جستجوی مقالات مرتبط با کلیدواژه « پایداری » در نشریات گروه « علوم پایه »

Considering the importance of the stability of solar cells in their industrialization, 2D perovskites in the interface between 3D perovskite and charge transfer layers play a key role in improving the stability of perovskite solar cells. In this research, 3D triple-cation perovskite and 2D PTA2PbI4 perovskite have been used as light absorbing materials in fabricated solar cells. Considering the penetration of moisture from all sides of the perovskite layer, we investigated 3D/2D, 2D/3D and 2D/3D/2D perovskite structures. Experimental results show that the formation of 2D perovskite above the 3D perovskite (2D/3D) in addition to protecting the 3D perovskite layer against moisture, leads to the improvement of the morphology of the perovskite layer. The formation of 2D perovskite under the 3D perovskite (3D/2D) is effective in improving the crystallinity of 3D perovskite. 2D/3D perovskite solar cells have 9.81 efficiency due to the improvement of surface defects and reduction of charge recombination. Besides, 2D/3D/2D perovskite solar cells by improving the crystallinity of 3D perovskite and the double protection of 3D perovskite by 2D perovskite, maintained 98% of the initial efficiency for 240 days.

‎In this paper‎, ‎the time-space distributed-order fractional diffusion equations with weakly singular solutions are considered‎. We provide the difference scheme using a nonuniform mesh to solve ‎equations‎‎. ‎The stability and convergence of the difference scheme are discussed‎, ‎We prove that the difference scheme is unconditionally stable‎. ‎We find that the difference scheme is convergent‎. ‎We also show that the temporal convergence order on the nonuniform mesh is higher than on the uniform mesh‎. Finally, some numerical examples are given to verify the theoretical analysis‏.

Chondroitinase ABCI is a bacterial lyase that degrades glycosaminoglycans and promotes axonal growth and functional improvement. However the stability and maintenance of this enzyme is very limited. One of the strategies to overcome this limitation is to immobilize the enzyme. In this research, chondroitinase ABCI (cABCI) from Proteus Vulgaris was immobilized on hydroxyapatite nanoparticles. Hydroxyapatite is a non-toxic ceramic biomaterial that has a high surface area, which is beneficial for loading a large amount of enzyme. Therefore, to increase the stability of chondroitinase ABCI, immobilization on hydroxyapatite nanoparticles for 4 hours through physical adsorption in  phosphate buffer pH 5, 6.8, and 8 at 4◦C was carried out. Enzyme immobilization on hydroxyapatite nanoparticles was then confirmed by field emission gun-scanning electron microscopy and UV-spectroscopy, before and after immobilization. Then, in order to obtain the optimal pH and temperature, the activity of the nanosystem was investigated at three pH and temperatures (4°C, 25°C, and 37°C). Results revealed higher activity at pH 5 and temperature 4 ◦C than the other pH and temperatures for the nanosystem. Based on the obtained results, which show the stability of the nanosystem at all three temperatures compared to the free enzyme, this nanosystem could be a potential candidate for clinical applications in future.

The human enzyme carbonic anhydrase II (HCA II) is a cytosolic protein located in the membrane of red blood cells, and it is involved in various physiological and pathological processes. It can catalyze the reversible hydration of carbon dioxide efficiently. Given the critical role of the HCA II, computational methods such as molecular dynamics simulation (MD) are used to study the structure and dynamics of the wild-type and the mutant enzymes. Based on the previous experimental studies, mutant enzymes enhance kinetic activity or decrease stability. Before MD, quantum mechanics studies were performed. The native enzyme was in a stable state after MD in terms of potential energy and Gibbs-free energy. As evidenced by RMSD, RMSF, and Rg, One of the mutated enzymes that affect the activity of the enzyme has more stability, less fluctuation, and less Rg than other enzymes. In two other mutants that also affected the stability of the enzyme, compared to the previous two enzymes, lower stability, more fluctuations, and potential energy level were observed, which caused the instability of these enzymes during the simulation. These results can help in the engineering and design of new variants of carbonic anhydrase enzyme.

