As the most abundant biopolymer in nature, cellulose has become a fascinating building block for the design of functional nanomaterials. Owing to the presence of numerous hydroxyl groups, cellulose ...provides a unique platform for the preparation of new materials via versatile chemical modifications. This critical review aims to present the advances about nanomaterials based on cellulose derivatives with the focus on cellulose esters within the last two decades, including the chemistry and application of these nanostructured materials. This review starts with the introduction on first fundamental aspects about diverse esterification techniques used up to now to modify cellulose. The in situ esterification for the isolation of nanocelluloses and diverse post esterification methods of nanocelluloses for the surface functionalization were highlighted in the following description. Various esterification strategies and further nanostructure constructions have been developed aiming to confer specific properties to cellulose esters, extending therefore their feasibility for highly sophisticated applications, which were summarized with respect to the categories of the introduced ester moieties. Thus, this review assembles and emphasizes the state-of-art knowledge of functional nanomaterials derived from diverse esterified cellulose compounds.
•Elevated temperature performance of recycled concrete (RC) were studied.•Nano-silica (NS) and basalt fiber (BF) can improve the mechanical properties of RC.•Degradation mechanisms of RC with NS and ...BF were examined by SEM and XRD analysis.•The splitting tensile strength has a linear relationship with the compressive strength.
In this study, basalt fibre and nano-silica were used to reinforce recycled concrete, to enhance the elevated temperature performance of the recycled concrete and expand its application space. The mechanical properties and microstructures at 25, 200, 400, and 600 °C were studied using a static load test, scanning electron microscopy and X-ray diffraction. The results indicate that with an increase in temperature, the compressive strength and splitting tensile strength decrease, the mortar matrix gradually loosens, the properties of the interface transition zone and the bonds of the mortar to the fibres deteriorate, the influence of the replacement ratio on the compressive strength is weakened, and the influence of the nano-silica on the compressive strength is enhanced. At elevated temperatures, basalt fibre is beneficial to the improvement of the compressive strength of the recycled concrete, and basalt fibre has a more significant effect on the splitting tensile strength than the replacement ratio and nano-silica content. The relative residual splitting tensile strength increases as the basalt fibre content increases. Nano-silica is generally beneficial to the improvement of the compressive strength at different temperatures. The results indicate that basalt fibre and nano-silica contribute to the improvement of the interface transition zone performance and to the elevated temperature performance of the recycled concrete.
Different types of crowdfunding backers adopt various social and economic roles, beyond just financial support. Yet the most appropriate message strategy for attracting these different types of ...backers remains unclear. To fill this gap, using insights into advertising appeals and the elaboration likelihood model (ELM), we propose a conceptual framework reflecting how the emphasis of the appeals in a crowdfunding message might influence support decisions by two types of backers: consumers and investors. Objective data from a crowdfunding website reveal that appeals that emphasize information (emotion) exert more positive persuasive effects on consumer (investment) backers than on investment (consumer) backers. When devising the appeal emphasis, entrepreneurs thus must make a trade-off while also considering contingent factors such as decision control, social orientation, and reward tangibility. The practical implications of these findings suggest that entrepreneurs should activate backers’ information processing routes differentially, using distinct appeal emphases, rather than relying on an undifferentiated message strategy.
Purpose
Despite managers’ investments in facilitating knowledge sharing, knowledge hiding remains prevalent in organizations. Existing studies shed light on the antecedents and consequences of ...knowledge hiding from the hider’s perspective. This study, the first, aims to examine the consequences of perceived knowledge hiding on the performance of knowledge seekers individually and organizations more broadly.
Design/methodology/approach
The authors develop a theoretical framework, drawing on self-determination theory (SDT) and social exchange theory (SET). The framework is tested empirically via hierarchical regression analyses, using survey data collected from salespersons (n = 296) and supervisors (n = 83) employed by one of the largest distribution and market expansion companies in Myanmar.
Findings
Consistent with SDT, the results show that perceived knowledge hiding exerts a positive effect on knowledge seekers’ individual sales performance, although this relationship is moderated by social interaction. Conversely, the results show a negative relationship between perceived knowledge hiding and team viability, which is moderated by reward structure, consistent with SET.
Research limitations/implications
The results have several strategic implications, including on the type of reward structures (i.e. individual vs team-based) that most effectively mitigate the negative consequences of perceived knowledge hiding.
