scholarly journals Criterion model of chemical stability under static conditions

The purpose of the investigation carried out is a definition of qualification express-tests parameters of chemical stability of hydrocarbon oxidation mixtures under static conditions. There was formed a criterion model assigned for the recalculation of express-tests results to operation conditions and including criteria of geometrical, thermo-dynamic and kinetic similarity. There was developed a procedure for parameterization of the model mentioned and synthesized a procedure of the recalculation mentioned based on the model of the bimolecular interaction of a hydrocarbon mixture with oxygen. A method for the account of the additional factors impact based on the factor planning of an experiment and allowing the choice of extremal conditions for maximum oxidation acceleration is offered. There is developed a procedure for a comparative check of the efficiency of the most efficient catalyst based on the application of Grubbs criterion. A similar approach may be used at the assessment of the significance of an irradiation impact, and in whole – for the transformation of multi-level planning into two-level one.

Author(s):  
Juan de Lara ◽  
Esther Guerra

AbstractModelling is an essential activity in software engineering. It typically involves two meta-levels: one includes meta-models that describe modelling languages, and the other contains models built by instantiating those meta-models. Multi-level modelling generalizes this approach by allowing models to span an arbitrary number of meta-levels. A scenario that profits from multi-level modelling is the definition of language families that can be specialized (e.g., for different domains) by successive refinements at subsequent meta-levels, hence promoting language reuse. This enables an open set of variability options given by all possible specializations of the language family. However, multi-level modelling lacks the ability to express closed variability regarding the availability of language primitives or the possibility to opt between alternative primitive realizations. This limits the reuse opportunities of a language family. To improve this situation, we propose a novel combination of product lines with multi-level modelling to cover both open and closed variability. Our proposal is backed by a formal theory that guarantees correctness, enables top-down and bottom-up language variability design, and is implemented atop the MetaDepth multi-level modelling tool.


Mathematics ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1259
Author(s):  
Francisco G. Montoya ◽  
Raúl Baños ◽  
Alfredo Alcayde ◽  
Francisco Manuel Arrabal-Campos ◽  
Javier Roldán Roldán Pérez

This paper presents a new framework based on geometric algebra (GA) to solve and analyse three-phase balanced electrical circuits under sinusoidal and non-sinusoidal conditions. The proposed approach is an exploratory application of the geometric algebra power theory (GAPoT) to multiple-phase systems. A definition of geometric apparent power for three-phase systems, that complies with the energy conservation principle, is also introduced. Power calculations are performed in a multi-dimensional Euclidean space where cross effects between voltage and current harmonics are taken into consideration. By using the proposed framework, the current can be easily geometrically decomposed into active- and non-active components for current compensation purposes. The paper includes detailed examples in which electrical circuits are solved and the results are analysed. This work is a first step towards a more advanced polyphase proposal that can be applied to systems under real operation conditions, where unbalance and asymmetry is considered.


2019 ◽  
Vol 9 (7) ◽  
pp. 1464 ◽  
Author(s):  
Alfonso Romero-Conrado ◽  
Jairo Coronado-Hernandez ◽  
Gregorio Rius-Sorolla ◽  
José García-Sabater

The definition of lot sizes represents one of the most important decisions in production planning. Lot-sizing turns into an increasingly complex set of decisions that requires efficient solution approaches, in response to the time-consuming exact methods (LP, MIP). This paper aims to propose a Tabu list-based algorithm (TLBA) as an alternative to the Generic Materials and Operations Planning (GMOP) model. The algorithm considers a multi-level, multi-item planning structure. It is initialized using a lot-for-lot (LxL) method and candidate solutions are evaluated through an iterative Material Requirements Planning (MRP) procedure. Three different sizes of test instances are defined and better results are obtained in the large and medium-size problems, with minimum average gaps close to 10.5%.


Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1827 ◽  
Author(s):  
Eva Contreras ◽  
Javier Herrero ◽  
Louise Crochemore ◽  
Ilias Pechlivanidis ◽  
Christiana Photiadou ◽  
...  

