196 research outputs found

    Crystallization behavior of poly(lactide)/poly(β-hydroxybutyrate)/talc composites.

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    The authors thank Dr. Patrice Lefrançois (CNAM) for SEM observations. They are also grateful to Pr. Jack R. Plimmer USDA, Agricultural Research Service, USA for his discussions during this work.The morphology and miscibility of commercial poly(lactide) (PLA)/poly(b-hydroxybutyrate) (PHB, from 5 to 20 wt %) blends prepared by melt extrusion method, were investigated using differential scanning calorimetry (DSC) and Fourier transform infra-red spectroscopy (FTIR) observations. The results show that for all the studied blend contents, PLA/PHB blends are immiscible. The effects of PHB and talc on the nonisothermal cold crystallization kinetics of PLA were examined using a differential scanning calorimetry (DSC) at different heating rates. PHB acted as a nucleating agent on PLA and the addition of talc to the blend yielded further improve-ment, since significant increase in the enthalpy peak was observed for samples containing 10 wt % PHB and talc (from 0.5 to 5 phr). The crystallization kinetics were then examined using the Avrami–Jeziorny and Liu–Mo approach. The simultaneous presence of PHB and talc induced a decrease of the crystallization half time. The evolution of activation energies determined with Kissinger’s equation suggests that blending with PHB and incorporating talc promote nonisothermal cold crystallization of PLA. The synergistic nucleating effect of PHB and talc was also observed on isothermal crystallization of PLA from the melt

    Viết tiếp giấc mơ nửa triệu

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    Đêm ngày 28-7-2023, bài NS đã lăn qua mốc 40 vạn lượt đọc, chính xác là hết ngày 28-7, đạt mốc mới 401066 lượt đọc duy nhất tính theo IP [1]. Đây là cách tính lượt đọc rất khắt khe, vì từ một địa chỉ IP, có cả trăm người đọc thì vẫn chỉ được tính là 1 mà thôi

    BMF CP70: Exploring the climate change-related factors constraining stakeholders’ willingness to protect the ocean

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    The current study is conducted to examine the following research questions: - Do perceptions that mitigate climate change risk (e.g., developing technology to help address climate change) reduce stakeholders’ willingness to protect the ocean? - Do perceptions of the costs associated with combating climate change (e.g., the belief that responding to climate change will harm economies and societies that are already actively addressing the issue) reduce stakeholders’ willingness to protect the ocean? The findings from this study are expected to provide insights into how perceptions of climate change mitigation and cost beliefs influence stakeholders’ willingness to protect the ocean. This information can inform targeted strategies for policymakers and conservationists to enhance support for marine protection and build the eco-surplus culture in the face of climate change challenges

    The Effects of Technology-Assisted Listening Practice on Moodle on English-Majored Freshmen’s Motivation for Learning Listening at a University in The Mekong Delta

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    Purpose: This study was to investigate the effects of technology-assisted listening practice on MOODLE on English-majored freshmen's motivation for learning English listening at a university in the Mekong Delta. Approach/Methodology/Design: Two groups of sixty-four mixed-gender freshmen majoring in English language studies participated in this quasi-experimental study. To collect data, a pre-questionnaire, a post-questionnaire, and interviews were employed. Findings: The findings indicated that technology-assisted listening practice on MOODLE improved English-majored freshmen's listening motivation in specific areas for learning listening; however, this was a variance development. Practical Implications: This study was aimed to help language teachers and students benefit from technology-assisted listening teaching and learning. Originality/value: This study innovates by applying the MOODLE system to increase students’ listening motivation at a university in the Mekong Delta

    Using SiO2 nano-particles for better color uniformity and lumen output in 8500 K conformal and in-cup white LEDs

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    In the effort of improving the performance of white light LEDs devices (WLEDs), the SiO2 nano-particles were applied and have shown a significant impact on the optical properties. Specifically, the light output of the lighting devices is enhanced when a mixture of SiO2 particles and silicone gel is diffused on the encapsulation layer surface. This enhancement is the result of light scattering from SiO2 that strengthens the emitted blue light at further angles and reduces the color discrepancy. The evidence is that CCT deviation in SiO2-doped structure decline from 1000 K to 420 K in -70° to 70°. In addition, the SiO2 with refractive index in between the phosphor material and outside environment allows light to be emitted outward more effectively. This lighting enhancement of SiO2-doped structure increases the lumen output by 2.25% at 120 mA power source in comparison to structure without SiO2. These experimental outcomes suggest that SiO2 is an effective material to add in WLEDs structure for better lighting efficiency

    Effect of recycling process in twin screws extruder HAAK on structure and crystallization behavior of polypropylene

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    Recycling process of polypropylene (PP) in twin screws extruder HAAK at high (195 - 230oC) and low (175-190oC) temperature ranges was studied. IR spectra and solubility of recycled samples show that neither oxidative degradation nor network formation has occurred at recycling conditions. So only degradation of PP molecules to smaller fractions may take place, that contributes to increasing of Melt Flow Index (MFI) of recycled samples. The results show also the stronger effect of recycling temperatures on the structure changes than that of number of recycling times. We can see also the structure changes of recycled PP cause the higher crystallization rate, higher crystalline percentage of spherulite formations with smaller dimensions. It leads to higher crystallization temperatures (3-4oC) but lower melting temperatures (4-5oC) of recycled PP in comparison with virgin PP

    Biomolecular evaluation of three contrasting rice cultivars (Oryza sativa L.) in salt stress response at seedling stage.

