Response of portable gamma monitors for dose rate measurements under various radiation conditions

Journal of Radioanalytical and Nuclear Chemistry - Responses of the hand-held gamma monitors available for the ambient dose equivalent rate measurements in the Federation of Bosnia and Herzegovina...     

Calculation of the brillouin frequencies close to phase transitions in NaNO2.

We calculate here the Brillouin frequencies of the L-mode [010], [001] and [100] of NaNO2 for the phase transitions from the paraelectric phase to the sinusoidal anti-ferroelectric phase near the Neel temperature (TN = 437.7 K) and to the ferroelectric phase near the critical temperature (TC = 436.3 K) in this crystalline system. For calculating the frequencies. we use the thermal expansivity data for the phase regions considered, under the assumption that the mode Gruneisen parameter determined for each mode remains constant across the phase transitions. Our calculated frequencies agree well with the observed frequencies for the modes studied in NaNO2.     

Benzamide species retained by DMSO composites at a kaolinite surface

The surface area of kaolinite-benzamide (K-Bz)6.62 m² g^–1, whichis noticeably lower than that of kaolinite-dimethyl sulphoxide (K-DMSO) 14.61m² g^–1, the co-perturbationof the inner-surface hydroxyl features at 3697 and 3650 cm^–1,and the increase of d(001) value by 7.44 Å are all related to the benzamidespecies inserted into the kaolinite structure through the replacement of theK-DMSO composites. Disappearance of the DMSO reflections and emergence ofwell-defined features at 6.04(2θ) and 11.16(2θ), 001 and 002 reflectionswith d values of 14.62 and 7.92 Å, respectively point out that the DMSOspecies were substituted efficiently by benzamide molecules. The thermal stabilityof the K-Bz derivative up to 300°C can be attributed to the slightly tiltedaromatic ring keying into the gibbsitic sheets via the –NH₂groups.     

Synthesis and characterization of a bifunctional amido-thiophene monomer and its copolymer with thiophene and electrochemical properties

A bifunctional amido-thiophene namely hexamethylene (bis-3-thiophene acetamide) (HMTA) was synthesized by the reaction of 3-thiophene acetic acid with hexamethylene diamine. Copolymerization in the presence of thiophene was achieved electrochemically in tetrabutylammonium tetrafluoroborate/acetonitrile (TBAFB/AN). Spectroelectrochemical analysis of the resulting copolymer [P(HMTA-co-Th)] reflected electronic transitions at 505 nm, 740 nm and ∼1000 nm, revealing π to π* transition, polaron and bipolaron band formation respectively. Switching ability was evaluated by a kinetic study via measuring the transmittance (%T) at the maximum contrast. Dual type polymer electrochromic devices (ECDs) based on P(HMTA-co-Th) and poly(ethylene dioxythiophene) (PEDOT) have been constructed. Spectroelectrochemistry, switching ability and stability of the devices were investigated by UV-vis spectroscopy and cyclic voltammetry. These devices exhibit low switching voltages (between 0.0 V and +1.6 V), short switching times with reasonable switching stability under atmospheric conditions.     

Preparation and characterization of Co(II), Ni(II) and Cu(II) complexes of a ligand containing 1,3,4-thiadiazole groups

(1R,2R)-1,2-bis-(5-amino-1,3,4-thiadiazole-2-yl)ethane-1,2-diol (L) has been prepared by the reaction of thiosemicarbazide with (2R,3R)-(+)-tartaric acid (I) and phosphorous oxychloride, and its complexes with Co(II), Ni(II) and Cu(II) have been obtained. The structures of the ligand and its complexes have been established by i. r., ¹H- and ¹³C-n.m.r. spectra, u.v.–vis–nir spectroscopy, elemental analyses, T.g.-D.t.a. and magnetic susceptibility measurements.     

Investigations of regio- and stereoselectivities in the synthesis of cytotoxic isoxazolidines through 1,3-dipolar cycloadditions of nitrones to dipolarophiles bearing an allylic oxygen

Regio- and stereoselectivities in cycloadditions of nitrones to dipolarophiles bearing an allylic oxygen, which furnishes substituted-isoxazolidine analogs of the furanose ring of nucleosides, have been investigated. Although the obtained regioselectivities are anticipated, a rationalization of the preferred formation of endo-cycloadducts necessitates the involvement of an allylic oxygen in secondary interaction. The obtained isoxazolidines display cytotoxic activities against a number of human cancer cell lines.     

