In recent years, dye wastewater caused serious effects on environmental ecology and human health. Thus, in the present study, hydroxylamine (HA) was used to improve the Fe3O4/H2O2 process for ...removing the typical dye pollutant (tartrazine). Only 2.8% tartrazine could be removed in Fe3O4/H2O2 system within 60 min at the reaction of 1 g/L Fe3O4, 1 mM H2O2, and pH 4 while 97.5% tartrazine could be removed within 20 min after adding 1 mM HA into the Fe3O4/H2O2 system. Compared with Fe3O4/H2O2 system, the removal rate for removing tartrazine in Fe3O4-HA/H2O2 system could enhance more than 100 times. Electron paramagnetic resonance tests (EPR), radical quenching experiments and quantitative determination demonstrated that •OH was the major reactive species for removing tartrazine in Fe3O4-HA/H2O2 system and •OH produced concentration in Fe3O4-HA/H2O2 system was also much higher than that in Fe3O4/H2O2 system. The key factors affecting tartrazine removal in Fe3O4-HA/H2O2 system were also conducted. The optimal HA dosage, Fe3O4 dosage, and H2O2 dosage was 1 mM, 1 g/L and 1 mM. The optimal initial pH in Fe3O4-HA/H2O2 system was 3, but compared with Fe3O4/H2O2 system, the tatrazine removal efficiency could significantly improve under any initial pH condition. Fe3O4-HA/H2O2 process had strong adaptability to inorganic ions and good applicability to different pollutants. Fe3O4-HA/H2O2 process also exhibited good recycle ability for tartrazine removal. Overall, Fe3O4-HA/H2O2 process is an effective and good practical applicability approach for dye wastewater treatment.
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•A high NRE of 70% was obtained by a PNA-AICB with 50 mg-NH4/L influent.•Control of DO and aeration rate were the key factors for the stable operation.•A long time was needed for ...performance recovery via aeration adjustment.•Candidatus Brocadia and Nitrosomonas were dominant after the recovery.•Activated AOB, dominated AMX, suppressed NOB & controlled HB were vitally important.
A one-stage airlift internal circulation biofilm reactor was continuously operated for 668 days to treat 50 mg/L of ammonia wastewater to pursue the long-term stability of partial nitritation and anammox (PNA) process. The operational performance and microbial community structure of the biofilm and the flocs were investigated. A nitrogen removal efficiency (NRE) of 70% was obtained successfully at a dissolved oxygen (DO) of 0.05–0.15 mg/L by regulating aeration rate. The microbial analysis indicated Candidatus Brocadia (29.5%) and Nitrosomonas (6.8%) were dominant in both biofilms and flocs. It was found that DO control and aeration rate were the key factors in performance stability, and a stable performance could be recovered and maintained under oxygen-limiting conditions. Further, the achievement of activated ammonia oxidation bacteria (AOB), dominated anammox bacteria (AMX), suppressed NOB, and controlled heterotrophic bacteria (HB) in the biofilms played a major role in the long-term stable operation.
