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The paper presents three operative models whose purpose is to improve the practice of preventive maintenance to a wide range of technical installations. Although the calculation criteria are different, the goal is the same: to determine the optimum time between two consecutive preventive interventions. The optimum criteria of these models are: - the maximum share of technical entity operating probabilities, in the case of the Ackoff - Sasieni [1] method; -the optimum time interval for preventive verification depending on the preventive-corrective maintenance costs imposed by the deciding factor, for the AsturioBaldin [2] model; - the minimum number of renewals – preventive and/or corrective maintenance operations [3]

This paper is presenting a method used to confirm the necessity of practicing maintenance works for two vehicles, tramways, whose operational statuses, defined by the levels of exploitation parameters, proved to be in precarious condition. Wear and tear has been the main cause leading to the occurrence of unnumbered moments when the vehicles were unavailable. Studies performed on data collected during a compelling enough period of time are highlighting, a tendency to increase the failure frequency with more than 10%. The wear and tear of the analyzed technical equipment is expressed by the status probabilities that are related to a later moment, and determined by using Markov chain theory, and entropic level - unit of measure for incertitude or chaos - phenomenons that are specific for system degradation - to be determined based on Shannon entropy concept[7],[11]. Based on these two sizes, the decision-maker may impose the optimal strategy regarding the maintenance works practice.

The present paper investigates and compares the performance of three configurations of Gas Turbine systems allowing cogeneration of heat and electricity, on the basis of an irreversible regenerative Brayton-Joule cycle. The proposed model is developed for two different cycle constraints, namely, an imposed heat transfer rate released by the fuel combustion, or an imposed maximum cycle temperature. The model also includes the irreversibility due to the friction in the compressor and turbine, and due to the heat losses in the combustion chamber and heat exchangers. Energy efficiency for the system without and with cogeneration, and the exergetic efficiency are used in order to emphasize the cogeneration advantages, but also to help the designer to choose the best configuration of the Gas Turbine system that suits to his needs. Experimental data from a real operating microturbine were used to validate the model. The power output and the energy and exergetic efficiencies are optimized with respect to a set of operating parameters. The optimum values of the Gas Turbine engine parameters corresponding to maximum power output and respectively to maximum thermodynamic efficiency are discussed. The results show same optimal values of the compression ratio corresponding to almost all maximum performances for an imposed heat transfer rate released by the fuel combustion, excepting the maximum exergetic efficiency that requires higher optimal values of the compression ratio than the maximum exergy rate one. A performance comparison of the three configurations is done and future perspectives of the work are proposed. Cet article explore et compare les performances des trois configurations de systèmes de turbine à combustion permettant la production combinée de chaleur et d’électricité, sur la base du cycle irréversible régénératif de Brayton-Joule. Le modèle proposé est développé pour deux contraintes différentes sur le cycle, notamment le flux de chaleur produit par combustion imposé ou la température maximale du cycle imposée. Le modèle considère également l’irréversibilité due au frottement dans le compresseur et la turbine et celle due aux pertes de chaleur dans la chambre de combustion et les échangeurs de chaleur. Le rendement au sens du premier principe du système sans et avec cogénération et le rendement exergétique rendent compte des avantages de la cogénération, et aident le concepteur à choisir la meilleure configuration de turbines à combustion en fonction de ses besoins. Des données expérimentales d’une microturbine opérationnelle ont été utilisées pour valider le modèle. La puissance fournie et les rendements au sens du premier principe et exergétique sont optimisés par rapport à un ensemble de paramètres de fonctionnement. Les valeurs optimales des paramètres du moteur à turbine à combustion qui correspondent au maximum de puissance fournie, respectivement au maximum de rendement thermodynamique sont discutées. Les résultats montrent que la plupart des performances maximales correspondent aux mêmes valeurs optimales du taux de compression pour le flux imposé, sauf le rendement exergétique maximum qui demande des valeurs plus élevées du taux de compression que celles pour le maximum du flux d’exergie. Une comparaison des performances de ces trois configurations et les perspectives sont proposées.

In present-day dialogues pertaining to the stewardship of the environment, the essential interconnectedness between the management of resources sustainably and the conservation of biodiversity has surfaced as an issue of considerable significance. The efficacious overseeing of natural resources, which includes both ecosystems found on land and in water, is fundamentally necessary for the preservation of the fragile equilibrium that supports the resilience of ecosystems. The intensifying pressures stemming from climate change, urban expansion, and the exploitation of resources compel the adoption of novel strategies which must not only safeguard the resource availability for forthcoming generations but also actively advance the well-being of ecological systems. This discourse will delving into the complex interrelation between practices of sustainable resource management and their repercussions on biodiversity, positing that an all-encompassing approach is crucial. By amalgamating principles of ecology with considerations rooted in socio-economics, it is plausible to bolster the resilience of ecosystems that are progressively susceptible to human-induced influences. In conclusion, the discussion will elucidate potential routes toward a future characterised by sustainability, emphasising the recognition that the health and vitality of our natural resources are fundamentally intertwined with biodiversity and the stability of ecosystems. A crucial component of the safeguarding of ecological integrity pertains to the sustainable administration of natural resources, which is characterised as the action of utilising these resources in a way that addresses current demands without endangering the capacity of subsequent generations to satisfy their own. This necessitates the equilibrium of ecological, economic, and social imperatives, thereby enhancing biodiversity and the resilience of ecosystems. [ABSTRACT FROM AUTHOR]

