Remediation of groundwater is complex and often challenging. But the cost of pump and treat technology, coupled with the dismal results achieved, has paved the way for newer, better technologies to ...be developed. Among these techniques is permeable reactive barrier (PRB) technology, which allows groundwater to pass through a buried porous barrier that either captures the contaminants or breaks them down. And although this approach is gaining popularity, there are few references available on the subject. Until now. Permeable Reactive Barrier: Sustainable Groundwater Remediation brings together the information required to plan, design/model, and apply a successful, cost-effective, and sustainable PRB technology. With contributions from pioneers in this area, the book covers state-of-the-art information on PRB technology. It details design criteria, predictive modeling, and application to contaminants beyond petroleum hydrocarbons, including inorganics and radionuclides. The text also examines implementation stages such as the initial feasibility assessment, laboratory treatability studies (including column studies), estimation of PRB design parameters, and development of a long-term monitoring network for the performance evaluation of the barrier. It also outlines the predictive tools required for life cycle analysis and cost/performance assessment. A review of current PRB technology and its applications, this book includes case studies that exemplify the concepts discussed. It helps you determine when to recommend PRB, what information is needed from the site investigation to design it, and what regulatory validation is required.
Despite the promised benefits of MOOCs (Massive Open Online Courses) to address the digital divide and promote equity in educational opportunities, the use of MOOCs is still lagging especially in ...developing countries. The purpose of this study is to investigate the barriers underlying the adoption of MOOCs in the context of a developing country. Drawing from the theoretical framework of innovation resistance theory, this study conducted focus group discussions with 69 college students in China, a major developing country in Asia. It was found that innovation resistance theory is plausible to explain the barriers to adopting MOOCs. Our results showed that the main barriers in the adoption of MOOCs encountered by students in a developing country are usage barrier, value barrier, and tradition barrier. Furthermore, to complement the perspective of innovation resistance theory, this study also conducted an inductive analysis to identify other types of obstacles hindering students' use of MOOCs. It was found that individual factors (e.g., self-control and attitude) as well as the environment (e.g., promotion and economical circumstance) are also barriers to the use of MOOCs. Implications and suggestions for practice are also discussed.
A well-based, reactive barrier system using controlled-release potassium permanganate (CRP system) was recently developed as a long-term treatment option for dilute plumes of chlorinated solvents in ...groundwater. In this study, we performed large-scale (LxWxD=8mx4mx2m) flow-tank experiments to examine remedial efficacy of the CRP system. A total of 110 CRP rods (ODxL=5cmx150cm) were used to construct a well-based CRP system (LxWxD = 3mx4mx1.5m) comprising three discrete barriers installed at 1-m interval downstream. Natural sands having oxidant demand of 3.7g MnO sub(4) super(-)kg super(-) super(1) for 500mgL super(-) super(1)MnO sub(4) super(-) were used as porous media. After MnO sub(4) super(-) concentrations were somewhat stabilized (0.5-6.0mgL super(-) super(1)), trichloroethylene (TCE) plume was flowed through the flow-tank for 53d by supplying 1.19m super(3)d super(-) super(1) of TCE solution. Mean initial TCE concentrations were 87kgL super(-) super(1) for first 20d and 172kgL super(-) super(1) for the next 33d. During TCE treatment, flow velocity (0.60md super(-) super(1)), pH (7.0-8.2), and concentrations of dissolved metals (Al=0.7mgL super(-) super(1), Fe=0.01mgL super(-) super(1)) showed little variations. The MnO sub(2)(s) contents in the sandy media measured after the TCE treatment ranged from 21 to 26mgkg super(-) super(1), slightly increased from mean baseline value of 17mgkg super(-) super(1). Strengths of the TCE plume considerably diminished by the CRP system. For the 87kgL super(-) super(1) plume, TCE concentrations decreased by 38% (53), 67% (29), and 74% (23kgL super(-) super(1)) after 1st, 2nd, and 3rd barriers, respectively. For the 172kgL super(-) super(1) plume, TCE concentrations decreased by 27% (125), 46% (93), and 65% (61kgL super(-) super(1)) after 1st, 2nd, and 3rd barriers, respectively. Incomplete destruction of TCE plume was attributed to the lack of lateral dispersion in the unpumped well-based barrier system. Development of delivery systems that can facilitate lateral spreading and mixing of permanganate with contaminant plume is warranted.
