222,640 research outputs found
Development of titanium dioxide nanoparticles/nanosolution for photocatalytic activity
Biological and chemical contaminants by man-made activities have been serious
global issue. Exposure of these contaminants beyond the limits may result in serious
environmental and health problem. Therefore, it is important to develop an effective
solution that can be easily utilized by mankind. One of the effective ways to
overcome this problem is by using titanium dioxide (TiO2). TiO2 is a well-known
photocatalyst that widely used for environmental clean-up due to its ability to
decompose organic pollutant and kill bacteria. Although it is proven TiO2 has an
advantage to solve this concern, its usefulness unfortunately is limited only under
UV light irradiation. Therefore, the aim of this work was to investigate the potential
of TiO2 that can be activated under visible light by the incorporation of metal ions
(Fe, Ag, Zr and Ag-Zr). In this study, sol-gel method was employed for the synthesis
of metal ions incorporated TiO2. XRD analysis revealed that all samples content
biphasic anatase-brookite TiO2 of size 3 nm to 5 nm. It was found that the
incorporation of these metal ions did not change the morphology of TiO2 but the
crystallinity and optical properties were affected. The crystallinity of anatase in the
biphasic TiO2 was found to be decreased and favored brookite formation. PL analysis
showed metal ions incorporation suppressed the recombination of electron-hole pairs
while the band gap energy of TiO2 (3.2 eV) was decreased by the incorporation of Fe
(2.46 eV) and Ag (2.86 eV). Among this incorporation, Ag-Zr incorporated TiO2
showed highest performance for methyl orange degradation (93%) under fluorescent
xxv
light irradiation for 10 h. This follows by Zr-TiO2 (82%), Fe-TiO2 (75%) and Ag�TiO2 (43%). Meanwhile, the highest antibacterial performance was exhibited by Ag�TiO2. TEM images showed that E.coli bacterium was killed within 12 h after treated
with Ag-TiO2. The results obtained from the fieldwork study established that Ag-Zr
incorporation have excellent performances for VOC removal and antibacterial test.
The VOC content after treated with Ag-Zr-TiO2 fulfilled the Industry Code of
Practice on Indoor Air Quality 2010 which is lower than 3 ppm. In addition, the
percentage of microbes also found to be decrease around 45 % within 5 days of
monitoring
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A systematic review of software development cost estimation studies
This paper aims to provide a basis for the improvement of software estimation research through a systematic review of previous work. The review identifies 304 software cost estimation papers in 76 journals and classifies the papers according to research topic, estimation approach, research approach, study context and data set. A web-based library of these cost estimation papers is provided to ease the identification of relevant estimation research results. The review results combined with other knowledge provide support for recommendations for future software cost estimation research, including: 1) Increase the breadth of the search for relevant studies, 2) Search manually for relevant papers within a carefully selected set of journals when completeness is essential, 3) Conduct more studies on estimation methods commonly used by the software industry, and, 4) Increase the awareness of how properties of the data sets impact the results when evaluating estimation methods
Statistical methods of SNP data analysis with applications
Various statistical methods important for genetic analysis are considered and
developed. Namely, we concentrate on the multifactor dimensionality reduction,
logic regression, random forests and stochastic gradient boosting. These
methods and their new modifications, e.g., the MDR method with "independent
rule", are used to study the risk of complex diseases such as cardiovascular
ones. The roles of certain combinations of single nucleotide polymorphisms and
external risk factors are examined. To perform the data analysis concerning the
ischemic heart disease and myocardial infarction the supercomputer SKIF
"Chebyshev" of the Lomonosov Moscow State University was employed
Rigorously assessing software reliability and safety
This paper summarises the state of the art in the assessment of software reliability and safety ("dependability"), and describes some promising developments. A sound demonstration of very high dependability is still impossible before operation of the software; but research is finding ways to make rigorous assessment increasingly feasible. While refined mathematical techniques cannot take the place of factual knowledge, they can allow the decision-maker to draw more accurate conclusions from the knowledge that is available
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