scholarly journals Chemical Modification and Foam Processing of Polylactide (PLA)

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 306 ◽  
Author(s):  
Tobias Standau ◽  
Chunjing Zhao ◽  
Svenja Murillo Castellón ◽  
Christian Bonten ◽  
Volker Altstädt
Keyword(s):  
Environmental Issues ◽  
Review Article ◽  
Chain Extension ◽  
Chemical Modifiers ◽  
Chemically Modified ◽  
Renewable Feedstock ◽  
Wide Range ◽  
Foaming Behavior ◽  
Industrial Use ◽  
Foam Injection Molding

Polylactide (PLA) is known as one of the most promising biopolymers as it is derived from renewable feedstock and can be biodegraded. During the last two decades, it moved more and more into the focus of scientific research and industrial use. It is even considered as a suitable replacement for standard petroleum-based polymers, such as polystyrene (PS), which can be found in a wide range of applications—amongst others in foams for packaging and insulation applications—but cause strong environmental issues. PLA has comparable mechanical properties to PS. However, the lack of melt strength is often referred to as a drawback for most foaming processes. One way to overcome this issue is the incorporation of chemical modifiers which can induce chain extension, branching, or cross-linking. As such, a wide variety of substances were studied in the literature. This work should give an overview of the most commonly used chemical modifiers and their effects on rheological, thermal, and foaming behavior. Therefore, this review article summarizes the research conducted on neat and chemically modified PLA foamed with the conventional foaming methods (i.e., batch foaming, foam extrusion, foam injection molding, and bead foaming).

scholarly journals The Location of Magnetic Reconnection at Earth’s Magnetopause

2021 ◽  
Vol 217 (3) ◽  
Author(s):  
K. J. Trattner ◽  
S. M. Petrinec ◽  
S. A. Fuselier
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Reconnection ◽  
Ion Beams ◽  
Review Article ◽  
Observational Evidence ◽  
Magnetic Shear ◽  
General Direction ◽  
Shear Model ◽  
Wide Range

AbstractOne of the major questions about magnetic reconnection is how specific solar wind and interplanetary magnetic field conditions influence where reconnection occurs at the Earth’s magnetopause. There are two reconnection scenarios discussed in the literature: a) anti-parallel reconnection and b) component reconnection. Early spacecraft observations were limited to the detection of accelerated ion beams in the magnetopause boundary layer to determine the general direction of the reconnection X-line location with respect to the spacecraft. An improved view of the reconnection location at the magnetopause evolved from ionospheric emissions observed by polar-orbiting imagers. These observations and the observations of accelerated ion beams revealed that both scenarios occur at the magnetopause. Improved methodology using the time-of-flight effect of precipitating ions in the cusp regions and the cutoff velocity of the precipitating and mirroring ion populations was used to pinpoint magnetopause reconnection locations for a wide range of solar wind conditions. The results from these methodologies have been used to construct an empirical reconnection X-line model known as the Maximum Magnetic Shear model. Since this model’s inception, several tests have confirmed its validity and have resulted in modifications to the model for certain solar wind conditions. This review article summarizes the observational evidence for the location of magnetic reconnection at the Earth’s magnetopause, emphasizing the properties and efficacy of the Maximum Magnetic Shear Model.

scholarly journals Ring-Forming Polymerization toward Perfluorocyclobutyl and Ortho-Diynylarene-Derived Materials: From Synthesis to Practical Applications

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1486
Author(s):  
Eugene B. Caldona ◽  
Ernesto I. Borrego ◽  
Ketki E. Shelar ◽  
Karl M. Mukeba ◽  
Dennis W. Smith
Keyword(s):  
Chemical Resistance ◽  
Structural Features ◽  
Review Article ◽  
Aryl Ether ◽  
Aromatic Rings ◽  
Practical Applications ◽  
Repeat Units ◽  
Wide Range ◽  
Synthetic Routes ◽  
The Cost

Many desirable characteristics of polymers arise from the method of polymerization and structural features of their repeat units, which typically are responsible for the polymer’s performance at the cost of processability. While linear alternatives are popular, polymers composed of cyclic repeat units across their backbones have generally been shown to exhibit higher optical transparency, lower water absorption, and higher glass transition temperatures. These specifically include polymers built with either substituted alicyclic structures or aromatic rings, or both. In this review article, we highlight two useful ring-forming polymer groups, perfluorocyclobutyl (PFCB) aryl ether polymers and ortho-diynylarene- (ODA) based thermosets, both demonstrating outstanding thermal stability, chemical resistance, mechanical integrity, and improved processability. Different synthetic routes (with emphasis on ring-forming polymerization) and properties for these polymers are discussed, followed by their relevant applications in a wide range of aspects.

