scholarly journals Novel Composite Materials for Lake Restoration: A New Approach Impacting on Ecology and Circular Economy

2020 ◽  
Vol 12 (8) ◽  
pp. 3397
Author(s):  
Miltiadis Zamparas ◽  
Grigorios L. Kyriakopoulos ◽  
Marios Drosos ◽  
Vasilis C. Kapsalis ◽  
Ioannis K. Kalavrouziotis
Keyword(s):  
Composite Materials ◽  
Water Column ◽  
Circular Economy ◽  
Maximum Adsorption Capacity ◽  
Modified Bentonite ◽  
Composites Materials ◽  
Lake Bottom ◽  
Agricultural Use ◽  
Sustainable Ecology ◽  
Living Organisms

The purpose of this study is to promote a new way of application composite materials to restore eutrophic waters. A new sustainable way of application is based on the “teabag” method, in which materials were placed in water-permeable bags and immersed in the water column in order to sorb phosphate—one of the main contributory element for the eutrophication problem. Particularly, the two composites materials of Phoslock™ (lanthanum-modified bentonite, LMB) and Bephos™ (Fe-modified bentonite, f-MB) were tested and bench-scale batch experiments were employed to investigate their sorption efficiency in the forms of slurry and teabag. The adsorption kinetics and the relevant adsorption isotherms were deployed, while the effect of the materials on turbidity and their aging were also investigated. Experimental results showed that Phoslock™ and Bephos™ (as teabag), being applied at initial concentration range: 0.05–5 mg/L, they sustained a maximum adsorption capacity of 7.80 mg/g and 25.1 mg/g, respectively, which are considered sufficient rates for P concentrations reported at natural aquatic ecosystems. At the same time this new method did not cause turbidity in the water column, since the material was not released into the water, thus, preventing potential harmful consequences for the living organisms. Moreover, the “teabag” method prevents the material to cover the lake bottom, avoiding the phenomenon of smothering of benthos. Βy teabag method, the materials can be collected for further applicability as soil improver or crops fertilizer. Finally, it was argued that the possibility to recycle LMB and f-MB materials for agricultural use is of paramount importance, sustaining also positive impacts on sustainable ecology and on the routes of circular economy (CE).

scholarly journals Composite Materials and Their Fiber Reinforcement Technology in Aerospace Field

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Kailin Zhou
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Research And Development ◽  
Carbon Fibers ◽  
Fiber Reinforcement ◽  
Space Structures ◽  
Advanced Composite ◽  
Advanced Composite Materials ◽  
Composites Materials ◽  
Definition Of

The need to reduce the overall weight of aeronautical and space structures while preserving or even improving their performances make the research and development in the field of advanced composite materials necessary for the advancement of aerospace technologies. This paper provides an overview of composite materials and their fiber reinforcement technology in aerospace field. We discuss the reasons for aircraft manufacturers and airlines to use composites and illustrate the definition of composite material. Then, we list the advantages and disadvantage of composite materials and cite different fiber reinforcement technologies of carbon fibers, aramid fiber, UHMWPE, etc. At last, we summarize the present and future applications of composites materials in aerospace and other civil fields. A conclusion is drawn that in the future, composite materials are set for their development, while continually decreasing its costs is still an important task.

Green Material for Fused Filament Fabrication

2020 ◽  
pp. 1-27 ◽  
Author(s):  
Mastura Mohammad Taha ◽  
Ridhwan Jumaidin ◽  
Nadlene M. Razali ◽  
Syahibudil Ikhwan Abdul Kudus
Keyword(s):  
Additive Manufacturing ◽  
Composite Materials ◽  
Manufacturing Process ◽  
Extrusion Process ◽  
Fused Filament Fabrication ◽  
Green Material ◽  
Additive Manufacturing Technology ◽  
Green Materials ◽  
Composites Materials ◽  
The Right

Fused filament fabrication (FFF) has been developed in additive manufacturing technology as a fast and simple manufacturing process in product design. Advantage of the process such as flexibility in terms of the materials employment has attracted many researchers to develop new materials for the feed stock filament in the heat extrusion process of FFF. Green materials or bio-composites materials have been found in FFF and successfully commercialized in the market. However, a deep research should have been performed prior the application because of the unique characteristics of the material itself. The challenge for the researchers to develop bio-composite materials as the filament in FFF technology is to determine the right composition of the composites with the right thermal, mechanical, and rheological properties. Therefore, in this study, a review has been conducted to highlight the important requirements of the process and materials. Green materials such as bio-composites have a great potential in the FFF technology and could improve the sustainability impact.

