فیلترها/جستجو در نتایج    

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متن کامل


اطلاعات دوره: 
  • سال: 

    1403
  • دوره: 

    13
  • شماره: 

    4
  • صفحات: 

    135-150
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    39
  • دانلود: 

    9
چکیده: 

A B S T R A C T Green city is one of the approaches to sustainable development. “green city” is an environmentally friendly city compatible with the concept of sustainable development and can be used for the welfare and security of its inhabitants. Based on the concept of a “green city,” urban managers try to have the least destructive effect on the ecosystems upon which cities rely. Green city is one of the sustainable development approaches that reduce the environmental footprint of cities. The purpose of this study is to evaluate the situation of Mashhad metropolis in terms of the objective characteristics of the green city. In this study, 14 indicators of electricity consumption per capita, green space per capita, population density, water availability, sewage availability, superior public transportation network, urban mass transportation, traffic reduction, annual production waste per capita, carbon monoxide, concentration nitrogen dioxide, sulfur dioxide concentration, particulate matter concentration, and air quality were exerted. To determine the importance of research indicators, the Shannon entropy method, and the status of Mashhad city areas in terms of green city indicators, the VIKOR multi-criteria decision-making method has been applied. The results showed that most areas of Mashhad are average and below average in terms of green city characteristics, and only District 9 is in very good condition (0.636). Also, based on the results of this part of the research, District 5, with the value of VIKOR index of 0.969, is in the last rank in terms of objective characteristics of the green city Extended Abstract Introduction Green city is one of the approaches to sustainable development. A “Green city” is an environmentally friendly city compatible with the concept of sustainable development and can be used for the welfare and security of its inhabitants. Based on the concept of a “green city,” urban managers try to have the least destructive effect on the ecosystems upon which cities rely. Green cities constantly try to manage their environmental effects by reducing waste, increasing recycling, reducing air pollution, increasing population density, developing open urban spaces, and encouraging the development of sustainable local businesses. Green cities were first used to evaluate 30 European cities by the Economist Intelligence Unit (EIU) in 2009 with the financial support of Siemens and the aim of reducing the environmental effects of human activities in cities. In that study, eight indices of carbon dioxide, energy, construction, transportation, water, recycling and land use, air quality, and environmental governance were used. Later, the Economist Intelligence Unit, with the financial support of Siemens, evaluated the status of the green city index in 17 Latin American cities, 15 African cities, 22 major Asian cities, and 27 cities in United States, Canada, Australia, and New Zealand. In recent years, even some Western Islamic scholars have, in various publications, shown that Islam is an ecological religion. In Iran, the issue of protecting the environment has not received much attention regardless of its rich cultural and religious background and its confirmation in Article 50 of the Constitution of the Islamic Republic of Iran. Mashhad is the second metropolis of Iran, located in North-East of Iran, and is one of the counties of Khorasan Razavi Province. According to the 2016 Iranian Population and Housing Census, its population was 3057679 people (The Vice-Presidency of Planning and Development of Mashhad Municipality). In Mashhad, due to several reasons including the presence of Imam Reza Shrine (PBUH) and arrival of millions of pilgrims per year, population growth, increased garbage production (production of 896534 tons of garbage in 2016 (The Vice-Presidency of Planning and Development of Mashhad Municipality), air pollution (increased number of unhealthy days from 46 days per year in 2015 to 88 days in 2016 for sensitive groups and 4 days of unhealthy air for all groups in 2016 (Center for Monitoring Environmental Pollutants of Mashhad Municipality) the 2025 vision of the city has paid attention to the environment in the form of five general objectives; however, just like the national level, no specific pattern for environmentally-compatible urban development, such as green city, is determined. Analysis of the green city index in Mashhad metropolis can considerably contribute to urban managers and planners in addition to providing a pattern for evaluating the present situation in other cities of Iran and improving the quality of life regardless of the current status of the urban environment in Iranian cities; we can preserve these environments as parts of the natural environment for future generations.   Methodology In terms of its goal, the present study is an applied one; in the study, drawing upon other studies and library sources and considering the conditions of Iran and the metropolis of Mashhad in terms of green city, 14 quantitative indices were exerted. To this end, the required data for the quantitative indices was gathered by library research from the relevant institutions. Next, the weights of quantitative indices were determined using Shannon's entropy. Then, using the VIKOR method of multi-criteria decision-making, the status of various districts of the metropolis of Mashhad in terms of quantitative indices of green city was determined. Finally, the map of the spatial distribution of quantitative indices was drawn using the ARC GIS software package.   Results and discussion In this study, to analyze the status of the metropolis of Mashhad in terms of green city features, 14 quantitative indices were used. Considering the value of the VIKOR index ranges from 0 to 1, various districts of Mashhad can be classified into five categories; very satisfactory, satisfactory, average, unsatisfactory, and very unsatisfactory in terms of quantitative indices of green city. The results of the current situation of Mashhad showed that in terms of objective indicators of the green city, District 9 of Mashhad metropolis with a value of VIKOR index of 0.056 is in first place, and the seventh region with a value of VIKOR index of 0.433 is in second place. Also, based on the results of this part of the research, District 5, with the value of VIKOR index of 0.969, is in the last rank in terms of objective characteristics of the green city.   Conclusion Similarly, the results of studies by Afshar (2011) and Shabani et al. (2017) on Tehran metropolis are indicative of the unsatisfactory situation of Tehran (the biggest metropolis of Iran) in terms of green city features. Comparing the results of the studies by Afshar (2011) and Shabani et al. (2017) with the present study on Mashhad (the second biggest metropolis of Iran) reveals the necessity for a comprehensive plan toward achieving green cities. It should be mentioned that, due to the specific conditions of Mashhad metropolis and availability or unavailability of the required data, the indices used in the present study are somewhat different from the ones used by Afshar (2011) and Shabani et al. (2017).   Funding There is no funding support.   Authors’ Contribution All of the authors approved the content of the manuscript and agreed on all aspects of the work.     Conflict of Interest Authors declared no conflict of interest.   Acknowledgments We are grateful to all the scientific