In many developing countries, natural resource conservation has not been a priority despite an increase in production, resulting in reduced agricultural productivity and compromised sustainability. Sustainable agriculture, as a rapidly expanding concept, emphasizes the economic, environmental, and social dimensions of producing food and energy for present and future generations. Smart agriculture, including the intelligentization of agricultural production units and greenhouses, is a key solution to address sustainability challenges by optimizing crop production through environmental control and reducing the impact of climate change. While sustainability is interpreted differently across fields and regions, there is a consensus on the need to use sustainability indicators to measure changes. This study aims to evaluate and validate the environmental sustainability indicators of smart greenhouses, which are unique to each region and country. By adopting a sustainability perspective, this study contributes to a better understanding of the multidimensional nature of agricultural sustainability and the need to consider the social and environmental implications of agricultural practices. The results of this study can help policymakers and practitioners in the field of smart agriculture to develop and implement sustainable agricultural practices that maximize productivity while minimizing environmental and social impacts. Therefore, this study was conducted with the aim of evaluating and validating the environmental sustainability indicators of smart greenhouses.

This study targeted greenhouse managers in Isfahan province who utilized intelligent greenhouse management equipment in their production units due to the technological nature of the subject and climatic conditions. The agricultural Jihad Organization's statistics showed that there were 303 greenhouse units in the province, of which 170 were selected as the statistical sample. Isfahan province, known for its advanced technology and high greenhouse production, ranks fourth in greenhouse products in Iran, accounting for 12.33% of the country's greenhouse products.The data collection tool in this research is a questionnaire designed by the researcher in the form of a 5-option Likert scale including "very low", "low", "moderate", "much", "very much". To develop a measurement tool, the study identified three components of economic justification, environmental renewability, and social viability by systematically reviewing previous research on sustainable agriculture:Economic justificationSEC1 Increasing crop productivity using precision agricultureSEC2 reduction of consumption inputs in smart agricultureSEC3 increasing the income of smart greenhouses compared to traditional production unitsSEC4 Improving the quality and marketability of productsSEC5 Optimal management of water consumption in smart greenhousesSEC6 Optimum energy consumption in smart greenhousesEnvironmental renewal SEM1 Use of biological and non-chemical control to control pests and weedsSEM2 use of bio and green fertilizersSEM3 Planting modified and resistant seed varietiesSEM4 Utilization of renewable energiesSEM5 planning of recycling process and waste managementSEM6 Modifying and meeting the needs of the soil or planting bedSocial viabilitySSC1 Employing expert and educated personnel in the production unitSSC2 desire to learn and acquire knowledge of smart technologiesSSC3 Reducing human error in smart greenhouse managementSSC4 Creating sustainable employment for local youth in the regionConfirmatory factor analysis (CFA) was used to measure the factor structure of the environmental sustainability measurement index. The calculated indices in the research measurement model showed good validity and reliability. One of the advantages of using CFA to evaluate environmental sustainability indicators of smart greenhouses is its ability to systematically measure the validity and reliability of the measurement tool. This approach can be used continuously in similar environments in the future. This study contributes to the literature by providing a systematic approach to measure environmental sustainability in smart greenhouses, which can inform policymakers and practitioners in sustainable agriculture to maximize productivity while minimizing environmental and social impacts.

Descriptive statistics revealed that most greenhouse owners were between the ages of 31-40 and held university degrees, and the majority of production units were personally owned. Given the need for human and financial resources, there is potential for developing the cooperative sector and knowledge-based companies in this field.The study introduced 15 indicators for measuring the environmental sustainability of greenhouses, and factor loading values and t values for each index showed that all identified factors played an important role in explaining the sustainability of smart greenhouses. The factor load values for the selected markers (above 0.5) were statistically significant at the error level of one percent (P<0.01).The confirmatory model revealed that the components of social livability and environmental renewability had a greater role than economic justification in explaining the underlying variable of sustainability, with path coefficients of 0.844 and 0.858, respectively. The results highlight the importance of paying more attention to natural resources and empowering active human resources in the sector. While most agricultural policies in Iran prioritize increasing productivity and efficiency, less attention is given to aspects of justice, social welfare, durability, stability, and compatibility. The study emphasizes that agricultural sustainability is a multidimensional phenomenon, and policymakers should consider other dimensions of efficiency beyond crop production and productivity.

This study has made a significant contribution to the development of scientific concepts and sustainability evaluation indicators in new technologies in the field of agriculture.Despite numerous studies on agricultural sustainability, few efforts have been made to design and validate sustainability measurement indicators specifically for smart agriculture, particularly in greenhouse production units. Valid and reliable indicators are crucial for the agricultural sector worldwide, as farmers, policy makers, decision makers, and agricultural extension workers require accurate information about agricultural activities.However, in most cases, these stakeholders lack the tools to evaluate such information, leading to incorrect decisions, policies, and actions due to the absence of documented knowledge and indices on the sustainability of smart agriculture. Therefore, this article presents a multi-step process for designing and validating sustainability indicators for smart greenhouses in future research. This process is essential to improve the accuracy and reliability of sustainability information and promote sustainable agricultural practices in the greenhouse sector.The development and validation of the environmental sustainability index in this study can have a significant impact on the direction of agricultural policies in the field of intelligentizing greenhouse activities. Researchers, decision-makers, and policymakers face significant challenges in achieving greenhouse sustainability, and this study provides valuable insights and recommendations for addressing these challenges.

