Academic literature on the topic 'Stiffness factor'

Supporting system of external suspension tower crane is the key factor which impairs the safety of the tower cranes. In this article, the problem is studied about the influence of different supporting point stiffness on the force of the tower crane external suspension. Based on the structural mechanics theory, the displacement of the lower statically indeterminate beam and the horizontal displacement of the upper statically indeterminate truss are solved firstly, then the stiffness of the supporting point on the lower beam and the entirety stiffness of the upper horizontal combination struts can be obtained. We can get the optimal supporting structure by drawing the relationship of stiffness1-stiffness2-force which is of significant to the external suspension’s design and installation in Matlab software.

Axisymmetric finite element modeling of bolted joints was performed to show the effects of the magnitude and position of the external load, member thickness, and member material on the bolt and member stiffnesses. The member stiffness of the bolted joint was found to decrease 10 to 42 percent for the 20-mm to 8-mm bolts, respectively, as the magnitude of the external load was increased. Member stiffness appears to be independent of the radial location of the external load and increases as the member thickness decreases. Member stiffness decreased by a factor of 2.5 to 3 with a change in the member material from steel to aluminum. The cast iron members had a decrease in member stiffness of a factor of 1.7 to 1.9. The aluminum over cast iron combination had a member stiffness between the aluminum and cast iron alone. Bolt stiffnesses varied by less than two percent for changes in the magnitude of the external load for all bolt sizes and member materials, except for the 8-mm bolt where stiffness increased by approximately 11 percent. Changes in radial position of the external load had no effect on the bolt stiffness. A 3 to 13-percent decrease in the bolt stiffness was found when changing from steel to aluminum members. A 2 to 3-percent bolt stiffness decrease resulted when the member material was changed from steel to cast iron and similarly from steel to the aluminum over cast iron combination

ABSTRACTChang explicit method (2007) has been shown to be unconditionally stable for a linear elastic system and any instantaneous stiffness softening system while it is only conditionally stable for any instantaneous stiffness hardening system. Its coefficients of the difference equation for displacement increment are functions of initial tangent stiffness. Since Chang explicit method is unconditionally stable for a linear elastic system and any instantaneous stiffness softening system, its stability range can be enlarged if the initial tangent stiffness is enlarged by an amplification factor and then this amplified initial tangent stiffness is used to determine the coefficients. The detailed implementation of this scheme for Chang explicit method is presented and the feasibility of this scheme is verified.

The Comprehensive Handle Evaluation System for Fabrics and Yarns (CHES-FY) is capable of measuring multiple physical and mechanical properties of fabrics, which are related to fabric handle. In this study, ten curve parameters were defined from the pulling-out force–displacement curve of the CHES-FY. Factor analysis was used to remove the co linearity of the curve parameters in order to better characterize the stiffness handle of fabrics. Three principal factors were established using the factor analysis, and the first principal factor was termed the stiffness index based on loadings of the curve parameters to the rotated factors. Comparisons between the evaluation results of the CHES-FY, cantilever test, and newly-developed dual subjective/objective assessments showed that the CHES-FY, together with the stiffness index resulting from the factor analysis, provided a fast and effective method to characterize a fabric’s stiffness handle, and the evaluation process of the CHES-FY appears to closely simulate the tactile response to stiffness when a person touches or pinches a fabric.

During manipulation, force is exerted with the expectation that an object will move in an intended manner. This prediction is a learned coordination between force and movement. Mechanically, impedance is a way to describe this coordination, and object interaction could be anticipated by setting impedance before the hand moves the object. This strategy would be especially important at the end of a reach, because feedback is ineffective for rapid force changes. Since mechanical impedance is not subject to the time delays of feedback, it can, if set properly, produce the desired motion on impact. We examined this possibility by instructing subjects to move a handle to a specific target position along a track. The handle was locked in place until the subject exerted enough force to cross a threshold; the handle was then released abruptly to move along the track. We hypothesized that this ballistic release task would encourage subjects to modify impedance in anticipation of the upcoming movement and found that one component of impedance, stiffness, varied in a way that matched the behavioral demands of the task. Analysis suggests that this stiffness was set before the handle moved and governed the subsequent motion. We also found separate components of muscle activity that corresponded to stiffness and to changes in force. Our results show that subjects used a robust and efficient strategy to coordinate force and displacement by modulating muscle activity in a way that was behaviorally relevant in the task. NEW & NOTEWORTHY The arm can behave like a spring, and this mechanical behavior can be advantageous in situations requiring rapid changes in force and/or displacement. Selection of a proper “virtual” spring before the occurrence of a rapid transient could facilitate a desired responsive movement. We show that these spring-like arm mechanics, set in anticipation of an instantaneous force change, function as an efficient strategy to control movement when feedback is ineffective.

