Theoretical Assessment Research Articles

Theoretical performance assessment of a multi-effect distillation system integrated with thermal vapour compression unit running on solar energy

Abstract Mathematical models can be successfully applied to predict the multi-effect distillation system integrated with thermal vapour compression unit (MED-TVC) performance under different operating conditions. In this work, a one-dimensional (1-D) mathematical model was developed to perform the theoretical analysis of a small-scale parallel feed MED-TVC desalination system driven by solar heat. A parametric study was conducted allowing the ejector motive steam temperature, first effect temperature, between effects temperature difference and ejector compression ratio to vary within an expectable range. The results showed that higher motive steam temperatures, had a positive impact on the water yield up to an optimal point. Any additional increase of driving steam temperature reduced water yield. Gain output ratio ($GOR$) was maximum at the highest considered motive temperature. It was found that the calculated specific heat transfer area does not depend on the motive temperature variation. Water yield, $GOR$ and specific heat transfer area decrease with the ejector compression ratio. The temperature difference between the evaporator effects had no effect on the water yield and $GOR$. It only decreases the specific heat transfer area. First effect temperature should be as low as possible with respect to operational constraints. Based on the parametric study, the optimal design operating conditions, corresponding to the maximum water yield is identified for a small-scale three-effect desalination system. The unit can produce up to 204 l/h drinking water with a gain output ratio of 8.6 and specific heat transfer area of 575 m2/kg/s using about 22 kW of solar heat.

Efficiency of Simulation-Based Learning Using an ABC POCUS Protocol on a High-Fidelity Simulator.

Critically ill patients with rapidly deteriorating clinical status secondary to respiratory and cardio-vascular compromise are at risk for immediate collapse if the underlying pathology is not recognized and treated. Rapid diagnosis is of utmost importance regardless of the setting. Although there are data to support the use of point-of-care ultrasound in critical patients, there is no consensus about the best educational strategy to implement. We designed a curriculum based on the ABC (Airway, Breathing, Circulation) protocol that covers essential airway, lung, and cardiac ultrasound skills needed for fast diagnosis in critical patients and applied it in high-fidelity simulation-based medical education sessions for anesthesia and intensive care residents year one and two. After theoretical and practical assessments, our results show statistical differences in the theoretical knowledge and above-average results in practical assessment. Our proposed curriculum based on a simple ABC POCUS protocol, with an Airway, Breathing, and Circulation approach, is useful in teaching ultrasound basics regarding airway, lung, and cardiac examination using high-fidelity simulation training to anesthesia and intensive care residents, but further research is needed to establish the utility of Simulation-Based Medical Education in Point of Care Ultrasound in the critical patient.

Nutrient recovery from wastewater for hydroponic systems: A comparative analysis of fertilizer demand, recovery products, and supply potential of WWTPs

Nutrient recovery from wastewater treatment plants (WWTPs) for hydroponic cultivation holds promise for closing the nutrient loop and meeting rising food demands. However, most studies focus on solid products for soil-based agriculture, thus raising questions about their suitability for hydroponics. In this study, we address these questions by performing the first in-depth assessment of the extent to which state-of-the-art nutrient recovery processes can generate useful products for hydroponic application. Our results indicate that less than 11.5% of the required nutrients for crops grown hydroponically can currently be recovered. Potassium nitrate (KNO3), calcium nitrate (Ca(NO3)2), and magnesium sulfate (MgSO4), constituting over 75% of the total nutrient demand for hydroponics, cannot be recovered in appropriate form due to their high solubility, hindering their separated recovery from wastewater. To overcome this challenge, we outline a novel nutrient recovery approach that emphasizes the generation of multi-nutrient concentrates specifically designed to meet the requirements of hydroponic cultivation. Based on a theoretical assessment of nutrient and contaminant flows in a typical municipal WWTP, utilizing a steady-state model, we estimated that this novel approach could potentially supply up to 56% of the nutrient requirements of hydroponic systems. Finally, we outline fundamental design requirements for nutrient recovery systems based on this new approach. Achieving these nutrient recovery potentials could be technically feasible through a combination of activated sludge processes for nitrification, membrane-based desalination processes, and selective removal of interfering NaCl. However, given the limited investigation into such treatment trains, further research is essential to explore viable system designs for effective nutrient recovery for hydroponics.

