scholarly journals Effect of Weathering on Surface Functional Groups of Charred Norway Spruce Cladding Panels

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1373
Author(s):  
Maija Kymäläinen ◽  
Hannu Turunen ◽  
Lauri Rautkari
Keyword(s):  
Norway Spruce ◽  
Functional Groups ◽  
Future Research ◽  
Process Conditions ◽  
Feed Speed ◽  
Cladding Panels ◽  
Prototype Device ◽  
Modified Lignin ◽  
Charred Wood ◽  
Poor Stability

Norway spruce cladding panels were surface charred with a prototype device utilizing a hot plate method. The panels were used to construct a test wall that was exposed to natural weathering for a period of two years. The changes in functional groups were evaluated with photoacoustic FTIR spectroscopy. The analysis revealed degradation of the thermally modified lignin component, indicating poor stability in weathering. Improvements in the prototype device process conditions, such as increased surface pressure and slower feed speed, and future research needs regarding surface charred wood are discussed.

scholarly journals Enhanced Wastewater Treatment by Immobilized Enzymes

2021 ◽  
Author(s):  
Jakub Zdarta ◽  
Katarzyna Jankowska ◽  
Karolina Bachosz ◽  
Oliwia Degórska ◽  
Karolina Kaźmierczak ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Process Optimization ◽  
Organic Pollutants ◽  
Large Scale ◽  
Removal Rate ◽  
Immobilized Enzymes ◽  
Future Research ◽  
Process Conditions ◽  
Removal Rates ◽  
Catalytic Cycles

Abstract Purpose of Review In the presented review, we have summarized recent achievements on the use of immobilized oxidoreductases for biodegradation of hazardous organic pollutants including mainly dyes, pharmaceuticals, phenols, and bisphenols. In order to facilitate process optimization and achievement of high removal rates, effect of various process conditions on biodegradation has been highlighted and discussed. Recent Findings Current reports clearly show that immobilized oxidoreductases are capable of efficient conversion of organic pollutants, usually reaching over 90% of removal rate. Further, immobilized enzymes showed great recyclability potential, allowing their reuse in numerous of catalytic cycles. Summary Collected data clearly indicates immobilized oxidoreductases as an efficient biocatalytic tools for removal of hazardous phenolic compounds, making them a promising option for future water purification. Data shows, however, that both immobilization and biodegradation conditions affect conversion efficiency; therefore, process optimization is required to achieve high removal rates. Nevertheless, we have demonstrated future trends and highlighted several issues that have to be solved in the near-future research, to facilitate large-scale application of the immobilized oxidoreductases in wastewater treatment.

scholarly journals Principles and Characteristics of Different EDM Processes in Machining Tool and Die Steels

2020 ◽  
Vol 10 (6) ◽  
pp. 2082 ◽  
Author(s):  
Jaber E. Abu Qudeiri ◽  
Aiman Zaiout ◽  
Abdel-Hamid I. Mourad ◽  
Mustufa Haider Abidi ◽  
Ahmed Elkaseer
Keyword(s):  
Large Scale ◽  
Removal Rate ◽  
Surface Characteristics ◽  
Future Research ◽  
Process Conditions ◽  
Process Performance ◽  
Die Steels ◽  
Wide Range ◽  
Complex Shapes ◽  
Manufacturing Technologies

Electric discharge machining (EDM) is one of the most efficient manufacturing technologies used in highly accurate processing of all electrically conductive materials irrespective of their mechanical properties. It is a non-contact thermal energy process applied to a wide range of applications, such as in the aerospace, automotive, tools, molds and dies, and surgical implements, especially for the hard-to-cut materials with simple or complex shapes and geometries. Applications to molds, tools, and dies are among the large-scale initial applications of this process. Machining these items is especially difficult as they are made of hard-to-machine materials, they have very complex shapes of high accuracy, and their surface characteristics are sensitive to machining conditions. The review of this kind with an emphasis on tool and die materials is extremely useful to relevant professions, practitioners, and researchers. This review provides an overview of the studies related to EDM with regard to selection of the process, material, and operating parameters, the effect on responses, various process variants, and new techniques adopted to enhance process performance. This paper reviews research studies on the EDM of different grades of tool steel materials. This article (i) pans out the reported literature in a modular manner with a focus on experimental and theoretical studies aimed at improving process performance, including material removal rate, surface quality, and tool wear rate, among others, (ii) examines evaluation models and techniques used to determine process conditions, and (iii) discusses the developments in EDM and outlines the trends for future research. The conclusion section of the article carves out precise highlights and gaps from each section, thus making the article easy to navigate and extremely useful to the related research community.

