In this study, the functionalized smectitic clay (SC)-based nanoscale hydrated zirconium oxide (ZrO-SC) was successfully synthesized and utilized for the adsorptive removal of levofloxacin (LVN) from ...an aqueous medium. The synthesized ZrO-SC and its precursors (SC and hydrated zirconium oxide (ZrO(OH)2)) were extensively characterized using various analytical methods to get insight into their physicochemical properties. The results of stability investigation confirmed that ZrO-SC composite is chemically stable in strongly acidic medium. The surface measurements revealed that ZrO impregnation to SC resulted in an increased surface area (six-fold higher than SC). The maximum sorption capacity of ZrO-SC for LVN was 356.98 and 68.87 mg g−1 during batch and continuous flow mode studies, respectively. The mechanistic studies of LVN sorption onto ZrO-SC revealed that various sorption mechanisms, such as interlayer complexation, π-π interaction, electrostatic interaction, and surface complexation were involved. The kinetic studies of ZrO-SC in the continuous-flow mode indicated the better applicability of Thomas model. However, the good fitting of Clark model suggested the multi-layer sorption of LVN. The cost estimation of the studied sorbents was also assessed. The obtained results indicate that ZrO-SC is capable of removing LVN and other emergent pollutants from water at a reasonable cost.
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•ZrO(OH)2 nanoparticles were successfully impregnated into the smectitic clay.•The synthesized ZrO-SC exhibits excellent stability in strongly acidic medium.•The ZrO-SC surface area increased more than six-fold after ZrO impregnation.•Complete mechanistic study of LVN sorption by ZrO-SC was successfully provided.•Cost estimation and economic evaluation of SC and ZrO-SC were precisely presented.
Volumes of oily wastewater are inevitably generated by every walk of life. The removal of oil particles from oil-contaminated wastewater which is characterized as huge amounts, intricate composition, ...and great threats to human health and the ecological environment is a research hotspot in water treatment fields. Due to high treatment costs and undesirable treatment efficiencies, oily wastewater treatment remains a topical and urgent issue. At present, coagulation/flocculation as an indispensable oily wastewater treatment technology receives much attention because it is very well established, economical, practical and relatively efficient. The influencing factors of oil wastewater treatment by coagulation/flocculation have also been summarized in-depth, like dosage, pH, etc. In consideration of its complex composition and treatment difficulty, this paper will also compare the treatment effects of different coagulants/flocculants used alone and combined effects in oily wastewater treatment: inorganic coagulants, organic synthetic polymeric flocculants, natural flocculants and modified polymeric flocculants. Additionally, in this review, the mechanisms of removing oily substance by coagulation/flocculation are emphasized. Given strict emission standards and the refractory nature of oily wastewater, the combination process with coagulation/flocculation, such as electrocoagulation, coagulation-membrane filtration hybrid process, and coagulation/flocculation-flotation can present better application potential and are discussed in this review. To provide a proper choice in practical application, the operating cost of coagulation and several conventional technologies are also compared. Finally, the existing challenges in the treatment of oily wastewater by coagulation are analyzed, and the feasible research direction is proposed.
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•Few articles focus on the technology of coagulation/flocculation in oily wastewater.•The mechanisms, challenges and research direction of oily wastewater treatment by coagulation/flocculation are discussed.•Coagulation/flocculation presents an excellent removal efficiency on oily wastewater.•Combined technologies for oil removal can meet strict effluent guidelines.
Evaluation of cost estimates should be fair and give incentives for accuracy. These goals, we argue, are challenged by a lack of precision in what is meant by a cost estimate and the use of ...evaluation measures that do not reward the most accurate cost estimates. To improve the situation, we suggest the use of probabilistic cost estimates and propose guidelines on how to evaluate such estimates. The guidelines emphasize the importance of a match between the type of cost estimate provided by the estimators and the chosen cost evaluation measure, and the need for an evaluation of both the calibration and the informativeness of the estimates. The feasibility of the guidelines is exemplified in an analysis of a set of 69 large Norwegian governmental projects. The evaluation indicated that the projects had quite accurate and unbiased P50 estimates and that the prediction intervals were reasonably well-calibrated. It also showed that the cost prediction intervals were noninformative with respect to differences in cost uncertainty and, consequently, not useful to identify projects with higher cost uncertainty. The results demonstrate the usefulness of applying the proposed cost estimation evaluation guidelines.
Effective degradation technologies have been extensively investigated and used to remove azo dyes from wastewater for decades. However, no review dealing with both electrooxidation and chemical ...reduction of azo dyes from an economic and, therefore, application-relevant perspective has been found in the current literature. A novelty of this review article consists not only in the brief summarization and comparison of both methods but mainly in the evaluation of their economic side. Based on the literature survey of the last 15 years, the costs of treatment approaches published in individual research articles have been summarized, and the missing data have been calculated. A broad spectrum of advanced electrode materials and catalysts have been developed and tested for the treatment, specifically aiming to enhance the degradation performance. An outline of the global prices of electrode materials, reducing agents, and basic chemicals is involved. All additional costs are described in depth in this review. The advantages and disadvantages of respective methods are discussed. It was revealed that effective and cheap treatment approaches can be found even in advanced degradation methods. Based on the collected data, electrooxidation methods offer, on average, 30 times cheaper treatment of aqueous solutions. Concerning chemical reduction, only ZVI provided high removal of azo dyes at prices <100 $ per kg of azo dye. The factors affecting total prices should also be considered. Therefore, the basic diagram of the decision-making process is proposed. In the conclusion, challenges, future perspectives, and critical findings are described.