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نویسندگان: 

Faraji Hassan

اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    13
  • شماره: 

    3
  • صفحات: 

    31-45
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    144
  • دانلود: 

    16
چکیده: 

A B S T R A C TFor choosing suitable place multiple methods are introduced, which examine the qualities, methods and patterns of location selection. The current methods use global approach and do not pay attention to spatial differences, environmental variation in variables, local changes modeled by local weighting indicators. It has been selected as a case study to evaluate the EMS center of Fars province and to evaluate the indicators of distance from the power plant, distance from logistics centers, industries, transportation terminals, hospitals, hotels and tourism, cities, rural areas and custom centers. has been used, using the AHP method to weight the qualities, and then for local weights, non-overlapping neighborhood filtering within a radius of 25 km are used and calculate the corresponding changes, quantity, ratio Presented in this article, the obtained weights, then the compute local weighted layers, and then local weight was multiplied in the normalized layers and the final layer were obtained. In the next step, it was combined and calculated to compare the data using the global method. The results of the two methods were transferred to the points of the EMS and the results were analyzedExtended AbstractIntroductionIn geographical studies and spatial planning, there are different approaches to choosing the right place for all kinds of applications and uses, and a process is followed to choose the best places. This process includes stating the research problem (cognition), choosing the criteria and preferences of decision makers and how to determine the weight of indicators, combining criteria (design) and finally, choosing the best option. In the current methods of spatial decision, the criteria are given a fixed weight, while in geographical locations, the distribution of geographical phenomena is not uniform. In this case, attention should be paid to the spatial distribution pattern of geographical phenomena based on the principle of sensitivity of the range of changes, the size of the range of changes affects the outputs, and the data with a smaller range of changes also have a lesser effect on the output. The data with a larger range of changes will have a more significant effect on the output. Therefore, in spatial analysis, indicators that have small changes are less important. Local models have been presented to model local changes in spatial multi-criteria decision-making; in this research, the main issue is how to model the local changes that affect the expected outputs. MethodologyThe research process is based on multi-criteria spatial decision-making methods (national and local). First, spatial patterns of indicators were analyzed through exploratory analyzes of ESDA spatial data. Then based on the review of the research criteria, the direct weighting method was used to calculate the weight of the indicators, and the experts were asked to specify the weight of the criteria in the range of 1 to 10. The opinions were combined, and the final weight was obtained. First, the data were spatially modelled to model and calculate the local weights. Then Block Statistics spatial filter without overlap was used to determine the neighborhood. The range of local changes, maximum and minimum values, were calculated, and local weights were obtained based on that. Finally, the information layers were descaled. After that, the unscaled criterion layers were multiplied by the national weights and the final national scores were obtained. In the next step, the data of the evaluated information layers (local and national) were transferred to the points of emergency databases. Based on the analysis, the fit was done. Results and discussionGeneral or global weights pay attention to the relative importance of indicators, which is the starting point for calculating local weights. Based on the research results, the most critical indicators are industries, cities and hospitals, which are more important in the location of road emergency stations. However, in order to achieve better results, it is necessary to build a local weight layer. The results of the research show that the indicators' weight and the difference in the criteria (general weight) are not equal in the entire geographical area, and the areas with a larger range of changes have a higher coefficient.Because, unlike general weights that are obtained based on different methods, local weights are estimated based on the principle of sensitivity of the range of changes and are changed spatially, and a fixed value is not considered for all areas. According to the research findings, the highest level in the general and local EVALUATION method corresponds to 0.5 to 0.7. Based on the local (geographic) weight method, it is less than the national or general method in the range of 0.9 to 1. Furthermore, this is due to the more precise nature of this method, which models the effects of local changes. To evaluate the compliance of the emergency centers with the final maps of suitability assessment, the information on the suitability maps was transferred to the map of the emergency center points of Fars province. Based on the EVALUATION of 207 emergency stations, according to the general method, 14 percent are in the high group (0.9-1), and according to the local or geographical method (16.9), percent are in this group. ConclusionAt the level of space and geographical regions, phenomena and geographical complications are not uniformly distributed, some phenomena have a homogeneous distribution, and some have a heterogeneous distribution. On the one hand, the phenomena and decision issues are affected by the context in which they are formed and evolve; on the other hand, these phenomena are placed in the network of mutual relations. Furthermore, the results of the set of phenomena may differ from the results of the phenomena individually and separately; in this article, an attempt has been made to address the issue that in spatial analysis and planning, it is necessary to pay attention to geographical differences in decision-making. Furthermore, it should not be evaluated in general terms of spatial decision problems; one of the methods of modelling these differences and spatial changes is to consider the local weight of the criteria. Based on the research findings, local (geographical) and national analysis results are different and can better show these changes. On the other hand, the pattern of spatial differences also has its spatial pattern, and paying attention to these differences in spatial differences can be the subject of further studies. FundingThere is no funding support. Authors’ ContributionAuthors contributed equally to the conceptualization and writing of the article. All of the authors approved the content of the manuscript and agreed on all aspects of the work declaration of competing interest none. Conflict of InterestAuthors declared no conflict of interest. Acknowledgments We are grateful to all the scientific consultants of this paper.