scholarly journals Bioremediation of Chromium by Microorganisms and Its Mechanisms Related to Functional Groups

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Abate Ayele ◽  
Yakob Godebo Godeto
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ions ◽  
Functional Groups ◽  
Heavy Metal Ions ◽  
Future Research ◽  
Oil Well ◽  
Toxic Heavy Metals ◽  
Toxic Heavy Metal ◽  
Minimum Concentration

Heavy metals generated mainly through many anthropogenic processes, and some natural processes have been a great environmental challenge and continued to be the concern of many researchers and environmental scientists. This is mainly due to their highest toxicity even at a minimum concentration as they are nonbiodegradable and can persist in the aquatic and terrestrial environments for long periods. Chromium ions, especially hexavalent ions (Cr(VI)) generated through the different industrial process such as tanneries, metallurgical, petroleum, refractory, oil well drilling, electroplating, mining, textile, pulp and paper industries, are among toxic heavy metal ions, which pose toxic effects to human, plants, microorganisms, and aquatic lives. This review work is aimed at biosorption of hexavalent chromium (Cr(VI)) through microbial biomass, mainly bacteria, fungi, and microalgae, factors influencing the biosorption of chromium by microorganisms and the mechanism involved in the remediation process and the functional groups participated in the uptake of toxic Cr(VI) from contaminated environments by biosorbents. The biosorption process is relatively more advantageous over conventional remediation technique as it is rapid, economical, requires minimal preparatory steps, efficient, needs no toxic chemicals, and allows regeneration of biosorbent at the end of the process. Also, the presence of multiple functional groups in microbial cell surfaces and more active binding sites allow easy uptake and binding of a greater number of toxic heavy metal ions from polluted samples. This could be useful in creating new insights into the development and advancement of future technologies for future research on the bioremediation of toxic heavy metals at the industrial scale.

scholarly journals Current overview of carbon fiber: Toward green sustainable raw materials

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 7234-7259
Author(s):  
Yongjian Xu ◽  
Yan Liu ◽  
Shenglin Chen ◽  
Yonghao Ni
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
Melt Spinning ◽  
Raw Materials ◽  
Future Research ◽  
Process Conditions ◽  
Preparation Methods ◽  
Advantages And Disadvantages ◽  
Solution Spinning ◽  
And Performance

Lignin, as a potential precursor of carbon fiber, has the characteristics of abundant reserves, renewable and high carbon content, and its application in the preparation of carbon fibers has substantial cost advantages if some important processing and quality hurdles can be overcome. This paper reviews the preparation process of lignin-based carbon fibers, and moreover, describes the characteristics of carbon fiber prepared by different precursors compared with the presently used precursors. Three preparation methods for lignin-based carbon fibers are introduced: melt spinning, solution spinning, and electrospinning. The applicability, advantages, and disadvantages of the three preparation methods are analyzed from the aspects of process conditions and performance characteristics. Possible directions for future research are considered, with the goal of providing a reference for further study of lignin-based carbon fibers.

scholarly journals Aldehydes as Wort Off-Flavours in Alcohol-Free Beers—Origin and Control

2019 ◽  
Vol 13 (2) ◽  
pp. 195-216 ◽  
Author(s):  
D. C. Gernat ◽  
E. Brouwer ◽  
M. Ottens
Keyword(s):  
Process Integration ◽  
Future Research ◽  
Process Conditions ◽  
Brewing Industry ◽  
Leverage Points ◽  
Adsorptive Removal ◽  
Unit Operations ◽  
Packaging Industry ◽  
Removal Technologies ◽  
And Control