AbstractProblem definition: The need for attention has been raised more than before to the border areas and the competitiveness of these areas by entering the age of globalization. The ...competitiveness of border regions is an effort to eliminate unfavorable social and economic situations and protection and pay attention to the capabilities of these areas as well as the improvement of physical, natural, and artificial capitals.Purpose: The present research has been done with the aim of expressing competitiveness in Kurdistan and analysis of possible situations from future competitiveness in the province.Methodology: The type of the current research is applied in terms of purpose and it is exploratory in terms of nature based on the future research method. Data collection has been done in both library and field methods. To express the status of indicators and extraction of key factors and scenarios from forecasting software, MicMac, and ScenarioWizard were used. Meta swot software was used to identify the competitiveness strategy. Qualitative data were gathered with an open questionnaire and document review and quantitative data were collected numerically which was used in the first stage from the open questionnaire for general extraction of effective factors on competitiveness. In the second stage, key factors were extracted from the weighting of Delphi questionnaires in MicMac software.Results: The results indicated that the competitiveness model of Kurdistan is unstable and fragile. In addition, the research coefficient has shown the realization of scenarios with unfavorable situations. The best solution for moving from unfavorable scenarios to favorable situations has been to emphasize indicators with the most success, inimitability, and compatibility with competitiveness.Keywords: Key Factors, Scenario, Strategy, Kurdistan Province.IntroductionFrom the 1970s onwards, the border regions were placed in the economic core, and competitiveness is a central issue and a means to achieve the desired economic growth and sustainable development. In the global economy, it is a key criterion for evaluating the degree of success and the possibility of gaining a position. In this connection, serious attention is paid to the competitiveness of the regions in this direction and generally, there are significant differences between the regions of a country in terms of economic performance. On the other hand, many important levers of competitiveness can only be applied at regional levels. In this connection, while explaining the competitiveness situation of Kurdistan province and extracting key factors, the study aims to identify the possible competitiveness situations of the province in the framework of the scenario. Moreover, the competitiveness strategies of the region have been extracted. Materials and MethodsThe research type is applied in terms of purpose and descriptive-analytical in terms of data collection. Data collection has been done in two forms: library and field methods. In this research, 60 indicators have been evaluated in 4 dimensions using MicMac and ScenarioWizard software to determine the key factors and competitiveness scenarios of the province. Then, Metaswat software was used to identify the best strategy. It should be noted that according to the method used to analyze and present strategies, the research sample was expert-oriented. For this purpose, a sample of experts has been selected using a targeted method. In this regard, the acceptance criteria in the sample were: having research activities in the field of regional competitiveness, implementation experience in the management and planning of the province, and being an expert in the fields of economics, geography, and management. In this regard, after conducting 20 interviews, the sample size reached saturation. In addition, to ensure the validity of the measurement, a questionnaire was sent to 5 professors and after receiving the experts' corrective opinions, the questionnaire was compiled. In order to ensure the reliability of the research, 10 forms were completed by retesting, and these forms were presented to 10 experts after 10 days. Finally, the evaluation results were checked in two forms. The coefficient is estimated to be 0.80. Research FindingsBy examining the distribution of indicators in the diagram of the direct and indirect effects on the future trend of the competitiveness of the Kurdistan region, it can be said that most of the variables are around the diagonal axis of the distribution plane. Therefore, the system has an unstable state. For this purpose, 5 categories can be identified (controlling, bidirectional, regulatory, dependent, and output). In this regard, out of thirty possible and realizable scenarios, only two scenarios have been in a favorable situation. In the second rank, there are static factors, which have 9 scenarios. Meanwhile, scenario 6 has the highest coefficient (80%). In the next order, scenarios with an unfavorable situation are placed. Seventeen scenarios are assigned to this category. Meanwhile, scenario 30 has the highest realization coefficient with a coefficient of 90%. Discussion of Results and ConclusionConsidering the results of the study, investment security in the province has been at a low level and the government has not supported businesses in a favorable way. In addition, research and development units (R&D) in companies are not at the desired and appropriate level. Therefore, the specialization of production units is not based on merit and it was at a medium and low level and could not compete with foreign samples. Therefore, foreign investors are not willing to invest. In such a situation, marketing for the production of products has been very small. In this regard, in order to reduce the coefficient of realization of unfavorable scenarios, in contrast to the desire for favorable scenarios, according to the goals that can be drawn and the resources available in the province, the most successful and inimitable factor for metal and non-metal mines is being on the border, customs, and infrastructure facilities. In addition, the most compatible factor with the competitiveness of the existence of a common culture and language in the border areas of the two countries, customs, and border markets were production-transformation industries. Macro policies, social security, sanctions, and relations between countries have been identified as the most important obstacles to the competitiveness of Kurdistan Province.
The objective of this study was to investigate how higher secondary students perceive the online and to identify the factors that affect their perceptions during the Covid 19 epidemic in Bangladesh. ...The research is quantitative in nature. 1078 students' data were gathered using an online survey questionnaire through multistage random sampling. The results demonstrate that three factors—online learning's challenges and difficulties, the effectiveness of online learning, and students' motivation for online learning—have a substantial impact on how students view online learning. Despite various difficulties using online platforms, students have a favorable attitude toward online learning.