ADVANTAGES AND DISADVANTAGES OF THE REMOTE TEAMWORK

Remote teamwork has become common during the pandemic and continues even after it is over. In Lithuania alone, during the pandemic, around 40% of employees worked or still work remotely, while in the US this number reaches 50%. The purpose of this article is to compare the theoretical advantages and disadvantages of remote teamwork presented by scientists with the opinion of experts. Several main factors were selected after literature analysis and were given to the experts to evaluate them in a survey which was created using Likert scale. Experts were selected from one financial company and they lead teams of 7–10 people and have been working remotely for the past two years. The obtained results were evaluated using Kendall’s concordance coefficient and factor analysis methods. These methods helped evaluate the compatibility of the experts’ opinions and factors were divided into advantages and disadvantages based on the experts’ evaluations. The theoretical and practical assessment of the advantages of remote teamwork showed that the opinions of scientists and experts differ. This research can help remote teams and their managers to find what they can improve.

ON THE ISSUE OF ENSURING THE RIGHT TO A MANDATORY SHARE IN THE INHERITANCE IN THE CASE OF MAKING A JOINT WILL

The reform of Russian inheritance legislation, which introduced the institutions of a joint will of spouses and an inheritance fund into the domestic legal order, has already received a thorough theoretical assessment. At the same time, the problem of ensuring the right to an obligatory share in the case of certification of a joint will rarely becomes an independent object of scientific research. In the article, based on an analysis of scientific works devoted to the issues under study, the prerequisites for the positivity of the institution of a joint will are clarified; attention is paid to the signs of the relevant transaction; the specifics of the legal regulation of social relations related to a joint will have been clarified; the procedural features of a joint will are outlined. Particular attention is paid to two controversial issues: when a compulsory heir is called upon to inherit and how his share is calculated if the testator and his spouse have made a joint will. A conclusion is formulated about the importance of eliminating legal uncertainty in this subject area.

Simulators in urology resident's training in retrograde intrarenal surgery.

To evaluate the impact of simulators on the training of urology residents in retrograde intrarenal surgery (RIRS). The study involved training eight urology residents, using two artificial simulators; one developed by the Universidade Estadual do Pará, using three-dimensional printing technology, and the other one patented by the medical equipment manufacturer Boston Scientific The qualification of residents took place through a training course, consisting of an adaptation phase (S0), followed by three training sessions, with weekly breaks between them (S1, S2 and S3). Study members should carry out a RIRS in a standardized way, with step-by-step supervision by the evaluator using a checklist. The participants' individual performance was verified through a theoretical assessment, before and after training (pre- and post-training), as well as by the score achieved in each session on a scale called global psychomotor skill score. In S3, residents performed an analysis of the performance and quality of the simulation, by completing the scale of student satisfaction and self confidence in learning (SSSCL). At the end of the course, everyone was able to perform the procedure in accordance with the standard. The training provided a learning gain and a considerable improvement in skills and competencies in RIRS, with p < 0.05. SSSCL demonstrated positive feedback, with an overall approval rating of 96%. Artificial simulators proved to be excellent auxiliary tools in the training of urology residents in RIRS.

Democratic Backsliding, Resilience, and Resistance

This article assesses two next-level questions in the study of democratic backsliding: democratic resilience and political polarization. It first advances a set of methodological decision points to improve clarity in contemporary debates surrounding democratic backsliding measurement and the possibility of identifying moments of democratic recovery. It then moves to a theoretical and empirical assessment of pathways by which democratic backsliding takes place, under what conditions, which specific actors are involved, and what opportunities exist for democratic recovery given sources of resilience and strategies of resistance. The authors examine the role of political polarization in backsliding and highlight the combined importance of political agency and institutional levers for regime outcomes. The authors argue that regime outcomes are not predetermined by antecedent conditions, and particularly not by the level of development.