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•Literature on electrooxidation and chemical reduction of azo dye has been collected.•Data with respect to cost estimations have been critically reviewed.•The economics of both degradation methods has been evaluated.•Factors affecting the price of degradation techniques have been considered.•Comparison and future perspectives have been proposed.
•Agile and non-agile software development typically have similar front-end phases.•Agile software development with less detail in the front-end phase performed better.•The front-end phase content ...should be context-dependent avoiding one-size-fits-all.•Studies show a lack of robustness regarding causal connections.•There has been a low research interest in the front-end phase.
Software development of new products and services often involves a front-end phase where user needs are analysed, costs and benefits are estimated, and initial plans are created.
This study aims to learn more about how the introduction of agile software development has affected practices and outcomes related to cost and benefit estimation in this front-end phase and to understand better what would improve this phase.
We identified, reviewed and aggregated the results from 42 relevant research articles by searching literature databases and snowballing relevant articles.
The front-end phase of agile was found to be, on average, similar and just as comprehensive as that of non-agile software development. This may be unfortunate, given the finding that more successful agile software development is connected with less detail in cost estimation and planning-related activities. A less comprehensive front-end phase may be especially beneficial for low-risk agile software development.
The results of this review suggest that agile principles, so far, have had a limited influence on the front-end phase. We recommend more flexibility and context-dependency in how the front-end phase of agile software development is conducted, including less comprehensive estimation and planning activities for low-risk software development contexts.
•Software scrum development.•Software cost estimation is still a complex task.•Effort estimation techniques in scrum still has some flaws that need to be resolve.
Scrum methodology is the most useful ...and adopted part of the agile methodology. Many organizations are adopting Scrum for the last decade to meet their software requirements. It is facilitating the software industries to develop software applications according to the user's requirements.
Scrum helps to fulfill the customer's requirements by interacting with the client and developer. Instead of this, scrum still has some challenges that influence the cost of a scrum. These challenging factors include coordination, team size, change request, complexity, and issues in daily meeting sessions. Due to these factors mostly the cost and time exceed scrum-based projects. To overcome these issues from the accurate and precise estimation in the scrum project we have developed a web-based software system to estimate the effort of a user story as well as the budget.
There are some sophisticated cost estimation techniques for scrum-based projects. But all estimation techniques have some limitations that make them less useful for estimation and overcoming the effects of these factors in the scrum. We have surveyed the multiple software industries to get the static findings of the survey. We have designed the 30 hypotheses that main aim to reveal how much the proposed estimation technique is valuable for the accuracy of estimation. For the inclusion of participants, we have set the age criteria to get the opinions of the most experienced programmers.
The main aim of this paper is to provide knowledge about key challenging factors in Scrum that cause exceed in cost and time, and also briefly explain why existing scrum cost estimation techniques are not pertinent for projects. In the last, we propose a framework as a solution to manage these factors and control cost and time from exceeding. We also adopted this estimation technique in different case studies in software industries for findings and results. The technique calculates the efforts autonomously. We design a software-based estimation technique that collects inputs from team/s and estimates the cost and time of a project.
In outcomes, we found that our cost estimation approach reduced the issues from scrum software project development and make it more proficient for estimation of projects. Our proposed estimation technique introduced the new concept of estimation that facilitate the client, software industry, and developers as well to meet the requirements of the client, fulfill the changes during the sprints/s development and deliver the project within the time and cost.
•Biochar may facilitate a circular bioeconomy for agricultural waste.•Stochastic cost modeling is used to evaluate uncertainty in cost estimations.•Production costs ∼$448.78–$1,846.96 (USD) Mg−1 ...biochar.•A biochar enterprise budget is provided as supplemental material.•Indirect and induced regional economic benefits are shown.
It is well established that the global practice of burning crop residues, such as orchard biomass, harms human health and the environment. A bioeconomy for orchard biomass may reduce open burning, facilitate the recovery of nutrients that improve soil health, and boost economic growth. We present a techno-economic analysis for converting orchard waste into biochar, a charcoal-like substance that shows promise for improving soil health, but that is considered an experimental product with emerging efficacy and limited market demand. We impute values derived from a cost analysis of biochar production in California’s Central Valley into a regional economic input-output model to demonstrate economic growth and a bioeconomy for biochar made with orchard waste. Results from a stochastic Monte Carlo simulation show a probable range of biochar production costs between $448.78 and $1,846.96 (USD) Mg−1, with 90% probability that costs will range between $571 and $1,455 Mg−1. A sensitivity analysis shows that production costs are most responsive to biochar production rates. A modifiable Excel-based biochar enterprise budget that includes fixed and variable biochar production costs is provided as Supplementary Material. The regional economic analysis demonstrates positive economic growth as defined by job creation, labor compensation, value-added product, and gross output. Stochastic cost estimates and net positive regional economic impacts support economic feasibility of a circular bioeconomy for waste orchard biomass when coupled with governmental policy initiatives. Results may contribute to developing a circular bioeconomy for biochar and orchard biomass in the study region and elsewhere in the world.
