Comparative analysis of radon, thoron and thoron progeny concentration measurements

Janik, Miroslaw,Tokonami, Shinji,Kranrod, Chutima,Sorimachi, Atsuyuki,Ishikawa, Tetsuo,Hosoda, Masahiro,Mclaughlin, James,Chang, Byung-Uck,Kim, Yong Jae Oxford University Press 2013 Journal of radiation research Vol.54 No.4

<P>This study examined correlations between radon, thoron and thoron progeny concentrations based on surveys conducted in several different countries. For this purpose, passive detectors developed or modified by the National Institute of Radiological Sciences (NIRS) were used. Radon and thoron concentrations were measured using passive discriminative radon-thoron detectors. Thoron progeny measurements were conducted using the NIRS-modified detector, originally developed by Zhuo and Iida. Weak correlations were found between radon and thoron as well as between thoron and thoron progeny. The statistical evaluation showed that attention should be paid to the thoron equilibrium factor for calculation of thoron progeny concentrations based on thoron measurements. In addition, this evaluation indicated that radon, thoron and thoron progeny were independent parameters, so it would be difficult to estimate the concentration of one from those of the others.</P>

The EU-South Korea FTA: Which Sector Benefits the Most?

Janik Evert,Jinhwan Oh 한국무역학회 2019 Journal of Korea trade Vol.23 No.2

Purpose - This study empirically analyzes the effects of the European Union-South Korea Free Trade Agreement on Korean exports in major sectors. Design/Methodology - This study is based on the augmented gravity model with a panel data set covering 51 countries between the years 2000 and 2015. Findings - Main findings of the present study is that the agreement has affected the chemical sector the most. Fixed effects estimation predicted a positive trade effect of 38.3%, while Poisson maximum likelihood estimation predicted an impact of 4.75% in the chemical export sector. Regression results for the other sectors only show insignificant effects. Originality/value - The findings imply that the effects of the EU-South Korea free trade agreement on the Korean exports are quite specific compared to the European ones, meaning that the Korean government should focus on sector-specific programs to maximize the welfare benefits of the free trade agreement.

Redesigned Sensor Holder for an Atomic Force Microscope with an Adjustable Probe Direction

Janik Schaude,Maxim Fimushkin,Tino Hausotte 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.9

The article presents a redesigned sensor holder for an atomic force microscope (AFM) with an adjustable probe direction, which is integrated into a nano measuring machine (NMM-1). The AFM, consisting of a commercial piezoresistive cantilever operated in closed-loop intermitted contact-mode, is based on two rotational axes, which enable the adjustment of the probe direction to cover a complete hemisphere. The axes greatly enlarge the metrology frame of the measuring system by materials with a comparatively high coefficient of thermal expansion. The AFM is therefore operated within a thermostating housing with a long-term temperature stability of 17 mK. The sensor holder, connecting the rotational axes and the cantilever, inserted one adhesive bond, a soldered connection and a geometrically undefined clamping into the metrology circle, which might also be a source of measurement error. It has therefore been redesigned to a clamped senor holder, which is presented, evaluated and compared to the previous glued sensor holder within this paper. As will be shown, there are no significant differences between the two sensor holders. This leads to the conclusion, that the three aforementioned connections do not deteriorate the measurement precision, significantly. As only a minor portion of the positioning range of the piezoelectric actuator is needed to stimulate the cantilever near its resonance frequency, a high-speed closed-loop control that keeps the cantilever within its operating range using this piezoelectric actuator further on as actuator was implemented and is presented within this article.

Novel Biodegradable Potato Starch-based Compositions as Candidates in Packaging Industry, Safe for Marine Environment

Helena Janik,Maciej Sienkiewicz,Agnieszka Przybytek,Agnieszka Guzman,Justyna Kucinska-Lipka,Alicja Kosakowska 한국섬유공학회 2018 Fibers and polymers Vol.19 No.6

About 70 % of our planet’s surface is covered by seas and oceans to which even 10 million tons of waste go every year. It makes these places the largest global landfills, containing up to 90 % of plastic waste. In this article we present the results of research on novel starch-based compositions expected to be more safe for the marine environment. For these purpose biopolymers such as, thermoplastic starch (TPS), polylactide (PLA) and poly(vinyl alcohol) (PVA) were reactive extruded and formed into films by high-pressure compressing. Their physical, thermal and mechanical properties were examined. Compositions were tested in seawater collected from the Gulf of Gdansk Baltic Sea. The obtained samples were completely disintegrated after 3 weeks. BOD test in the presence of bacteria pseudomonas augerinosa confirmed biodegradation of prepared compositions. The impact assessment of received materials on the marine environment was also evaluated by degradation tests in the presence of Phaeodactylum tricornutum diatom. Cells growth of Phaeodactylum tricornutum diatoms was only slightly inhibited in the presence of TPS/PLA/PVA compositions.

From static to evolving geometries-R-charged hydrodynamics from supergravity

Bak, D.,Janik, R.A. North-Holland Pub. Co 2007 Physics letters: B Vol.645 No.2

We show that one can obtain asymptotic evolving boost-invariant geometries in a simple manner from the corresponding static solutions. We exhibit the procedure in the case of a supergravity dual of R-charged hydrodynamics by turning on a supergravity gauge field and analyze the relevant thermodynamics. Finally we consider turning on the dilaton and show that electric and magnetic modes in the plasma equilibrate before reaching asymptotic proper times.

