Thermodynamic stability of austenitic Ni-Mn-Cu cast iron

The performed research was aimed at determining thermodynamic stability of structures of Ni-Mn-Cu cast iron castings. Examined were 35 alloys. The castings were tempered at 900 °C for 2 hours. Two cooling speeds were used: furnace-cooling and water-cooling. In the alloys with the nickel equivalent value less than 20,0 %, partial transition of austenite to martensite took place. The austenite decomposition ratio and the related growth of hardness was higher for smaller nickel equivalent value and was clearly larger in annealed castings than in hardened ones. Obtaining thermodynamically stable structure of castings requires larger than 20,0 % value of the nickel equivalent

Sustainable Solutions for Human Security and Anti-Corruption: Integrating Theories and Practices

Corruption is a real issue affecting the understanding and practices promoting human security. This article introduces the frameworks of sustainable human security in relation to anticorruption. Human security is explored in its historical evolution and the more recent expansion of its frameworks, including the sustainability and systemic elements. The notion of sustainable human security is examined in relation to corruption and anti-corruption, as expressed in the current challenges and opportunities on sustainable development and human international development

Scale of Collieries and their Top-Level Management Capability in the Polish Coal Mining Industry: Recent Results

In this paper the following topics are considered: retrospective research into the effect of coal mine scale on its effectiveness; research results on the effect of the "system size" (coal mine) on the top-level management capability; and problem specifications for further research work in this area. The research results presented in this paper are part of the work accomplished within the IIASA project called "Coal -- Issues for the Eighties". Among others, elements of the IIASA concept "S-IOT" have been used

On Finite Element Computations of Contact Problems in Micropolar Elasticity

Within the linear micropolar elasticity we discuss the development of new finite element and its implementation in commercial software. Here we implement the developed 8-node hybrid isoparametric element into ABAQUS and perform solutions of contact problems. We consider the contact of polymeric stamp modelled within the micropolar elasticity with an elastic substrate. The peculiarities of modelling of contact problems with a user defined finite element in ABAQUS are discussed. The provided comparison of solutions obtained within the micropolar and classical elasticity shows the influence of micropolar properties on stress concentration in the vicinity of contact area

On strength analysis of highly porous materials within the framework of the micropolar elasticity

We discuss the finite element approach to modelling of static deformations of porous materials such as foams, beam lattices, and others within the linear micropolar elasticity. It is known that the micropolar elasticity may be used for microstructured solids and fluids since it can forecast size-effect near geometrical singularities such as holes, notches, small contact areas of two solids. Within the micropolar elasticity the translational and rotational interactions of the material particles can be taken into account. Here we present the recent developments in the theory of finite elements calculations for micropolar solids in order to capture the stress behaviour in the vicinity of geometric singularities such as holes, notches, imperfections or contact areas. The fundamental equations of the micropolar continuum are presented. The FEM implementation in micropolar elasticity is given. The new 8-node hybrid micropolar isoparametric element and its implementation in ABAQUS are introduced. The solutions of few 3D benchmark problems of the micropolar elasticity are given. Among them are analysis of stresses and couple stresses near notches and holes, contact problem of parabolic stamp and half space. The main attention is paid to modelling of interaction between a biodegradable porous implant and a trabecular bone. Comparison of classical and micropolar solutions is carefully discussed. Comparison of classical and micropolar solutions is discussed. Numerical tests have shown that couple stress appears almost in the vicinity of geometrical singularities. It is shown that micropolar elasticity allows to obtain better results for domains with microstructures and singularities than classical theory of elasticity

Leveraging limited data from wildlife monitoring in a conflict affected region in Venezuela