This thesis describes the development of artificial disc technology for the replacement of intervertebral discs in the human lumbar spine. The clinical problem is back pain. There may be a relationship between certain forms of back pain and disc degeneration. The mechanical properties of human intervertebral discs are examined in detail. The genetic basis of disc degeneration is presented. The hypothesis is that such degeneration leads to a loss of normal stiffness in the segments affected leading to abnormal mechanical behaviour which in turn leads to pain. The evidence for this is presented. The development of surgical solutions to relieve back pain, from fusion through first generation mechanical artificial discs to elastomeric designs, is traced. The author‘s personal contributions to this area of knowledge are set out. The appreciation of the requirement for a restoration of physiological stiffness is argued throughout, showing where fusion and first generation discs have not met the clinical aim of pain relief, because they have not restored physiological stiffness. The path to an elastomeric, viscoelastic, polyhydrocarbon, rubber solution in the form of the “Freedom“ disc has filled 17 years of the author‘s academic pursuits. It will be shown that this technology may represent a possible solution to the clinical problem. Failure is part of all new advancement and this too is presented, to show how that has influenced thinking, producing original ideas to overcome these failures. Providing lessons are learned from these failures then our patients in the future will benefit.

"During heart valve remodeling, and in many disease states, valvular interstitial cells (VICs) shift to an activated myofibroblast phenotype which is characterized by enhanced synthetic and contractile activity. Pronounced alpha smooth muscle actin (alpha-SMA)-containing stress fibers, the hallmark of activated myofibroblasts, are also observed when VICs are placed under tension due to altered mechanical loading in vivo or during in vitro culture on stiff substrates or under high mechanical loads and in the presence of transforming growth factor-beta 1 (TGF-beta 1). The work presented herein describes three distinct model systems for application of controlled mechanical environment to VICs cultured in vitro. The first system uses polyacrylamide (PA) gels of defined stiffness to evaluate the response of VICs over a large range of stiffness levels and TGF-beta 1 concentration. The second system controls the boundary stiffness of cell-populated gels using springs of defined stiffness. The third system cyclically stretches soft or stiff two-dimensional (2D) gels while cells are cultured on the gel surface as it is deformed. Through the use of these model systems, we have found that the level of 2D stiffness required to maintain the quiescent VIC phenotype is potentially too low for a material to both act as matrix to support cell growth in the non-activated state and also to withstand the mechanical loading that occurs during the cardiac cycle. Further, we found that increasing the boundary stiffness on a three-dimensional (3D) cell populated collagen gel resulted in increased cellular contractile forces, alpha-SMA expression, and collagen gel (material)stiffness. Finally, VIC morphology is significantly altered in response to stiffness and stretch. On soft 2D substrates, VICs cultured statically exhibit a small rounded morphology, significantly smaller than on stiff substrates. Following equibiaxial cyclic stretch, VICs spread to the extent of cells cultured on stiff substrates, but did not reorient in response to uniaxial stretch to the extent of cells stretched on stiff substrates. These studies provide critical information for characterizing how VICs respond to mechanical stimuli. Characterization of these responses is important for the development of tissue engineered heart valves and contributes to the understanding of the role of mechanical cues on valve pathology and disease onset and progression. While this work is focused on valvular interstitial cells, the culture conditions and methods for applying mechanical stimulation could be applied to numerous other adherent cell types providing information on the response to mechanical stimuli relevant for optimizing cell culture, engineered tissues or fundamental research of disease states."