The operation feasibility of small hydropower plants in mountainous sites is subjected to the run-of-river flow, which is also dependent on a high variability in precipitation and snow cover. Moreover, the management of this kind of system has to be performed with some particular operation conditions of the plant (e.g., turbine minimum and maximum discharge) but also some environmental flow requirements. In this context, a technological climate service is conceived in a tight connection with end users, perfectly answering the needs of the management of small hydropower systems in a pilot area, and providing a forecast of the river streamflow together with other operation data. This paper presents an overview of the service but also a set of lessons learnt related to the features, requirements, and considerations to bear in mind from the point of view of climate service developers. In addition, the outcomes give insight into how this kind of service could change the traditional management (normally based on past experience), providing a probability range of the future river flow based on future weather scenarios according to the range of future weather possibilities. This highlights the utility of the co-generation process to implement climate services for water and energy fields but also that seasonal climate forecasting could improve the business as usual of this kind of facility.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yanina Chevtchouk ◽  
Cleopatra Veloutsou ◽  
Robert A. Paton

Purpose The marketing literature uses five different experience terms that are supposed to represent different streams of research. Many papers do not provide a definition, most of the used definitions are unclear, the different experience terms have similar dimensionality and are regularly used interchangeably or have the same meaning. In addition, the existing definitions are not adequately informed from other disciplines that have engaged with experience. This paper aims to build a comprehensive conceptual framework of experience in marketing informed by related disciplines aiming to provide a more holistic definition of the term. Design/methodology/approach This research follows previously established procedures by conducting a systematic literature review of experience. From the approximately 5,000 sources identified in three disciplines, 267 sources were selected, marketing (148), philosophy (90) and psychology (29). To address definitional issues the analysis focused on enlightening four premises. Findings This paper posits that the term brand experience can be used in all marketing-related experiences and proposes four premises that may resolve the vagaries associated with the term’s conceptualization. The four premises address the what, who, how and when of brand experience and aim to rectify conceptual issues. Brand experience is introduced as a multi-level phenomenon. Research limitations/implications The suggested singular term, brand experience, captures all experiences in marketing. The identified additional elements of brand experience, such as the levels of experience and the revision of emotions within brand experience as a continuum, tempered by repetition, should be considered in future research. Practical implications The multi-level conceptualization may provide a greater scope for dynamic approaches to brand experience design thus providing greater opportunities for managers to create sustainable competitive advantages and differentiation from competitors. Originality/value This paper completes a systematic literature review of brand experience across marketing, philosophy and psychology which delineates and enlightens the conceptualization of brand experience and presents brand experience in a multi-level conceptualization, opening the possibility for further theoretical, methodological and interdisciplinary promise.


2019 ◽  
Vol 8 (1) ◽  
pp. 69-96
Author(s):  
Armando Gallo Yahn Filho

 A globalização ampliou a participação de outros atores nas relações internacionais, tais como governos subnacionais e diversas instituições não governamentais (ONGs, empresas, universidades etc.). Nesse sentido, o objetivo deste trabalho é demonstrar, com um estudo de caso da inserção internacional de Uberlândia-MG, que uma cidade pode se internacionalizar com a participação de diversos atores, por meio de uma governança multinível. Ademais, tomando-se como referência a definição de cidade internacional, de Panayotis Soldatos – que aponta ser a paradiplomacia pública um dos critérios para se chegar a esta característica –, demonstra-se, também, o fato de que Uberlândia-MG vem avançando na sua internacionalização, mesmo sem a existência de uma paradiplomacia pública. Este trabalho também utiliza o método prospectivo de Michel Godet, a fim de criar um simples cenário de médio prazo para a inserção internacional de Uberlândia-MG, baseando-se nos chamados “fatos portadores de futuro”. Nesse sentido, ao se observar as ações que já vêm sendo colocadas em prática, por diversos atores, ao longo dos últimos 18 anos – ressaltando a criação, em 2017, de uma Câmara Técnica para fins de internacionalização, numa instituição municipal não governamental (o CODEN), com a participação do setor privado, das universidades, da sociedade civil e do governo municipal –, é possível visualizar um cenário de evolução, cada vez maior, dessa internacionalização, até o final da próxima década. Afinal, isso criou uma pressão natural sobre o governo municipal, a fim de que ele começasse a participar, efetivamente, dessa inserção internacional, por meio de uma paradiplomacia pública que também fortalecerá esse processo.     Abstract: The globalization process has expanded the participation of other actors in the international relations, such as subnational governments and many non-governmental institutions (NGOs, private corporations, universities etc.). In this sense, the objective of this paper is to demonstrate – taking a case study about the international insertion of Uberlândia City, in the State of Minas Gerais, Brazil – that a city can be International with the participation of many actors, through multi-level governance. Moreover, taking as reference Panayotis Soldatos´ definition of international city – which considers the public paradiplomacy as one of all factors needed to reach that characteristic –, it is also demonstrated the fact that Uberlândia City has evolved in its process of internationalization, even without the existence of a public paradiplomacy. This paper also utilizes some basic principles from the Michel Godet´s prospective method, in order to elaborate a simple mid-term scenario for the internationalization of Uberlândia City, based on the “fact bearer of future”. Then, observing many actions that have already been put into practice by several actors along the last 18 years – highlighting the creation of a Technical Chamber for internationalization, inside a local institution (CODEN), in 2017, which is composed by private sector, universities, civil society and local government –, it is possible to elaborate a scenario that indicates the evolution of this internationalization until the end of the next decade. Eventually, it was created a natural pressure on the municipal government to participate effectively in the process of international insertion, elaborating a public paradiplomacy, which will further strengthen this process.         Keywords: Subnational actors, internationalization of cities, public paradiplomacy, multi-level governance, Uberlândia City.     Recebido em: agosto/2018.Aprovado em: novembro/2018.