In the near future and with the cost of energy becoming more expensive, more plants tend to use waste for energy production. The cost of landfilling is increasing and it is increasing the cost of recycling. On the other hand, alternative fuels are necessary for the production of efficient cement from an economic point of view. Wastes, packaging, and other materials can replace expensive fossil fuels such as coal and oil. But first, they should be converted into high-quality fuel (RDF: Refuse Derived Fuel) and stored safely in factories. This is a duty cement production companies set for themselves by being a member of the Cement Sustainability Initiative (CSI) and the World Business Council for Sustainable Development (WBCSD). The goal has been to replace expensive fossil energy sources such as coal, gas, and oil in production and reduce CO2 emissions. This study provides valuable insights into RDF production as a sustainable component of an integrated MSW management system, especially for developing countries, in order to achieve 17 SDGs (17 Sustainable Development Goals) and a circular economy. Suitable RDF has higher moisture, ash, chlorine, sulfur, and nitrogen content than LHV municipal solid waste.

Natural capital is essential for human survival and achieving sustainable development goals. Therefore, a scientific framework is required to evaluate regional natural capitals consumption and their capacity to ensure sustainable development. Natural capitals represent the limiting and irreplaceable factors in human well-being and sustainability of every developmental intervention. Degradation of the accumulation and flows of the natural capitals are the fundamental issues in the discussion of environmental sustainability. The current research has been conducted with the aim of investigating the state of ecosystem sustainability by adopting two approaches of ecological footprint and ecosystem services, and in other words, comparing the amount of demand for resources with the supply of goods and services provided by the ecosystem.

In this research, to investigate the sustainability of Nowshahr's natural and urban ecosystem as the case study, first, the trend of land use changes and its associated phenomena in the region have been investigated using ENVI 5.6 software for processing the satellite images. In order to investigate the change process of the study area, Landsat satellite reference images, TM, ETM+ and OLI sensors were used for the time scale of 2002, 2013 and 2020. Then, the classic ecological footprint of the region was calculated for six types of productive ecosystems, including agricultural lands, pastures, fishing areas, forests, built-up lands, and the carbon demand. The areas of these six land cover types were converted into global hectares using yield and equivalence factors. Subsequently, the maximum amount of ecosystem service flow per global hectare was estimated. And after that, the amount of consumption of natural capital accumulation and the occupation of capital flow in the region were investigated. Finally, the ecosystem stability of the study area was investigated using indicators such as the ecological pressure index (EPI), ecological sustainability index (ESI), ratio of capital stock to flows index, flow occupation ratio index, and excessive natural capital flow index.

According to the research results in the city of Nowshahr, during the period of 2011-2019, the amount of ecological footprint, ecological deficit and pressure have gradually increased, resulting in a reduction of the ecological balance and stability. Only the pasture, forest and fishing areas are in a stable state meaning that the supply of ecological resources is more than the demand, and the pressure is still within the carrying capacity of the ecosystem. In the period of investigation, the amount of use of stock to natural capital flow has increased and has reached almost four times of natural capital flow.

Measuring human demand for natural capital and nature's supply is essential for tracking progress, setting goals, and orientating sustainability policies. By combining the two approaches of evaluating ecosystem services and ecological footprint, it is possible to track human demand and nature's supply from a precise subset of ecosystem services, and therefore ecological balance and sustainability can be examined at the local level. Based on the results of the research, the stability of the region and the status of its ecosystem services is threatened by the cultivated land, and mainly the consumption of fossil energy. Based on the results of the research, in the period of investigation, the stability of the city of Nowshahr has decreased and the status of its ecosystem services are threatened by the cultivated land, and mainly the consumption of fossil energy. During this period and considering factors such as land use level, ecological deficit, footprint depth, ecosystem service flow, ecological pressure index, and ecological sustainability index, agricultural land use was the most unsustainable and fishing was the most sustainable use in city of Nowshahr.

This paper studies the dynamical behavior of a discrete-time predator-prey analytically and numerically. The conditions and the critical coefficients for the transcritical, flip (period-doubling), and Neimark-Sacker are computed by using the center manifold and normal form technique. Besides, codimension-two bifurcations including strong resonances 1:2, 1:3, and 1:4  have been achieved. The numerical simulation and continuation method, not only confirm our analytical results but also reveals richer dynamics of the model, especially in the higher iteration.