scholarly journals Diffuse Water Pollution from Agriculture: A Review of Nature-Based Solutions for Nitrogen Removal and Recovery

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1893
Author(s):  
Giuseppe Mancuso ◽  
Grazia Federica Bencresciuto ◽  
Stevo Lavrnić ◽  
Attilio Toscano
Keyword(s):  
Water Pollution ◽  
Nitrogen Removal ◽  
Plant Uptake ◽  
Environmental Issues ◽  
Polluted Water ◽  
Health Issues ◽  
Agricultural Wastewater ◽  
Research Activities ◽  
Wide Range ◽  
Different Types

The implementation of nature-based solutions (NBSs) can be a suitable and sustainable approach to coping with environmental issues related to diffuse water pollution from agriculture. NBSs exploit natural mitigation processes that can promote the removal of different contaminants from agricultural wastewater, and they can also enable the recovery of otherwise lost resources (i.e., nutrients). Among these, nitrogen impacts different ecosystems, resulting in serious environmental and human health issues. Recent research activities have investigated the capability of NBS to remove nitrogen from polluted water. However, the regulating mechanisms for nitrogen removal can be complex, since a wide range of decontamination pathways, such as plant uptake, microbial degradation, substrate adsorption and filtration, precipitation, sedimentation, and volatilization, can be involved. Investigating these processes is beneficial for the enhancement of the performance of NBSs. The present study provides a comprehensive review of factors that can influence nitrogen removal in different types of NBSs, and the possible strategies for nitrogen recovery that have been reported in the literature.

Lymphoedema after head and neck cancer treatment: an overview for clinical practice

2021 ◽  
Vol 26 (Sup4) ◽  
pp. S24-S29
Author(s):  
Claire Jeans ◽  
Bena Brown ◽  
Elizabeth C Ward ◽  
Anne E Vertigan
Keyword(s):  
Head And Neck Cancer ◽  
Head And Neck ◽  
Neck Cancer ◽  
Lymphatic System ◽  
Review Article ◽  
Psychological Issues ◽  
Wide Range ◽  
The Face ◽  
Protein Rich ◽  
The Impact

Lymphoedema is a disorder of the lymphatic system that presents as an atypical swelling and accumulation of protein-rich fluid within the interstitial spaces. Head and neck lymphoedema (HNL) is highly prevalent in patients who have been treated for head and neck cancer (HNC) and may manifest externally on the face and neck; internally within the oral cavity, pharynx or larynx; or as a combination of both. HNL is known to contribute to a wide range of physical, functional and psychological issues, and presents several unique challenges in terms of its management. This review article provides an overview of HNL for clinicians and aims to improve awareness of this condition and the impact it has on patients.

Steroidal pyrazolines as a promising scaffold in drug discovery

2020 ◽  
Vol 12 (10) ◽  
pp. 949-959
Author(s):  
Ranju Bansal ◽  
Ranjit Singh
Keyword(s):  
Drug Discovery ◽  
Broad Spectrum ◽  
Chemical Reactivity ◽  
Biological Activities ◽  
Antimicrobial Activities ◽  
Review Article ◽  
Pharmacological Activities ◽  
Neuroprotective Effects ◽  
Wide Range

Steroidal pyrazolines constitute an interesting and promising scaffold for drug discovery as they display diverse chemical reactivity and a wide range of biological activities. Literature reports indicate potent anticancer potential of steroidal pyrazolines along with broad-spectrum antimicrobial activities. Strong neuroprotective effects with steroids possessing pyrazoline moiety have also been observed. Among all the therapeutically active steroidal pyrazolines, D-ring-substituted derivatives are highly potent and the least toxic. The current and futuristic research approaches in this area are focused towards the exploration of this promising scaffold to develop molecules with widespread pharmacological activities. This review article mainly covers the synthetic and pharmacological aspects of steroidal pyrazolines, which will assist the medicinal chemists working in this area in their scientific endeavors.

scholarly journals Effects of chain extender on properties and foaming behavior of polypropylene foam

RSC Advances ◽  
2019 ◽  
Vol 9 (44) ◽  
pp. 25496-25507 ◽  
Author(s):  
Do Young Kim ◽  
Ji Hun Cha ◽  
Kwan Ho Seo
Keyword(s):  
Chain Extender ◽  
Chain Extension ◽  
Foaming Behavior ◽  
Polypropylene Foam