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Remarkable advances in nano delivery systems have provided new hope for tumor prevention, diagnosis and treatment. However, only limited clinical therapeutic effects against solid ...tumors were achieved. One of the main reasons is the presence of abundant physiological and pathological barriers in vivo that impair tumoral penetration and distribution of the nanodrugs. These barriers are related to the components of tumor microenvironment (TME) including abnormal tumor vasculature, rich composition of the extracellular matrix (ECM), and abundant stroma cells. Herein, we review the advanced strategies of TME remodeling to overcome these biological obstacles against nanodrug delivery. This review aims to offer a perspective guideline for the implementation of promising approaches to facilitate intratumoral permeation of nanodrugs through alleviation of biological barriers. At the same time, we analyze the advantages and disadvantages of the corresponding methods and put forward possible directions for the future researches.
The pathway for pyranose ring conformational transitions in both anomers of glucose has been studied using molecular mechanics calculations both in vacuum and in aqueous (SPC/E) solution. The pathway ...for the transition in vacuum from the 4C1 to the 1C4 chair conformations in I--d-glucopyranose was found to proceed over a low barrier between the 4E and E5 conformers, and centred almost on 4H5, and then downhill through the 1S5 conformation to 1C4. A dead end pathway, with no early barrier, was found to lead to the 5S1 conformation, which thus would represent a kinetic trap impeding interconversion to the opposite chair in vacuum. Hydration was found to significantly lower the transition barriers, and in particular, to make the blocked pathway though 5S1 is feasible at lower temperatures. Transitions between the chair forms for the I2-anomer of glucopyranose were in general found to be somewhat more facile, and to exhibit less influence from the presence of solvent.
•The paper provides a systematic review of research work on safety barriers in the chemical process industries.•A novel classification of safety barriers, based on the identification and management ...of performance indicators, is proposed.•Safety barrier functions are identified and illustrated using the resilience engineering concepts.•The roadmap for future studies to develop integrated management of safety and security barriers for assurance of the resilience of chemical plants is suggested.
Barriers are used in various forms to assure the safety of chemical plants. A deep understanding of the literature related to safety barriers is essential to tackle the challenges in improving their design and management. This paper first provides an overview of the history of the development of the safety barrier concept. Subsequently, this paper elaborates a systematic review of the definition, classification, evaluation, performance assessment, and management of safety barriers in the chemical process industries. Based on the literature review, this study proposes a practical classification of safety barriers benefiting the identification of performance indicators and the collection of indicator-related data for safety barriers. The safety barrier functions are extended and illustrated by involving the resilience concept. Performance assessment criteria are proposed corresponding to the adaptability and recoverability of the safety barriers. Finally, the management of safety barriers is discussed. The roadmap for future studies to develop integrated management of safety and security barriers to ensure the resilience of chemical plants is suggested.
Photovoltaic noise barriers (PVNBs) have the potential to contribute to sustainable urban development by increasing the supply of renewable energy to cities while decreasing traffic noise pollution. ...However, estimating the power generation of PVNBs at the city or national scale remains a challenge due to the complexities of the urban environment and the difficulties associated with collecting data on road noise barriers (RNBs) and radiation. This study used RNBs, 2.5-dimensional (2.5D) buildings, and hourly time resolution radiation data, to estimate the power generation of PVNBs in 52 of China's major cities. First, hourly building shadows were estimated for each day of the year, covering the period from sunrise to sunset, to identify areas of RNB that are shaded at any given time. Second, hourly clear-sky radiation data were collected and corrected using a radiation correction model to simulate real weather radiation. Finally, utilizing an inclined surface radiation estimation model, the photovoltaic (PV) potential both inside and outside RNBs affected by building shadows was assessed. Subsequently, the power generation of PVNB was estimated based on parameters of mainstream PV systems in the market. The results show that the RNB mileage in 52 selected cities represents 87.7% of China's total RNB mileage. Building shadows often result in a radiation loss of approximately 30% for RNBs reception. The installed capacity and annual power generation of PVNBs in all investigated cities are 2.04 GW and 690.74 GWh, respectively. This study estimates the comprehensive PV potential of potentially exploitable PVNBs in China, offering essential scientific insights to inform and facilitate the strategic development of PVNB projects at both the national and municipal levels.