Possibility of Usage of Aluminium Rivet Nuts Connections in Composite Materials

2015 ◽  
Vol 240 ◽  
pp. 137-142 ◽  
Author(s):  
Radosław Bielawski ◽  
Michał Kowalik ◽  
Karol Suprynowicz ◽  
Paweł Pyrzanowski
Keyword(s):  
Composite Materials ◽  
Tensile Test ◽  
Composite Structures ◽  
Test Method ◽  
Damage Models ◽  
Constant Torque ◽  
Composite Damage ◽  
Composites Materials ◽  
Riveted Joints ◽  
Static Tensile

Development and application of composite materials in modern industry are very dynamic. Composite materials seem to be replacing steel and aluminium ones. Composites are a cheaper solution, with similar mechanical strengths. Generally, there are two types of joints in composite structures: mechanical and adhesively bonded ones. The aim of the study was to determine the feasibility of riveted joints in composites materials. Static tensile test method was used. In the test there was used one type of glass fabric (Interglas 92140) from which two types of composite samples were prepared. In each sample there was used the same type of fiber with the same fiber orientation – 3 layers. Samples had dimensions of 220x100 mm and thickness of approximately 1.5 mm. They were connected to each other with aluminium rivet nuts (from 1 to 3) and placed in a metal frame with a screw connection which was made of screws with nominal thread pitch M5. Screws were tightened with constant torque. It was to provide an axial force to the sample during the tensile test. The frame was placed between cross-bars of tensile machine INSTRON 8516. The samples were stretched at a speed of 0.05 mm/s at a distance up to 20 mm. During the tensile test displacement of the samples and pull force were registered. Depending on the fiber orientations and number of rivet nuts composite damage models were described. On the basis of the results the possibility of usage of aluminium rivet nuts connections in composite materials was determined.

Comparative Study on Determining the Drilling Force Regression at Drilling Composites Materials

2013 ◽  
Vol 436 ◽  
pp. 213-218
Author(s):  
Constantin Ocnărescu ◽  
Doru Bardac ◽  
Maria Ocnărescu
Keyword(s):  
Composite Materials ◽  
Comparative Study ◽  
Polymeric Matrix ◽  
Fiber Glass ◽  
Drilling Force ◽  
Composites Materials ◽  
Current Article

Composite materials are used extensively because of their higher strength to weight ratios and, when compared to metals, offer new opportunities for design. However, being non-homogenous, anisotropic and reinforced with very abrasive fibers, these materials are difficult to machine. In this current article is present a comparative study of results obtained in determining the drilling force regression at drilling a tree types composites material with polymeric matrix and fiber glass.

scholarly journals EFFECTS OF THERMODYNAMICAL PROCESSES ON RADIOCESIUM BEHAVIOR IN LAKE TAPELIAI / TERMODINAMINIŲ PROCESŲ ĮTAKA RADIOCEZIO ELGSENAI TAPELIŲ EŽERE

2012 ◽  
Vol 3 (6) ◽  
pp. 95-100
Author(s):  
Anastasija Moisejenkova ◽  
Aloyzas Girgždys ◽  
Nikolaj Tarasiuk
Keyword(s):  
Lake Sediments ◽  
Water Column ◽  
Lake Water ◽  
Sediment Surface ◽  
Main Process ◽  
Complex Data ◽  
Data Set ◽  
Activity Concentrations ◽  
Lake Bottom ◽  
Integrated Study

The article presents the results of the integrated study of radiocesium behavior in Lake Tapeliai using not only conventional data on radiocesium activity concentrations in lake water and sediments but also a complex data set on seasonal variations and vertical profiles of standard water variables. Radiocesium activity concentrations in lake water as well as the vertical structure of the water column considerably depend on the inflows of the colored waters from the swampy watershed of the lake enriched in radiocesium. The global fallouts are mainly responsible for radiocesium inventory in lake sediments, which reaches maximum in the upper part of the water column above the ~5.4-m depth. The maximum values of radiocesium inventories in lake sediments are consistent with the respective densities of its deposits in the nearest forest soils. The main process of sediment activation is the direct sorption of radiocesium onto the sediment surface. Sedimentation rates in the lake vary mainly in the range of 3.5–5 mm·a–1. Lake bottom feeding sources located mainly on the southern terrace as well as their related near-bottom flows reduce respective sedimentation and radiocesium inventories in the sediments. Santrauka Straipsnyje nagrinėjama radiocezio elgsena Tapelių ežere, naudojant ne tik radiocezio savitojo ir tūrinio aktyvumų duomenis, bet ir standartinius vertikaliuosius parametrus, tokius kaip temperatūra, elektros laidumai ir oksiduoto sluoksnio storis. Radiocezio aktyvumas ežero vandenyje priklauso nuo spalvoto pelkinio vandens, kuriame yra radiocezio, patekimo į ežerą. Radiocezio apkrova dugno nuosėdose yra didžiausia viršutinėje ežero dalyje, t. y. iki 5,4 m gylio. Sedimentacijos greitis svyruoja 3,5–5 mm·m–1. Ežero priedugniniai vandens šaltiniai daugiausia išsidėstę pietinėje ežero terasoje, jų srovės sumažina sedimentaciją ir radiocezio apkrovą dugno nuosėdose.

