scholarly journals Effects of leachates from UV-weathered microplastic on the microalgae Scenedesmus vacuolatus

2021 ◽  
Author(s):  
Christoph D. Rummel ◽  
Hannah Schäfer ◽  
Annika Jahnke ◽  
Hans Peter H. Arp ◽  
Mechthild Schmitt-Jansen
Keyword(s):  
Water Distribution ◽  
Degradation Products ◽  
Electronic Waste ◽  
Dicarboxylic Acids ◽  
Test System ◽  
Algae Biomass ◽  
Chemical Leaching ◽  
Weathering Processes ◽  
Scenedesmus Vacuolatus ◽  
Insight Into

AbstractPlastics undergo successive fragmentation and chemical leaching steps in the environment due to weathering processes such as photo-oxidation. Here, we report the effects of leachates from UV-irradiated microplastics towards the chlorophyte Scenedesmus vacuolatus. The microplastics tested were derived from an additive-containing electronic waste (EW) and a computer keyboard (KB) as well as commercial virgin polymers with low additive content, including polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), and polystyrene (PS). Whereas leachates from additive-containing EW and KB induced severe effects, the leachates from virgin PET, PP, and PS did not show substantial adverse effects in our autotrophic test system. Leachates from PE reduced algae biomass, cell growth, and photosynthetic activity. Experimental data were consistent with predicted effect concentrations based on the ionization-corrected liposome/water distribution ratios (Dlip/w) of polymer degradation products of PE (mono- and dicarboxylic acids), indicating that leachates from weathering PE were mainly baseline toxic. This study provides insight into algae toxicity elicited by leachates from UV-weathered microplastics of different origin, complementing the current particle- vs. chemical-focused research towards the toxicity of plastics and their leachates. Graphical abstract

A Novel Integrated Reliability Test System for BEOL TDDB Study

2012 ◽  
Author(s):  
Jifeng Chen ◽  
Peilin Song ◽  
Thomas M. Shaw ◽  
Franco Stellari ◽  
Lynne Gignac ◽  
...  
Keyword(s):  
Preliminary Analysis ◽  
Dielectric Breakdown ◽  
Test System ◽  
Accurate Information ◽  
Reliability Test ◽  
Electrical Measurements ◽  
Time Dependent Dielectric Breakdown ◽  
Microscopy Images ◽  
Insight Into

Abstract In this paper, we propose a new methodology and test system to enable the early detection and precise localization of Time-Dependent-Dielectric-Breakdown (TDDB) occurrence in Back-End-of-Line (BEOL) interconnection. The methodology is implemented as a novel Integrated Reliability Test System (IRTS). In particular, through our methodology and test system, we can easily synchronize electrical measurements and emission microscopy images to gather more accurate information and thereby gain insight into the nature of the defects and their relationship to chip manufacturing steps and materials, so that we can ultimately better engineer these steps for higher reliable systems. The details of our IRTS will be presented along with a case study and preliminary analysis results.

scholarly journals Strecker degradation products of aspartic and glutamic acids and their amides

2013 ◽  
Vol 19 (No. 2) ◽  
pp. 41-45 ◽  
Author(s):  
J. Rössner ◽  
J. Velíšek ◽  
F. Pudil ◽  
J. Davídek
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Degradation Products ◽  
Dicarboxylic Acids ◽  
Reaction Products ◽  
Degradation Reactions ◽  
Strecker Aldehydes ◽  
Volatile Products ◽  
Acid Acid

Aspartic and glutamic acids, asparagine and glutamine were oxidised with either potassium peroxodisulphate or glyoxal. Nonvolatile products were derivatised and analysed by GC/FID and GC/MS. Volatile reaction products were isolated and analysed by the same methods. It was found that the degradation reactions of amino acids are complex. Amino acids are principally degraded via the corresponding a-keto acids to Strecker aldehydes (aspartic acid to oxalacetic and 3-oxopropionic acids and glutamic acid to a-ketoglutaric and 4-oxobutyric acids), which are unstable and decomposed by decarboxylation to the corresponding aldehydes. Aspartic acid also eliminates ammonia and yields fumaric acid whereas glutamic acid gives rise to an imine, pyroglutamic acid. A recombination of free radicals leads to dicarboxylic acids (succinic acid from aspartic acid, succinic, glutaric and adipic acids from glutamic acid). The major volatile products (besides the aldehydes) are lower carboxylic acids (acetic acid from aspartic acid and propionic acid acid from glutamic acid) that can at least partly arise by radical reactions. In both quality and quantity terms, a higher amount of degradation products arises by oxidation of amino acids by peroxodisulphate.