«МЕТОДОЛОГИЧЕСКИЙ АНАРХИЗМ» ПОЛА ФЕЙЕРАБЕНДА И ЭПИСТЕМОЛОГИЧЕСКИЙ СТАТУС ДЕЯТЕЛЬНОСТИ УЧЕНОГО В ПОЛИТАРНУЮ ЭПОХУ

The relevance of the article is determined by the importance of comprehension and theoretical explication of the origins and forms of specifically scientific cognition of objective reality, which originated in the civilizations of the ancient and medieval East (ancient Egypt and Babylon, ancient and medieval India and China, the medieval Arab-Muslim East), generally designated in the article as «politary societies». The purpose of the article is to show the possibility and effectiveness of applying the concept of the so-called «methodological anarchism» developed by the American philosopher Paul Feyerabend (1924–1994) to the epistemological activity that took place over the course of about three millennia in societies of the politary type. As the main method of research, the author uses the ascent from the abstract to the concrete: from the abstract generalized description of the methodological principles proclaimed by Feyerabend, the author moves on to the concrete realities of the epistemological discourse of the politary epoch, demonstrating the relevance of these principles in this respect and the fruitfulness of the coverage of politary science from this perspective. Three principles of Feyerabend’s were chosen as the supporting pillars of the study: 1) «Leave science to scientists!»; 2) «Anything goes!»; 3) separation of science from the state. The unity of the logical and the historical acts as an auxiliary method: the concrete-historical features of natural-scientific and mathematical work under the conditions of politarism appear as more or less pronounced individualized specifications of those general, universal criteria of scientific activity which modern philosophy of science tries to logically reconstruct, and which (as Feyerabend never tired of showing) are still very far from perfection. As a result of the study, the author draws conclusions that have a novelty. First of all, the very possibility of successful application of the concepts developed by Feyerabend on the material of the history of Western science, far beyond the socio-cultural sphere with which the American thinker directly dealt is substantiated. Secondly, it has been demonstrated that the reasons that ensured, on the one hand, the success of scientific and cognitive research, and, on the other hand, hindered it and harmed it, were, in fact, of the same type both on the European continent and in the politary East. Thirdly, it is shown that it is the acquisition by the research community of subjectness, the right to independently form research priorities, that is the condition for obtaining significant scientific innovations, and a condition that works in any culture and in any era - from antiquity to the present. The practical significance of the work carried out by the author of the article is seen in the fact that a methodological basis is created for a stricter demarcation between the concepts of «science» and «proto- (pre-) science» and for qualified theoretical and moral assessments of the intellectual and creative work that was done by scientists of the ancient and medieval East.

Обоснование безопасного расстояния между размещенными в одной пожарной зоне кабелями каналов безопасности атомных электростанций с водо-водяными реакторами

Currently, there are no methods of mathematical modeling of the operability of power and signal cables used at the nuclear power plants in real and standard fire conditions, including the use of intumescent flame retardants. The purpose of the article is a theoretical assessment of the safe distance between the cables of the safety channels of nuclear power plants with pressurized water reactors located in the same fire zone. To achieve it, the time of occurrence of a short circuit in the cables of the channels of safety systems from the beginning of a real fire and depending on the distance between adjacent cable lines was estimated. An integral method of mathematical modeling of the development of a fire in a room is used. To determine the temperature distribution inside the cable insulation, the thermal conductivity equation is solved. The analysis of the obtained results is carried out. The calculation results made it possible to formulate the requirements for the swelling temperature of fire retardant compounds for treating the outer surfaces of SB cables: the above temperature should be no more than 150 °C for the flame retardant cables, and 180 °C for the non-flame retardant cables, as well as at distances between open cables of two safety systems smaller than 2, the outer surfaces of the safety cables must be treated with a fire retardant compound with a fire retardant efficiency of at least 120 minutes. The conducted theoretical assessment of the safe distance between the cables of the safety channels of nuclear power plants with pressurized water reactors located in the same fire zone, using the proposed mathematical model, showed that in a real fire, in order to prevent a short circuit in the cables of the safety systems, as well as ignition of the insulation of adjacent cables, it is required to justify safe distances between the adjacent cables of the safety system of nuclear power plants, taking into account the specific dimensions of the premises and the properties of the cable insulation material and the fire-retardant coatings used.