The objectives of the thesis are to estimate the prevalence of pathological arterial stiffness (measured with the Cardio-Ankle Vascular Index –CAVI-) in a general Mediterranean population and in a Mediterranean intermediate cardiovascular risk population, and to assess the association of this condition with lifestyle, cardiovascular risk factors, and socioeconomic status. The prevalence of pathological CAVI was high, mainly in the intermediate cardiovascular risk population. Pathological CAVI was associated with hypertension and diabetes, and negatively associated with obesity in both populations. Regarding lifestyles, only physical activity in men from the general Mediterranean population was associated with pathological CAVI. Completion of instruction only up to primary education level was associated with pathological arterial stiffness in men from the intermediate cardiovascular risk population. To improve primary prevention of cardiovascular disease we should focus on the early detection of pathological CAVI, and on the control of diabetes and hypertension
Els objectius de la tesi són calcular la prevalença de la rigidesa arterial patològica (mesurada amb el Cardio-Ankle Vascular Index -CAVI-) en una població general mediterrània i en una població mediterrània de risc entremig i avaluar l’associació d’aquesta amb estils de vida, factors de risc cardiovascular i nivell socioeconòmic. La prevalença de CAVI patològic era elevada, sobretot en la població de risc entremig, i aquest s’associà positivament a la hipertensió i la diabetis, i negativament a l’obesitat en les dues poblacions. Només l’activitat física en els homes en la població general estava relacionada amb el CAVI patològic. Cap altre estil de vida no hi estava relacionat. A més, tenir un nivell d’estudis màxim de primària també estava associat a CAVI patològic en homes de la població de risc entremig. Per prevenir les malalties cardiovasculars cal incidir en la detecció precoç del CAVI i controlar la diabetis i la hipertensió

This thesis investigates full-scale pipe stem reinforced cob walls under in-plane cyclic shear loads. Cob is the combination of clay subsoils, sand, straw and water that is built in lifts to produce monolithic walls. There is insufficient amount of information on cob as a building material in today’s age. The prior research that exists has examined varying straw content and type, water content, and mixture ratios to determine their effect on strength. There is currently one report that analyzes full-scale cob walls under in-plane loading. This thesis looks to iterate the full-scale tests and specifically studies the effect of reinforcement on cob walls. Concurrent to this research, another thesis was written that investigates a full-scale wire mesh reinforced cob wall under in-plane cyclic shear loads. From the data collected, a shear failure was suggested for the stem pipe wall. There appeared to be a large amount of ductility from the data and the cracks formed. Ductility, a seismic response modification factor (R-Factor) and stiffness were calculated using the yield point and ultimate loads.Iterations of this research and those performed in the past can be helpful in integrating cob in to the California Building Code.

The thesis deals with the behaviour of a cracked rail wheel. The aim was to perform the strain analysis of intact wheel as well as the fracture analysis of the primary direct cracked wheel. Solution includes an analysis of operating conditions, assessment of the substantiality of articular components of load, stiffness of the wheel, a comprehensive analysis of fracture of the selected railway wheel profile and optimization of the wheel shape depending on the matching fracture properties.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, February 1999.
"December, 1998."
Includes bibliographical references.
This research investigated the pre-failure stress-strain behavior of cohesive soils through an ex.tensive testing program conducted on Resedimented Boston Blue Clay (RBBC). The uniformity and reproducibility in the behavior of this soil permitted a detailed study of the role of the following factors on both initial stiffness and small strain (Eaby Maria Caterina Santagata.
Ph.D.