One of the main factors in increasing income and employment, as the most important pillar of livable cities, is attracting the creative class and investors. Implementing innovative plans and making ...basic investments in line with sustainable development requires many conditions and fields, one of the most important of which is the availability of cultural and social fields. But so far, this field and categories have been less in the focus of attention. For this purpose, in this study, an attempt was made to take into account the role and position of culture and social contexts in attracting investors to the city of Mashhad by using the descriptive-analytical method. For this purpose, emphasis was mainly placed on the main drivers of this field. To reach this goal, the required information was collected from library and field sources. In the field part, the research sample included 30 qualified people in this field, who were selected by purposeful sampling. Micmac software was also used for data analysis. The results showed that the factors that influence the attraction of the creative class and investors and the increase of targeted investments in the city of Mashhad are: Investment in research and development, laws and regulations, number of resident foreigners, information and communication technology, appropriate financing, flight destinations and active airlines, rate of invention and innovation, level of literacy and education, performance evaluation and reward system, financial policies, flexible financial systems, scientific and technical exchanges and interaction between university and industry.
•Plot context primarily explains tree-related microhabitats occurrence.•Plot context is a black box combining environmental, management and biotic factors.•From the literature, we identified 21 ...factors that may play a key role in TreM formation.•A sub-set of 9 factors that should be prioritised in the future is suggested.
Tree-related microhabitats (TreMs) have been identified as key features for forest-dwelling taxa and are often employed as measures for biodiversity conservation in integrative forest management. However, managing forests to ensure an uninterrupted resource supply for TreM-dwelling taxa is challenging since TreMs are structures with a limited availability, some of which are triggered by stochastic events or require a long time to develop. At the tree scale, the role of tree species, diameter at breast height (dbh) and status (i.e. living vs standing dead) for favouring TreM occurrence has been quantified and modelled in several studies, since these tree features are routinely recorded in the field. However, TreM occurrence remains difficult to predict, hampering the elaboration of applicable management strategies that consider TreMs. Using an international database encompassing 110,000 trees, we quantified the explanatory power of tree species, dbh, status, time since last harvest and plot context for predicting TreM occurrence at the tree level. Plot context is so far a “black box” that combines local environmental conditions, past and current management legacies, with local biotic features that have high explanatory power for predicting TreM occurrence. Then, based on the literature, we established a set of 21 factors related to site, stand and tree features for which there is a strong assumption that they play a key role in TreM formation. Finally, we identified a sub-set of nine features that should be recorded in the future to provide additional information to enable better prediction of the occurrence of particular TreMs: (i) at plot level: slope, exposure, altitude and presence of cliffs; and (ii) at tree level: bark features, phyllotaxis and compartmentalization capacity of the tree species, plus ontogenic stage and physiological state of the individual tree sampled.
This study aims to find out the key factors that influence the sustainability of the dairy business in the lowlands of Malang Regency. The research was conducted on January 20-February 20, 2022, in ...Kalipare, Gondanglegi, and Bantur Districts. The location was selected using purposive with the criteria of the location being at an altitude of <400masl, which is lowland. The research method used is a quantitative descriptive survey. Information was obtained from respondents through a Focus Group Discussion with a total of 6 respondents consisting of the livestock and animal health service, the head of the livestock unit, and the head of the livestock group. The results of this study are the key factors that influence and support the sustainability of dairy cattle in the lowlands of Malang Regency are 1) Variable A (air temperature and humidity) with a global strength score of 1.86; 2) Variable B (distance between cage and settlement) with a total global strength score of 1.72; 3) Variable C (forage availability) with a total global strength score of 2.31; 4) Variable D (average dairy cow ownership) with a total global strength score of 2.98; 5) Variable E (amount of subsidy) with a total global strength score of 2.44, and 6) Variable F (marketing information system) with a total global strength score of 1.02.