Project based learning and Proctored online assessment in Lab courses to enhance CDIO Skills – A case study of Microcontroller laboratory course

Abstract: CDIO(Conceive/Design/Implement/Operate) is an educational framework for engineering programs that aims to produce graduates possessing all- rounded set of skills and competencies. The laboratory courses plays important role in inculcating CDIO skills. This proposal explains an attempt conducted in a Microcontroller laboratory course which uses proctored online theoretical assessment and project-based learning in lab course. Thus, a blend of group and individual activities are inserted during the conduct of lab. It is proposed to give one project relating the concepts of the course and to conduct at least two online theoretical assessments, one at the end of first cycle of experiments and second at the end of second cycle experiments. A representative list of project titles is provided to the students. Assessment questions include all the aspects such as background theory of the experiments, conduction of experiments, observation, calculations and inferences. Three research questions are formulated and addressed. It is found from the assessment results that these projects and assessments results in the better understanding of the concepts in the experiments. On the other hand, these assessments helps teachers to analyze the difficulty faced by the students in understanding the theory back ground of the laboratory experiment and plan accordingly. The results are strengthened using statistical tests. Keywords: CDIO, PBL, online assessment, lab courses, Microcontroller

What are the minimal folding seeds in proteins? Experimental and theoretical assessment of secondary structure propensities of small peptide fragments.

Certain peptide sequences, some of them as short as amino acid triplets, are significantly overpopulated in specific secondary structure motifs in folded protein structures. For example, 74% of the EAM triplet is found in α-helices, and only 3% occurs in the extended parts of proteins (typically β-sheets). In contrast, other triplets (such as VIV and IYI) appear almost exclusively in extended parts (79% and 69%, respectively). In order to determine whether such preferences are structurally encoded in a particular peptide fragment or appear only at the level of a complex protein structure, NMR, VCD, and ECD experiments were carried out on selected tripeptides: EAM (denoted as pro-'α-helical' in proteins), KAM(α), ALA(α), DIC(α), EKF(α), IYI(pro-β-sheet or more generally, pro-extended), and VIV(β), and the reference α-helical CATWEAMEKCK undecapeptide. The experimental data were in very good agreement with extensive quantum mechanical conformational sampling. Altogether, we clearly showed that the pro-helical vs. pro-extended propensities start to emerge already at the level of tripeptides and can be fully developed at longer sequences. We postulate that certain short peptide sequences can be considered minimal "folding seeds". Admittedly, the inherent secondary structure propensity can be overruled by the large intramolecular interaction energies within the folded and compact protein structures. Still, the correlation of experimental and computational data presented herein suggests that the secondary structure propensity should be considered as one of the key factors that may lead to understanding the underlying physico-chemical principles of protein structure and folding from the first principles.

The permeability of diamond and other microphase-separated morphologies in copolymer films.

A method is proposed for the theoretical assessment of potential membrane properties in materials based on microphase-separated block copolymer films subjected to the etching of one of the components. The concepts of topological permeability and connectivity contrast introduced by the authors are used to compare the percolation characteristics of simple cubic, diamond, and diamond-like morphologies compatible with the slit geometry and specified by a given distribution of the order parameter. The diamond-like morphology, which has the most promising transport characteristics, can be formed in a thin film of diblock copolymer AB placed on a chemically structured substrate. For this case, the quantitative analysis of permeability for certain parameters of the model system is carried out using the local distribution of A and B units calculated with the self-consistent field theory of microphase separation. The results obtained may be useful for the design of isoporous membranes based on block copolymers.

Enterprises’ Financial Performance and Operational Risk Management: A Theoretical Assessment of the Literature

The scope of the operational risk phenomena and its management has been made clear, among other things, by scandals that have happened in the financial sector. It has become crucial to implement an operational risk management system because performance cannot be achieved without having addressed the operational risk management-related issues. Operational risk management is a process by which businesses identify and evaluate the risks impacting their business. Performance is the culmination of an organization's efforts to reach its goals in the field of management. In fact, due to the negative effects of this kind of failure on a company's performance and stability, operational risk has a significant impact on the performance of a firm, regardless of its industry of operation. The purpose of this article is to examine the impact of operational risk management on the financial performance of companies to review the literature and determine whether risk management has a positive or negative impact on financial performance.