Hypertension is a multifactorial disease, in which vascular dysfunction plays a prominent role. It occurs in over 30% of adults worldwide and an additional 30% are at high risk of developing the disease. Vascular pathology is both a cause of the disease and a key manifestation of hypertension-associated target-organ damage. It leads to clinical symptoms and is a key risk factor for cardiovascular disease. All layers of the vascular wall and the endothelium are involved in the pathogenesis of hypertension. Pathogenetic mechanisms, whereby vascular damage contributes to hypertension, are linked to increased peripheral vascular resistance. At the vascular level, processes leading to change sin peripheral resistance include hyper-contractility of vascular smooth muscle cells, endothelial dysfunction, and structural remodelling, due to aberrant vascular signalling, oxidative and inflammatory responses. Increased vascular stiffness due to vascular remodelling, adventitial fibrosis, and inflammation are key processes involved in sustained and established hypertension. These mechanisms are linked to vascular smooth muscle and fibroblast proliferation, migration, extracellular matrix remodelling, calcification, and inflammation. Apart from the key role in the pathogenesis of hypertension, hypertensive vasculopathy also predisposes to atherosclerosis, another risk factor for cardiovascular disease. This is linked to increased transmural pressure, blood flow, and shear stress alterations in hypertension, as well as endothelial dysfunction and vascular stiffness. Therefore, understanding the mechanisms and identifying potential novel treatments targeting hypertensive vasculopathy are of primary importance in vascular medicine.

Ankylosing spondylitis (AS) is a chronic inflammatory disease predominantly of the sacroiliac joint (SIJ) and the spine. It starts normally in the second decade of life and has a slight male predominance. The prevalence is between 0.2 and 0.8% and is strongly dependent on the prevalence of HLA B27 in a given population. For the diagnosis of AS, the presence of radiographic sacroiliitis is mandatory. However, radiographs do not detect active inflammation but only structural bony damage. Most recently new classification criteria for axial spondyloarthritis (SpA) have been developed by the Assessement of Spondylo-Arthritis international Society (ASAS) which cover AS but also the earlier form of non-radiographic axial SpA. MRI has become an important new tool for the detection of subchondral bone marrow inflammation in SIJ and spine and has become increasingly important for an early diagnosis. HLA B27 plays a central role in the pathogenesis but its exact interaction with the immune system has not yet been clarified. Besides pain and stiffness in the axial skeleton patients suffer also from periods of peripheral arthritis, enthesitis, and uveitis. New bone formation as a reaction to inflammation and subsequent ankylosis of the spine determine long-term outcome in a subgroup of patients. Currently only non-steroidal anti-inflammatory drugs (NSAIDs) and tumour necrosis factor (TNF) blockers have been proven to be effective in the medical treatment of axial SpA, and international ASAS recommendations for the structured management of axial SpA have been published based on these two types of drugs. Conventional disease-modifying anti-rheumatic drugs (DMARDs) such as methotrexate are not effective.

Axial spondyloarthritis (axSpA) is a chronic inflammatory disease predominantly of the sacroiliac joint (SIJ) and the spine. It starts normally in the second decade of life and has a slight male predominance. The prevalence is between 0.2% and 0.8% and is strongly dependent on the prevalence of HLA-B27 in a given population. AxSpA can be split in patients with radiographic axSpA (also termed ankylosing spondylitis (AS)) and in patients with non-radiographic axSpA (nr-axSpA). For the diagnosis of AS, the presence of radiographic sacroiliitis is mandatory. However, radiographs do not detect active inflammation but only structural bony damage. Most recently new classification criteria for axSpA have been developed by the Assessment of Spondylo-Arthritis International Society (ASAS) which cover AS but also the earlier form of nr-axSpA. MRI has become an important new tool for the detection of subchondral bone marrow inflammation in SIJ and spine and has become increasingly important for an early diagnosis. HLA-B27 plays a central role in the pathogenesis but its exact interaction with the immune system has not yet been clarified. Besides pain and stiffness in the axial skeleton patients suffer also from periods of peripheral arthritis, enthesitis, and uveitis. New bone formation as a reaction to inflammation and subsequent ankylosis of the spine determine long-term outcome in a subgroup of patients. Currently only non-steroidal anti-inflammatory drugs (NSAIDs) and tumour necrosis factor (TNF) blockers have been proven to be effective in the medical treatment of axial SpA, and international ASAS recommendations for the structured management of axial SpA have been published based on these two types of drugs. Conventional disease-modifying anti-rheumatic drugs (DMARDs) such as methotrexate are not effective.

