scholarly journals Challenges in Determining the Location of Dopants, to Study the Influence of Metal Doping on the Photocatalytic Activities of ZnO Nanopowders

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 481 ◽  
Author(s):  
Takuya Tsuzuki ◽  
Rongliang He ◽  
Aaron Dodd ◽  
Martin Saunders
Keyword(s):  
Analytical Techniques ◽  
Data Interpretation ◽  
Metal Doping ◽  
Doping Effects ◽  
Photocatalytic Activities ◽  
Impurity Doping ◽  
Semiconductor Nanomaterials ◽  
Metal Doped

Impurity doping is one of the common approaches to enhance the photoactivity of semiconductor nanomaterials by increasing photon-capture efficiency in the visible light range. However, many studies on the doping effects have produced inconclusive and conflicting results. There are some misleading assumptions and errors that are frequently made in the data interpretation, which can lead to inconsistent results about the doping effects on photocatalysis. One of them is the determination of the location of dopants. Even using advanced analytical techniques, it is still challenging to distinguish between bulk modification and surface modification. The paper provides a case study of transition-metal-doped ZnO nanoparticles, whereby demonstrating common pitfalls in the interpretation of the results of widely-used analytical methods in detail, and discussing the importance of using a combination of many characterization techniques to correctly determine the location of added impurities, for elucidating the influence of metal doping on the photocatalytic activities of semiconductor nanoparticles.

IMPROVEMENT OF PHOTOCATALYTIC ACTIVITY OF TiO2 VIA COMBINED ROUTE OF METAL DOPING AND SURFACE ACIDIFICATION

2006 ◽  
Vol 13 (04) ◽  
pp. 429-438 ◽  
Author(s):  
YONG LUAN ◽  
PINGFENG FU ◽  
XUEGANG DAI
Keyword(s):  
Photocatalytic Activity ◽  
Sol Gel ◽  
Emission Spectra ◽  
Favorable Effect ◽  
Infrared Analysis ◽  
X Ray Diffraction ◽  
Metal Doping ◽  
Ultraviolet Light Irradiation ◽  
Photocatalytic Activities ◽  
Metal Doped

In the present work, a combined route involving first doping of iron or neodymium ions via sol–gel method followed by acidification of the metal-doped TiO 2 particles for the improvement of the photocatalytic capability of TiO 2 was reported. The obtained metal-doped/acidified TiO 2 photocatalysts were thoroughly characterized by X-ray diffraction, Fourier transform infrared analysis, and photoluminescence emission spectra. At the same time, their photocatalytic activities were evaluated in simulant photodegradation of methylene blue (MB). The results based on these characterizations showed that not only a rutile layer formed on the surface of original TiO 2 particles after surface cladding, but also the doped Fe or Nd ion had a favorable effect on suppression of the electron–hole recombination in the titania under ultraviolet light irradiation. Furthermore, the photocatalytic activity of the material obtained by Fe doping and acidification was substantially improved in comparison to the untreated TiO 2. However, the sample prepared from Nd -doping and acidification of TiO 2 showed decreased capability relative to the untreated TiO 2 in degradation of MB under similar conditions. Finally, the reason why the photocatalytic activities of the obtained catalysts are sensitive to the metal-doping was discussed in details.

PEMAKNAAN HADIS ANJURAN MENUNTUT ILMU RIWAYAT MUSLIM DARI ABU HURAIRAH DI KALANGAN AKADEMISI KOTA AMBON

2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Rustina Nurdin
Keyword(s):  
Data Analysis ◽  
Analytical Techniques ◽  
Sampling Technique ◽  
Data Interpretation ◽  
Research Subjects ◽  
Is Success ◽  
Purposive Sampling ◽  
Teachers And Students ◽  
The City

