Literatura científica selecionada sobre o tema "Bond length"

The distortion theorem of the bond-valence theory predicts that the mean bond length 〈D〉 increases with increasing deviation of the individual bond lengths from their mean value according to the equation 〈D〉 = (D′ + ΔD), whereD′ is the length found in a polyhedron having equivalent bonds and ΔDis the bond distortion. For a given atom,D′ is expected to be similar from one structure to another, whereas 〈D〉 should vary as a function of ΔD. However, in several crystal structures 〈D〉 significantly varies without any relevant contribution from ΔD. In accordance with bond-valence theory, 〈D〉 variation is described here by a new equation: 〈D〉 = (DRU + ΔDtop + ΔDiso + ΔDaniso + ΔDelec), whereDRUis a constant related to the type of cation and coordination environment, ΔDtopis the topological distortion related to the way the atoms are linked, ΔDisois an isotropic effect of compression (or stretching) in the bonds produced by steric strain and represents the same increase (or decrease) in all the bond lengths in the coordination sphere, ΔDanisois the distortion produced by compression and stretching of bonds in the same coordination sphere, ΔDelecis the distortion produced by electronic effects. If present, ΔDeleccan be combined with ΔDanisobecause they lead to the same kind of distortions in line with the distortion theorem. EachD-index, in the new equation, corresponds to an algebraic expression containing experimental and theoretical bond valences. On the basis of this study, the ΔDindex defined in bond valence theory is a result of both the bond topology and the distortion theorem (ΔD= ΔDtop + ΔDaniso + ΔDelec), andD′ is a result of the compression, or stretching, of bonds (D′ =DRU + ΔDiso). The deficiencies present in the bond-valence theory in explaining mean bond-length variations can therefore be overcome, and the observed variations of 〈D〉 in crystal structures can be described by a self-consistent model.

The molecular structure of the title compound, C11H15NO2S, features a sulfonamide group with S=O bond lengths of 1.4357 (16) and 1.4349 (16) Å, an S—N bond length of 1.625 (2) Å, and an S—C bond length of 1.770 (2) Å. When viewing the molecule down the S—N bond, both N—C bonds of the pyrrolidine ring are oriented gauche to the S—C bond with torsion angles of −65.6 (2)° and 76.2 (2)°. The crystal structure features both intra- and intermolecular C—H...O hydrogen bonds, as well as intermolecular C—H...π and π–π interactions, leading to the formation of sheets parallel to the ac plane.

Bond-length distributions have been examined for 33 configurations of the metalloid ions and 56 configurations of the post-transition metal ions bonded to oxygen, for 5279 coordination polyhedra and 21 761 bond distances for the metalloid ions, and 1821 coordination polyhedra and 10 723 bond distances for the post-transition metal ions. For the metalloid and post-transition elements with lone-pair electrons, the more common oxidation state between n versus n+2 is n for Sn, Te, Tl, Pb and Bi and n+2 for As and Sb. There is no correlation between bond-valence sum and coordination number for cations with stereoactive lone-pair electrons when including secondary bonds, and both intermediate states of lone-pair stereoactivity and inert lone pairs may occur for any coordination number > [4]. Variations in mean bond length are ∼0.06–0.09 Å for strongly bonded oxyanions of metalloid and post-transition metal ions, and ∼0.1–0.3 Å for ions showing lone-pair stereoactivity. Bond-length distortion is confirmed to be a leading cause of variation in mean bond lengths for ions with stereoactive lone-pair electrons. For strongly bonded cations (i.e. oxyanions), the causes of mean bond-length variation are unclear; the most plausible cause of mean bond-length variation for these ions is the effect of structure type, i.e. stress resulting from the inability of a structure to adopt its characteristic a priori bond lengths.