Osteoarthritis (OA) is a disorder that can affect any joint. It results in a high clinical burden in many patients. Patients with OA experience a wide range of symptoms and clinical signs such as pain, disability, stiffness, tenderness, crepitus, and decreased mobility and strength in their osteoarthritic joints, where the impact depends on the involved joint. Also general symptoms such as fatigue and psychosocial consequences are experienced by OA patients. The impact of symptoms and signs does not only depend on osteoarthritic abnormalities, but also on patient factors, such as coping strategies and illness perceptions, and co-morbidities. In this chapter, general and joint-specific symptoms and signs as well as the impact of patient factors are discussed.

Hypertension affects multiple groups of patients characterized by different clinical presentations and a spectrum of potential causes. The pathophysiology is complex and multifactorial. Although most patients are labelled ‘essential hypertension’, multiple mechanisms are involved in blood pressure regulation. Factors that influence blood pressure homeostasis include endothelial function, the renin-angiotensin system, and the sympathetic nervous system. In elderly patients, hypertension is common as the vascular system and arterial stiffness also contribute. Other important factors include inflammatory processes as part of systemic diseases, including atherosclerosis,which may contribute to renal and vascular injury. Hypertension is also associated with metabolic disturbances including dyslipidaemia that manifests in obese patients who also have insulin resistance. These different pathways all represent potential targets for treatment, but also increase the challenge of multimodal pathophysiology.

Composite Filament Winding describes the engineering involved in the design and construction of filament-wound products and the processes and equipment by which they are made. It covers everything from the geometry, physics, and math of winding theory to best practices for handling fibers and resins. It explains how constituent materials and winding patterns influence production quality and costs, how to estimate variables such as laminate thickness and roving dimensions, and how to express fiber trajectories on curved surfaces using vector calculus and intuitive observations. It discusses the design and operation of filament winding systems, the origin of various processes, and test methods and procedures. It presents examples demonstrating accepted design practices and the consideration of factors such as stiffness, discontinuities, stress ratio, mandrel geometry, and process control. It also includes a glossary of related terms. For information on the print version, ISBN 978-1-61503-722-3, follow this link.

The well-known severity of cardiovascular disease in patients suffering from chronic kidney disease (CKD) requires an accurate risk stratification of these patients in several clinical situations. Imaging has been used successfully for such purpose in the general population and it has demonstrated excellent potential among CKD patients as well. Two main forms of arterial pathology develop in patients with CKD: atherosclerosis, with accumulation of inflammatory cells, lipids, fibrous tissue and calcium in the subintimal space, and arteriosclerosis. The latter is characterized by accumulation of deposits of hydroxyapatite and amorphous calcium crystals in the muscular media of the vessel wall, and is believed to be more closely associated with alterations of mineral metabolism than with traditional atherosclerosis risk factors. The result is the development of what appears to be premature arterial ageing, with loss of elastic properties, increased stiffness, and increased overall fragility of the arterial system. Despite intensifying research and increasing awareness of these issues, the underlying pathophysiology of the aggressive vasculopathy of CKD remains largely unknown. As a consequence, there are currently very limited pathways to prevent progression of vascular damage in CKD. The indications, strengths and weaknesses of several imaging modalities employed to evaluate vascular disease in CKD are described, focusing on coronary arterial circulation and the peripheral arteries, with the exclusion of the intracranial arteries.