scholarly journals Living organisms and sedimentary remains from high mountain lakes in the Alps

2021 ◽  
Author(s):  
Aldo Marchetto ◽  
Angela Boggero ◽  
Diego Fontaneto ◽  
Andrea Lami ◽  
André F. Lotter ◽  
...  
Keyword(s):  
Aquatic Organisms ◽  
Mountain Lakes ◽  
Biological Data ◽  
Environmental Data ◽  
High Mountain ◽  
High Mountain Lakes ◽  
Data Set ◽  
Lake Bottom ◽  
The Alps ◽  
Living Organisms

We publish a data set of environmental and biological data collected in 2000 during the ice-free period in high mountain lakes located above the local timberline in the Alps, in Italy, Switzerland and Austria. Environmental data include coordinates, geographical attributes and detailed information on vegetation, bedrock and land use in lake catchments. Chemical analyses of a sample for each lake collected at the lake surface in Summer 2000 are also reported. Biological data include phytoplankton (floating algae and cyanobacteria), zooplankton (floating animals), macroinvertebrates (aquatic organisms visible to the naked eye living in contact with sediments on lake bottom), benthic diatoms. Diatoms, cladocera and chironomids remains and algal and bacterial pigments were also analysed in lake sediments.

scholarly journals Removal of Cd (II) in Water Samples Using Modified Magnetic Iron Oxide Nanoparticle

2016 ◽  
Vol 10 (1) ◽  
pp. 9-14
Author(s):  
Ahmad Kakaei ◽  
◽  
Mohammad Kazemeini ◽  
Keyword(s):  
Water Samples ◽  
High Capacity ◽  
Absorption Spectrometry ◽  
Iron Oxide Nanoparticle ◽  
Maximum Adsorption Capacity ◽  
Magnetite Nanoparticle ◽  
Cadmium Ions ◽  
Flame Atomic Absorption ◽  
Low Concentrations ◽  
Living Organisms

Background: Heavy metals, even at low concentrations, are harmful to human health and environment. Cadmium as a heavy metal is highly toxic and can cause serious threat to living organisms. This research was designed to evaluate the adsorption potential of modified magnetic iron nanoparticles by 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol ligand for the removal of cadmium ions from water solutions. Methods: This study was conducted in Ilam Branch, Islamic Azad University, Iran, in 2014. Modified magnetic iron nanoparticle was used as adsorbent for the removal of cadmium from aqueous solution. In batch extraction, the effects of parameters like pH of sample solution (3.0-11.0), initial metal concentrations (50-300) mgL-1), contact time (1.0-10 min) and adsorbent dose (10.0-60.0 mg) were studied on the adsorption process. Modified magnetite nanoparticle was presented as the adsorbent for the removal of cadmium ions from aqueous samples and later was confirmed by flame atomic absorption spectrometry. Results: The adsorption of cadmium ions on modified magnetite nanoparticles strongly depends on pH. The experimental isothermal data were analyzed using the Langmuir and Freundlich equations. The removal process followed the Langmuir isotherm. Maximum adsorption capacity for the adsorption of cadmium ions by the sorbent was 24.09 mgg-1. Conclusion: The method was successfully applied to adsorption of cadmium in water samples with satisfactory results. Other advantages include high capacity, good stability and fast adsorption kinetics. High pre-concentration factor was obtained easily by this method (120) and low analysis cost.

scholarly journals Preparation of Amazonian Palm Tree Fiber (Manicaria saccifera Gaertn.) for Composite Materials

2021 ◽  
Vol 7 (2) ◽  
pp. 31-36
Author(s):  
Amanda Sousa Monteiro ◽  
Denise Dantas ◽  
Takashi Yojo
Keyword(s):  
Composite Materials ◽  
Raw Materials ◽  
Local Communities ◽  
Palm Tree ◽  
Stopping Criterion ◽  
New Materials ◽  
New Approach ◽  
Composites Materials ◽  
Local Materials ◽  
Potential Use