Within the framework of the bond-valence model, one may write equations describing the valence-sum rule and the loop rule in terms of the constituent bond valences. These are collectively called the network equations, and can be solved for a specific bond topology to calculate its a priori bond valences. A priori bond valences are the ideal values of bond strengths intrinsic to a given bond topology that depend strictly on the formal valences of the ion at each site in the structure, and the bond-topological characteristics of the structure (i.e. the ion connectivity). The a priori bond valences are calculated for selected rock-forming minerals, beginning with a simple example (magnesiochromite, = 1.379 bits per atom) and progressing through a series of gradually more complex minerals (grossular, diopside, forsterite, fluoro-phlogopite, phlogopite, fluoro-tremolite, tremolite, albite) to finish with epidote (= 4.187 bits per atom). The effects of weak bonds (hydrogen bonds, long Na+—O2− bonds) on the calculation of a priori bond valences and bond lengths are examined. For the selected set of minerals, a priori and observed bond valences and bond lengths scatter closely about the 1:1 line with an average deviation of 0.04 v.u. and 0.048 Å and maximum deviations of 0.16 v.u. and 0.620 Å. The scatter of the corresponding a priori and observed bond lengths is strongly a function of the Lewis acidity of the constituent cation. For cations of high Lewis acidity, the range of differences between the a priori and observed bond lengths is small, whereas for cations of low Lewis acidity, the range of differences between the a priori and observed bond lengths is large. These calculations allow assessment of the strain in a crystal structure and provide a way to examine the effect of bond topology on variation in observed bond lengths for the same ion-pair in different bond topologies.

Bond-length distributions are examined for 63 transition metal ions bonded to O2− in 147 configurations, for 7522 coordination polyhedra and 41 488 bond distances, providing baseline statistical knowledge of bond lengths for transition metals bonded to O2−. A priori bond valences are calculated for 140 crystal structures containing 266 coordination polyhedra for 85 transition metal ion configurations with anomalous bond-length distributions. Two new indices, Δtopol and Δcryst, are proposed to quantify bond-length variation arising from bond-topological and crystallographic effects in extended solids. Bond-topological mechanisms of bond-length variation are (1) non-local bond-topological asymmetry and (2) multiple-bond formation; crystallographic mechanisms are (3) electronic effects (with an inherent focus on coupled electronic vibrational degeneracy in this work) and (4) crystal-structure effects. The indices Δtopol and Δcryst allow one to determine the primary cause(s) of bond-length variation for individual coordination polyhedra and ion configurations, quantify the distorting power of cations via electronic effects (by subtracting the bond-topological contribution to bond-length variation), set expectation limits regarding the extent to which functional properties linked to bond-length variation may be optimized in a given crystal structure (and inform how optimization may be achieved) and more. These indices further provide an equal footing for comparing bond-length variation and the distorting power of ions across ligand types, including resolution for heteroligand polyhedra. The observation of multiple bonds is found to be primarily driven by the bond-topological requirements of crystal structures in solids. However, sometimes multiple bonds are observed to form as a result of electronic effects (e.g. the pseudo Jahn–Teller effect, PJTE); resolution of the origins of multiple-bond formation follows calculation of the Δtopol and Δcryst indices on a structure-by-structure basis. Non-local bond-topological asymmetry is the most common cause of bond-length variation in transition metal oxides and oxysalts, followed closely by the PJTE. Non-local bond-topological asymmetry is further suggested to be the most widespread cause of bond-length variation in the solid state, with no a priori limitations with regard to ion identity. Overall, bond-length variations resulting from the PJTE are slightly larger than those resulting from non-local bond-topological asymmetry, comparable with those resulting from the strong JTE, and less than those induced by π-bond formation. From a comparison of a priori and observed bond valences for ∼150 coordination polyhedra in which the strong JTE or the PJTE is the main reason underlying bond-length variation, the JTE is found not to have a cooperative relation with the bond-topological requirements of crystal structures. The magnitude of bond-length variation caused by the PJTE decreases in the following order for octahedrally coordinated d 0 transition metal oxyanions: Os8+ > Mo6+ > W6+ >> V5+ > Nb5+ > Ti4+ > Ta5+ > Hf4+ > Zr4+ > Re7+ >> Y3+ > Sc3+. Such ranking varies by coordination number; for [4] it is Re7+ > Ti4+ > V5+ > W6+ > Mo6+ > Cr6+ > Os8+ >> Mn7+; for [5] it is Os8+ > Re7+ > Mo6+ > Ti4+ > W6+ > V5+ > Nb5+. It is concluded that non-octahedral coordinations of d 0 ion configurations are likely to occur with bond-length variations that are similar in magnitude to their octahedral counterparts. However, smaller bond-length variations are expected from the PJTE for non-d 0 transition metal oxyanions.