If in today's world, in business units, the focus is only on increasing the interests of capital providers and shareholders and profitability is the criterion of the success of the business units without considering the social and environmental effects, this view is a wrong interpretation of success, so business units have responsibilities beyond their traditional role (profitability) and must be accountable for the impact they have on their environment and society. The purpose of this study is to investigate how social responsibility is expanded, to pay more attention to sustainability reporting and research in this field and to encourage researchers to move towards exciting and challenging social and environmental accounting and auditing research. Therefore, the research method used in this research is to review the research literature with the aim of identifying barriers to sustainable development goals and providing guidelines for researchers interested in research in this field. Methods used to gather information include searching for books, documents, websites, and publications. This study reveals the importance of corporate social responsibility, environmental accounting and auditing and sustainability and research in this field, and therefore it is important that standard setters in the accounting profession set standards on social issues and sustainability.

The competitive environment of today has focused the attention of organizations on meeting the requirements of quality and social responsibility. Because organizations that adhere to the quality management framework achieve a higher level of customer satisfaction. To consider the convergence between sustainability and reliability, an economic, responsible, and reliable supply chain network design model has been comprehensively and efficiently modeled. In this article, a non-linear mixed integer programming model is considered for the design problem of the supply chain network in the form of three objectives, multi-product, multi-level, multi-source, multi-capacity, and multi-stage. The Pareto optimal solutions of the proposed model have been obtained using the evolved epsilon constraint (AEC) method. In addition, a numerical example with random data has been used to measure the accuracy and overall performance of the proposed model. The results showed that the profit value of the problem increases with the increase of the demand parameter. At the same time, reliability and social responsibility decrease. In addition, with the increase in greenhouse gas emissions, the value of the objective function of profit and social responsibility decreases, while the value of the objective function of reliability remains almost constant. Achieving synergy between sustainability and reliability in the design of the supply chain network requires the development of more detailed and long-term guidelines.

Improving living conditions in human settlements is the ultimate goal of urban development programs and projects. The prerequisite for achieving this goal is necessary to provide suitable living conditions. The purpose of this study is to assessment the livability of Tabriz metropolitan regions based on environmental indicators in mental and objective dimensions. This research is applied in terms of purpose and descriptive and analytical in terms of research method. In order to measure the mental condition of environmental livability (including 3 indicators and 25 items), after identifying the indicators, first the relevant questionnaire was designed, after determining the statistical sample at the level of the 10 regions of Tabriz using Cochran's method (413 samples). Also, the latest statistical yearbook of Tabriz metropolis (year 2019) was used to examine the objective dimension (including 17 items). In order to analyze the data, Shannon entropy method has been used to weight the indicators and items of the research and Morris correction method has been used to determine the environmental livability of the regions based on the world literature at 5 levels; Finally, GIS software is used to draw maps to better understand the spatial condition of environmental livability at the region level. The research findings indicate that in terms of mental dimension, 80% of the regions are in a very unsuitable and critical situation and only two regions, 2 and 5, are in a suitable environmental livability condition. Objectively, none of the regions are in good condition and 10 regions are in an unfavorable and unacceptable condition. Finally, in the combined dimension (both objective and mental dimensions), region 2 with a score of 71.23 Morris is in a tolerable environmental condition, region 5 is in an average condition and the other 8 regions of Tabriz metropolis are in an unsuitable and critical condition. The following are suggestions for improving the environmental livability of Tabriz metropolis.

Operational risk is one of the identified risks in organizations, especially in banks, and Basel committees on banking supervision pay special attention to it. In this paper, the mathematical model based on the advanced operational risk model is considered to calculate the probability of survive as a partial Volterra integro-differentail equation. This equation has been solved numerically by applying the finite differences method with trapezoidal rule to estimate its integral part and the effect of changing the model parameters on the output of the problem has been investigated. In addition, the stability and convergence of the method are discussed and its numerical results are presented.

‎In this paper, we propose a three-component mathematical model, including Suspected-Infected-Recovered individuals (SIR), under the control of maple vaccination, for infectious diseases. In such, infectious disease can be transmitted through contact with an infected person (horizontal transmission). Vaccination of suspected population will reduce the horizontal transmission of patients in the community. The mathematical model has two disease-free and endemic equilibrium points. The basic reproduction rate of the model, the existence and local asymptotic stability of these two equilibrium points are investigated. By using Pontriagin's minimum principle, we have investigated the conditions of reducing the suspected and infected population and increasing the recovered population due to the use of vaccination in the community. Numerical simulations to the optimal control problem show that control measures can lead to a decrease in the number of suspected population and an increase in recovered population ‎a‎nd it prevents the spread of the disease and becoming into an epidemic.

