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In this work a comprehensive theoretical and numerical study on the cyclic elastic–plastic notch stress and strain distributions is carried out. In more detail, the incremental cyclic plasticity theory, already proposed by other authors to determine the actual stress and strain state arising in two-dimensional or axis-symmetric notched components, is extended to the study of three dimensional effects at the tip of rounded notches in plates of finite thickness. The analytical frame is initially validated considering some bi-dimensional problems and later modified to consider the out-of-plane 3D-effects. Different notch geometries and loading conditions are investigated, such as axis-symmetric specimens weakened by a circumferential U-notch, subjected to cyclic torsional and multiaxial (tension–torsion) in-phase loading, and plane specimens with finite thickness, weakened by rounded V-notches and subjected to cyclic mode II loading. A nominal load ratio R = −1 has been taken into account in all cases. Theoretical results based on the incremental cyclic plasticity theory are compared with time-consuming elastic–plastic finite element analyses carried out with a commercial FE code showing a very satisfactory agreement. Finally, a link between the averaged strain energy density (SED) criterion and the area inside the hysteresis loops tied to the different stress and strain components acting at the notch tip has been investigated.

The effect of out-of-phase loadings in multiaxial fatigue is still an open problem which is of interest for engineers and researchers engaged with design against fatigue. In the present contribution, the effect of the phase angle on sharp V-notches subjected to multiaxial fatigue loading is theoretically studied with an analytical frame based on the maximum shear stress averaged over an entire fatigue cycle. The formulation is applicable as it stands to varying V-notch opening angles, biaxiality ratios and phase angles. The proposed frame has in common with critical plane approaches, which in principle cannot be straightforwardly applied to sharp V-notches, the consideration of the shear stress as critical parameter but uses the notch stress intensity factors to describe the asymptotic stress distributions in the highly stressed region surrounding the V-notch tip. Based on linear elastic stress fields, the frame does not take into account the non-linear effects related to cyclic plasticity. Some considerations on the effect of the phase angle can be drawn on the basis of the obtained results. The main conclusion is that the phase angle plays a non-negligible effect on the fatigue strength of pointed notches. This effect is strongly influenced by the biaxiality ratio.

The work deals with multiaxial fatigue strength of notched round bars made of 40CrMoV13.9 steel and tested under combined tension and torsion loading, both in-phase and out-of-phase. The axis-symmetric V-notches present a constant notch root radius, 1 mm, and a notch opening angle of 90°; the notch root radius is equal to 4 mm in the semi-circular notches where the strength in the high cycle fatigue regime is usually controlled by the theoretical stress concentration factor, being the notch root radius large enough to result in a notch sensitivity index equals to unity. In both geometries the diameter of the net transverse area is 12 mm. The results from multi-axial tests are discussed together with those obtained under pure tension and pure torsion loading from notched specimens with the same geometry. Altogether more than 120 new fatigue data are summarised in the present work, corresponding to a one-year of testing programme. All fatigue data are presented first in terms of nominal stress amplitudes referred to the net area and then re-analysed in terms of the mean value of the strain energy density evaluated over a given, crescent shape volume embracing the stress concentration region. For the specific steel, the radius of the control volume is found to be independent of the loading mode.

It is well known that in cracked plates under in-plane shear loading, an induced out-of-plane mode, due to the Poisson's effect, is automatically generated. Some recent studies have shown the importance of this coupled mode (called mode O) in plates weakened by sharp V-notches characterized by different notch opening angles. Particular attention has been paid to the scale effect focusing also on the implications of the coupled mode to different material scale levels. Also when the notch root radius is different from zero, the out-of-plane mode continues to exist, and its intensity with respect to the generating mode depends on the notch radius and the plate thickness. Aim of this paper is to discuss the main features of the out-of-plane mode dealing with three-dimensional plates weakened by blunt notches. In particular, some results from blunt V-notches, circular and elliptic holes are discussed in detail and presented here. The main key-point highlighted in the present contribution is that always three-dimensional effects exist in finite thickness plates, because mode I, II and III cannot exist in isolation. The importance of induced modes varies from case to case and depends on the geometry of the component and on the externally applied load. These effects cannot be neglected a priori even if, in some cases, they may be negligible.

Dealing with the material microstructure an analytical multiscale model has recently been developed by Sih. Physically, the different orders of the stress singularities are related to the different constraints associated with the defect thought as a microscopic V-notch at the tip of the main crack. Irregularities of the material microstructure tend to curl the crack tip being the clamped-free boundary conditions the more realistic and general representation of what occurs on the microscopic V-notch. As a result, mixed mode conditions are always present along the V-notch bisector line. It is known for a long time that at the antisymmetric (mode II) stress distribution ahead of the crack tip generates a coupled out-of-plane singular mode. Recent theoretical and numerical analyses have demonstrated that this out-of-plane mode due to three-dimensional effects occurs also in the case of large V-notches where the mode II stress field is no longer singular. In addition, when the notch opening angle is non-zero, the three-dimensional singular stress state is strongly influenced by the plate thickness. The aim of this paper is to investigate the effect of free-fixed boundary conditions along the notch edges in three dimensional plates weakened by pointed V-notches and quantify the intensity of the out-of-plane singularity occurring under this constraint configuration. For the sake of simplicity a macronotch is considered rather than a micronotch. A synthesis of the magnitude of the stress state through the plate thickness is carried out by using the mean value of the strain energy density over a given control volume embracing the notch tip. The capability of the strain energy density to capture all the combined effects due to the out-of-plane mode make it a powerful parameter at every scale levels.