A large amount of information concerning interatomic distances in the solid state is available, but little has been done in recent times to comprehensively filter, summarize and analyze this information. Here, I examine the distribution of bond lengths for 135 ions bonded to oxygen, using 180,331 bond lengths extracted from 9367 refined crystal structures collected from the Inorganic Crystal Structure Database (ICSD). The data are used to evaluate the parameterization of the bond-length—bond-valence relation of the bond-valence model. Published bond-valence parameters for 135 cations bonded to oxygen, and the various methods used in their derivation, are evaluated. New equations to model the relation are tested and the common form of the equation is found to be satisfactory. A new method (the Generalized Reduced Gradient Method, GRG method) is used to derive new bond-valence parameters for 135 cations bonded to oxygen, leading to significant improvements in fit for many of the ions. The improved parameterization is used to gain crystal-chemical insight into the milarite structure. A literature review of 350+ published compositions is done to review the end-members of the milarite group and to identify compositions that should have been described as distinct minerals species. The a priori bond-valences are calculated for minerals of this structure, and are used to examine the controls of bond topology on site occupancy, notably by localizing the major source of strain of the structure (the B site). Examination of the compositions of all known milarite-group minerals shows that compositions with a fully occupied B site are less common than those with a vacant B site, in accord with the idea that the B site is a local region of high strain in the structure. The bond-length distributions for the ions of the alkali and alkaline-earth metal families are examined. Variations in mean bond-lengths are only partly explained by the distortion theorem of the bond-valence model. I have found that bond length also correlates with the amount of vibrational displacement of the constituent ions. The validity of some uncommon coordination numbers, e.g., [3]-coordinated Li+, [3]-coordinated Be2+, is confirmed.
October 2016

The first objective of this thesis was to determine the material properties of grade 270 and grade 300 prestressing strand of various sizes. Tension tests were performed on each type of strand. The data from these tests was used to determine modulus of elasticity, yield stress, ultimate stress, and ultimate elongation for each strand. The yield stresses and ultimate stresses for many of the strands did not meet the requirements found in ASTM A416. The ultimate elongation results far exceeded the requirements and the measured elastic moduli were near the modulus recommended by AASHTO LRFD. A secondary objective from the tension tests was to evaluate a gripping method which used aluminum tubing to cushion the strands against notching. The grips performed very well. Most of the strand breaks did not occur in the grips and when a strand did break in the grips, the failure occurred after significant post-yield elongation. The second objective was to evaluate the bond properties of grade 270 and grade 300 prestressing strands. The North American Strand Producers (NASP) Bond Test and Large Block Pullout Test (LBPT) were performed on six different strand grade and strand size combinations. Both of the tests are simple pullout tests on untensioned strand. The results for each strand type were compared to one another as well as to measured transfer and development lengths from beams using the strand from the same reel. All of the strands showed sufficient bond in the beams, but one strand type did fail both the NASP Test and the LBPT. Both pullout tests were acceptable methods to evaluate strand surface condition and the benchmarks set for 0.5 in. diameter regular strand were conservative for the strands used in this thesis. Little difference was evident in the bond performance of grade 270 and grade 300 prestressing strand.
Master of Science

Dissertação (mestrado)—Universidade de Brasília, Instituto de Física, Programa de Pós-Graduação em Física, 2016.
A alternância dos comprimentos de ligação (Bond Length Alternation, BLA) em cadeias moleculares conjugadas longas tem sido tópico de discussões por muitas décadas, tanto experimental quanto teoricamente. O BLA é um parâmetro estrutural que vem da diferença entre o comprimento de ligações duplas e simples ao longo da cadeia conjugada. Neste trabalho nós utilizamos um método estatístico muito utilizado em várias áreas do conhecimento, a Análise dos Componentes Principais (do inglês Principal Components Analysis - PCA), criado por Karl Pearson em 1901, para redefinir o parâmetro BLA. Com esta técnica calculamos um parâmetro estrutural, comparável ao BLA, de um grupo de 17 moléculas derivadas de tertiofeno e, a partir disto, fizemos comparações com a forma mais comum de calcular o BLA, o que nos forneceu uma forma alternativa de calcular este parâmetro. Com a PCA podemos ir mais além ao cálculo do parâmetro estrutural e, por exemplo, podemos identificar quais ligações têm maior relevância para o valor do BLA. Outro ponto desta análise que merece destaque, foi mostrar a evolução dos coeficientes gerados por esta técnica, chamados de PC1, assim como, a evolução dos valores do BLA com o aumento do número de moléculas presentes no grupo inicial para o cálculo e a diferença em relação a aromaticidade de tais moléculas, mostrando qual o número mínimo para que esta técnica possa ser aplicada.
The Bond Length Alternation (BLA) in long conjugated molecular chains have been the topic of discussion for many decades, both experimentally and theoretically. The BLA is a structural parameter that comes from the difference between the length of double and single bonds along the conjugated chain. In this work we have used a statistical method widely used in many fields of knowledge, the Principal Component Analysis, created by Karl Pearson in 1901, to redefine the parameter BLA. With this technique we calculated the BLA of a group of 17 molecules derived from terthiophene and made comparisons with the most common way to calculate the BLA, which provided us with an alternative way to calculate the parameter. With the PCA we can go further the BLA and we can also identify which bonds are more relevant to its value. Another point that is worth mentioning, was showing the evolution of the coefficients generated by this technique, as well as the evolution of BLA values, along with the increasing number of molecules present in the initial group for the calculation and the differences between the aromaticity of such molecules, resulting in the minimum number to apply this technique.