2021 ◽  
Vol 9 ◽  
Author(s):  
L. Lauren Brown ◽  
Erika G. Martin ◽  
Hannah K. Knudsen ◽  
Heather J. Gotham ◽  
Bryan R. Garner

The COVID-19 pandemic has adversely affected people with HIV due to disruptions in prevention and care services, economic impacts, and social isolation. These stressors have contributed to worse physical health, HIV treatment outcomes, and psychological wellness. Psychological sequelae associated with COVID-19 threaten the overall well-being of people with HIV and efforts to end the HIV epidemic. Resilience is a known mediator of health disparities and can improve psychological wellness and behavioral health outcomes along the HIV Continuum of Care. Though resilience is often organically developed in individuals as a result of overcoming adversity, it may be fostered through multi-level internal and external resourcing (at psychological, interpersonal, spiritual, and community/neighborhood levels). In this Perspective, resilience-focused HIV care is defined as a model of care in which providers promote optimum health for people with HIV by facilitating multi-level resourcing to buffer the effects of adversity and foster well-being. Adoption of resilience-focused HIV care may help providers better promote well-being among people living with HIV during this time of increased psychological stress and help prepare systems of care for future catastrophes. Informed by the literature, we constructed a set of core principles and considerations for successful adoption and sustainability of resilience-focused HIV care. Our definition of resilience-focused HIV care marks a novel contribution to the knowledge base and responds to the call for a multidimensional definition of resilience as part of HIV research.


2021 ◽  
pp. 171-180
Author(s):  
Alexandra Ugryumova ◽  
◽  
Lyudmila Pautova ◽  

The level of professional development of personnel is a determining resource for the effectiveness of land reclamation industry and the agro-industrial complex, since the availability and level of development of modern competencies by the workforce largely determine the competitiveness of industry organizations and land reclamation in general. The purpose of the paper is to study the scientific and methodological features and technologies of the system of modern additional professional education of land reclamation personnel, to find reserves for its development. The scientific novelty of research lies in the definition of a complex of organizational and scientific-methodological approaches to the management of additional professional education of the personnel in the industry of land reclamation. The following research methods were used: theoretical analysis, systematization of scientific and methodological materials on additional professional education system, logical and situational analysis, methods of processing and generalization of results. Based on the results of scientific and practical analysis, the structural and content indicators of the readiness of programs of additional professional education of reclamation personnel are determined, a set of scientific and methodological approaches to the implementation of educational programs of additional professional education and the mechanism of sectoral multi-level professional and educational interaction between organizations implementing professional education programs for the reclamation sector of the agro-industrial complex are proposed. The elements of this interaction in the development and implementation of educational programs of additional professional education in the reclamation industry are specified. The following conclusions are drawn. In the course of the conducted scientific and practical research of scientific and methodological features of additional professional education of land reclamation personnel, an attempt is made to solve the problem of scientific, methodological and methodological support for industrial additional education. A mechanism for multi-level professional and educational interaction between industry organizations was developed. The results of this study may be of interest to the heads of organizations that implement additional professional education programs for specialists of the agro-industrial complex, specialists in the field of continuing education.


2020 ◽  
Author(s):  
C Atkinson ◽  
R Gerbig ◽  
Thomas Kuehne

Structural models are often augmented with additional well-formedness constraints to rule out unwanted configurations of instances. These constraints are usually written in dedicated constraint languages specifically tailored to the conceptual framework of the host modeling language, the most well-known example being the OCL constraint language for the UML. Many multi-level modeling languages, however, have no such associated constraint language. Simply adopting the OCL for such multi-level languages is not a complete strategy, though, as the OCL was designed to support the UML's two-level class/instance dichotomy, i.e., it can only define constraints which restrict the properties of the immediate instances of classes, but not beyond. The OCL would consequently not be able to support the definition of deep constraints that target remote or even multiple classification levels. In fact, no existing constraint language can address the full range of concerns that may occur in deep modeling using the Orthogonal Classification Architecture (OCA) as an infrastructure. In this paper we consider what these concerns might be and discuss the syntactical and pragmatic issues involved in providing full support for them in deep modeling environments.


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