The role of farmers in the modern era is both pivotal and complex, as they stand at the nexus of food production, environmental stewardship, and economic sustainability. This abstract delves into the multifaceted challenges and pressing issues that confront farmers in this dynamic landscape. In an era defined by rapid technological advancements, shifting consumer demands, environmental concerns, and global market dynamics, the modern farmer faces a unique set of challenges. In the intricate web of our contemporary world, the role of farmers emerges as nothing short of pivotal, and yet their journey is one that traverses a landscape as intricate as the crops they cultivate. The modern farmer, often obscured beneath the broad brim of a sun-worn hat, is a figure who carries the aspirations of a global society—a society demanding sustenance, stewardship, and stability. Modern farmers find themselves at the confluence of diverse challenges that shape the dynamics of contemporary agriculture. This abstract provides a concise overview of the critical issues that weigh on the minds and shoulders of those who till the soil and tend to livestock. In an era marked by technological innovation, shifting consumer preferences, environmental concerns, and global market fluctuations, the challenges facing modern farmers are both intricate and pressing. In conclusion, modern farmers confront a complex web of challenges, including technological disparities, environmental sustainability, consumercentric farming, economic uncertainties, rural depopulation, and policy advocacy. Their journey is one of adaptation and resilience as they navigate the evolving landscape of agriculture and its multifaceted challenges. [ABSTRACT FROM AUTHOR]

Many today’s scientists think that religion can never come to terms with science. In sharp contrast to the widespread opinion, the authors of this paper consider that historically scientific reasoning and religious belief joined hands in their effort to investigate and understand reality. In fact, the current divorce between science and religion is nothing else than the final outcome of a gradual long-term, and deliberately assumed process of science secularization of science. However, especially during the last decades, we have all been equally confronted with the advance of a new concern over the fact that contemporary scientists have been approaching an area of investigation that had been usually addressed by the theological thought. This recent development has generated an emerging new field of investigation of Science and Religion within modern scientific epistemology.Against this background, the purpose of this paper is three-fold: firstly, to briefly emphasize that one of the defining dimensions of the dialogue between science and religion is given by the discontinuity, in which, the knowledge acquired through scientific reasoning is placed in relation to the divinely revealed knowledge; secondly, to argue that another defining dimension of the dialogue consists in the hierarchical harmony mediating the encounter between the two, thus transgressing the discontinuity and making the dialogue between theology and science possible and viable; and thirdly, to advocate the idea that the apodictic method (based on antinomic logic) can successfully structure such a dialogue.

Climatic aggressiveness is one of the most important factors in relief dynamic. Of all climatic parameters, rainfall is directly involved in versant dynamic, in the loss of soil quality and through pluvial denudation and the processes associated with it, through the erosivity of torrential rain. We analyzed rainfall aggressiveness based on monthly and annual average values through the Fournier's index (1970) and Fournier's index modified by Arnoldus (1980). They have the advantage that they can be used not only for evaluating the land susceptibility to erosion and the calculation of erodibility of land and soil losses, but also in assessing land susceptibility to sliding (Aghiruş, 2010). The literature illustrates the successful use of this index which provides a summary assessment of the probability of rainfall with significant erosive effects. The results obtained allow observation of differences in space and time of the distribution of this index. [ABSTRACT FROM AUTHOR]

This article approaches the methodology of designing customized footwear for high arched foot. The authors propose to reconsider the classical structure of footwear bottom components for people with high arched foot and recommend incorporating custom components, with the role of compensation or adjustment. This study continues the authors’ research, starting from a foot’s 3D shape obtained by 3D scanning, the anthropometrical and biomechanical parameters, shoe lasts’ 3D modelling and continuing with 3D footwear design. Including customized orthosis can help to stop the evolution of abnormalities, diminishes sensations of pain during walking and improves performance in various physical activities carried out during the day, walking, running, and standing. The prophylactic footwear has to meet four main requirements: to protect the foot and ankle during walking and static; to ensure the normal resistance systems (bones), muscle and joint of the foot; to prevent the installation of irreversible structural changes by reducing stress on the foot; to contribute to increased performance in conducting regular physical activity. It is presented the steps of modelling an orthosis, a virtual simulation of its cutting process, followed by the integration and development of the insole, filling and sole for a customized shoe. Delcam Crispin CAD system and its applications for orthopaedics are used to design the bottom components of prophylactic footwear for a high arched foot.

This paper presents a method to evaluate the durability of a batch of electrical starters, fitted on buses used by the public transportation company of the municipality of Oradea. These starters have a short transient working regime, characterized by frequent start-stop usage, especially during the cold season. Based on statistical sample obtained from the exploitation documentation, it was proven that the temporal evolution of these starters is characterized by a Weibull model, but with a conspicuos tendincy towards the Rayleigh version - a distinctive model of equipments that have an operational regime characterized by strong attrition. Also, this paper analyzes the topic of acquiring this sort of equipments based on preliminary testing. These tests are meant to assess the probable durability level of these operational entities. [ABSTRACT FROM AUTHOR]

This paper presents some of thepreliminary results of the anemometricalmeasurements campaign on the hill areas. These areascould benefit from the installation of some smalldimension wind generators.The analysis refers to areas known as “marginal”,that is, they have an energetic density and mediumspeed that do not really justify, from an economic pointof view, the investment in a high dimension windstation. (according to a vague classification, the areasconsidered “poor” have less than 200W/m2 and the“marginal” areas have between 200 and 300W/m2).The final decision will be determined by the windstatistic analysis from the areas of this type, with thehelp of Weibull distribution and some other parametersdesignated to quantify the zone turbulence. It will bedemonstrated how one of the most interestingcharacteristic of this area type, that is the highenergetic density of the speed distribution “heads” issignificant and not only the relatively small value ofthe medium speed.