Abstract: This study aims to analyze the meaning of Ambon City academics on the Prophet's hadith regarding the recommendation to study from Abu Hurairah ra. Muslim history. This type of research is descriptive qualitative research. The research object of the Prophet's hadith. about suggestions and orders to actively seek knowledge for his people. The research subjects are academics; lecturers, teachers and students who live in the city of Ambon. Determination of informants is done through purposive sampling technique, data collection is done through observation, in-depth interviews and documentation. The data analysis was carried out through two analytical techniques; 1) the analysis of the meaning of the hadith was carried out through the tahliliy method; 2) through qualitative data analysis techniques, namely data display, data verification, data interpretation and drawing conclusions. The results of the study are stated as follows that the meaning of this hadith among academics in Ambon City is in line and in accordance with what has been explained by hadith scholars. Most academics interpret this hadith in a meaningful or contextual way that the science referred to in this hadith is the science of religion and general science (not only religious science), seeking knowledge is like worship which is a basic human spiritual need, and heaven (al-jannah) is meant. is success and happiness that will be obtained in this world and in the hereafter for those who are serious about learning and seeking knowledge. Key Words: hadith; recommendation to study; academics  Abstrak: Penelitian ini bertujuan untuk menganalisis pemaknaan akademisi Kota Ambon terhadap hadis Nabi saw tetang anjuran menuntut ilmu dari Abu Hurairah ra. riwayat Muslim. Jenis penelitian ini adalah penelitian deskriptif kualitatif. Obyek penelitian hadis Nabi saw. tentang anjuran dan perintah giat mencari ilmu bagi ummatnya. Adapun subyek penelitian adalah akedemisi; dosen, guru dan mahasiswa yang berdomisili di kota Ambon. Penentuan informan dilakukan melalui teknik purposive sampling, pengumpulan data dilakukan melalui observasi, wawancara mendalam dan dokumentasi. Adapun analisis data dilakukan melalui dua teknik analisis;1) analisis makna hadis ditempuh melalui metode tahliliy;  2)melalui teknik analisis data kualitatif, yaitu display data, verifikasi data, interpretasi data dan penarikan kesimpulan.  Hasil penelitian dikemukakan sebagai berikut bahwa pemaknaan hadis ini di kalangan akademisi Kota Ambon sejalan dan sesuai dengan apa yang telah dijelaskan oleh ulama hadis. Sebagian besar akademisi memaknai hadis ini secara maknawiyah atau kontekstual bahwa ilmu yang dimaksud dalam hadis ini adalah ilmu agama dan ilmu umum (bukan hanya ilmu agama), menuntut ilmu ibarat ibadah yang merupakan kebutuhan pokok rohani manusia, serta surga (al-jannah) yang dimaksud adalah kesuksesan dan kebahagiaan yang akan diperoleh di dunia ini maupun di akhirat kelak bagi mereka yang bersungguh-sungguh belajar dan menutut ilmu. Kata Kunci: hadis; anjuran menuntut ilmu; akademisi

A novel method for the determination of linting propensity of paper

TAPPI Journal ◽  
2012 ◽  
Vol 11 (10) ◽  
pp. 9-17
Author(s):  
ALESSANDRA GERLI ◽  
LEENDERT C. EIGENBROOD
Keyword(s):  
Ash Content ◽  
The Novel ◽  
Offset Printing ◽  
Excellent Correlation ◽  
End Conditions ◽  
Bottom Side ◽  
Novel Method ◽  
Total Fraction

A novel method was developed for the determination of linting propensity of paper based on printing with an IGT printability tester and image analysis of the printed strips. On average, the total fraction of the surface removed as lint during printing is 0.01%-0.1%. This value is lower than those reported in most laboratory printing tests, and more representative of commercial offset printing applications. Newsprint paper produced on a roll/blade former machine was evaluated for linting propensity using the novel method and also printed on a commercial coldset offset press. Laboratory and commercial printing results matched well, showing that linting was higher for the bottom side of paper than for the top side, and that linting could be reduced on both sides by application of a dry-strength additive. In a second case study, varying wet-end conditions were used on a hybrid former machine to produce four paper reels, with the goal of matching the low linting propensity of the paper produced on a machine with gap former configuration. We found that the retention program, by improving fiber fines retention, substantially reduced the linting propensity of the paper produced on the hybrid former machine. The papers were also printed on a commercial coldset offset press. An excellent correlation was found between the total lint area removed from the bottom side of the paper samples during laboratory printing and lint collected on halftone areas of the first upper printing unit after 45000 copies. Finally, the method was applied to determine the linting propensity of highly filled supercalendered paper produced on a hybrid former machine. In this case, the linting propensity of the bottom side of paper correlated with its ash content.