Molecular orbital calculations on 18 hydrosulfide molecules containing selected main group X-cations yield minimum energy bond lengths, R_t(XS), that reproduce those observed in chemically similar sulfide crystals. A least-squares analysis shows that R_t(XS) can be estimated by the equation R = l.83(s/r)^-0.21, where s is the Pauling bond strength and r is the row number of the X-cation in the periodic table, with 98% of the variation of R_t(XS) being explained in terms of a linear dependence on R. In addition, R serves to rank observed XS bond lengths in sulfide crystals for main group X-cations for rows 1 through 5 of the periodic table to within 0.12Å on average, with R accounting for 96% of the variation in the observed bond lengths. Bonded radii obtained from electron density maps calculated for the molecules show that the radii of both the X-cations and S atom increase with R_t(XS). A similar trend has been found to hold for the bonded radii and the R_t(XO) bond lengths calculated for hydroxyacid molecules (Finger and Gibbs 1985). The radius of S is smaller (1.16Å) when bonded to highly electronegative atoms like 4-coordinate As and larger (1.67Å) when bonded to a considerably less electronegative atoms like 4-coordinate Li but is smaller than Shannon's (1.70Å) crystal radius and Pauling's ionic crystal radius (1.84Å).
M.S.

A proper bond between reinforcement and concrete is key for an appropriate composite action of both materials in reinforced concrete structures. However, to-date limited studies exist on bond of fiber reinforced polymer (FRP) bars in concrete members under flexure. In this paper, the bond strength developed by FRP and steel rebars is evaluated and compared, by testing reinforced concrete beams under three point bending load. The investigation included several beams that were 183 cm long × 15 cm wide × 36 cm deep: many of them were reinforced with sand coated GFRP rebars, while steel was used to reinforce the remaining ones. For each of the reinforcing systems, various different embedded lengths were tested. The beams were tested under a 3-point-bending setup and they were monitored using several measuring devices: LVDTS, potentiometers and strain gauges. Preliminary results show that the GFRP rebars have lower bond capacity than the ones made of steel. Moreover, it was inferred that the embedded lengths suggested by actual code provisions for GFRP rebars are too conservative.

Drilled shafts are large cylindrical cast-in-place concrete structural elements that can be favored due to cost-effectiveness. These elements however, require strict quality control during construction to ensure a stable excavation. Drilling fluid is often used in construction to attain this stability. Drilling fluid, or slurry, can be ground water or salt water, but is typically made from a mixture of water and mineral or polymer powder to form a viscous fluid slightly more dense than ground water. During concreting, the drilling fluid is displaced by the heavier concrete, which is tremie placed at the base of the excavation from the center of the reinforcement cage. While concrete used for drilled shafts should be highly fluid, it does not follow an ideal, uniform flow. The concrete rather builds up inside the reinforcement cage to a sufficient height before then pressing out radially into the annular cover region. This concrete flow pattern associated with drilled shafts has been shown to trap slurry around/near the steel reinforcement and affect reinforcement bond strength. Presently there are no specifications relating to slurry effects on reinforcing bar bond strength from the American Concrete Institute (ACI) or the American Association of State and Highway Transportation Officials (AASHTO). This dissertation analyzes longitudinal reinforcing bar concrete bond strength data recorded from 268 specimens constructed with tremie-placed concreting conditions in varying drilling fluids. Reinforcement used for testing were No. 8 deformed rebar. Based on the results found from this analysis, this dissertation recommends the use of a slurry modification factor to current bond strength and development length specifications.