Originality/value
This is the first empirical study of the consequences of perceived knowledge hiding. This model integrates two theoretical perspectives which highlight positive and negative consequences of perceived knowledge hiding.
Wound dressings with high flexibility, mechanical strength, and porosity have received increasing attention. Herein, nanocomposite sponges of sodium alginate/graphene oxide (GO)/polyvinyl alcohol ...were prepared by a freeze-thawing cyclic process and freeze-dried molding. The properties of the sponges were investigated including morphology, mechanical properties, swelling, water vapor permeability, in vitro norfloxacin (NFX) release, antibacterial property, and biocompatibility as well as in vivo wound healing in a mouse model. A GO concentration of 1 wt% resulted in the sponges with a homogeneously porous and interconnected network structure, which exhibited suitable water absorption, breathability, and mechanical properties. Hemolysis tests indicated that the prepared sponges were non-hemolytic material. The CCK-8 assay demonstrated that the presence of an appropriate amount of GO could promote the cell proliferation. The sponges displayed excellent bioavailability of NFX, with a sustained release behavior and a strong inhibitory effect against both Escherichia coli and Staphylococcus aureus. The in vivo evaluations demonstrated that the sponges enhanced wound healing. Therefore, these novel nanocomposite sponges are promising candidates for wound healing applications.
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•The sponges (SPG) were prepared by a freeze-thawing method and freeze-dried technology.•The SPG exhibited uniform pore structure and excellent flexibility.•Graphene oxide improved biocompatibility of the SPG.•The SPG could be used as an excellent wound dressing for biomedical field.
Adopting electric vehicles (EVs) is regarded as one of the leading solutions to environmental issues. However, recent research on the promotion of EVs adoption focuses on perceptions and attitudes ...towards EVs and neglects the importance of different human needs in consumers' purchase decision-making processes. Maslow's Hierarchy of Needs model provides a basic concept stating different human needs which play essential roles in shaping consumers purchase behaviors towards a particular product or service. Based on Maslow's Hierarchy of Needs model, this study predicts the determinants of consumers' purchase motivation for EVs. Data were collected from 550 Chinese residents and analyzed using multiple regression analysis. Result shows that environmental concern is the most significant predictor of EVs purchase motivation, followed by price consciousness, openness to experience, social influence, and self-esteem. From a practical point of view, we make useful recommendations for local policymakers to formulate and implement policies regarding promoting EVs adoption among society. We also provide global EVs marketers and manufacturers with a deeper understanding of Chinese consumers' motivation to purchase EVs.
•This study has extended Maslow's Hierarchy Needs model.•We perform multiple regression analysis to test the hypotheses.•Environmental concern is found to be the most significant predictor.•Suggestions are made for local policymakers and global EVs marketers.
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•A 1D quantity-quality model was built for water projects influences assessment.•The long-term time series from with four hydrological schemas were collected.•The South-to-North Water ...Diversion Project brings adverse effects.•The Yangtze-Hanjiang Water Diversion Project has limited compensation.•The cascade reservoirs tremendously change the flow regimes of Hanjiang River.
The effects of inter-basin water diversion projects and cascade reservoirs are typically complex and challenging, as the uncertain temporal-spatial variation of both water quality and quantity. The purpose of this paper is to propose a coupled 1D hydrodynamic model with water-quality model to analyze the effects of current and future inter-basin water diversion projects, i.e., South-to-North Water Diversion Project (SNWD) and Yangtze-Hanjiang Water Diversion Project (YHWD), and cascade reservoirs (CRS) on water quantity and quality in the middle-lower Hanjiang River. Considering water use and pollution contribution, the middle-lower Hanjaing River basin is generalized and divided into 18 land use units with tributaries, reservoirs and water exchanges. Each unit is considered with the processes of lateral inflow, point and non-point pollution loads, irrigation return flow, and stream-aquifer exchanges in the model. The long-term time series from 1956 to 1998 of water quality and quantity with four engineering scenarios is collected. The validation of results shows that the relative errors between the simulated and observed values at certain control sections are within 5% for water levels and 20% for water quality. The water level will be decreased by 0.38–0.65m (decreasing rate 0.44–2.68%), the annual runoff will be significantly decreased over 4billionm3 and the water quality will be changed after the SNWD. As a compensation project, the YHWD partly offsets the negative effects of the SNWD in water flow rate, but at the same time it rises the water level and reduces the flow velocity. This, together with the effect of cascade reservoirs, leads to water quality concentration increasing and deteriorating to Grade IV of the Chinese Surface Water Quality Criteria. The water resource reduction and water quality problems in the Middle-lower Hanjiang River require attention after these projects.
