جستجوی مقالات مرتبط با کلیدواژه "پایداری" در نشریات گروه "علوم پایه"

Changes in temperature and salinity in the water column, sea water always faces phenomena such as inversion of temperature and salinity and changes in layering and instability. Strait of Hormuz, which is the place of water exchange between the Persian Gulf and the Gulf of Oman, due to the interaction of water masses, has the ability of double diffusion convection and change in water stratification. The area studied in this research is east of the Strait of Hormuz and west of the Gulf of Oman. The data used are the temperature and salinity data obtained from the ROPME2006 cruise in 21 stations, which were first filtered in the Excel software. The data were divided into 7 equal stations in three sections: northern, middle and southern sections. Then graphs were drawn and analyzed with the ODV software package,. The maximum frequency of buoyancy increases while moving from northern to southern waters, and its minimum decreases. In other words, it can be said that the most stable and unstable layers are observed in the southern section. Static instability can be seen in northern waters up to a depth of 53 meters and in the middle and southern waters up to the last measured depth. In the northern and middle waters up to the last measured depth of the finger regime and in the southern waters up to a depth of 120 meters and below it to the last measured depth, the diffusion regime has a greater contribution in creating double diffusion convection.

Survivable Capacitated Networks Design Problem (SCNDP for short) is one of the most essential issues in telecommunication and transportation networks. A survivable network is a network that is designed to remain operational in the event of a component(s) failure(s) (cable cuts, electronic failures on switching centers and so forth). In SCNDP, researchers usually consider survivability with two different ways named diversification and reservation. Diversification consists of dividing the demand of source-sink node pairs into two or more node-disjoint (or arc-disjoint) paths, and in reservation after the failure of a component(s) of the network, part of the demand for node pairs can still be satisfied by rerouting. To implement reservation, the links on the network ought to have enough capacity to support the new flows after the rerouting has been made. ‎Therefore, in this paper, we first present one model for the problem of survivable capacitated network design based on the reservation strategy. In many real-world applications, the observed values are often uncertain, for example random, fuzzy, etc. Therefore, we consider the demand vector (the right hand side values) randomly and then by using joint chance-constrained and probability concepts, obtain the corresponding deterministic model. Then, we propose an approximation optimization approach and use piecewise tangent approximation and piecewise linear methods to obtain the lower and upper bounds for it, respectively. Finally, computational results show the efficiency of the proposed model and approximation methods for relatively large-scale networks.

This paper investigates the application of geomechanical and geological engineering methods to determine the optimum working face width for the safe and efficient extraction of manganese ore extraction at the Venarch Mine (Qom Province, Central part of Iran). The underground workings on the west face (240m depth) present significant geotechnical challenges due to the presence of faults, clay seams, and loose rock layers. These features require careful careful stability analysis to ensure the safety and economic viability of the underground mining operation. This study uses three established methods for rock mass classification and stability assessment. The Rock Mass Rating (RMR) classification system, the Q-system (Barton), and the numerical analysis using Plaxis 3D software. A robust and data-driven approach to determining the optimum workshop width was achieved by employing a synergistic combination of these three methods, together with meticulous ground observations and expert engineering judgement. This framework offers a powerful tool for determining the optimal and safe workshop width for this sector of the mine. By capitalizing on the strengths of each methodology, this research aims to establish a data-driven and informed decision-making process to ensure a stable and economically viable approach.

The increase in population, combined with climate change, has significant implications for water and food in Iran. Given the intensification of these issues, concerns about the future are heightened. It is crucial to reconsider the logic and practices of governance and policymaking in the country with a forward-looking perspective, making this a serious demand and a vital necessity. The average annual consumption in Iran is about 96 billion cubic meters of water, which is about 8% more than the total incoming water resources of Iran (89 billion cubic meters). Hence, a big gap has emerged between water needs and sustainable water, which can lead the country to a social and environmental crisis affecting the lives of future generations. In this research, by using documentary data and their qualitative, empirical analysis, first the available water and the country's water needs were studied in relation to food needs. Then, possible solutions to deal with the water crisis were evaluated. The result showed that in addition to the known water limitations, land resources also create significant obstacles for sustainable food production for Iran's growing population; modernization the irrigation system, using the greenhouse system, and building more dams cannot solve the country's water crisis in a sustainable and cost-effective way; As a result, hoping for self-sufficiency in the long term will not have a favorable perspective, instead, policymakers should make their main goal to ensure the food security of the country, which can be done through optimally exploiting water and soil resources, strengthening other sectors of the economy and the possibility of importing Water-intensive goods and the production of these goods in water-rich areas of the world through joint ventures.

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 article‎, ‎we present an $SIR$ model with a general nonlinear incidence rate‎, ‎assuming a $100\%$ effective vaccine‎. ‎This system has a disease-free equilibrium point‎, ‎corresponding to which a basic reproduction number $\mathscr{R}_0$‎​ ‎is obtained‎. ‎For $\mathscr{R}_0 > 1$‎, ‎the system will also have an endemic equilibrium point‎. ‎We study the local and global stability of these equilibrium points‎. ‎Considering the change in the stability status of the equilibrium points with the change of one of the parameters‎, ‎we will examine the existence of a transcritical bifurcation‎. ‎Additionally‎, ‎we calculate the sensitivity index of $\mathscr{R}_0$​‎, ‎which essentially determines the susceptibility of the system to the existing parameters‎. ‎Finally‎, ‎we examine the obtained results with numerical examples‎.

‎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.

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.

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.

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.