This case explores how bone health can be affected by antiepileptic drugs (AEDs), and why this is an important issue in women with epilepsy (WWE). AEDs affect bone health through activation of the cytochrome P450 system in the liver, leading to increased metabolism of vitamin D. The enzyme-inducing AEDs include phenytoin, carbamazepine, phenobarbital, and primidone. Risk factors for osteoporosis include female gender, low body mass, inadequate vitamin D intake, and smoking. The specific AEDs used and the length of treatment confer additional risks. Furthermore, in WWE, risks are magnified related to falls, either from seizures or related to medication toxicity. Screening with bone density and measures to promote bone health are extremely important in these at-risk women.

In the wake of inadequate histories of radical writing and activism, Nancy Cunard: Perfect Stranger rejects stereotypes of Cunard as spoiled heiress and “sexually dangerous New Woman,” offering instead a bold, unapologetic, evidence-based portrait of a woman and her significant contributions to twenty-first-century considerations of gender, race, and class. This full length critical study by the late, path-breaking feminist scholar, Jane Marcus, rereads Cunard’s identity as a poet, an anthologist, a journalist, and political activist against racism and fascism.

♦ Hip Dysplasia• Despite screening programs, a large number of patients are affected by dysplastic hips and their sequelae• An understanding of anatomical abnormalities is crucial• Appropriate techniques and implants make arthroplasty feasible• Complications are significantly higher than standard primary hip replacements♦ Protrusio Acetabuli• Technical difficulties include inadequate medial wall and restoring offset, hip centre and leg lengths• Neck may need to be cut in-situ; bone graft is usually necessary and ideally should be taken from the femoral head• Antiprotrusio cages or custom implants may be needed in cases with excessive bone loss♦ Arthrodesed hip to total hip replacement• Careful evaluation of the gluteal muscles is mandatory and predicts final walking ability and patient satisfaction• Long-term effectiveness of total hip replacement in ankylosed hips is satisfactory but there is a higher complication rate

Classically, the study of skeletal growth in earlier human populations has involved the study of long-bone lengths versus dental age, making comparisons between archaeological groups or between archaeological and modern populations. Although this continues to be an important avenue of scholarly enquiry in archaeological growth studies, some important new directions have recently been explored. There has also been an increased diversity to the statistical methods used to model and investigate skeletal growth in archaeological populations, and increased recognition of some of the limitations of growth studies using archaeological populations. This chapter outlines developments in these areas and discusses prospects for the future of archaeological studies of human skeletal growth.