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بازدید 144

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نویسندگان: 

Lugten Peter

اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    17
  • شماره: 

    45
  • صفحات: 

    159-174
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    157
  • دانلود: 

    16
چکیده: 

This paper examines the work of Immanuel Kant in the light of a new theory on the nature of truth, knowledge and falsehood (the Inversion Theory of Truth). Kant’s idea that knowledge could be absolutely certain, and that its truth must correspond with reality, is discredited by a dissection of the Correspondence Theory of Truth. This examination of the nature of truth, as well as knowledge and falsehood, is conducted with reference to Sir Karl Popper’s writings on regulative ideas, the criterion of demarcation and the principle of falsifiability. It is argued that if truth is to be regarded as certain, it should be used to describe objects and events in the objective (noumenal) state, and that subjective knowledge must contain (and is improved by) falsehood. Perceptions and knowledge are obtained by the biological and evolutionary process of Active Subjectivism. Ideas we have knowledge of can be metaphysical or scientific, according to Popper’s Criterion of Demarcation. Kant’s “Copernican revolution” claim that our intellect imposes absolutely true laws on nature could not allow for the possibility that ideas might be constructed from fallible perceptions, and hence that all knowledge is uncertain. Instead, he developed a Critique of Practical Reason in which religion, though not provable through logical reasoning, could be proved by our innate moral sense, giving us a Categorical Imperative that could lead to perverse results. By rejecting the absolute certainty of a priori knowledge, and admitting a degree of essential falsehood, we arrive at a more reasonable grounding for moral behavior.

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بازدید 157

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مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    52
  • شماره: 

    1
  • صفحات: 

    43-49
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    120
  • دانلود: 

    20
چکیده: 

Monitoring and EVALUATION of transformers are essential to prevent their insulation failure. In this paper, the use of 2-furan-carboxaldehyde (2-FAL) and methanol (MeOH) concentrations as the main products of paper insulation degradation, and insulation condition markers, has been studied. In order to study the degradation process and production of degradation products, the thermal aging process of the transformer insulation system was implemented in laboratory conditions. The results of laboratory studies show that in the early stages of degradation the amount of MeOH is significant compared to 2-FAL. Also, the estimation of the degree of polymerization (DP) in the early stages of degradation (DP>800) through MeOH concentration and with decreasing DP (DP <800) through 2-FAL concentration is closer to the real value. The results of studies performed on 35 distribution transformers confirm the production of significant amounts of MeOH in the early stages of degradation. Also, the estimated DP values for the studied transformers were obtained through 2-FAL and MeOH concentration. The results show that estimating the amount of DP through MeOH concentration is associated with a probability of error of about 9% compared to estimating DP through 2-FAL concentration.

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اطلاعات دوره: 
  • سال: 

    1403
  • دوره: 

    13
  • شماره: 

    4
  • صفحات: 

    151-171
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    52
  • دانلود: 

    11
چکیده: 

