Asphalts as inhibitors of radical polymerization

The results of investigations concerning the effect of asphalts on radical polymerization of a monomer for model systems composed of styrene and two petroleum asphalts originated from two different crude oils: low sulphur nonparaffinic crude oil and medium sulphur paraffinic crude oil. Based on determination of styrene conversion in the radical polymerization process in the presence of asphalts, it was found that both asphalts act as inhibitors of this reaction. The inhibiting effect of asphalts is weakened by using higher temperatures and prolongation of polymerization time or application of greater initiator rates. On the basis of the analysis of group and elementary chemical composition of both asphalts as well as electron paramagnetic resonance, it was found that the inhibiting effect to radical polymerization is caused mainly by the presence of structures which are stable free radicals in character. The probability of inhibiting effect by sulphur compounds present in asphalts is also discussed.     

Hydroxyl Functionalized Methacrylic Terpolymers as Supports for Mn(III) Salen Catalysts and Their Application in Asymmetric Epoxidation

Hydroxyl functionalized gel type resins derived from 2-hydroxyethyl, 2-hydroxypropyl and 2-hydroxy-3-phenoxypropyl methacrylates were applied to covalent immobilization of Mn(salen) complexes via glutarate and carbonate linkers. The obtained catalysts were characterized by FTIR and DR UV–Vis methods and elemental analysis. It was found that the activity of polymeric catalysts obtained in this way depended on both the nature of the functional and cross-linking monomers and the degree of the cross-linking of polymer matrices and the way of complex immobilization. The highest activity was observed for the complexes immobilized on the HEMA resins cross-linked with 3%-mol of diethylene glycol dimethacrylate. For instance, in the presence of the catalysts with (S,S)-salen ligand S-epoxystyrene and (1S, 2R)-epoxyindene could be obtained with 46% and 69% ee, respectively. Attempts have also been made to recycle the selected catalyst. However, a rapid fall off in the activity was observed, although the selectivity was similar in which three cycles.     

Laboratory tests of filtration coefficient of selected materials used in liquidating shafts in collieries

There are a lot of dangers associated with closing mine shafts which may emerge during its liquidation works, and after liquidation of a shaft. The most important of them are: methane hazard, water hazard, and public safety hazard, which are commonly connected with occurrence of sinkholes. In the process of shaft liquidation it is extremely important to choose the right backfill materials, which determine stability of the backfill column and proper drainage of the backfill, which will match or exceed potential flow of water into a shaft. When the water flows into a liquidated shaft the main problem is a change in permeability coefficient of the used backfill materials due to grain degradation resulting from the fall into a shaft and the pressure within the backfill column. The article presents results of laboratory tests on the influence of vertical pressure on filtration coefficient and compressibility of the most commonly used backfill materials. During the tests, samples of the materials were loaded in a hydraulic press, simulating in this way the increase in vertical pressure within the backfill column. Compressibility of a given material and the change in filtration coefficient were assessed.     

Addressing the Needs of People Using Elevators for Emergency Evacuation

US model codes and building regulations are recognizing the provision of protected elevators for occupant self-evacuation after more than two decades of training people that elevators are unsafe in fires. This reversal will require that people can readily identify those elevators that are safe to use and be provided with information and reassurances during use that the system is functioning safely. Lengthy discussions on the interactions between the systems and users have resulted in requirements for visual, audible, and voice messaging systems and operational protocols designed to provide reliable, real-time information needed by users to make informed decisions. The discussions have further identified the need for public education to provide for effective use by infrequent visitors to buildings equipped with these systems. The paper will discuss the approaches being developed to address these needs by a consortium of public and private organizations including the American Society of Mechanical Engineers (ASME), National Institute of Standards and Technology (NIST), National Elevator Industry Inc. (NEII), disability advocacy groups, and the fire alarm and model building code developers. There is an expectation that since a building’s elevators are used daily by the occupants, by keeping the system used in emergencies as close as possible to normal use, the provision of additional information on status and safety will represent sufficient reassurance to users. One of the outstanding issues identified in the discussions is the need for testing and verification that the approaches will be effective. Due to the difficulties inherent in human testing, there is a need for the inclusion of these features into observational research being conducted through required evacuation drills. Since elevator use is not prohibited now for non-fire emergency egress, this may provide the opportunity to test public response to the approaches being contemplated. The paper will suggest ideas for such research being included in planned studies and as a part of building commissioning.     