AbstractAlthough present in concentrations in microgrammes per litre level, aldehydes, in particular those derived from Strecker degradation, are known to majorly contribute to the undesired wort flavour of alcohol-free beers. In order to improve currently available products, one needs to understand the underlying cause for the over-prevalence and identify leverage points and methods to selectively reduce the aldehydes in alcohol-free beers. This work gives a short overview on relevant flavour-active wort flavours identified in alcohol-free beer and on their involved chemical formation pathways. Consequently, aldehyde removal technologies in general and in brewing industry are presented. Adsorptive removal of off-flavours by aldehyde-scavenging groups is already widely exploited in the packaging industry and may achieve reduction of these components to near depletion, depending on the process conditions. Its principles are adaptable to recovering off-flavours before filling. Also, supercritical CO2 extraction has been successfully applied to separate flavours from food matrices. In brewing, the focus has been set to biologic conversion by restricted fermentation steps, but the reduction of key components of more than 70% is not achieved. Newer developments focus on thermal separation techniques that not only include non-specific physical dealcoholisation but also more selective technologies such as pervaporation, where aldehydes are reduced to near depletion. However, for most unit operations, selectivity and capacity are not yet investigated. Future research should explore the shortcomings of current techniques and overcome bottlenecks either by developing more specific methods for aldehyde removal and/or a clever combination of unit operations to optimise the separation and process integration.

scholarly journals A Permanent Research Platform for Ecological Studies in Intact Temperate Mountainous Forests from Slătioara UNESCO Site and Its Surroundings, Romania

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1004
Author(s):  
Gabriel Duduman ◽  
Mihai-Leonard Duduman ◽  
Daniel Avăcăriței ◽  
Ionuț Barnoaiea ◽  
Cătălina-Oana Barbu ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Tree Species ◽  
Dead Wood ◽  
Future Research ◽  
Silver Fir ◽  
Wood Volume ◽  
Square Grid ◽  
Main Research ◽  
Research Platform ◽  
Unesco Site

This paper describes a permanent research platform (PRP) designed and implemented in “Codrul secular Slătioara” and its surroundings (2205.85 ha), having also the role of introductory paper for future research articles based on data collected from this platform. “Codrul secular Slătioara” is known as one of the largest temperate mountainous intact forests of Europe and, in 2017, it was included in UNESCO World Heritage List, as part of the “Ancient and Primeval Beech Forests of the Carpathians and Other Regions of Europe”. Moreover, the PRP overlaps other three scientific reserves, the share of strictly protected forests exceeding 70%. This platform has a multiple role, being developed for research, conservation and educational activities. The PRP was designed for an ecological analysis of the intact forest ecosystems. It contains 193 circular sample plots, each of them of 500 m2, and it is structured on two levels. The first level contains 58 sample plots corresponding to a square grid of 500 × 500 m, stretching over the entire forested area, and the second level contains 135 plots, placed according to a square grid of 100 × 100 m, covering 136 ha within the core area of the UNESCO site. We measured the characteristics of 8296 living trees, 1743 standing dead trees, 1900 dead wood trunks, 3214 saplings, and the abundance–dominance indices of flora species. Thus, we identified 14 tree species, 17 shrub species, and 248 other cormophyte species forming the herbaceous layer. In terms of volume, the main tree species are Norway spruce, silver fir and European beech. The tallest species are Norway spruce (56 m) and silver fir (51 m). The average volume of living trees is 659 m3·ha−1, with a maximum of 1441 m3·ha−1. The mean total dead wood volume is about 158 m3·ha−1, with sample plots where the total dead wood volume exceeds 600 m3·ha−1. After presenting the results of preliminary data processing, the paper describes the main research topics to be further considered, based on the PRP, and the foresights related to the PRP’s monitoring and development.

Diamond Disc Pad Conditioning in Chemical Mechanical Polishing: A Literature Review of Process Modeling

2009 ◽  
Author(s):  
Emmanuel A. Baisie ◽  
Z. C. Li ◽  
X. H. Zhang
Keyword(s):  
Process Modeling ◽  
Chemical Mechanical Polishing ◽  
Research Work ◽  
Mechanical Polishing ◽  
Process Models ◽  
Future Research ◽  
Process Conditions ◽  
Paper Briefly ◽  
Pad Conditioning ◽  
Diamond Disc

Chemical Mechanical Polishing (CMP) is a major manufacturing step extensively used to planarize semiconductor wafers. In CMP, the polishing pad surface is glazed by residues. A diamond disc conditioner is used to dress the pad to regenerate new pad profile and asperity in order to maintain favorable process conditions. This paper presents a review on process modeling of diamond disc pad conditioning in CMP. Following the introduction, the paper briefly introduces a technical background of the conditioning process and process control. It then summarizes research work on the various analytical process models proposed and ends with conclusions and topics for future research.