Robots in recycling and disassembly

2019 ◽  
Vol 46 (4) ◽  
pp. 461-466 ◽  
Author(s):  
Robert Bogue
Keyword(s):  
Research Effort ◽  
Electronic Waste ◽  
Waste Recycling ◽  
Content Type ◽  
Research Activities ◽  
Wide Range ◽  
Electronic Waste Recycling ◽  
Product Disassembly ◽  
Insight Into

Purpose This paper aims to illustrate the growing role robots are playing in recycling and product disassembly and provide an insight into recent research activities. Design/methodology/approach Following a short introduction, this first considers robotic waste sorting systems and then describes two systems for the disassembly of electronic products. It then provides details of some recent research activities. Finally, brief conclusions are drawn. Findings Robotic systems exploiting artificial intelligence combined with various sensing and machine vision technologies are playing a growing role in the sorting of municipal and industrial waste, prior to recycling. These are mostly based on delta robots and can achieve pick rates of 60-70 items/min and be configured to recognise and select a wide range of different materials and items from moving conveyors. Electronic waste recycling is yet to benefit significantly from robotics although a limited number of systems have been developed for product disassembly. Disassembly techniques are the topic of a concerted research effort which often involves robots and humans collaborating and sharing disassembly tasks. Originality/value This provides an insight into the present-day uses and potential future role of robots in recycling which has traditionally been a highly labour-intensive industry.

Thermal Breakdown of Rubber

1946 ◽  
Vol 19 (2) ◽  
pp. 277-282 ◽  
Author(s):  
J. L. Bolland ◽  
W. J. C. Orr
Keyword(s):  
Degradation Products ◽  
Chain Scission ◽  
Contributory Factor ◽  
Theoretical Treatment ◽  
Thermal Breakdown ◽  
Chain Molecules ◽  
Random Fashion ◽  
Efficient Alternative ◽  
Resonance Stabilization ◽  
Insight Into

Abstract The degradation of rubber observed during various technological processes may arise from several different causes. Since one such contributory factor is possibly degradation by a purely thermal mechanism, it is of interest to estimate experimentally the importance of this type of degradation under the temperature conditions normally used in the processing of rubber. It may be stated immediately that the authors' experiments confirm that thermal breakdown of rubber is of negligible importance under such circumstances and is always overshadowed by more efficient alternative modes of degradation. The thermal degradation of rubber, constituting as it does its formally simplest chemical reaction, has real possibilities of giving insight into the chemical stability and reactivity of the rubber molecule. Moreover, the theoretical treatment of the degradation of long-chain molecules has apparently far outstripped the experimental investigation of the problem. To date, attention has been confined to long polymeric chains which are assumed to break in quite random fashion at the regularly recurring bonds joining the monomeric units, and it is of importance to see how far this simplifying suggestion regarding the manner of chain scission does in fact correspond to reality. With these two ends in view the writers have investigated the thermal breakdown of rubber in some detail. A preliminary report is now presented on certain complexities of the reaction which may, however, be resolved by consideration of the resonance stabilization of the intermediate degradation products.

scholarly journals Development of a Test System To Apply Virus-Containing Particles to Filtering Facepiece Respirators for the Evaluation of Decontamination Procedures

2009 ◽  
Vol 75 (6) ◽  
pp. 1500-1507 ◽  
Author(s):  
Edward Fisher ◽  
Samy Rengasamy ◽  
Dennis Viscusi ◽  
Evanly Vo ◽  
Ronald Shaffer
Keyword(s):  
Protective Factors ◽  
Sodium Hypochlorite ◽  
Protective Factor ◽  
Test System ◽  
Relative Standard ◽  
Pathogenic Viruses ◽  
Virucidal Efficacy ◽  
Different Levels ◽  
Insight Into

ABSTRACT A chamber to apply aerosolized virus-containing particles to air-permeable substrates (coupons) was constructed and validated as part of a method to assess the virucidal efficacy of decontamination procedures for filtering facepiece respirators. Coliphage MS2 was used as a surrogate for pathogenic viruses for confirmation of the efficacy of the bioaerosol respirator test system. The distribution of virus applied onto and within the coupons was characterized, and the repeatability of applying a targeted virus load was examined. The average viable virus loaded onto 90 coupons over the course of 5 days was found to be 5.09 ± 0.19 log10 PFU/coupon (relative standard deviation, 4%). To determine the ability to differentiate the effectiveness of disinfecting procedures with different levels of performance, sodium hypochlorite and steam treatments were tested in experiments by varying the dose and time, respectively. The role of protective factors was assessed by aerosolizing the virus with various concentrations of the aerosol-generating medium. A sodium hypochlorite (bleach) concentration of 0.6% and steam treatments of 45 s and longer resulted in log reductions (>4 logs) which reached the detection limits for both levels of protective factors. Organic matter (ATCC medium 271) as a protective factor afforded some protection to the virus in the sodium hypochlorite experiments but was not a factor in the steam experiments. The evaluation of the bioaerosol respirator test system demonstrated a repeatable method for applying a targeted viral load onto respirator coupons and provided insight into the properties of aerosols that are of importance to the development of disinfection assays for air-permeable materials.