Variability in peer group perceptions: Support for the "controversial" sociometric classification group.

Examined whether there would be greater variability in children's perceptions of Ss in a controversial group than in their perceptions of peers in other sociometric classification groups. 480 3rd–5th graders nominated 3 same-sex children as best friends and 3 same-sex children as least-liked peers and rated each of their same-sex peers on 8 social roles and a liking scale. On the basis of the sociometric nominations, Ss were identified as being of popular, average, neglected, rejected, or controversial sociometric status. The 8 social roles were grouped to form 3 clusters labeled aggression, prosociability, and withdrawal. Ss were assigned variability scores that were the standard deviation of the ratings they received from their peers. Consistent with their sociometric classification, controversial sociometric group Ss evidenced higher variability scores on the liking ratings and on the withdrawal and prosociability clusters. In addition to providing support for the controversial sociometric classification, these results suggest the possible value of considering variability measures in conjunction with traditional cumulative or central tendency measures of sociometric status. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrical transport in UNi0.5Sb2 single crystals

Single crystals of UNi₀.₅Sb₂ were investigated by means of Seebeck coefficient and Hall effect measurements in the temperature range 5–300 K. The results corroborated the occurrence of two magnetic phase transitions: from para- to antiferromagnetic state at T_N = 161.5 K and a spin-reorientation near T_t = 64 K. The first-order character of the latter feature was proved by studying in detail the electrical resistivity and the magnetic susceptibility of single-crystalline UNi₀.₅Sb₂ in the vicinity of T_t.     

Anisotropy of Superconducting Single Crystal SmFeAsO0.8F0.2 Studied by Torque Magnetometry

Single crystals of the oxypnictide superconductor SmFeAsO_0.8F_0.2 with T _c≃45(1) K were investigated by torque magnetometry. The crystals of mass ≤0.1 μg were grown by a high-pressure cubic anvil technique. The use of a high-sensitive piezoresistive torque sensor made it possible to study the anisotropic magnetic properties of these tiny crystals. The anisotropy parameter γ was found to be field independent, but varies strongly with temperature ranging from γ≃8 at T≲T _c to γ≃23 at T≃0.4T _c. This unusual behavior of γ signals unconventional superconductivity.      

Long-term intravesical oxybutynin chloride therapy in children with myelodysplasia

PURPOSE: We evaluated the clinical use of long-term intravesical oxybutynin chloride in the treatment of neurogenic bladder dysfunction in children with myelodysplasia who could not tolerate oral anticholinergics. MATERIALS AND METHODS: We retrospectively reviewed the records of all patients recommended for intravesical oxybutynin chloride therapy. A total of 12 girls and 18 boys 1 to 17 years old was recruited for study. Oxybutynin chloride (5 mg.) was instilled 2 times daily and pretreatment cystograms were compared to followup urodynamic studies. Duration of therapy was 2 to 26 months (mean 13, median 12). RESULTS: Mean total capacity plus or minus standard deviation increased from 209 +/- 103 to 282 +/- 148 ml. (p < 0.01), mean safe capacity increased from 157 +/- 105 to 234 +/- 147 ml. (p < 0.01) and mean age adjusted safe capacity increased from 76 +/- 36 to 115 +/- 62%. Of the 29 patients who were incontinent 3 (10%) achieved continence and 19 (65%) reported a decreased use of sanitary pads. None of the patients had systemic side effects related to intravesical treatment. CONCLUSIONS: We believe that intravesical oxybutynin chloride is a viable treatment option for patients with myelodysplasia in whom oral therapy fails.