Dye sensitized solar cells (DSSCs) based on indigo dyes exhibit suitable conversion efficiency. These organic dyes have been undergone for aggregation. Electron transfer process is reduced due to an aggregation of molecular dyes. Therefore, anti-aggregation agent is commonly utilized in fabrication of DSSCs. In the present study, two anti-aggregation agents namely as 3α,7α-dihydroxy-5β-cholanic acid (cheno) and 3α,7α,12α-trihydroxy-5β-cholanic acid (cholic acid) were added to indigo dye solution in DSSCs in order to determine the photovoltaic parameters such as short circuit photocurrent, open circuit voltage and conversion efficiency of each individual dye in the absence and presence of anti-aggregation agents. The results show that the conversion efficiencies are improved with reduced aggregation. Spectrophotometric evaluations of the indigo dyes in solution and on a TiO2 substrate were carried out in the absence and presence of anti-aggregation agents in order to estimate changes in the status of the dyes in different environments. J-type aggregates on the nano TiO2 are reduced in the presence of anti-aggregation agents.
Structural and optical properties of graphene with a vacancy and B, N, O and F doped graphene have been investigated computationally using density functional theory (DFT). We find that B is a p-type while N, O and F doped graphene layers, as well as graphene with a vacancy are n-type semiconductors. Optical properties for both cases of in plane (E ⊥ c) and out of plane (E || c) polarization of light are investigated. It is observed that with the increase in the number of electrons entering the supercell, the amount of absorption of the system decreases and the absorption peaks are transferred to higher energies (blue shift).
There are 40 coal mines in Poland now. One of them (coal mine “Bogdanka”) is situated in Lublin Coal Basin, other are localised in Silesia and Małopolska regions. Coal mining is a source of large amounts of wastes. Mean annual production of wastes in only Lublin Coal Basin exceeds 2 million Mg, 65% of which is disposed on a heap. The rest is used to restore opencast excavations, to construct and repair local roads and to produce building materials. It seems that large amount of these wastes could be used to construct or modernize flood embankments and dykes. Using mine wastes as building materials requires the knowledge of their geotechnical parameters. A characteristic feature of mine wastes is their gradual weathering which affects geotechnical parameters largely determined by their mineral and petrographic composition.
This paper describes analyses of geotechnical parameters of mine wastes from Lublin Coal Basin (heap near coal mine “Bogdanka”) of various storage times and of samples collected after 10 years of exploitation of a dyke between ponds made of these wastes at the break of 1993 and 1994. Detailed analyses involved: grain size distribution, natural and optimum moisture content, maximum dry den-sity, shear strength and coefficient of permeability. Obtained results were compared with literature data pertaining to mine wastes from Upper Silesian Coal Basin and from other European coal basins.
Performed studies showed that coal mining wastes produced in Lublin Coal Basin significantly differed in the grain size distribution from wastes originating from Upper Silesian Coal Basin and that weathering proceeded in a different way in wastes produced in both sites.
Climate, land use, and land cover change can propagate alteration to the watershed environment. The interaction be-tween natural and human activities probably accelerates the change, a phenomenon that will generate serious environmental problems. This study aims to evaluate the change in the hydrological regime due to natural and human-induced processes. The study was conducted in Brantas watershed, Indonesia, which is the largest watershed in East Java. This area is populat-ed by more than 8 million inhabitants and is the most urbanized area in the region. An analysis of rainfall time series use to shows the change in natural phenomena. Two land-use maps at different time intervals were used to compare the rapid de-velopment of urbanization, and the discharge from two outlets of the sub-watersheds was employed to assess hydrological changes. The indicator of hydrological alteration (IHA) method was used to perform the analysis. The daily discharge data are from 1996 to 2017. The research results show an increase in flow (monthly, 1-day, 3-day, 7-day, 30-day, and 90-day flows) in the two sub-watersheds (Ploso and Kertosono) from the pre-period (1996–2006) to the post-period (2007–2017).
The article focuses on two aspects of the end of the First World War. Recalled is the interpretation of the WW1 as a ‘seminal catastrophe’ of the twentieth century. This opinion does not apply, however, to the countries of East Central Europe that regained independence in the year 1918. Taking Poland as an example, we can point to three levels of internal discussions which took place after 1918. First, a debate evolved around the nation-building process and whether the nation which regained independence should be regarded as a purely ethnically-based or political community. The political breakthrough moreover triggered debates concerning the state-building process through an attempt at creating structures of a strong, modern state; lastly, discussed were attempts to find a place for a reborn Poland on the international scene.
Scanning probe microscopy (SPM) since its invention in the 80’s became very popular in examination of many different sample parameters, both in university and industry. This was the effect of bringing this technology closer to the operator. Although the ease of use opened a possibility for measurements without high labour requirement, a quantitative analysis is still a limitation in Scanning ProbeMicroscopes available on the market. Based on experience of Nano-metrology Group, SPM still can be considered as a tool for quantitative examination of thermal, electrical and mechanical surface parameters. In this work we present an ARMScope platform as a versatile SPM controller that is proved to be useful in a variety of applications: fromatomic-resolution STM (Scanning TunnellingMicroscopy) toMulti-resonance KPFM (Kelvin Probe force microscopy) to commercial SEMs (Scanning electron microscopes).
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