•A framework to assess the photovoltaic (PV) potential of noise barriers is developed.•Building shadows are considered when assessing the PV potential of photovoltaic noise barriers (PVNB).•The RNB mileage of each city is closely and positively related to the PV potential on RNBs.•The annual power generation of PVNBs in China's 52 cities was estimated.
Analyzing barriers to cyberpreneurship adoption Sidek, Syamsuriana; Hasbolah, Hazrina; Rahman, Muhammad Khalilur ...
Journal of open innovation,
September 2024, 2024-09-00, 2024-09-01, Volume:
10, Issue:
3
Journal Article
Peer reviewed
Open access
The expanding field of cyberpreneurship presents both possibilities and challenges to potential entrepreneurs. This study investigates the interaction of variables affecting cyberpreneurship ...adoption, with a particular emphasis on functional, psychological, and organizational barriers. The study uses the partial least squares-structural equation modeling (PLS-SEM) technique to analyze a dataset of 384 survey responses, investigating the barriers to cyberpreneurship adoption. The findings demonstrate the significant and direct impact of functional barriers on the adoption of the psychological barrier and cyberpreneurship. However, its effect on organizational barriers is negative. Psychological barriers have a significant influence on cyberpreneurship adoption, while organizational barriers do not have a statistically significant. The significant nature of the mediating effect of psychological barriers is evident in the relationship between functional barriers and cyberpreneurship adoption. While the moderating effect of education on the association between functional and psychological barriers was shown to be statistically negligible, it has a substantial impact on the relationship between functional barriers, organizational barriers, and cyberpreneurship adoption. This study highlights the importance of addressing psychological and organizational barriers to promote cyberpreneurship, offering valuable insights for policymakers, educators, and aspiring cyberpreneurs.
Active innovation resistance is considered to be a main driver of innovation rejection, and traditionally related to five product-specific adoption barriers driving this negative attitude formation. ...While recent literature introduced a more comprehensive typology encompassing nine functional and eight psychological barriers driving active innovation resistance, an empirical validation of this framework is still missing. In order to close this research gap, we employed a two-study design. First, we conducted a qualitative study to empirically evaluate whether the typology including 17 adoption barriers encompasses all possible negative, product driven reactions of consumers within new product evaluations. Second, we used a quantitative large-scale study to assess the relative importance of each single product-specific adoption barrier within new product evaluations in the context of product and mobile service innovation. Both studies confirm that innovations are commonly rejected owing to these 17 product-specific adoption barriers. However, our results also highlight that functional and psychological barriers vary in their effect on adoption intention depending on whether a new product or service gets evaluated. This study provides first empirical evidence in favor of applying a more comprehensive typology of product-specific barriers when assessing effects of active innovation resistance on consumers' adoption behavior in future research.
•We empirically assess a comprehensive active innovation resistance typology.•We determine the relative importance of functional and psychological barriers.•Results show that innovations are generally rejected owing to 17 barriers.•Findings confirm varying predominance of several barriers in different contexts.
Release and spreading of permanganate (MnO super(-) sub(4)) in the well-based controlled-release potassium permanganate barrier system was investigated. After flushing the sandy media with the tap ...water for 150 days, a tracer test was conducted to describe solute transport in the flow tank. Soil oxidant demand (SOD) was estimated by batch experiments. The MnO super(-) sub(4) that was continuously released from the controlled-release KMnO sub(4) (CRP) system was removed by soil oxidant demand at decay rates that yielded somewhat constant mean MnO super(-) sub(4) values within the CRP system. Through development of advanced tools for describing agent transport and facilitating lateral agent spreading, the CRP system could prove to be an efficient scheme for long-term and passive in situ treatment of contaminants in groundwater.
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