Structural modelling and functional analysis of Pseudomonas ACC deaminase: An in silico study

The activity of 1-aminocyclopropane-1-carboxylate (ACC) deaminase enzyme and its impact on regulating ethylene concentrations and plant ACC are fundamental characteristic found in plant-associated rhizobacteria. ACC deaminase-producing bacteria, such as Pseudomonas mitigate the detrimental effects of high levels of ethylene and ACC in plant-microbe interactions, resulting in improved plant growth and development. Different species within the Pseudomonas genus are commonly found in plant microbiome worldwide. Their adaptation to the plant-associated environment makes several Pseudomonas strains highly promising for advancing novel sustainable biotechnological and agricultural solutions, particularly those exhibiting ACC deaminase activity. Thus, the present study conducted a comprehensive in silico analysis focusing on the structural and functional characteristics of ACC deaminase protein of Pseudomonas spp. The study explored correlations based on phylogenetic relatedness using both ACC deaminase enzymes and their respective genes across different Pseudomonas species and strains. This study also investigated physiochemical properties, CATH classification and STRING analysis using various bioinformatics tools. Pseudomonas brassicacearum was selected as the representative species from the Pseudomonas genus for the 3D modeling of ACC deaminase protein. The acidic ACC deaminase protein has an average molecular weight of around 25.30 kDa, with a high percentage of alpha helices in its secondary structure, demonstrating its thermal stability. This theoretical assessment of the structure and function of ACC deaminase-producing Pseudomonas could assist researchers in understanding the ACC deaminase protein, potentially facilitating a better understanding of plant-microbe interactions, and aiding in the selection of highly efficient strains for various agricultural applications.

Vectors of development of energy cooperation between Russia and foreign countries under economic sanctions

The subject of this study is the modern aspects of Russia’s positioning in the global energy space. They are associated with the shift from the previously established liberal world order and the trend towards new polarisation in the world economic system, as well as with the increasing risks of turbulence in world energy markets. In this regard, it is extremely important to assess the real impact of economic sanctions on the nature of relationships and determine promising vectors for the development of energy cooperation between Russia and foreign countries. The research methodology includes analysis and synthesis methods and a historical approach, which are productively used to assess the tactical and strategic actions of our country in the system of international energy cooperation. The scientific novelty of the study lies in the substantiation of theoretical approaches and assessment of the practical implementation of energy cooperation with foreign countries. Those priority interests are considered that determine the economic sovereignty and identity of Russia in the conditions of a gradual but categorical shift of the world community from the previously established imperatives of liberalism and economic globalisation. The article is of an overview nature and describes the key areas of cooperation in the oil and gas and coal industries. Its main provisions may be used for long-term researches related to modernising the strategy of Russia’s foreign economic relations and increasing the level of its foreign economic security in the context of new global challenges.

Electrochemical and theoretical assessment of two heterocyclic Schiff bases as effective corrosion inhibitors for carbon steel in sulfuric acid solution

This article aimed to synthesize and study the efficacy of two tryptophan Schiff base derivatives as corrosion inhibitors for carbon steel in 0.5 M H2SO4: (Z)− 3-(1 H-indol-3-yl)− 2-((4-nitro benzylidene)amino)propanoic acid (INB) and (Z)− 3-(1 H-indol-3-yl)− 2-((4-methoxybenzylidene)amino)propanoic acid (IMB). Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used in this investigation. The findings demonstrate that INB and IMB exhibit strong anticorrosive activity against the 0.5 M H2SO4 medium; the inhibition efficiency for 10−3 M of IMB inhibitor was 92%. The Langmuir adsorption isotherm demonstrates that both INB and IMB have strong adsorption on the metal substrate, with free energy ΔGads of − 36.8 kJ mol−1 and − 38.5 kJ mol−1, respectively. Using simulations based on density functional theory (DFT) and molecular dynamics simulation (MDS), the molecular structure of INB and IMB and their influence on the inhibition mechanism was discussed. By using DFT/MDS computational research, a strong correlation between the theoretical and experimental results was found.