MBE Growth and Properties of ZnTe- and CdTe-Based Nanowires

T. Wojtowicz,E. Janik,W. Zaleszczyk,J. Sadowski,G. Karczewski,P. D luZewski,S. Kret,W. Szuszkiewicz,E. Dynowska,J. Domagala,M. Aleszkiewicz,L. T. Baczewski,A. Petroutchik,A. Presz,W. Pacuski,A. Golnik 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

We review our results on the growth of ZnTe- and CdTe-based nanowires (NWs) and on their basic structural and optical properties. The nanowires were produced by using molecular beam epitaxy (MBE) with the use of a mechanism of catalytically-enhanced growth. The growth of ZnTe, CdTe, ZnMgTe and ZnMnTe nanowires was performed from elemental Zn, Cd, Mn, Mg and Te sources on the surfaces of (001)-, (110)- and (111)B-oriented GaAs substrates with Au nanocatalysts. The morphological and structural properties of the nanowires were assessed by using X-ray diffractometry, field-emission scanning electron microscopy, and high resolution transmission electron microscopy. Additional studies of the compositions of both the nanowires and the Au-rich nanocatalysts were performed with the use of energy dispersive X-ray spectroscopy. The optical properties of the NWs were assessed by using photoluminescence and Raman-scattering studies performed in both macro and micro modes. The studies revealed that binary and quaternary nanowires with average diameters from 30 to 70 nm and lengths from 1 to 2.6 µm were monocrystalline in their upper parts, their growth axis was h111i, and they grow along the [111] direction of the substrate, independent of the substrate orientation used. A Au-rich (with 20 % Ga) spherical nanocatalyst was always visible at the tip of a nanowire, thus indicating that a vapor-liquid-solid mechanism was responsible for the growth of the ZnTe- and the CdTe-based nanowires. The formation of homogeneous mixed crystal ZnMnTe and ZnMgTe nanowires was demonstrated by measurements of the variation of the lattice constant and by Raman experiments that revealed the expected shift and appearance of new phonon lines and a strong enhancement of the LO-phonon structures for an excitation close to the exciton energy of the NW materials. The photoluminescence from the internal Mn2+ transition between crystal-field-split energy levels (4T1 → 6A1) was observed in the ZnMnTe nanowires. We review our results on the growth of ZnTe- and CdTe-based nanowires (NWs) and on their basic structural and optical properties. The nanowires were produced by using molecular beam epitaxy (MBE) with the use of a mechanism of catalytically-enhanced growth. The growth of ZnTe, CdTe, ZnMgTe and ZnMnTe nanowires was performed from elemental Zn, Cd, Mn, Mg and Te sources on the surfaces of (001)-, (110)- and (111)B-oriented GaAs substrates with Au nanocatalysts. The morphological and structural properties of the nanowires were assessed by using X-ray diffractometry, field-emission scanning electron microscopy, and high resolution transmission electron microscopy. Additional studies of the compositions of both the nanowires and the Au-rich nanocatalysts were performed with the use of energy dispersive X-ray spectroscopy. The optical properties of the NWs were assessed by using photoluminescence and Raman-scattering studies performed in both macro and micro modes. The studies revealed that binary and quaternary nanowires with average diameters from 30 to 70 nm and lengths from 1 to 2.6 µm were monocrystalline in their upper parts, their growth axis was h111i, and they grow along the [111] direction of the substrate, independent of the substrate orientation used. A Au-rich (with 20 % Ga) spherical nanocatalyst was always visible at the tip of a nanowire, thus indicating that a vapor-liquid-solid mechanism was responsible for the growth of the ZnTe- and the CdTe-based nanowires. The formation of homogeneous mixed crystal ZnMnTe and ZnMgTe nanowires was demonstrated by measurements of the variation of the lattice constant and by Raman experiments that revealed the expected shift and appearance of new phonon lines and a strong enhancement of the LO-phonon structures for an excitation close to the exciton energy of the NW materials. The photoluminescence from the internal Mn2+ transition between crystal-field-split energy levels (4T1 → 6A1) was observed in the ZnMnTe nanowires.

Study on the Influence of Nickel Additions on AA7020 Formability Under Superplastic Forming Like Conditions

S. Taylor,V. Janik,R. Grimes,R. Dashwood 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.9

This study set out to look at the influence of nickel additions on a commercially available AA7020 to understand the impactof the resultant intermetallics on recrystallization, formability and material strength. Elevated temperature tensile testingacross a range of strain rates (5 × 10−4 s−1 × 10−1 s−1) and three temperatures (450− 500 °C) to compare material ductilityfollowed by gas bulge testing at 475 °C and two gas pressures to investigate formability in a test closer to industrial formingconditions. Material strength was established using standard tensile testing, and EBSD used to understand the microstructuralevolution of the materials. It was seen that the nickel additions increased ductility of the material across all test conditions,coupled with increasing the material strength. This was achieved due to the formation of nickel rich intermetallics whichrefine the microstructure during pre-heating through particle stimulated nucleation and subsequently improve strength throughprecipitation hardening in aging treatments.