Efficient monitoring of biodiversity-rich areas in conflict-affected areas with poor rule of law requires a combination of different analytical approaches to account for data biases and incompleteness. In the upland Amazon region of Venezuela, in Canaima National Park, we initiated biodiversity monitoring in 2015, but it was interrupted by the establishment of a large-scale mining development plan in 2016, compromising the temporal and geographical extent of monitoring and the security of researchers. We used a resource selection function model framework that considers imperfect detectability and supplemented detections from camera trap surveys with opportunistic off-camera records (including animal tracks and direct sighting) to (1) gain insight into the value of additional occurrence records to accurately predict wildlife resource use in the perturbated area (deforestation, fire, swidden agriculture, and human settlements vicinity), (2) when faced with security and budget constraints. Our approach maximized the use of available data and accounted for biases and data gaps. Adding data from poorly sampled areas had mixed results on estimates of resource use for restricted species, but improved predictions for widespread species. If budget or resources are limited, we recommend focusing on one location with both on-camera and off-camera records over two with cameras. Combining camera trap records with other field observations (28 mammals and 16 birds) allowed us to understand responses of 17 species to deforestation, 15 to fire, and 13 to swidden agriculture. Our study encourages the use of combinations of methods to support conservation in high-biodiversity sites, where access is restricted, researchers are vulnerable, and unequal sampling efforts exist

Influence of molding and core sands matrix on the effectiveness of the microwaves absorption

The paper presents the results of applying microwaves to support the drying, redrying and hardening process of molding and core sands made of different types of matrix. In the tests of the microwave heating process a slot line measuring stand was used. Being based on the dielectric parameter measurement it enabled the evaluation of power losses of microwaves penetrating: chromite, magnesite, corundum, zircon and silica molding matrix samples. The survey revealed an impact of humidity and chemical compound of sands on microwave absorption. The study enabled the systematization of knowledge about the influence of selected types of matrix on the effectiveness of the microwave heating process

Shifting cultivation and hunting across the savanna-forest mosaic in the Gran Sabana, Venezuela: Facing changes

Background. Human encroachment and overexploitation of natural resources in the Neotropics is constantly increasing. Indigenous communities all across the Amazon, are trapped between a population rise and a hot debate about the sustainability of hunting rates. The Garden Hunting hypothesis states that shifting cultivation schemes (conucos) used by Amazon indigenous communities may generate favorable conditions, increasing abundance of small and medium wildlife species close to the `gardens' providing game for indigenous hunters. Methods. Here, we combined camera trap surveys and spatially explicit interview dataset on Pemón indigenous hunting scope and occurrence in a mosaic of savanna and forest in the Gran Sabana, Venezuela to evaluate to what extent the wildlife resource use corresponds to Garden Hunting hypothesis. We applied the Royle_Nichols model and binomial regression in order to: (1) assess whether abundance of small and medium wildlife species is higher close to conucos and (2) evaluate whether hunters select hunting localities based on accessibility to wildlife resources (closeness to conuco) more than wildlife abundance. Results. We find mixed evidence supporting the Garden Hunting hypothesis predictions. Abundance of small and medium species was high close to conucos but the pattern was not statistically significant for most of them. Pemón seem to hunt in locations dominated by forest, where species abundance was predicted to be higher, than in close vicinity to conucos. Hunting scope was focused on the most abundant species located close to the conuco (Cuniculus paca), but also in less abundant and unavailable species (Crax alector, Tapirus terrestris and Odocoileus virginianus). Conclusions. Our research provided the first attempt of a systematic sampling survey in the Gran Sabana, generating a quantitative dataset that not only describes the current pattern of wildlife abundance, but sets the base-line to monitor temporal and spatial change in this region of highland Amazon. We discuss the applicability of the estimates generated as a baseline as well as, environmental challenges imposed by economic, social and cultural changes such as mining encroachment for wildlife management. Subjects Anthropology, Biodiversity, Conservation Biology, Ecology, Natural Resource Management

Linear Micropolar Elasticity Analysis of Stresses in Bones under Static Loads

We discuss the finite element modeling of porous materials such as bones using the linear micropolar elasticity. In order to solve static boundary-value problems, we developed new finite elements, which capture the micropolar behavior of the material. Developed elements were implemented in the commercial software ABAQUS. The modeling of a femur bone with and without implant under various stages of healing is discussed in details.Рассматривается моделирование таких пористых материалов, как кость, методом конечных элементов с помощью линейной микрополярной теории упругости. Для решения статических краевых задач разработаны новые конечные элементы, которые воспринимают микрополярное поведение этого материала. Разработанные элементы были реализованы в коммерческом программном комплексе ABAQUS. Рассматривается моделирование бедренной кости с имплантатом и без него на различных стадиях заживлени