In this paper, we propose a fuzzy sliding mode controller (FSMC) for Multi-agent Systems (MAS) and investigate the leader-follower consensus problem for the network of nonlinear dynamic agents with an undirected graph topology. A new sliding mode controller is suggested to address the consensus problem in MASs. The proposed sliding mode controller is based on a separating hyperplane. In addition, a fuzzy controller is designed to eliminate the chattering phenomenon. According to the communication graph topology and the Lyapunov stability condition, the proposed FSMC satisfies the consensus condition. As an advantage of the control presented in this paper, the states of the system reach the sliding surface very quickly and remain on the surface. The advantage of the proposed approach is also illustrated by simulation results.

In this paper, an iterative method for obtaining the numerical solutions of fractional partialdifferential equations (FPDEs) is introduced. This method is based on the combination of the differentialtransformation method (DTM) with fractional linear multistep methods (FLMM). The proposed methodhas a very low computational cost, with the help of which partial fractional differential equations areconverted into a system of ordinary differential equations. Then the resulting equations are solved with highaccuracy by applying fractional linear multi-step methods such as fractional Euler The series of solutionsobtained in the differential transformation method has a slow convergence speed in large regions. In thisstudy, by combining the mentioned method with linear multi-step methods, this shortcoming is solved.Numerical results show that the obtained solutions. They are in good agreement with the exact solution ofthe fractional differential equation. The obtained results confirm the proven stability and accuracy of themethod.

In world literature there have been many disparate uses of the terms sustainability and resilience, with some framing sustainability and resilience as the same concept, and others claiming them to be entirely different and unrelated. However, global and local policy processes often use vague or narrow definitions of the concepts of sustainability and resilience, leading to deep confusion, particularly in instances when the two are used interchangeably. In this regard, the extensive analysis of valid scientific documents and a lot of world-produced knowledge in this field can help most of the researchers on integrated use of sustainability and resilience and provide a framework in this field. In this regard, the data were collected and refined from the Scopus information database and was analyzed with algorithms based on social network analysis in VOSviewer software. A systematic literature review showed that sustainability and resilience are interrelated paradigms that emphasize a system’s capacity to move toward desirable development paths. The findings showed of three generalized management frameworks for organizing sustainability and resilience were found to dominate the literature: (1) Resilience as a component of sustainability, (2) sustainability as a component of resilience, and (3) resilience and sustainability as separate objectives. Applying the knowledge network analysis approach and mapping it is recommended to achieve a holistic perspective in the field of sustainability and resilience research and in the future.

Coastal areas are one of the busiest and most touristy areas, the design and beautification of the landscape is very important, but what is important is to improve safety and security against all kinds of accidents, in other words, to make it resilient.

The main purpose of this research is to design the coastal landscape of Salmanshahr with the aim of promoting resilience, which has been done by descriptive-analytical method and field studies. The statistical population consists of all factors involved with the range, including residents, tourists and experts, of which 100 people have been selected as a statistical sample. Data analysis was performed using T-statistic analysis, regression analysis and SWOT-QSPM analysis.

The results showed that there is a direct and significant relationship between landscape design and resilience promotion in the range. In addition, the findings indicate that there are many problems in the field of landscape and resilience in the area.

Organizing and designing the landscape of Salmanshahr beach with resilience can lead to the growth and development of tourism in the area.

Today, due to the fact that non-renewable energy resources are running out and the destruction caused by the use of these resources leads to the environment; The attention of countries has been drawn towards the use of renewable resources and sustainable development. At this time, the attitude towards green architectural approaches in schools has a special place because in addition to observing the basic points of green buildings and saving energy, the existence of such schools is an educational tool for teaching sustainable practices to students. The purpose of this research is to investigate the degree of realization of the components of green schools based on the LEED standard tool with an ecological approach in the secondary schools of Semnan province for improvement. In terms of practical purpose and in terms of descriptive-analytical method and rating and scoring tool, the present research is LEED in the sense of design and environmental guide. The statistical population includes all secondary schools in Semnan province. The data collection tool was a questionnaire and standard indicators, after collecting information and data from the questionnaires; The data were analyzed using Spss software version 22 and with descriptive and inferential statistics. The results showed that the LEED index for checking the improvement of suitable schools and from the point of view of having green schools and components are in the lower than average range.