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    Salt contamination of soils due to climate change faces a severe environmental issue that affects crop production today. However, the response mechanism in plants to salt stress is not fully understood. The present study investigated molecular and biochemical changes under salt stress in rice seedlings of three rice cultivars, i.e., AGPPS114 (salt-tolerant), OM6967 (moderately tolerance), VD20 (salt-sensitive). Increasing salt concentration leads to a reduction in shoot/root length but different levels among the cultivars. In contrast, reactive oxygen species (ROS) accumulation and lipid peroxidation increased progressively with increasing salt concentration and time course treatment. However, at 250 ?M of NaCl, these parameters were more adversely affected in VD20 than AGPPS114 and OM6967. Using ICP showed that Na+ accumulation in rice root increased gradually with increasing NaCl concentrations in all cultivars under salt treatment but was low in salt-sensitive cultivar VD20 compared to other cultivars. Antioxidant enzyme activity analysis indicated catalase (CAT) and superoxide dismutase (SOD) were induced during salt treatment in all cultivars. The results also showed greater proline and glycine betaine accumulation in the AGPPS114 than OM6976 and VD20. qPCR indicated a significant difference in transcript levels of the Na+-transporter gene OsSOS1, OsNHX1 and OsHKT1s in AGPPS114 and OM6967 cultivars compared to VD20 cultivar. In summary, the active regulation of genes related to Na+ transport at the transcription level and with high glycine betaine and proline accumulation levels may be involved in salt tolerance mechanisms and thus might be useful for selecting tolerant plants

    Investigating climate change-related factors that hinder stakeholders’ willingness to protect ocean

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    Community and stakeholder support for marine and coastal ecosystem conservation policies is crucial. However, extant multinational studies on climate change-related factors that constrain stakeholders’ willingness to protect the ocean are limited. Therefore, the dataset from 709 marine stakeholders across 42 countries, part of the MaCoBioS project funded by the European Commission, was analyzed using the Bayesian Mindsponge Framework (BMF) method to fill the knowledge gap. The findings reveal that for individuals who think society is doing too much to address climate change, new technologies can solve climate change. Responses to climate change can damage the country’s economy and might not be productive in supporting actions protecting the ocean. Based on the study results, we recommend policymakers raise awareness among individuals engaged in marine and coastal ecosystems about the crucial role of marine protection in combating climate change, taking into account the limitations of technology in solving climate change problems and the inadequacy of current efforts. The findings also provide insights for enhancing the effectiveness of awareness and knowledge-raising campaigns, conservation programs, and eco-surplus culture-building agenda

    Mindsponge-based investigation into the non-linear effects of threat perception and trust on recycled water acceptance in Galicia and Murcia, Spain

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    The water scarcity crisis is becoming more severe across the globe and recycled water has been suggested as a feasible solution to the crisis. However, expanding the use of potable and recycled public water has been hindered by public acceptance. Previous studies suggest threat perception and trust of provided information have positive linear relationships with recycled water acceptance. However, given the complex filtering role of trust in the human mental process, we argue that the effects of threat perception and trust may have non-linear relationships with acceptance of recycled water for drinking. To support and validate this argument, we employed Bayesian Mindsponge Framework analytics on 726 Spanish residents. We found that individuals more concerned about water shortage are less likely to accept using recycled water for drinking if their trust in the water quality and safety is low. Meanwhile, people more concerned about water shortage are more likely to accept using recycled water for drinking if they trust the water quality and safety. The findings suggest the non-linear relationships between threat perception, trust, and recycled water acceptance while validating mindsponge-based reasoning. Moreover, the results also highlight the importance of trust in influencing the mental process’s outcome: recycled water acceptance

    Achieving the successful lean implementation at manufacturing companies in Vietnam: Awareness of critical barriers

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    This study focuses on identifying the critical barriers/difficulties and exploring the roots of barriers/difficulties for successful Lean implementation at manufacturing companies in Vietnam. The literature review and in-depth interviews are applied in this study. The literature review is done to review and to obtain experiences of the inhibitors of Lean Implementation from previous studies. An in-depth interview is conducted with eight experts of eight manufacturing companies deployed Lean to explore and identify the critical barriers/difficulties for Lean implementation successfully. As a result, it finds that seven key barriers inhibiting the successful Lean implementation come from the leadership; the employees; the workplace; resources; operation process; the integration with customers; and from the integration with suppliers. These challenges are not easy and take a lot of time to overcome, though, this study provides helpful advice for business in Vietnam who has plans to follow Lean implementation in looking back to the company and restructuring strategies, objectives so that Lean implementation process would be more efficient and more open
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