The mechanism of the grafting and chain extension reaction and changes in the PP structure and foamability.

scholarly journals Walking Speed: The Functional Vital Sign

2015 ◽  
Vol 23 (2) ◽  
pp. 314-322 ◽  
Author(s):  
Addie Middleton ◽  
Stacy L. Fritz ◽  
Michelle Lusardi
Keyword(s):  
Vital Sign ◽  
Walking Speed ◽  
Review Article ◽  
Minimal Detectable Change ◽  
Detectable Change ◽  
Testing Procedures ◽  
Optimal Distance ◽  
Wide Range ◽  
Acceleration And Deceleration ◽  
Reference Tool

Walking speed (WS) is a valid, reliable, and sensitive measure appropriate for assessing and monitoring functional status and overall health in a wide range of populations. These capabilities have led to its designation as the “sixth vital sign”. By synthesizing the available evidence on WS, this scholarly review article provides clinicians with a reference tool regarding this robust measure. Recommendations on testing procedures for assessing WS, including optimal distance, inclusion of acceleration and deceleration phases, instructions, and instrumentation are given. After assessing an individual’s WS, clinicians need to know what this value represents. Therefore, WS cut-off values and the corresponding predicted outcomes, as well as minimal detectable change values for specific populations and settings are provided.

In Search of Sustainability

2005 ◽  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Water Resources ◽  
Urban Design ◽  
Environmental Issues ◽  
Economic Systems ◽  
Sustainable Society ◽  
Natural Ecosystems ◽  
Wide Range ◽  
Key Issues

What must we do to achieve a sustainable society? There is no one answer. The first steps towards sustainability cover a whole spectrum of economic, social and environmental issues. In this volume Australian leaders from a wide range of fields discuss the key issues we must address if we are to move towards a more just and sustainable future. They identify the major concerns and challenges for achieving sustainability in the areas of: human health, water resources, land use and natural ecosystems, energy, equity and peace, economic systems, climate change, labour forces and work, urban design and transport, and population. Achieving sustainability will require major changes in our current approaches. The thought-provoking chapters in this book provide a solid introduction to the issues in the search for a genuine path to sustainability.

Trust and Social Dilemmas

2017 ◽  
Author(s):  
Karen S. Cook ◽  
Bogdan State
Keyword(s):  
Collective Action ◽  
Social Dilemmas ◽  
Social Dilemma ◽  
Environmental Issues ◽  
Sharing Economy ◽  
Wide Range ◽  
Health Related

This chapter explores the linkages between trust and cooperation in social dilemmas. In the typical social dilemma individuals do not know what others will do, thus they must make assumptions about the likelihood that others will cooperate. This judgment is sometimes made on the basis of the presumed trustworthiness of the others involved, and, if so, trust makes cooperation possible. However, there are other mechanisms at work. This chapter considers when trust facilitates cooperation and when other factors are more likely to. In addition it discusses briefly the nature of the applications of work on trust and social dilemmas to a wide range of phenomena focusing on collective action in relation to corruption, systems of taxation, environmental issues, and health-related dilemmas as well as those that arise in the sharing economy. It ends with speculation about the potential for solutions of social dilemmas to improve trust in society.

Green HRM

2020 ◽  
Vol 10 (3) ◽  
pp. 1-8
Author(s):  
Anupama Lakhera ◽  
Pooja Sharma
Keyword(s):  
Sustainable Development ◽  
Carbon Footprint ◽  
Environmental Issues ◽  
Review Article ◽  
Sustainable Growth ◽  
Research Papers ◽  
Environment Friendly ◽  
Secondary Sources ◽  
Hr Practices ◽  
Social Wellbeing

Green HRM is a concept that is fast gaining prominence in the field of management. This review article discusses Green HRM for implementing best HR practices for reducing employees' carbon footprint and thus leading to sustainable growth within the organization. It explores how Green HRM can achieve the integration of environment-friendly HR practices and activities in order to achieve long-lasting sustainable development and a reduction of the employee carbon footprint. The data is collected on the basis of secondary sources such as articles, research papers, case studies, and internet websites. Green HRM does not only imply awareness and concern towards environmental issues, it favors the economic as well as social wellbeing of the employees and organization. This article deliberates on the Green HRM approach and the prominent part it can play in integrating and merging the HR practices within the organization in favour of the environment.

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