Bones are multifunctional passive organs of movement that supports soft tissue and directly attached muscles. They also protect internal organs and are a reserve of calcium, phosphorus and magnesium. Each bone is covered with periosteum, and the adjacent bone surfaces are covered by articular cartilage. Histologically, the bone is an organ composed of many different tissues. The main component is bone tissue (cortical and spongy) composed of a set of bone cells and intercellular substance (mineral and organic), it also contains fat, hematopoietic (bone marrow) and cartilaginous tissue. Bones are a tissue that even in adult life retains the ability to change shape and structure depending on changes in their mechanical and hormonal environment, as well as self-renewal and repair capabilities. This process is called bone turnover. The basic processes of bone turnover are: • bone modeling (incessantly changes in bone shape during individual growth) following resorption and tissue formation at various locations (e.g. bone marrow formation) to increase mass and skeletal morphology. This process occurs in the bones of growing individuals and stops after reaching puberty • bone remodeling (processes involve in maintaining bone tissue by resorbing and replacing old bone tissue with new tissue in the same place, e.g. repairing micro fractures). It is a process involving the removal and internal remodeling of existing bone and is responsible for maintaining tissue mass and architecture of mature bones. Bone turnover is regulated by two types of transformation: • osteoclastogenesis, i.e. formation of cells responsible for bone resorption • osteoblastogenesis, i.e. formation of cells responsible for bone formation (bone matrix synthesis and mineralization) Bone maturity can be defined as the completion of basic structural development and mineralization leading to maximum mass and optimal mechanical strength. The highest rate of increase in pig bone mass is observed in the first twelve weeks after birth. This period of growth is considered crucial for optimizing the growth of the skeleton of pigs, because the degree of bone mineralization in later life stages (adulthood) depends largely on the amount of bone minerals accumulated in the early stages of their growth. The development of the technique allows to determine the condition of the skeletal system (or individual bones) in living animals by methods used in human medicine, or after their slaughter. For in vivo determination of bone properties, Abstract 10 double energy X-ray absorptiometry or computed tomography scanning techniques are used. Both methods allow the quantification of mineral content and bone mineral density. The most important property from a practical point of view is the bone’s bending strength, which is directly determined by the maximum bending force. The most important factors affecting bone strength are: • age (growth period), • gender and the associated hormonal balance, • genotype and modification of genes responsible for bone growth • chemical composition of the body (protein and fat content, and the proportion between these components), • physical activity and related bone load, • nutritional factors: – protein intake influencing synthesis of organic matrix of bone, – content of minerals in the feed (CA, P, Zn, Ca/P, Mg, Mn, Na, Cl, K, Cu ratio) influencing synthesis of the inorganic matrix of bone, – mineral/protein ratio in the diet (Ca/protein, P/protein, Zn/protein) – feed energy concentration, – energy source (content of saturated fatty acids - SFA, content of polyun saturated fatty acids - PUFA, in particular ALA, EPA, DPA, DHA), – feed additives, in particular: enzymes (e.g. phytase releasing of minerals bounded in phytin complexes), probiotics and prebiotics (e.g. inulin improving the function of the digestive tract by increasing absorption of nutrients), – vitamin content that regulate metabolism and biochemical changes occurring in bone tissue (e.g. vitamin D3, B6, C and K). This study was based on the results of research experiments from available literature, and studies on growing pigs carried out at the Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences. The tests were performed in total on 300 pigs of Duroc, Pietrain, Puławska breeds, line 990 and hybrids (Great White × Duroc, Great White × Landrace), PIC pigs, slaughtered at different body weight during the growth period from 15 to 130 kg. Bones for biomechanical tests were collected after slaughter from each pig. Their length, mass and volume were determined. Based on these measurements, the specific weight (density, g/cm3) was calculated. Then each bone was cut in the middle of the shaft and the outer and inner diameters were measured both horizontally and vertically. Based on these measurements, the following indicators were calculated: • cortical thickness, • cortical surface, • cortical index. Abstract 11 Bone strength was tested by a three-point bending test. The obtained data enabled the determination of: • bending force (the magnitude of the maximum force at which disintegration and disruption of bone structure occurs), • strength (the amount of maximum force needed to break/crack of bone), • stiffness (quotient of the force acting on the bone and the amount of displacement occurring under the influence of this force). Investigation of changes in physical and biomechanical features of bones during growth was performed on pigs of the synthetic 990 line growing from 15 to 130 kg body weight. The animals were slaughtered successively at a body weight of 15, 30, 40, 50, 70, 90, 110 and 130 kg. After slaughter, the following bones were separated from the right half-carcass: humerus, 3rd and 4th metatarsal bone, femur, tibia and fibula as well as 3rd and 4th metatarsal bone. The features of bones were determined using methods described in the methodology. Describing bone growth with the Gompertz equation, it was found that the earliest slowdown of bone growth curve was observed for metacarpal and metatarsal bones. This means that these bones matured the most quickly. The established data also indicate that the rib is the slowest maturing bone. The femur, humerus, tibia and fibula were between the values of these features for the metatarsal, metacarpal and rib bones. The rate of increase in bone mass and length differed significantly between