Anthracene Substituted Co (II) and Cu (II) phthalocyanines; Preparations,Investigation of Catalytical and Electrochemical Behaviors

An approach to investigation of catalytical behaviors of Co (II) and Cu (II) phthalocyanines is reported that is based on changing any parameter to effect these behaviors. Towards this end, new anthracene substituted Co (II) and Cu (II) phthalocyanines were prepared and characterized spectroscopic methods. New cobalt (II) and copper (II) phthalocyanines were used as catalyst for oxidation of different phenolic compounds (such as 2,3‐dichlorophenol, 4‐methoxyphenol, 4‐nitrophenol, 2,3,6‐trimethylphenol) with different oxidants. Then, electrochemical characterization of cobalt (II) and copper (II) phthallocyanines were determined by using cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. Although copper (II) phthalocyanine showed similar Pc based electron transfer processes, cobalt (II) phthalocyanine showed metal and ligand based reduction reactions as expected.     

A simulation as a service cloud middleware

Many seemingly simple questions that individual users face in their daily lives may actually require substantial number of computing resources to identify the right answers. For example, a user may want to determine the right thermostat settings for different rooms of a house based on a tolerance range such that the energy consumption and costs can be maximally reduced while still offering comfortable temperatures in the house. Such answers can be determined through simulations. However, some simulation models as in this example are stochastic, which require the execution of a large number of simulation tasks and aggregation of results to ascertain if the outcomes lie within specified confidence intervals. Some other simulation models, such as the study of traffic conditions using simulations may need multiple instances to be executed for a number of different parameters. Cloud computing has opened up new avenues for individuals and organizations with limited resources to obtain answers to problems that hitherto required expensive and computationally-intensive resources. This paper presents SIMaaS, which is a cloud-based Simulation-as-a-Service to address these challenges. We demonstrate how lightweight solutions using Linux containers (e.g., Docker) are better suited to support such services instead of heavyweight hypervisor-based solutions, which are shown to incur substantial overhead in provisioning virtual machines on-demand. Empirical results validating our claims are presented in the context of two case studies.     

Synthesis and Liquid Crystalline Behavior of Random Copolymer of Poly(ethylene oxide) Macromonomer and Liquid Crystalline Monomer by the Photon Transmission Technique

Random copolymers of poly(ethylene oxide) macromonomer with p‐vinylbenzyl end‐functional group (PEOVB) and liquid crystalline monomer, namely 6‐(4‐cyanobiphenyl‐4′‐oxy)hexyl acrylate (COA), were prepared by conventional free radical polymerization. A living anionic polymerization technique was employed for the synthesis of PEO macromonomers bearing p‐vinylbenzyl moiety at one end. The photon transmission method was also applied to study the phase transitions of COA monomer and its random copolymer with PEO. It was found that, for both samples, the nematic‐smectic A transition is continuous, but the critical fluctuation regions do not allow to obtain 3D XY values. Instead, we have obtained the values close to mean field regime. Scaling of thermal hystersis for random copolymer sample near the nematic‐isotropic transition was studied as well. Thermal hysteresis loops were produced under linearly varying temperature. It was shown that the areas of the hysteresis loops scale with the temperature scanning rate with an exponent being equal to 0.614 which is in good agreement with the field‐theoretical value.     

Endo-cavity Complexes between Calix[6]arene Dianions and Aliphatic Ammonium Cations: Structure of a Hexylammonium Complex by X-ray Crystallography

The interactions of calix[6]arene and p-tert-butylcalix[6]arene with aliphatic amines in acetonitrile solution were studied by spectrophotometric titrations in the UV region and ¹H NMR spectrometry. Calix[6]arenes can undergo two deprotonations by aliphatic amines and the extent of the second proton transfer is mainly governed by the size of the α-substituent of the amine. ¹H NMR spectra show that the macrocycle adopts a 1,2,3-alternate conformation and that the α-hydrogens of the ammonium ions are shielded by the π-clouds of the aromatic rings. The X-ray crystal structure of the dihexylammonium complex of the p-tert-butylcalix[6]arene dianion, reported here, confirms the 1,2,3-alternate conformation and shows one of the two ammonium moieties encapsulated in the inner cavity of the macrocycle.