Sudden water pollution incidents (SWPI) are random and harmful, which is a problem that cannot be ignored in ecological environment governance and economic development. Identifying spatial-temporal ...distribution characteristics of SWPI is essential for the disaster prevention and the early warning of water environment. The Kernel Density (DE) and spatial mean center of SWPI transfer curve were used to explore the characteristics with the dataset of 1174 cases from 2006 to 2018 in China. Results showed that: (1) From the time point of view, there was an overall upward trend in the overall number of SWPI. (2) At a regional scale, Eastern China, Southwest China, and Southern China underwent a high frequency with 69.93% of SWPI. The Fujian, Guangdong and Chongqing provinces were specified as the top 3 provinces with incident frequencies. The Yangtze River Basin and the Pearl River Basin were two regions where water pollution incidents occur more often, more than 50% of incidents among basins in China every year. (3) In general, SWPI presents a northeast-southwest distribution pattern and center of SWPI moves in the direction of west by south. (4) More than half of the incidents (57.24% of the total) were induced by illegal pollutant discharge and production safety accidents.
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•Sudden water pollution incidents (SWPI) showed an upward trend from 2006 to 2018.•The number of SWPI were higher in the southeast than in the northwest China.•The Yangtze River Basin and the Pearl River Basin accounted for more than half of the total incidents.•Illegal pollutant discharge, production safety accidents and traffic accidents were major causes of SWPI.•The shift of the center of SWPI consistent with the westward transfer of pollution-intensive industries.
Purpose
Based on the business-to-business context in the service industry, this study aims to address two balancing problems that a supplier firm may face in an integrated framework: the trade-off ...between the two-dimensional market orientations (MO) (i.e. proactive and responsive MO) and the trade-off between two categories of governance mechanisms (i.e. contractual governance CG and relational governance RG). In doing so, the contingent effects of the governance mechanisms on the relationships between two-dimensional MO and service innovation capability (SIC) are empirically examined and tested.
Design/methodology/approach
A dyadic questionnaire survey of 168 services outsourcing firms’ project managers and strategy managers was used to collect data, which was then used to test the hypotheses by conducting hierarchical regression analysis.
Findings
It was observed that CG weakens the positive relationship between proactive MO (PMO) and SIC, while the positive impact of responsive MO (RMO) on SIC is strengthened. By contrast, RG plays an inverted U-shaped moderating role in the positive relationship between PMO and SIC. Nevertheless, the hypothesis that RG has an inverted U-shaped moderating effect on the effectiveness of RMO is not supported.
Originality/value
Drawing on transaction cost economics and relational exchange theory, this study contributes to the existing literature on MO by revealing how CG and RG differentially shape the value of PMO and RMO.
•Models for pollutants removal efficiency assessment was put forward.•Constructed subsurface flow wetlands can remove over 60% COD and 49% TN in a lake.•The TP, with removal efficiency 34%, is ...relatively difficult to remove by wetlands.•Higher water temperature and water depth will increase the removal efficiency.•The bigger flow velocity is disadvantage to removal performance of wetlands.
Ecological remediation with subsurface flow wetland is one of the most widely used methods for pollution abatement. Assessment on its implementation efficiency is necessary but difficult. To evaluate the pollutant removal effect of constructed subsurface flow wetlands, a wetland growth model coupling with a hydrodynamic water quality model has been put forward. The coupled model has been used to assess the impact of constructed subsurface flow wetlands on a polluted lake in Hubei Province, China. Four pieces of constructed subsurface flow wetlands composed of Reed and Smooth cordgrass with total area of 38.9 thousand square meters for pollutant removal have been designed for the lake. Results showed that reductions of chemical oxygen demand (COD), total phosphorus (TP) and total nitrogen (TN) were 246.38, 28.14 and 3.29 tons/year, respectively. Compared with the different pollutants, the removal efficiency of subsurface flow wetlands on TN (49%) is bigger than TP (34%), but less than COD (60%). Furthermore, the higher water temperature, smaller flow velocity and bigger water depth will improve the pollutants removal performance of subsurface flow wetlands.
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