A pilot interlaboratory comparison of protocols that simulate aging of nanocomposites and detect released fragments

2014 ◽  
Vol 11 (4) ◽  
pp. 402 ◽  
Author(s):  
Wendel Wohlleben ◽  
Gemma Vilar ◽  
Elisabet Fernández-Rosas ◽  
David González-Gálvez ◽  
Claus Gabriel ◽  
...  
Keyword(s):  
Interlaboratory Comparison ◽  
Critical Parameters ◽  
Release Rates ◽  
Sampling Protocol ◽  
Unbound Fraction ◽  
Run Off ◽  
Validity Range ◽  
Aging Conditions ◽  
Essential Input ◽  
Polydisperse Mixture

Environmental context Nanoparticles are contained in many commercialised products, but the lack of validated methods to assess their potential release into the environment hampers our ability to perform a reliable risk assessment. Equipment to simulate aging is available, but the challenge is to sample released entities, and to analyse those fragments with suitable nano-analytics. We describe methods to characterise the degradation and surface accumulation of nanoparticles, and to quantify fragments released during UV irradiation of polymer nanocomposites. Abstract The safe use of nanoparticles as fillers in nanocomposite materials depends, in part, on a good understanding of what is released from aging nanocomposites, and at which rate. Here we investigated the critical parameters of the nanoparticle release phenomenon by a pilot inter-laboratory study of a polyamide containing 4mass% of silica nanoparticles (nanosilica). The main focus is on the validity range of the aging and release protocols. Both induced release by mechanical shear after dry weathering at different UV intensities and spontaneous release during wet weathering were investigated. We propose a combined protocol based on the finding that the characteristics of released fragments – which are the essential input for fate, transport and (eco-)toxicological testing – were reproducible between laboratories and between different aging, sampling and analysis protocols: the released fragments were a polydisperse mixture of predominantly composite fragments from the nanometre up to several micrometre diameter, and of clustered or individual nanosilica unbound to polymer. The unbound fraction was microscopically observed but could not be quantified. We found that aging conditions are very critical for the release rates, not for release characteristics. The sampling protocol tolerates some differences. Simplified aging + immersion protocols can at least partially replace, complement and extend dedicated weathering apparatus with run-off collection.

Survey and Analysis of Computing Education at Japanese Universities: Non-IT Departments and Courses

2019 ◽  
Vol 13 ◽  
pp. 57-79
Author(s):  
Tetsuro KAKESHITA ◽  
Mika OHTSUKI
Keyword(s):  
Educational Achievement ◽  
Academic Discipline ◽  
Teaching Staff ◽  
Computing Environment ◽  
Computing Education ◽  
Major Subject ◽  
Curriculum Guidelines ◽  
Essential Input ◽  
Organization Quality ◽  
It Departments

We conducted the first national survey of computing education at Japanese universities in 2016. In this paper, we report the survey result of the computing education at non-IT departments and faculties whose major subject is not computing. The survey covers various aspects of computing education including program organization, quality and quantity of educational achievement, students, teaching staff and computing environment. We collected 994 answers through the survey. At least 87,000 non-ICT students are taking computing education in Japan. Although computing education is carried out at every major academic discipline, teaching effort greatly differs depending on the academic discipline. We also find shortage of teaching staff for computing education. The analysis result will be an essential input to develop reasonable curriculum guidelines and accreditation criteria to improve computing education at non-IT departments.

STRUKTUR BASIS DATA SISTEM INFORMASI MANAJEMEN ALOKASI LAHAN DALAM PENATAAN RUANG

2019 ◽  
Vol 3 ◽  
pp. 385
Author(s):  
Dinar Dwi Anugerah Putranto ◽  
Agus Lestari Yuono ◽  
Sarino Sarino ◽  
IC Juliana
Keyword(s):  
Run Off

Perubahan Pemanfaatan lahan yang begitu cepat, telah merubah pola-pola pengaliran permukaan (run-off) pada wilayah sub sistem sungai yang ada di daerah perkotaan. Permasalahan limpasan air permukaan dan genangan (storm watter), dipengaruhi oleh beberapa faktor, seperti masalah okupasi bantaran sungai, penimbunan rawa yang tidak sesuai, pengaruh pasang-surut sungai, yang mempengaruhi kapasitas sub sistem sungai pada wilayah bersangkutan (Putranto, 2016). Penelitian ini akan membahas isu spasial pada sistem aliran air permukaan dalam perencanaan tata ruang wilayah kota dengan menekankan integrasi aliran air permukaan (run-off) dan manajemen alokasi lahan. Metode yang digunakan dalam penelitian ini adalah melakukan analisis secara spasial menggunakan semua parameter Run-off dalam struktur database dengan memanfaatkan interface Sistem Informasi Manajemen Alokasi Lahan (SIMAL) yang dibangun untuk menguji besarnya puncak banjir menggunakan metode HSS Nakayatsu, dengan studi kasus sub sistem sungai Jakabaring, di Kota Palembang. Hasil yang diperoleh mampu melihat alih fungsi lahan rawa, yang dimanfaatkan untuk Kawasan Palembang Sport City dalam menghadapi Asian Games 2018 di Kota Palembang, telah menyebabkan genangan banjir pada wilayah sungai Kedukan, bagian dari Sub DAS Jakabaring, Kawasan Seberang Ulu, Kota Palembang, Indonesia. Berdasarkan Analisis menggunakan model hydrograft satuan Nakayatsu, terjadinya puncak banjir akan terjadi saat curah hujan mencapai lebih dari 120 mm/jam yang menyebabkan debit sungai kedukan mencapai hingga 400m3/det. Pembuatan danau buatan sebagai kolam retensi dan sekaligus sebagai venue olah raga, belum mampu mengurangi tinggi genangan yang terjadi sekitar 0,6 – 1,2 m dpl.

New Insights into the Nature of the Band Gap of CuGeO3 Nanoparticles: Synthesis, Electronic Structure, and Optical and Photocatalytic Properties

2019 ◽  
Author(s):  
Victor Y. Suzuki ◽  
Luís Henrique Cardozo Amorin ◽  
Natália H. de Paula ◽  
Anderson R. Albuquerque ◽  
Julio Ricardo Sambrano ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Material Design ◽  
Photocatalytic Properties ◽  
Critical Parameters ◽  
Synthetic Approach ◽  
Microwave Assisted ◽  
Theoretical Approaches ◽  
Nanoparticles Synthesis ◽  
First Time

<p>We report, for the first time, new insights into the nature of the band gap of <a>CuGeO<sub>3</sub> </a>(CGO) nanocrystals synthesized from a microwave-assisted hydrothermal method in the presence of citrate. To the best of our knowledge, this synthetic approach has the shortest reaction time and it works at the lowest temperatures reported in the literature for the preparation of these materials. The influence of the surfactant on the structural, electronic, optical, and photocatalytic properties of CGO nanocrystals is discussed by a combination of experimental and theoretical approaches, and that results elucidates the nature of the band gap of synthetized CGO nanocrystals. We believe that this particular strategy is one of the most critical parameters for the development of innovative applications and that result could shed some light on the emerging material design with entirely new properties.</p> <p><b> </b></p>

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