A B S T R A C TToday, all officials involved with the challenges of city sustainability have accepted the idea of a smarter city, using more technologies, creating better living conditions and protecting the environment for a better quality of life. The central part of the metropolis of Tabriz is based on Region 8 and part of Region 10, a historical-cultural area with an area of 286 hectares and a population of about 40 thousand people in 8 neighbourhoods. This research was compiled to evaluate and explain the regeneration of the central part of Tabriz city with the approach of smart growth and in line with the sustainable development of problematic neighbourhoods in the 8th district of Tabriz metropolis. The present review is methodologically practical, to describe and analyze the goals of regeneration based on library studies. The statistical population of the research includes experts and people living in the central context. In the first part, the Delphi method was used by asking experts. In the second part, the structural equation method of SPSS and AMOS software is used. According to the results of using the scales of design, pedestrian-oriented, intergenerational justice in the actual situation and 3 indicators of management and productivity, stable and value-creating jobs are in the potential situation. Also, two environmental indicators with the most direct and indirect effects and a cultural index have been decisive in the regeneration with the smart growth approach in the central part of Tabriz city. Therefore, in the regeneration of the central part, the studied indicators should be used simultaneously and integrated into the reconstruction projects of the central fabric of the city to lead to smart sustainabilityExtended AbstractIntroductionSmart growth is considered a lever for revitalizing neighborhoods and urban centers. In a general scenario of smart growth, knowing the time and resources of investment provides a new and sustainable life in the city center and worn-out and old textures. Moreover, finally, it will improve the quality of urban neighborhoods, especially worn-out ones, and revive them. Tabriz metropolis, one of the most important and largest cities in the country, with a long history of settlement, especially the central and old texture, due to developments in information and communication technology, extensive environmental, social, and economic changes in terms of time requirements, the traditional texture of roads, Deterioration of residential units, lack of equipment, infrastructure and urban services and environmental problems have caused the failure and physically turned into inefficient and problematic textures. Urban planning and development science must adopt a new decision and approach to face the existing and complex issues of worn-out texture. The main problem of the research is to evaluate and explain the regeneration of the central texture and strengthen them in line with the sustainable development of the problematic neighborhoods of Tabriz metropolis according to the solutions and principles of smart urban growth. Therefore, the main goal of this research is to answer the following question:- What are the effective indicators and components in the regeneration of the central texture of Tabriz metropolis with a smart growth approach? MethodologyThis research is applied and fundamental in terms of purpose and descriptive-analytical. The collection methods are based on documentary and library studies, surveys, and interviews. In the first part, qualitative data was prepared with an open questionnaire and through interviews, as well as the review of documents and quantitative data used in this research numerically and through the weighting of Delphi questionnaires based on the consensus index model to determine importance, certainty, and priority. The panel members were 19 people (including 5 university faculty members, 7 field research experts, 4 executive experts, and 3 graduate students) selected based on the non-probability (targeted) method. In the second part, Cronbach's alpha method was exerted to measure the reliability of the questions, which was obtained as 0.89. In order to evaluate the validity of the questionnaire, the Lawshe method was exploited. The statistical population of the second part includes District 8 of Tabriz, which is the central texture of the city and is equal to 34,231 people. According to Cochran's