In the last fifteen years, a new approach has emerged in the design field: the process of development of new materials and the involvement of designers as original creators, making use of underutilized local materials. This paper aims to describe the preparation of an Amazonian palm tree fiber (Manicaria saccifera Gaertn.) for the use at composites materials. The raw materials were extracted from the Marajó archipelago - Brazil by local communities that traditionally work with the material. The process involves the measure of weight, length, and thickness at six different points of the raw specimen; manual washing and cleaning; drying with stopping criterion; and visual analyses of the specimen with trimming and cutting, for the potential use at composites. The results for 80 specimens show that the method adopted allowed easy and quick preparation of the specimens and can be used for other local materials, respecting its characteristics.

scholarly journals Physical processes of thermokarst lakes in the continuous permafrost zone of northern Siberia – observations and modeling (Lena River Delta, Siberia)

2015 ◽  
Vol 12 (8) ◽  
pp. 6637-6688 ◽  
Author(s):  
J. Boike ◽  
C. Georgi ◽  
G. Kirilin ◽  
S. Muster ◽  
K. Abramova ◽  
...  
Keyword(s):  
Heat Flux ◽  
Numerical Modeling ◽  
Water Column ◽  
River Water ◽  
Lena River ◽  
Thermokarst Lakes ◽  
Continuous Permafrost ◽  
Lake Bottom ◽  
Break Up ◽  
Lena River Delta

Abstract. The thermal regimes of five lakes located within the continuous permafrost zone of northern Siberia (Lena River Delta) have been investigated using hourly water temperature and water level records covering a three year period (2009–2012), together with bathymetric survey data. The lakes included thermokarst lakes located on Holocene river terraces that may be connected to Lena River water during spring flooding, and a thermokarst lake located on deposits of the Pleistocene Ice Complex. The data were used for numerical modeling with FLake software, and also to determine the physical indices of the lakes. The lakes vary in area, depths and volumes. The winter thermal regime is characterized by an ice cover up to 2 m thick that survives for more than 7 months of the year, from October until about mid-June. Lake-bottom temperatures increase at the start of the ice-covered period due to upward-directed heat flux from the underlying thawed sediment. The effects of solar radiation return prior to ice break-up, effectively warming the water beneath the ice cover and inducing convective mixing. Ice break-up starts the beginning of June and takes until the middle or end of June for completion. Mixing occurs within the entire water column from the start of ice break-up and continues during the ice-free periods, as confirmed by the Wedderburn numbers. Some of the lakes located closest to the Lena River are subjected to varying levels of spring flooding with river water, on an annual basis. Numerical modeling using FLake software indicates that the vertical heat flux across the bottom sediment tends towards an annual mean of zero, with maximum downward fluxes of about 5 W m−2 in summer and with heat released back into the water column at a~rate of less than 1 W m−2 during the ice-covered period. The lakes are shown to be efficient heat absorbers and effectively distribute the heat through mixing. Monthly bottom water temperatures during the ice-free period range up to 15 °C and are therefore higher than the associated monthly air or ground temperatures in the surrounding frozen permafrost landscape. The investigated lakes remain unfrozen at depth, with mean annual lake-bottom temperatures of between 2.7 and 4 °C. The data are available in the Supplement for this paper and through the PANGAEA website (http://www.pangaea.de/).

Influence of coupling agent on altering the reinforcing efficiency of natural fibre-incorporated polymers – A review

2020 ◽  
Vol 39 (13-14) ◽  
pp. 520-544 ◽  
Author(s):  
Manju Sri Anbupalani ◽  
Chitra Devi Venkatachalam ◽  
Rajasekar Rathanasamy
Keyword(s):  
Composite Materials ◽  
Polymer Matrix ◽  
Natural Fibre ◽  
Coupling Agents ◽  
Mechanical And Thermal Properties ◽  
Green Composites ◽  
Green Composite ◽  
Composites Materials ◽  
Current Scenario ◽  
Physical And Chemical

Natural fibre-reinforced polymer composites are increasingly replacing commercial composite materials. The limitations of conventional composites materials are overcome by green composites, which are easily available, more eco-friendly and less toxic. In the current scenario, green composites are emerging in the field of material science that involves improving their physical, mechanical and thermal properties. The poor interfacial adhesion and surface incompatibility between natural fibre and biodegradable polymers lead to reduced physico-mechanical properties. In order to overcome this issue, physical and chemical modification methodologies of the natural fibre and polymer matrix are employed, among which the addition of coupling agents has a critical contribution. This paper compiles several recent research works in the utilization of coupling agents such as silane, maleic anhydride, isocyanate, triazine, etc., with the various combinations of natural fibres and polymers. In addition to this, the extents of influence of coupling agents on the characteristics of the natural fibre reinforced composite materials are also reported. This gives an overview for the future researchers to identify the gap in the field of green composite materials and novel coupling agents for different natural fibre/polymer matrix combination.

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