On the mode O existence in three-dimensional plates weakened by circular and elliptical holes under mode II loading It is known for long time that in a cracked plate subjected to anti-symmetric plane loading, the Poisson’s effect leads to the generation of a coupled out-of-plane singular mode (Mode O). Recent theoretical and numerical analyses have shown that this effect is present also in plates weakened by pointed V-notches and might play a role in failure initiation phenomena in plates under mode II loading particularly in the presence of large opening angle. Since the degree of singularity characterising the mode O is greater than that of mode II, the mutual incidence of the two modes depends on the component size. Dealing with circular and elliptic holes, the presence or not of the out-of-plane mode has never been discussed in the literature. The main aim of this work is to demonstrate the existence of a three-dimensional effect tied to mode O. On the basis of a large bulk of numerical results the following conclusions can be drawn: - An out-of-plane mode is present in plates weakened by U-notches and subjected to Mode II loading, as previously demonstrated for plates weakened by cracks and pointed V-notches; its intensity is not negligible also for finite values of the notch radius. - Out-of-plane mode results in a shear stress distribution symmetric with respect to the mid-plane. The intensity of this stress component strongly depends on the Poisson’s ratio. It increases as increases. - The strain energy density averaged on a given control volume which should, in principle, be material dependent is a parameter suitable for the natural of capture all three dimensional effects occurring through the plate thickness. It is surely a powerful tool in practical cases where the role played by three-dimensionality is not negligible, or is not known in detail.

Avaliou-se, neste trabalho, a estrutura de um fragmento florestal antropizado denominado Mata das Galinhas, Engenho Humaitá, Catende, Pernambuco, e se utilizaram, para avaliar a composição florística e a estrutura fitossociológica, 14 parcelas de 10 x 25 m a fim de amostrar os indivíduos arbóreos com circunferência a 1,30 m do solo (CAP) ≥ 10 cm. Foram estimados, então, densidade, frequência e dominância e valor de importância (VI) e o índice de Shannon, além de registrados 438 indivíduos pertencentes a 63 espécies, 45 gêneros e 29 famílias. As famílias de maior importância foram Mimosaceae, Moraceae, Anacardiaceae e Lecythidaceae e as espécies com maiores valores de VI, foram Brosimum discolor, Parkia pendula, Eschweilera ovata, Thyrsodium spruceanum, Tapirira guianensis, Protium heptaphyllum, Casearia arborea, Helicostylis tomentosa, Dialium guianense, Schefflera morototoni, Himatanthus phagedaenicus e Cupania racemosa. Quando observado isoladamente, conclui-se que o fragmento estudado possui pouca relevância; entretanto, se considerado conjuntamente com outros fragmentos da área, sua diversidade é significativa o que justificaria esforços para sua conservação e manejo.The structure of a forest fragment, known as "Mata das Galinhas" at Humaitá sugar mill, Catende, Pernambuco, Brazil was evaluated. To evaluate the floristic composition and the phytosociological structure under anthropic action 14 plots of 10 x 25 m were used to sample the arboreal individuals with circumference at breast height (CBH) ≥ 10 cm. The density, frequency, and dominance, the importance value (IV) and the Shannon's index were calculated. A total of 438 individuals distributed into 63 species, 45 genera and 29 families were recorded. The families of larger importance in the study were Mimosaceae, Moraceae, Anacardiaceae and Lecythidaceae. The species with larger values of IV were Brosimum discolor, Parkia pendula, Eschweilera ovata, Thyrsodium spruceanum, Tapirira guianensis, Protium heptaphyllum, Casearia arborea, Helicostylis tomentosa, Dialium guianense, Schefflera morototoni, Himatanthus phagedaenicus and Cupania racemosa. When observed separately, the studied fragment possesses low relevance; however, when considered jointly with other fragments of the area, its diversity is significant, justifying efforts for conservation and management.