formula, the sample size was equal to 379 people. Results and discussionIn the next step, path analysis was performed using AMOS 23 software to compare the integrated model with the hypotheses. The results of the path analysis, while verifying the structures, show that the value of the index of the critical ratio to the degree of freedom (CMIN/DF) is equal to 4.01, which is an optimal value for the model fit. Also, the goodness of fit index (GFI) is 0.952, which indicates the acceptability of this amount for the optimal fit of the model. The value of the root means the square error of estimation (RMSEA) is 0.065, which is acceptable because it is smaller than 0.08 and indicates the confirmation of the research model. Also, the Tucker-Lewis index (TLI) is 0.917, the comparative fit index (CFI) is 0.92, and the normalized parsimonious fit index (PNFI) is 0.882, which all indicate that the fit and verification of the research model are desirable.Therefore, none of the objects are removed and remain in the model. Therefore, it is confirmed that the factor structure of regeneration indicators with the smart growth approach has reliability and construct validity. Also, the second-order factor analysis shows that the factor loadings of all regeneration indicators with the smart growth approach are greater than 0.4 and are significant at the 95% probability level. According to the results, the environmental dimension with a factor loading of 0.94 has the most significant effect on urban regeneration with the smart growth approach in the central texture of Tabriz city. After that, quality of life with a factor loading of 0.92, social dimension with a factor loading of 0.88, economic dimension with a factor loading of 0.83, physical dimension with a factor loading of 0.81, transportation dimension with a factor loading of 0.74 and cultural dimension in order with a factor loading of 0.72, are in the following ranks.According to the final structural model results, the environmental index has the highest value, with a direct effect of 0.594 and an indirect effect of 0.275. Moreover, after that, respectively, the quality of life index with a direct effect of 0.513 and an indirect effect of 0.236, a social index with a direct effect of 0.476 and an indirect effect of 0.217, an economic index with a direct effect of 0.451 and an indirect effect of 0.222, Physical with the direct effect of 0.435 and indirect effect of 0.205, mobility index with the direct effect of 0.373 and indirect effect of 0.182 and cultural index with the effect of direct values of 0.295 and indirect effect of 0.153 are influential in regeneration with smart growth approach in the central part of Tabriz city. ConclusionIn this research, seven main indicators related to the subject were investigated. The results showed that the environmental index with the most significant direct and indirect effect is the focus of the EVALUATION. After that, dimensions and indicators of quality of life, social index, economic index, physical index, mobility index, and cultural index have been influential. According to the results, the urban environment index was analyzed as the most important factor at a high level, and this means that for urban regeneration with a smart growth approach, improving the environmental and physical conditions in the worn-out and central texture of Tabriz city in the current situation is a priority. It is first. This is the most well-known part of regeneration with a smart growth approach. The analysis results show that this is not the case only in the case of transportation infrastructure. However, more comprehensive urban infrastructure such as the urban landscape, open spaces, green and parks, etc. are also crucial in improving the physical conditions of the infrastructure. Also, this study's results show that the economic sector's importance is as important as improving the physical conditions of the infrastructure. In addition, in the worn-out texture of District 8 of Tabriz city, the sociocultural sector is essential, and the revival of historical and cultural resources is considered one of the urban regeneration options. Funding There is no funding support. Authors’ Contribution All of the authors approved the content of the manuscript and agreed on all aspects of the work.  Conflict of Interest Authors declared no conflict of interest. AcknowledgmentsWe are grateful to all the scientific.