Interaction of laser beams with carbon textile materials

2015 ◽  
Vol 27 (5) ◽  
pp. 720-737
Author(s):  
Milesa Ž Sreckovic ◽  
Branka Kaludjerovic ◽  
Aleksander G Kovacevic ◽  
Aleksandar Bugarinovic ◽  
Dragan Družijanic
Keyword(s):  
Textile Industry ◽  
Laser Beams ◽  
Future Research ◽  
Process Conditions ◽  
Laser Applications ◽  
Content Type ◽  
Textile Materials ◽  
Different Types ◽  
Fs Laser ◽  
Fabric Materials

Purpose – The purpose of this paper is to present the results of interaction occurring during the exposition of some specific carbon textile materials obtained in laboratory conditions to beams of various laser types. Design/methodology/approach – Carbon fabric materials – fiber, felt and cloth – obtained from different precursor materials and prepared at various process conditions (oxidized, partially carbonized, carbonized, graphitized), were exposed to pulses of various lasers (Nd3+: YAG, alexandrite, ruby). Findings – Depending on the laser power, plasma and destructive phenomena occurred. In the case of an interaction between a Nd3+: YAG laser beam and specimens of thickness in millimeter range, the authors have estimated the threshold of the energy density for drilling and discussed the possible models of the interaction. Research limitations/implications – The results have implications in the estimations of quality as well as in the improvement of material processing, giving some new light to the changes of mechanical and optical constants of the material, as well as to the changes of carbon groups of the material, which would be useful for different types of modeling. Future research will be in the interaction of laser beams with various textile materials, where the investigation would cover the microstructure changes and the implications on cloth cutting and welding, concerning the damages as well as relief structures, specially renew for fs laser regimes. Originality/value – The area of laser applications in the textile industry is supported by scientific and applicative exploration. However, fewer results are concerned with deep introspection into the microstructure of the damages considering the laser interaction with carbon fiber and other carbon-based textiles.

Impact of gradual process change on onshore facilities

2012 ◽  
Vol 52 (1) ◽  
pp. 337
Author(s):  
Paul R. Russ ◽  
Andrew R Foote
Keyword(s):  
Functional Groups ◽  
Process Conditions ◽  
Gradual Change ◽  
Process Change ◽  
Production Rates ◽  
Offshore Production ◽  
Gradual Process ◽  
The Impact

This paper will demonstrate that a broad disciplined approach to monitoring and inspection programs is required in order to manage the impact of gradual changes in process conditions on operating facilities. Where no process or integrity issues existed previously, gradual changes in the process can have a significant effect on the integrity of pressure equipment. The impact of gradual change in offshore production rates on onshore pressure equipment integrity and in particular, the effects of sand and microbiological induced corrosion is described. The management of sand was found to be important in controlling integrity. Co-ordination and communication between different functional groups was essential to adopting new measures to control the integrity threat. The measures that were undertaken to ensure the ongoing integrity of the facilities are described. Gradual process changes can be recognised early, provided that appropriate monitoring and inspection programs are performed. These are outlined so that operators of other facilities can learn and take appropriate action.

Study on Surface Quality and Machining Efficiency of Diamond Wire Saw Slicing SiCp-Al Composites

2014 ◽  
Vol 1004-1005 ◽  
pp. 1295-1298
Author(s):  
Chun Yan Zhang ◽  
Wu Yang ◽  
Yuan Sun
Keyword(s):  
Surface Quality ◽  
Future Research ◽  
Basic Rule ◽  
Feed Speed ◽  
Machining Efficiency ◽  
Machined Surface ◽  
Diamond Wire ◽  
Speed Increase ◽  
Wire Saw ◽  
Diamond Wire Saw

In order to study the basic rule of diamond wire saw slicing SiCp-Al composites, the theoretical analysis and experiments were carried out. The influences of diamond wire saw slicing speed and workpiece feed speed on surface quality and machining efficiency were discussed. The analysis results show that the machined surface gets smoother when diamond wire saw slicing speed changes from 2m/s to 3.5m/s, but gets rougher when diamond wire saw slicing speed changes from 3.5m/s to 4m/s. And the surface gets rougher when workpiece feed speed changes from 0.5m/s to 1m/s.The machining efficiency gets higher when diamond wire saw slicing speed and workpiece feed speed increase. These results provide guidance for selecting reasonable parameters in future research.

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