagon and a furanose sugar is depicted as a pentagon. Usually an oxygen is placed at the upper right corner in pyranose and in

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3906-490: Was a three-storey building on the corner"; "it was an imposing edifice". In the broadest interpretation a fence or wall is a building. However, the word structure is used more broadly than building , to include natural and human-made formations and ones that do not have walls; structure is more often used for a fence. Sturgis' Dictionary included that "[building] differs from architecture in excluding all idea of artistic treatment; and it differs from construction in

3969-407: Was strongly limited, a typographic system arose to describe organic structures in a line of text. Although this system tends to be problematic in application to cyclic compounds, it remains a convenient way to represent simple structures: Parentheses are used to indicate multiple identical groups, indicating attachment to the nearest non-hydrogen atom on the left when appearing within a formula, or to

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