Coronary heart disease (CHD) and stroke, collectively cardiovascular disease (CVD), are caused by narrowing and blockage of the arteries supplying the heart and brain, respectively. In type 2 diabetes (DM₂) insulin is insufficient to maintain normal blood glucose. South Asians have high susceptibility to these diseases. Drawing upon the scientific literature and discussions with 22 internationally recognized scholars, this book focuses on causal explanations and their implications for prevention and research. Genetically based hypotheses are considered together with the developmental origins of health and disease (DOHAD) family of hypotheses. The book then considers how CHD, stroke, and DM₂ are closely linked to rising affluence and the accompanying changes in life-expectancy and lifestyles. The established causal factors are shown to be insufficient, though necessary, parts of a convincing explanation for the excess of DM₂ and CVD in South Asians. In identifying new explanations, this book emphasizes glycation of tissues, possibly leading to arterial stiffness and microcirculatory damage. In addition to endothelial pathways to atherosclerosis an external (adventitial) one is proposed, i.e. microcirculatory damage to the network of arterioles that nourish the coronary arteries. In addition to the ectopic fat in their liver and pancreas as the cause of beta cell dysfunction leading to DM₂, additional ideas are proposed, i.e. microcirculatory damage. The high risk of CVD and DM₂ in urbanizing South Asians is not inevitable, innate or genetic, or acquired in early life and programmed in a fixed way. Rather, exposure to risk factors in childhood, adolescence, and most particularly in adulthood is the key. The challenge to produce focused, low cost, effective actions, underpinned by clear, simple, and accurate explanations of the causes of the phenomenon is addressed.

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.

Increased salt consumption is believed to induce high blood pressure (BP)-mediated organ damage, although it is not yet clear whether it reflects a generalized micro- and macrovascular malfunction independent of BP. Exceeding dietary sodium intake is acknowledged to be the main modifiable environmental risk factor for cardiovascular events that accounts for an increase in blood pressure and induces hypertension (HTN)-related target organ damage. Arterial stiffness is well known as an independent cardiovascular risk factor, and sodium intake may be a determinant of arterial stiffness. Even so, the studies that investigated the effect of dietary sodium reduction intake on arterial stiffness in humans provided inconclusive results. Therefore, we aim to perform a review of the available evidence of salt restriction and arterial stiffness and its impact on hypertensive patients.

Clinical osteoarthritis (OA) is a syndrome of joint pain associated with structural deterioration of synovial joints that over time involves the whole joint organ. It is the most common form of arthritis and a leading cause of chronic pain, disability, and socioeconomic burden. Affected individuals report pain (especially on weight bearing) and joint stiffness leading to loss of muscle strength and poor joint function. This results in reduced participation in valued activities, low mood, sleep disturbance, and poor quality of life. The aetiology of joint deterioration, pain, and the interaction of the two remains unclear. OA is associated with a variety of both modifiable and non-modifiable risk factors including obesity, age, gender, occupational injury, trauma, and genetic predisposition. Obesity is the strongest potentially modifiable risk factor.

At the beginning of the chapter, the desktop of the software, its toolbars, and main windows are introduced. Examples of interactive calculations with MATLAB® language are presented. Elementary functions, input and output commands, numbers and strings, vectors, matrices and arrays, flow control commands, relational and logical operators are discussed. Each command is presented in its most applicable form and with practical examples. At the end of each subsection, the commands studied are applied to elementary problems in the field of mechanical and tribological (M&T) sciences and technology, in particular to such as stress intensity factor, stiffness of a threaded bolt, adhesive force in contact between two spheres, and many others.

Musculoskeletal problems are common, affecting up to one in five people. People with musculoskeletal problems are frequently admitted to hospital and it is important for nurses working in hospital ambulatory care, emergency care, and on wards to understand the nature of musculoskeletal conditions in order to provide high-quality care. Patients may present with an acute medical or surgical illness, trauma, or bone disease (e.g. osteoporosis, degenerative arthritis, or inflammatory arthritis). A range of drugs treatments are given to improve symptoms of pain and stiffness. Drugs for inflammatory arthritis are given to modify the immune system, such as methotrexate or biologics (e.g. tumour necrosis factor inhibitors). Patients can be very disabled by their musculoskeletal condition and they have specific care needs. Safety during hospitalization and on discharge is important and key aspects are covered in this chapter.

The main forms of inflammatory arthritis are rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis. They are long-term disorders and consequently their prevalence increases with age; the lifetime risk of developing rheumatoid arthritis is over 3% in women. Their characteristic features comprise joint pain, swelling, and tenderness, morning stiffness, and general symptoms such as malaise. Polyarthritis is commoner in rheumatoid arthritis. The ESR and C-reactive protein levels are high in active arthritis. The main radiological finding is erosive disease. Symptomatic treatment includes analgesics and non-steroidal anti-inflammatory drugs. Disease-modifying drugs (DMARDs) change the course of these diseases; their main use is in rheumatoid arthritis. Biologic drugs help when other treatments are insufficient; they include tumour necrosis factor inhibitors which benefit all types of inflammatory arthritis, and other biologics targeting B- and T-cells are mainly used in rheumatoid arthritis. The risks of adverse events and drug toxicity are higher in elderly patients.