HP8-to-cP4 structural transition in Ni3In compounds at high temperature and pressure: Theoretical assessment of compression and phase stability information

According to Webb et al. (1986) by heating the Ni3In (hP8) compound at 800–1200 °C under a pressure (P) of 6.5 GPa, a cP4 phase was formed, which reverted to hP8 when annealed at low pressure. A striking X-ray result is that the atomic volume (V) of cP4 was higher than that of hP8. Webb et al. determined the V versus P relations in samples quenched to room temperature and reported that the compressibility of the cP4 phase was significantly larger than that of the hP8 phase. These various findings have been theoretically analyzed in the current work by using ab initio density-functional-theory (DFT) calculations, including an account of the vibrational and electronic contributions to the thermodynamic properties. Calculations of the V versus P relations are used to reassess the compressibility relation between the cP4 and hP8 phases, and Gibbs energy calculations to characterize the relative stability of these structures. In particular, detailed comparisons are reported with the only information available on the thermal properties of the hP8 phase, viz., the Gibbs energy estimates obtained in CALPHAD-type phenomenological modeling of the Ni–In equilibrium diagram. The key qualitative result of the current work is that cP4 should be considered as a high-temperature phase, which might be stabilized by heating to the temperature chosen to anneal the hP8 material under pressure. On this basis it is suggested that the seemingly anomalous relative stability relations discussed by Webb et al. might be a consequence of considering only the effect of pressure on the cP4/hP8 relative phase stability.

«Улан-Баторский диалог» как особая инициатива Монголии в обеспечении безопасности в Северо-Восточной Азии

Introduction. The relevance of the study is determined by the increasing role of North-East Asia as one of the world and political centers, as well as the growth of various challenges and threats in the region, affecting safe and stable development of the world community as a whole. The study of the problem of regional security in Northeast Asia and the participation of Mongolia in its ensuring is important for the formation of theoretical and practical conclusions and assessments regarding its international status. Since the 1980s Mongolia has been consistently pursuing the policy of creating a mechanism for dialogue in Northeastern Asia. The result of these efforts was the Ulaanbaatar Northeast Asia Security Dialogue initiative. Mongolia's active foreign policy and the will to fully participate in regional cooperation in Northeastern Asia and in as many international and multilateral organizations as possible is one of the hallmarks of the phenomenon of modern Mongolia. The purpose of the study is to review the “Ulaanbaatar Dialogue on Security in Northeast Asia” and analyze its role in creating conditions for the interaction of all stakeholders in the interests of maintaining peace in Northeastern Asia. Results. This study presents a brief history of the formation and development of the Ulaanbaatar Dialogue, identifies advantages over similar discussion platforms in the region, and shows the importance of this event in increasing the international status of Mongolia. It is concluded that in the nearest future Mongolia may become an analogue of Asian Switzerland, the main platform for negotiations between countries in Northeast Asia due to the fact that Ulaanbaatar pursues an open, multifaceted foreign policy, and the adherence of this country to the “third neighbor” doctrine makes Mongolia a neutral state that does not participate in military-political blocks.

Novel saccharin derivatives are inhibitors for carbon steel corrosion in 1 M HCl: electrochemical, thermodynamic and theoretical assessment

Novel saccharin derivatives are inhibitors for carbon steel corrosion in 1 M HCl: electrochemical, thermodynamic and theoretical assessment

Fostering an enabling environment for equality and empowerment in agri-food systems: An assessment at multiple scales

Inequalities by gender and intersecting sources of social differentiation in access to resources, exercise of agency, and desirable outcomes persist in agri-food systems in low- and middle income countries. Despite decades of development and theoretical assessment efforts calling for multiscale approaches to addressing inequalities in agri-food systems, common approaches remain specific to a scale rather than holistic.In this paper, we make the case that achieving lasting equality and empowerment in agri-food systems requires transformative change. This depends on fostering an enabling environment by relaxing ‘deeper’ – often interrelated – institutionalized constraints to equality and empowerment across multiple nested scales of the state, markets, communities, household and individuals.Based on a review of recent literature focused on agri-food systems in low- and middle income countries, we present newly emerging thinking and a status update of key structural constraints to equality at different scales – rooted in policy and discriminatory, formal and informal, social and economic institutions, including norms. We give examples that show how structural constraints to equality at different nested scales are interdependent and mutually reinforcing; demonstrating the need for holistic approaches tackling constraints at multiple scales to foster transformative change in agri-food systems. We recommend designing holistic policy and development programs that combine strategies for relaxing constraints to equality and empowerment at multiple scales using inclusive processes of tailoring and prioritizing. To inform the design of such programs, we present recent evidence of effective or promising strategies for addressing structural constraints to equality that relate to policy, market systems, collectives and norms.