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نویسندگان: 

Jamshidi Amin | Fereidooni Davood

اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    15
  • شماره: 

    1
  • صفحات: 

    105-118
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    138
  • دانلود: 

    14
چکیده: 

Strength measurement of rock requires testing that must be carried out on test specimens with particular sizes in order to fulfill testing standards or suggested methods. Often, the coring process breaks up the weaker core pieces, and they are too small to be used in either index tests or conventional strength tests such as point load index (Is) and Brazilian tensile strength (BTS). One of the index tests to indirectly determine the rock strength is the block punch index (BPI) test, which requires flat disc specimens without special treatment. This study aimed to evaluate the applicability of the BPI test for predicting the uniaxial compressive strength (UCS), BTS and IS of the sandstones by empirical equations. Also, we have compared the performance of the BPI and IS for predicting the UCS and BTS. It was experimentally shown that BPI is a reliable method for predicting the UCS, BTS and Is of the sandstones under study. Moreover, the results indicate that BPI could be utilized with same importance as Is for predicting the UCS, while predicting the BTS by Is appears to be more reliable than BPI.

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مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
نویسندگان: 

اطلاعات دوره: 
  • سال: 

    0
  • دوره: 

    9
  • شماره: 

    2
  • صفحات: 

    28-39
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    310
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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نویسندگان: 

مرادی زینب

اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    1
  • شماره: 

    68
  • صفحات: 

    47-63
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    75
  • دانلود: 

    0
چکیده: 

1 بیماری همه گیر کرونا و پیامدهای آن باعث ایجاد اضطراب در اقشار مختلف جامعه شده است. به ویژه، گذار مجدد از آموزش آنلاین به آموزش های حضوری و آسیب های ناشی از این فرآیند، روند آموزش برخی دانش آموزان را با مشکل مواجه کرده است. بنابراین شناسایی نگرانی های دانش آموزان و درک پیش بینی های اضطراب در طول بازگشایی مراکز آموزشی به ما امکان می دهد تا به علل اصلی اضطراب پس از دوره ی همه گیری کرونا و بازگشایی های مجدد مراکز آموزشی بپردازیم.  این تحقیق یک پژوهش کیفی از نوع تحلیل محتوا است و جامعه ی آماری آن، دانش آموزان مقطع متوسطه دوره دوم شهر تهران طی بازگشایی های مجدد مدارس بعد از حدود دو سال آموزش انلاین در اواخر سال تحصیلی 1400-1401 و پس از همه گیری کرونا بوده که با روش نمونه گیری هدفمند 40 شرکت کننده، 20 شرکت کننده دختر و 20 شرکت کننده که دارای ملاک پژوهش بودند انتخاب شده و پس از مصاحبه با شرکت کننده ها و رسیدن به نقطه ی اشباع نظری، نتایج حاصل از تحلیل مصاحبه ها، حاکی از دو درون مایه ی اصلی، ساختار اجتماعی و نهاد خانواده و فرد بوده است.