The effect of the laminate stacking factor on homopolar magnetic bearing performance is examined. Stacked laminates are used on the bearing rotor and in the stator. These laminate stacks have anisotropic permeability. Equations for the effect of the stacking factor on homopolar bearing position stiffness are derived. Numerical results are calculated and compared to measurements. These results provide an answer for the common discrepancy between test and theory for homopolar magnetic bearing position stiffnesses.

Abstract The stiffness of a spur gear tooth mesh controls load sharing in an operating gearset as well as vibratory properties which further dictate fatigue resistance and gear noise. A spur gear mesh consisting of a pinion with a single cracked tooth and an uncracked gear is considered. Expressions are presented which allow the determination of stress intensity factors for small through face width fatigue cracks in spur gear teeth. Predictions of tooth pair stiffness for a cracked pinion tooth and uncracked gear tooth pair are made using an analytical model. The model is based on elastic energy methods and fracture mechanics principles. The model employs a conformal mapping technique from elasticity theory, often denoted in spur gear applications as the complex potential method, in which a gear tooth is mapped onto an elastic half-plane.

An API 579-1/ASME FFS-1 Failure Assessment Diagram based Fitness-for-Service assessment was carried out on an embedded crack-like flaw found in a nozzle to shell weld in a pressure vessel. Stress intensity factors were initially calculated by utilizing stress results from a Finite Element Analysis (FEA) of an uncracked configuration, with the standard embedded crack stress intensity factor solution given in API 579-1/ASME FFS-1. Due to the complex nozzle geometry and flaw size, a second analysis was carried out, incorporating a crack into the FEA model, to calculate the stress intensity factors and evaluate if the standard solution could be applied to this geometry. A large difference in the resulting stress intensity factors was observed, with those calculated by the FEA with the crack incorporated into the model to be twice as high as those calculated by the standard solutions, indicating the standard embedded crack stress intensity factor solution may be non-conservative in this case. An investigation was carried out involving a number of studies to determine the cause of the difference. Beginning with an elliptical shaped embedded crack in a plate, the stress intensity factor calculated with an idealized 3D crack mesh agreed with the API 579-1/ASME FFS-1 solution. Examining other crack locations, and crack shapes, such as a constant depth embedded crack, revealed how the solution began to differ. The greatest difference was found when considering a crack mesh with a small component height (i.e. the distance measured perpendicular from the crack face to the top of the mesh). A close agreement was then found between the stress intensity factors calculated in the nozzle model and an idealized crack mesh with component heights representative of the true geometry. This revealed that reduced structural stiffness is a key factor in the calculation of the stress intensity factors for this geometry, due to the close proximity of the embedded crack to the inner surface of the nozzle. It was found that this reduction is potentially significant even with relatively small crack sizes. This paper details the investigation, and aims to provide the reader with an awareness of situations when the standard stress intensity factor solutions may no longer be valid, and offers general recommendations to consider when calculating stress intensity factors in these situations.

An analytical model of a composite structure consisting of an F2MC tube embedded in epoxy is used to study the impact of confining structural media on the ability of F2MC tubes to pump fluid and change stiffness. The surrounding stiff epoxy reduces the performance relative to an isolated F2MC tube, but this disadvantage can be minimized by tailoring the tube wall thickness and fiber angle. The composite can pump 250 times more fluid than a piston of the same diameter if the F2MC tube has a thick shell wall and a near-axial fiber orientation. With a moderately thick wall and low fiber angle, the closed valve axial stiffness can be increased by a factor of 2.2 relative to the open valve stiffness. The maximum pumping factor and modulus ratio, however, are 80% and 2.6% of the F2MC tube without the surrounding epoxy.