Metal-Organic Frameworks vs. Buffers: Case Study of UiO-66 Stability

2020 ◽  
Author(s):  
Daniel Bůžek ◽  
Slavomír Adamec ◽  
Kamil Lang ◽  
Jan Demel
Keyword(s):  
Inductively Coupled Plasma ◽  
Buffer Capacity ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Analytical Techniques ◽  
Aqueous Dispersions ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Metal Organic

<div><p>UiO-66 is a zirconium-based metal-organic framework (MOF) that has numerous applications. Our group recently determined that UiO-66 is not as inert in aqueous dispersions as previously reported in the literature. The present work therefore assessed the behaviour of UiO-66 in buffers: 2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIS), 4-(2-hydroxyethyl)piperazine-1-ethane sulfonic acid (HEPES), N-ethylmorpholine (NEM) and phosphate buffer (PB), all of which are commonly used in many UiO-66 applications. High pressure liquid chromatography and inductively coupled plasma mass spectrometry were used to monitor degradation of the MOF. In each buffer, the terephthalate linker was released to some extent, with a more pronounced leaching effect in the saline forms of these buffers. The HEPES buffer was found to be the most benign, whereas NEM and PB should be avoided at any concentration as they were shown to rapidly degrade the UiO-66 framework. Low concentration TRIS buffers are also recommended, although these offer minimal buffer capacity to adjust pH. Regardless of the buffer used, rapid terephthalate release was observed, indicating that the UiO-66 was attacked immediately after mixing with the buffer. In addition, the dissolution of zirconium, observed in some cases, intensified the UiO-66 decomposition process. These results demonstrate that sensitive analytical techniques have to be used to monitor the release of MOF components so as to quantify the stabilities of these materials in liquid environments.</p></div>

The Calculation of Turbulent Diffusion Coefficients in Aquatic Ecosystems

2019 ◽  
Vol 70 (11) ◽  
pp. 3903-3907
Author(s):  
Galina Marusic ◽  
Valeriu Panaitescu
Keyword(s):  
Transport Equation ◽  
Turbulent Diffusion ◽  
Diffusion Coefficients ◽  
Aquatic Ecosystems ◽  
Specific Area ◽  
Left Bank ◽  
The Right ◽  
Prut River

The paper deals with the issues related to the pollution of aquatic ecosystems. The influence of turbulence on the transport and dispersion of pollutants in the mentioned systems, as well as the calculation of the turbulent diffusion coefficients are studied. A case study on the determination of turbulent diffusion coefficients for some sectors of the Prut River is presented. A new method is proposed for the determination of the turbulent diffusion coefficients in the pollutant transport equation for specific sectors of a river, according to the associated number of P�clet, calculated for each specific area: the left bank, the right bank and the middle of the river.

scholarly journals Food Bioactive Compounds and Emerging Techniques for Their Extraction: Polyphenols as a Case Study

Foods ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 37 ◽  
Author(s):  
José S. Câmara ◽  
Bianca R. Albuquerque ◽  
Joselin Aguiar ◽  
Rúbia C. G. Corrêa ◽  
João L. Gonçalves ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Chemical Structure ◽  
Experimental Studies ◽  
Analytical Techniques ◽  
Convincing Evidence ◽  
Protective Effects ◽  
Extraction Techniques ◽  
Biological Impact ◽  
Preventive Effects

Experimental studies have provided convincing evidence that food bioactive compounds (FBCs) have a positive biological impact on human health, exerting protective effects against non-communicable diseases (NCD) including cancer and cardiovascular (CVDs), metabolic, and neurodegenerative disorders (NDDs). These benefits have been associated with the presence of secondary metabolites, namely polyphenols, glucosinolates, carotenoids, terpenoids, alkaloids, saponins, vitamins, and fibres, among others, derived from their antioxidant, antiatherogenic, anti-inflammatory, antimicrobial, antithrombotic, cardioprotective, and vasodilator properties. Polyphenols as one of the most abundant classes of bioactive compounds present in plant-based foods emerge as a promising approach for the development of efficacious preventive agents against NCDs with reduced side effects. The aim of this review is to present comprehensive and deep insights into the potential of polyphenols, from their chemical structure classification and biosynthesis to preventive effects on NCDs, namely cancer, CVDs, and NDDS. The challenge of polyphenols bioavailability and bioaccessibility will be explored in addition to useful industrial and environmental applications. Advanced and emerging extraction techniques will be highlighted and the high-resolution analytical techniques used for FBCs characterization, identification, and quantification will be considered.

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