the examined bones, but in all cases it was lower (coefficient b <1) than the growth rate of the whole body of the animal. The fastest growth rate was estimated for the rib mass (coefficient b = 0.93). Among the long bones, the humerus (coefficient b = 0.81) was characterized by the fastest rate of weight gain, however femur the smallest (coefficient b = 0.71). The lowest rate of bone mass increase was observed in the foot bones, with the metacarpal bones having a slightly higher value of coefficient b than the metatarsal bones (0.67 vs 0.62). The third bone had a lower growth rate than the fourth bone, regardless of whether they were metatarsal or metacarpal. The value of the bending force increased as the animals grew. Regardless of the growth point tested, the highest values were observed for the humerus, tibia and femur, smaller for the metatarsal and metacarpal bone, and the lowest for the fibula and rib. The rate of change in the value of this indicator increased at a similar rate as the body weight changes of the animals in the case of the fibula and the fourth metacarpal bone (b value = 0.98), and more slowly in the case of the metatarsal bone, the third metacarpal bone, and the tibia bone (values of the b ratio 0.81–0.85), and the slowest femur, humerus and rib (value of b = 0.60–0.66). Bone stiffness increased as animals grew. Regardless of the growth point tested, the highest values were observed for the humerus, tibia and femur, smaller for the metatarsal and metacarpal bone, and the lowest for the fibula and rib. Abstract 12 The rate of change in the value of this indicator changed at a faster rate than the increase in weight of pigs in the case of metacarpal and metatarsal bones (coefficient b = 1.01–1.22), slightly slower in the case of fibula (coefficient b = 0.92), definitely slower in the case of the tibia (b = 0.73), ribs (b = 0.66), femur (b = 0.59) and humerus (b = 0.50). Bone strength increased as animals grew. Regardless of the growth point tested, bone strength was as follows femur > tibia > humerus > 4 metacarpal> 3 metacarpal> 3 metatarsal > 4 metatarsal > rib> fibula. The rate of increase in strength of all examined bones was greater than the rate of weight gain of pigs (value of the coefficient b = 2.04–3.26). As the animals grew, the bone density increased. However, the growth rate of this indicator for the majority of bones was slower than the rate of weight gain (the value of the coefficient b ranged from 0.37 – humerus to 0.84 – fibula). The exception was the rib, whose density increased at a similar pace increasing the body weight of animals (value of the coefficient b = 0.97). The study on the influence of the breed and the feeding intensity on bone characteristics (physical and biomechanical) was performed on pigs of the breeds Duroc, Pietrain, and synthetic 990 during a growth period of 15 to 70 kg body weight. Animals were fed ad libitum or dosed system. After slaughter at a body weight of 70 kg, three bones were taken from the right half-carcass: femur, three metatarsal, and three metacarpal and subjected to the determinations described in the methodology. The weight of bones of animals fed aa libitum was significantly lower than in pigs fed restrictively All bones of Duroc breed were significantly heavier and longer than Pietrain and 990 pig bones. The average values of bending force for the examined bones took the following order: III metatarsal bone (63.5 kg) <III metacarpal bone (77.9 kg) <femur (271.5 kg). The feeding system and breed of pigs had no significant effect on the value of this indicator. The average values of the bones strength took the following order: III metatarsal bone (92.6 kg) <III metacarpal (107.2 kg) <femur (353.1 kg). Feeding intensity and breed of animals had no significant effect on the value of this feature of the bones tested. The average bone density took the following order: femur (1.23 g/cm3) <III metatarsal bone (1.26 g/cm3) <III metacarpal bone (1.34 g / cm3). The density of bones of animals fed aa libitum was higher (P<0.01) than in animals fed with a dosing system. The density of examined bones within the breeds took the following order: Pietrain race> line 990> Duroc race. The differences between the “extreme” breeds were: 7.2% (III metatarsal bone), 8.3% (III metacarpal bone), 8.4% (femur). Abstract 13 The average bone stiffness took the following order: III metatarsal bone (35.1 kg/mm) <III metacarpus (41.5 kg/mm) <femur (60.5 kg/mm). This indicator did not differ between the groups of pigs fed at different intensity, except for the metacarpal bone, which was more stiffer in pigs fed aa libitum (P<0.05). The femur of animals fed ad libitum showed a tendency (P<0.09) to be more stiffer and a force of 4.5 kg required for its displacement by 1 mm. Breed differences in stiffness were found for the femur (P <0.05) and III metacarpal bone (P <0.05). For femur, the highest value of this indicator was found in Pietrain pigs (64.5 kg/mm), lower in pigs of 990 line (61.6 kg/mm) and the lowest in Duroc pigs (55.3 kg/mm). In turn, the 3rd metacarpal bone of Duroc and Pietrain pigs had similar stiffness (39.0 and 40.0 kg/mm respectively) and was smaller than that of line 990 pigs (45.4 kg/mm). The thickness of the cortical bone layer took the following order: III metatarsal bone (2.25 mm) <III metacarpal bone (2.41 mm) <femur (5.12 mm). The feeding system did not affect this indicator. Breed differences (P <0.05) for this trait were found only for the femur bone: Duroc (5.42 mm)> line 990 (5.13 mm)> Pietrain (4.81 mm). The cross sectional area of the examined bones was arranged in the following order: III metatarsal bone (84 mm2) <III metacarpal bone (90 mm2) <femur (286 mm2). The feeding system had no effect on the value of this bone trait, with the exception of the femur, which in animals fed the dosing system was 4.7% higher (P<0.05) than in pigs fed ad libitum. Breed differences (P<0.01) in the coross sectional area were found only in femur and III metatarsal bone. The value of this indicator was the highest in Duroc pigs, lower in 990 animals and the lowest in Pietrain pigs. The cortical index of individual bones was in the following order: III metatarsal bone (31.86) <III metacarpal bone (33.86) <femur (44.75). However, its value did not significantly depend on the intensity of feeding or the breed of pigs.