The adsorptive capability of superheated steam activated biochar (SSAB) produced from Colocasia esculenta was investigated for removal of Cu(2+), Fe(2+) and As(5+) from simulated coal mine ...wastewater. SSAB was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller analyser. Adsorption isotherm indicated monolayer adsorption which fitted best in Langmuir isotherm model. Thermodynamic study suggested the removal process to be exothermic, feasible and spontaneous in nature. Adsorption of Fe(2+), Cu(2+) and As(5+) on to SSAB was found to be governed by pseudo-second order kinetic model. Efficacy of SSAB in terms of metal desorption, regeneration and reusability for multiple cycles was studied. Regeneration of metal desorbed SSAB with 1 N sodium hydroxide maintained its effectiveness towards multiple metal adsorption cycles. Cost estimation of SSAB production substantiated its cost effectiveness as compared to commercially available activated carbon. Hence, SSAB could be a promising adsorbent for metal ions removal from aqueous solution.
The interest in Supercritical Carbon Dioxide (sCO2) power cycles has grown exponentially in the last decade, thanks to distinctive features like the possibility to achieve high thermal efficiencies ...at intermediate temperature, small footprint and adaptability to a wide variety of energy sources. In the present work, the potential of this technology is studied for Concentrated Solar Power applications, in particular Solar Tower systems with Thermal Energy Storage.
Further to a previous thorough sensitivity analysis of twelve sCO2 cycles assessing the impact of turbine inlet temperature and pressure ratio on thermal efficiency, specific work, solar share and temperature rise across the solar receiver, the present paper investigates the features of two of these cycles in more detail. The most important conclusions of this section are that: a) the peak values of these thermodynamic figures of merit are obtained at different pressure ratios; b) specific work and temperature rise across the receiver seem to follow parallel trends whilst this is not the case for thermal efficiency; c) for a given turbine inlet temperature, higher pressure ratios increase the temperature rise across the receiver strongly, but the effect on thermal efficiency is uncertain as this can either increase or decrease, depending on the cycle considered.
A deeper analysis of thermal efficiency and receiver temperature rise is therefore mandatory, given that these parameters have a very strong effect on the capital cost of CSP power plants. On one hand, a higher thermal efficiency implies a smaller solar field, the largest contributor to the plant capital cost; on the other, the temperature rise across the receiver is inversely proportional to the size of the thermal energy storage systems, as it is also the case for state of the art steam turbine based CSP plants. In order to quantify these trends, an economic analysis is developed using an in-house code and the open-source software System Advisor Model to evaluate the trade-offs between these two effects. As a result, the Overnight Capital Cost is estimated at some 5000 $/kW, with the individual contributions of solar field, thermal energy storage and power block being given in the paper.
•The capital cost of sCO2 cycles in CSP applications is in the order of 5000 $/kW.•The cost of the TES system is dominated by the corresponding temperature rise.•The cost of the solar field is dominated by thermal efficiency of the power block.•The cost of the power block is dominated by cycle layout (number of major equipment).•High pressure and moderate temperature at turbine inlet yield the optimum design.
The recent regulations pertaining to the circular economy have unlocked new prospects for researchers. In contrast to the unsustainable models associated with the linear economy, integration of ...concepts of circular economy braces reducing, reusing, and recycling of waste materials into high-end products. In this regard, adsorption is a promising and cost-effective water treatment technology for handling conventional and emerging pollutants. Numerous studies are published annually to investigate the technical performance of nano-adsorbents and nanocomposites in terms of adsorption capacity and kinetics. Yet, economic performance evaluation is rarely discussed in the literature. Even if an adsorbent shows high removal efficiency towards a specific pollutant, its high preparation and/or utilization costs might hinder its real-life use. This tutorial review aims at illustrating cost estimation methods for the synthesis and utilization of conventional and nano-adsorbents. The current treatise discusses the synthesis of adsorbents on a laboratory scale where the raw material, transportation, chemical, energy, and any other costs are discussed. Moreover, equations for estimating the costs at the large-scale adsorption units for wastewater treatment are illustrated. This review focuses on introducing these topics to non-specialized readers in a detailed but simplified manner.
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•Adsorbent cost includes raw material, transportation, chemicals, and energy costs.•Adsorbent costs comparison should be based on adsorption capacity not unit mass.•Estimation of large-scale costs depends on unit capacity, fixed and operating costs.
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