Objetivou-se, neste trabalho, analisar a estrutura diamétrica do componente arbóreo de um fragmento de Floresta Atlântica inserido em uma matriz de cana-de-açúcar, utilizando-se o quociente "q" de De Liocourt. O estudo foi realizado no fragmento denominado Mata das Caldeiras, no município de Catende, Pernambuco. Os indivíduos amostrados foram distribuídos em classes de diâmetro com amplitude de 5 cm, em que o centro da primeira classe tem o valor de 6,5 cm. Com o uso do quociente "q" de De Liocourt, aqui empregado, construíram-se as curvas de distribuição diamétrica, observadas e estimadas para a amostragem geral e para as espécies de maior Valor de Importância (VI). O fragmento Mata das Caldeiras apresentou déficit de árvores nas classes de diâmetro, geral e por espécies de maior VI, comparado a uma floresta balanceada. O quociente "q" de De Liocourt pode ser usado para avaliar estrutura diamétrica em fragmentos de Floresta Atlântica. Por meio da distribuição diamétrica e dos valores de "q" obtidos para o estágio de sucessão em que se encontram as áreas, pode-se inferir que o grau de perturbação nesses fragmentos ocorre de forma constante.This work aimed to analyze the diametric structure of arboreous component in an Atlantic Rain Forest fragment using De Liocourt quotient "q". The study was carried out at the Atlantic Rain Forest fragment, called Mata das Caldeiras, in Catende municipality, Pernambuco State, Brazil. The sampled individuals were distributed in class diameters with amplitude of 5 cm, with the first class having a value of 6.5 cm. Using the quotient "q" of De Liocourt the curves of diametric distribution, observed and estimated, were constructed, for the whole fragment and for species of higher Importance Value (VI). The fragment Mata das Caldeiras showed a deficit of trees in the diameter classes, generally and for species of greater VI, compared with a balanced forest. The De Liocourt quotient "q" may be used to evaluate diametric structure in fragments of Atlantic Forest. By the diametric distribution and obtained values of "q", for the period of succession found in the areas, it can be inferred that the degree of disturbance in these fragments occurs in a consistant manner.

Ozonolysis has proved its efficiency as a lignocellulosic biomass pretreatment, improving the production of second-generation biofuels such as ethanol, methane and hydrogen. Ozone is a powerful oxidant, highly reactive toward compounds with high electron densities, such as lignin. Ozone solubilizes and degrades the lignin and modifies the biomass structure, improving the yield of released sugar. The principal inhibitors generated from the ozonolysis of biomass are acetic, formic, and oxalic acids, whereas furfural and 5-hidroxymethylfurfural have not been detected. The inhibitors are efficiently removed by water washing. Process parameters such as reactor design, moisture, particle size, pH, ozone concentration, ozone/air flow and reaction time have a remarkable influence on process efficiency through factors such as ozone consumption, composition of the pretreated biomass, yields of sugar release and the formation of inhibitory compounds. Additional research is necessary to optimize ozonolysis pretreatment and achieve economic feasibility for the process by applying the biorefinery concept.

In this work, a comprehensive theoretical and numerical study on the cyclic elastic–plastic notch stress and strain distributions is carried out. In more detail, the incremental cyclic plasticity theory, already proposed by other authors to determine the actual stress and strain state arising in two-dimensional or axisymmetric notched components, is extended to the study of three-dimensional effects at the tip of rounded notches in plates of finite thickness. The analytical frame is initially validated considering a number of plane problems and later modified to consider three-dimensional effects. Different notch geometries are investigated, such as plane specimens with finite thickness weakened by circular holes, U-notches and rounded V-notches subjected to cyclic mode-I loading. Theoretical results based on the incremental cyclic plasticity theory are compared with time-consuming elastic–plastic finite element analyses carried out with a commercial finite element code showing a very satisfactory agreement. Finally, a link between the averaged strain energy density criterion and the area subtended by the hysteresis loops tied to the different stress and strain components acting at the notch tip has been investigated.

Aim The aim of this observational study was to assess mortality of patients with type 2 diabetes by type of healthcare delivery system, i.e. through specialist centers or generalist doctors, or integrated care. Methods The study was conducted at the “Vicentino Ovest” Local Health District in the Veneto Region (north-eastern Italy) from January 1, 2008 to December 31, 2010. Patients with diabetes (≥20 years old) were identified using different public health databases. They were grouped as: patients followed up by specialists at diabetes clinics (DS); patients seen only by their own general practitioner (GP); and patients receiving integrated care (DS-GP). Cox's regression analysis was used to estimate adjusted hazard ratios for available potential predictors of death by level of care. Results The crude mortality rate was highest in the GP group (26.1 per 1000 person-years), the difference being minimal when compared with the DS group (21.7 per 1000 person-years) and more marked when compared with the DS-GP group (8.8 per 1000 person-years). Patients followed up by their GPs had a 2.7 adjusted RR for mortality by comparison with the DS-GP group. Conclusions The findings of the present study could demonstrate that it is safe and cost-effective, after a first specialist assessment at a diabetes service, for low-risk diabetic patients to be managed by family physicians as part of a coordinated care approach, based on the specialist's clinical recommendations; GPs can subsequently refer patients to a specialist whenever warranted by their clinical condition.

Brittle fracture of isostatic polycrystalline graphite is studied experimentally, theoretically and numerically using U-notched samples under mode I and mixed mode loading (I + II) considering different combinations of the notch radius and the tilt angle of the notch. An experimental programme was performed to provide a new set of results. In total 60 new data are provided in the paper. The averaged value of the strain energy density over a control volume is used to assess the static strength of the specimens subjected to different mode mixities. The volume is centred where the principal stress reaches its maximum value on the notch edge, by rigidly rotating the crescent-shaped volume already used in the literature to analyse U- and V-shaped notches subject to mode I loading. The volume size depends on the fracture toughness and the ultimate tensile strength of the material. Good agreement is found between experimental data and theoretical predictions based on the constancy of the mean strain energy density over the control volume.