Relevance theory offers a model of communication where utterances are constantly updated by the speaker, inviting the listener to engage in a corresponding activity of inferential adjustment. In the case of literature, the potential time-scale of this activity is expanded, whether by the length of the text, the passage of historical time, or the demands of close reading. How then do incremental effects operate within the virtual time of literary utterance? How does one effect become a platform or trigger for others? This chapter touches on issues such as the situated logic of collocation and the ‘echoic’ as a way of approaching literary allusiveness, and brings together the micro-analysis of a line of poetry with a broader-scope reflection on the principles that operate over extended fictions. Adapting to literary understanding Davidson’s notion of a ‘passing theory’, it tracks the time-bound, ephemeral passage of verbal events through the reader’s cognitive focus.

This chapter is divided into three main sections. The first section concerns the patient population that presents for orthopaedic surgery, specifically examining chronic diseases of the musculoskeletal system and the medications commonly used for their management, and the impact this has when these patients present for surgery. Included in this section are the surgical considerations and the anaesthetic implications of orthopaedic surgery, ranging from patient positioning to bone cement implant syndrome. The last part of this first section looks at specific orthopaedic operations, starting with the most commonly performed, hip and knee arthroplasties, and moving onto the specialist areas of spinal deformity, paediatric, and bone tumour surgery that are not usually found outside of specialist centres. The middle section gives a brief overview on analgesia concentrating on pharmacological methods as, although orthopaedic surgery lends itself well to regional anaesthesia, this is covered elsewhere in its own dedicated chapters. No section on analgesia would be complete without mentioning enhanced recovery: the coordinated, multidisciplinary approach that improves the patient experience, increases early mobilization, and reduces length of stay, which should be the standard obtained for every patient. The final section covers the anaesthetic management of in-hospital trauma, giving an overview on initial assessment, timing of surgery, and management of haemorrhage and coagulopathy. This section finishes by covering the orthopaedic-specific topics of compartment syndrome, fat embolism syndrome, and the management of fractured neck of femur and spinal injury.

A study was conducted at Kansas State University to determine the correlation between tensioned-wire pullout tests and the corresponding transfer lengths in prestressed concrete railroad ties. Five different 5.32-mm-diameter pre-stressing wires were selected to be used on this project based on previous testing conducted at Kansas State University (KSU). The wires were tested to simulate the transfer-length bond. The transfer-length bond test involved tensioning each of the wires to 75% of their ultimate capacity, casting concrete around each wire and then de-tensioning the wire when the concrete had reached 4,500 psi. End-slip and force measurements were recorded on both sides of the specimen as the wire was de-tensioned. Transfer bond data was used to investigate the transfer length that each wire type would expect to see in a concrete railroad tie. Prisms with each wire type were cast and the transfer length was measured for each type of wire. Prism measurements were used along with the transfer bond data to correlate a relation between the transfer bond test and the transfer lengths of the prisms.

<p>Carbon Fibre Reinforced Polymer (CFRP) tendons present an alternative material that can mitigate steel corrosion problems in concrete bridges. The use of CFRP prestress tendons can result in more durable prestressed concrete structures. However, the potential matrix plasticisation of CFRP tendons in humid environments and their inherent lack of ductility need to be considered in the design process. A tension stiffening analysis is undertaken to study the effect of variations in bond strength parameters on the cracking behaviour, deformability and structural performance of CFRP prestressed beams. The bond strength scenarios under consideration reflect either low or high bond conditions. The former could be associated with epoxy plasticisation and bond degradation due to moisture ingress at a crack location. A low bond performance results in a smaller number of cracks and higher deflections at failure compared with high bond tendons.</p>

Abstract To overcome the obstacles in preparing high-precision cross-sections of 'blind' bond wires in integrated circuits, this article proposes a different technique that generates reliable, repeatable cross-sections of bond wires across most or all of their lengths, allowing unencumbered and relatively artifact-free analysis of a given bond wire. The basic method for cross-sectioning a 'blind' bond wire involves radiographic analysis of the sample and metallographic preparation of the sample to the plane of interest. This is followed by tracking the exact location of the plane on the original radiograph using a stereomicroscope and finally darkfield imaging in which the wire is clearly visible with good resolution.