There is a clear trend in the world to increase the use of sustainable drainage systems. In Poland, it is not as much noticeable, and as a consequence, the conventional stormwater system remains the ...most common method of stormwater management. As part of the research, an assessment of the issues affecting the implementation of sustainable stormwater management systems in an engineering practices was performed. For that purpose the PESTLE analysis was applied. Its results indicate that legal factors are the key for the development of sustainable drainage systems in Poland. The scale of public support and availability of funding is also not without importance. The possibilities of the implementation growth of sustainable drainage systems should be sought in changes in legal regulations regarding stormwater management, while ensuring at the same time an appropriate level of financing for sustainable solutions. In the second stage of the research, stormwater management models used in Poland were identified. The strengths and weaknesses of these models were presented. There were also discussed the potential opportunities and threats associated with their implementation. The balances of positive and negative sides that were created through a SWOT analysis could be treated as the basis for the detailed analyses of the legitimate application of individual systems in specific areas. It is expected that the results of the research will allow formulating clear principles of an innovation policy in the field of stormwater management and appointing objective and transparent criteria for financing individual types of drainage investments.
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•Key issues impacting stormwater management were identified using PESTLE analysis.•Strengths and weaknesses of stormwater systems were defined by SWOT analysis.•Opportunities and threats of stormwater systems were defined by SWOT analysis.•Legal factors are very significant for sustainable systems development.
Soil heterogeneity makes the vertical distribution of metal(loid)s in site soil vary considerably and poses a challenge for identifying the key factors of metal(loid)s migration in site soil ...profiles. In this study, a machine learning (ML) model was developed to study a typical abandoned Pb/Zn smelter using 267 site soils from 46 drilling points. Results showed that a well-trained ML model could be used to identify the key factors in determining the contamination vertical distribution and predict the metal(loid)s contents in subsurface soil. As, Cd, Pb, and Zn were the primary pollutants and their vertical migration depth arrived to 4–6 m. Based on the predictive performance of different ML algorithms, the extreme gradient boosting (XGB) was selected as the best model to produce accurate predictions for the most metal(loid)s content. Contents of As, Cd, Pb, and Zn in the heavily contaminated zones declined with an increase of soil depth. The metal(loid) contents in surface soil of 0–2 m could be readily used to predict the content of Cd, Cr, Hg, and Zn in subsurface soil from 2 m to 10 m. Based on the metal-specific XGB models, sulfur content, functional area, and soil texture were identified as key factors affecting the vertical distribution of As, Cd, Pb, and Zn in site soil. Results suggested the ML method is helpful to manage the potential environmental risks of metal(loid)s in Pb/Zn smelting site.
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•As, Cd, Pb, and Zn were the primary contamination in Pb/Zn smelting site soil.•Machine learning algorithms were developed to predict metal(loid)s contamination.•Extreme gradient boosting (XGB) model outperformed in interpreting non-linear soil data.•Key factors of metal(loid)s vertical distribution in site soil were identified.
In clinical practice, some patients undergoing surgery for thymoma require post-surgical ventilator support, although, factors associated with administration of ventilator support are unclear. This ...study aimed to explore factors associated with incidence of post-surgical severe respiratory failure requiring ventilator support after thymoma resection.
Clinical data of patients who underwent thymoma re-section in our thoracic surgery department between January 2001 and February 2020 was retrospectively analyzed. Multiple logistic regression analysis was used to identify factors associated with patient need for post-surgical ventilator support after thymoma resection.
Among 157 patients who underwent thymoma resection, 17.8% (28/157) required post-surgical ventilator support. Results of univariate analysis revealed that gender, myasthenia gravis (MG) grade, anti-MG medication use (neostigmine or prednisone), Masaoka thymoma stage, pulmonary function test index values, surgical approach, and intraoperative blood loss were associated with increased incidence of severe respiratory failure requiring post-operative ventilator support (P < 0.05). Results of multivariable logistic regression analysis revealed that median sternotomy, MG grade three status, and patient use of anti-MG drug treatments before thymoma resection surgery were associated with greater need for post-surgical ventilator support.
Our data suggest that median sternotomy, MG grade three status, and preoperative use of anti-MG drugs are associated with greater incidence of severe respiratory failure requiring respiratory support after thymoma surgery. Therefore, patients with these risk factors should be closely monitored to reduce the incidence of severe postoperative respiratory failure.
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