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بازدید 75

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نویسندگان: 

Reyhani Poul Soheyl | Yeganeh Sakineh

اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    20
  • شماره: 

    140
  • صفحات: 

    52-65
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    69
  • دانلود: 

    0
چکیده: 

1The aim of present research in the first stage was to extract astaxanthin from Haematococcus pluvialis using acid-acetone method and then nanoencapsulation of the pigment using maltodextrin-sodium caseinate coating. In the next step, antioxidant and antibacterial activities of nanocapsules carrying astaxanthin and the free form of the pigment was evaluated. In order to evaluate antibacterial activity of the samples, Listeria monocytogenes, Staphylococcus aureus, Streptococcus iniae, Bacillus subtilis (Gram positive), Yersinia ruckeri, Escherichia coli and Enterobacter aerogenes (Gram negative) were used. The results showed that the antioxidant activity of nanocapsules carrying astaxanthin is significantly higher than the free form of pigment (p<0.05); In addition, this activity was improved by increasing the concentration of samples from 100 to 200 µg/ml (p<0.05). By astaxanthin nanoencapsulation, the diameter of non-growth zone of the studied bacteria increased (p<0.05), but minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the pigment and its carrier nanocapsules decreased (p<0.05). According to the results of zone of inhibition, Gram positive (except Listeria monocytogenes) and Gram negative bacteria were resistant up to concentrations of 60 and 80 µg/ml of samples, respectively. In the following, the MIC and MBC of the pigment (free and nanoencapsulated forms) for the seven bacteria ranged from 50 to 400 and 100 to 500 µg/ml, respectively. The results of EVALUATION the antioxidant and antibacterial activities of nanocapsules carrying astaxanthin during storage period (30 days at 4ºC) indicated stability and no significant change of these properties (p>0.05). According to the values of diameter of non-growth zone, MIC and MBC, Listeria monocytogenes was the most sensitive bacteria against astaxanthin and its carrier nanocapsules. Based on the findings, astaxanthin extracted from Haematococcus pluvialis has antioxidant and antibacterial activities, and these properties are improved by the pigment nanoencapsulation using maltodextrin-sodium caseinate coating.

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بازدید 69

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اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    53
  • شماره: 

    4
  • صفحات: 

    255-271
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    102
  • دانلود: 

    17
چکیده: 

This experiment was designed to survey the nutritive value and estimate protected-protein level of Protanomix as a new protein source and compare it with soybean meal. Protanomix is a brown powder by separating the precipitate produced from the reaction of tannin with corn-steep liquor. Crude protein (CP) and metabolizable energy (ME) in this protein source is nearly similar to soybean meal, and more than 80% of its protein content is insoluble. In this study, potential of in vitro gas production in Protanomix was significantly (P˂0.001) lower than the control treatment (soybean meal); however, substitution of soybean meal at different levels of Protanomix in experimental diets did not lead to significant changes in gas production parameters (P˃0.05). Comparing Protanomix with soybean meal (control) showed that in vitro truly degraded dry matter (IVTDDM), estimated metabilizable energy (ME) and pH were similar (P˃0.05). However, short chain fatty acids (SCFA), apparently in vitro organic matter digestibility (IVOMAD) and ammonia nitrogen (N-NH3) were significantly higher in soybean meal (P˂0.01) than Protanomix, while partitioning factor (PF), microbial protein synthesis (MPS) and efficiency of microbial protein synthesis (EMPS) were greater in Protanomix than soybean meal (P˂0.05). Nonetheless, when soybean meal was substituted with different levels of Protanomix in the experimental diets, only concentration of ammonia nitrogen (N-NH3) was significantly decreased (P˂0.001).

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بازدید 102

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