scholarly journals Pigments—Lead-based whites, reds, yellows and oranges and their alteration phases

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Elisabetta Gliozzo ◽  
Corina Ionescu
Keyword(s):  
State Of The Art ◽  
Degradation Products ◽  
Raw Materials ◽  
Lead Chromate ◽  
Lead White ◽  
Mineral Phases ◽  
Starting Point ◽  
Key Concepts ◽  
Red Lead ◽  
Insight Into

AbstractThis review summarises the state-of-the-art of lead-based pigment studies, addressing their production, trade, use and possible alteration. Other issues, such as those related to the investigation and protection of artworks bearing lead-based pigments are also presented. The focus is mineralogical, as both raw materials and degradation products are mineral phases occurring in nature (except for very few cases). The minerals described are abellaite, anglesite, blixite, caledonite, challacolloite, cerussite, cotunnite, crocoite, galena, grootfonteinite, hydrocerussite, laurionite, leadhillite, litharge, macphersonite, massicot, mimetite, minium, palmierite, phosgenite, plattnerite, plumbonacrite, schulténite, scrutinyite, somersetite, susannite, vanadinite and an unnamed phase (PbMg(CO3)2). The pigments discussed are lead white, red lead, litharge, massicot, lead-tin yellow, lead-tin-antimony yellow, lead-chromate yellow and Naples yellow. An attempt is made to describe the history, technology and alteration of these pigments in the most complete manner possible, despite the topic's evident breadth. Finally, an insight into the analytical methods that can (and should) be used for accurate archaeometric investigations and a summary of key concepts conclude this review, along with a further list of references for use as a starting point for further research.

scholarly journals A Review on the environmental and health impacts due to electronic waste disposal in Bangladesh

2021 ◽  
Vol 8 (2) ◽  
pp. 116-125
Author(s):  
Romana Afrose Meem ◽  
Arif Ahmed ◽  
Md. Shamim Hossain ◽  
Ruhul Amin Khan
Keyword(s):  
Electronic Waste ◽  
Open Water ◽  
Health Impact ◽  
North Eastern ◽  
Open Land ◽  
Hazardous Compounds ◽  
Insight Into ◽  
Dust Ingestion ◽  
Land Filling

Bangladesh is one of the main importer countries of e-waste in the world. Moreover, country also generates e-waste about 2.81 million metric tons per year. However, majority of e-waste is being dumped into the open soil, open land, or open water bodies resulting problem on environment (i.e., pollution) and human population (i.e., health). Therefore, present review summarizes the environmental and health impact due to disposal of e-waste. Poorly management of e-waste during the collection, processing, recycling, and land filling causing environmental impact followed by air pollution, soil pollution, water pollution, and degradation of the beach because hazardous compounds spread to the surrounding or environment. Furthermore, e-waste also creates lots of health problems. Humans can be exposed to e-waste contaminants by the inhalation, dietary intake, dust ingestion, and dermic contact. In north eastern part of Bangladesh, about 36.3% women who lives near recycling sites experienced the death of a baby. Again, about 15% child laborers die, and 83% child laborers are affected by long term health problem because of e-waste mismanagement practice. There are about 120,000 Bhangaries who may be exposed to e-waste contaminants more seriously. The result of the study would provide us important insight into the growing concern of e-waste and would help policy maker for designing policy measure to recycle e-waste in a hazard free manner.

scholarly journals Prioritisation and Localisation of Sustainable Development Goals (SDGs): Challenges and Opportunities for Bulawayo

2020 ◽  
Vol 13 (5) ◽  
pp. 104
Author(s):  
Vinnet Ndlovu ◽  
Peter Newman ◽  
Mthokozisi Sidambe
Keyword(s):  
Sustainable Development ◽  
Coming Out ◽  
Distribution Systems ◽  
Water Distribution ◽  
Sustainable Development Goals ◽  
Challenges And Opportunities ◽  
Development Goals ◽  
The City ◽  
Insight Into

Cities are engines of socio-economic development. This article examines and provides insight into the extent of localisation of the UN’s Sustainable Development Goals (SDGs) using the City of Bulawayo (CoB), in Zimbabwe, as the case study. The key question posited is ‘Does Bulawayo demonstrate potential for sustainable development?’. Bulawayo is a strange case study as in the period of the Millennium Development Goals Zimbabwe had a massive increase in death rates from 2000 to 2010 due to the HIV pandemic, political chaos and economic disintegration of that period. Coming out of that period there was little to help cities like Bulawayo grasp the opportunity for an SDG-based development focus. However, after the paper creates a multi-criteria framework from a Systematic Literature Review on the localisation of the SDG agenda, the application to Bulawayo now generates hope. The city is emerging from the collapse of the city’s public transport and water distribution systems, once the envy of and benchmark for many local authorities in the country, and has detailed SDG plans for the future. Bulawayo now serves as a planning model for localisation of sustainable development goals.

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