ALBERT

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The LPCTrap experiment uses an open Paul trap which was built to enable precision measurements in the beta decay of radioactive ions. The initial goal was the precise measurement of the beta-neutrino angular correlation coefficient in the decay of 〈sup〉6〈/sup〉He . Its geometry results from a careful optimization of the harmonic potential created by cylindrical electrodes. It supersedes previously considered geometries that presented a smaller detection solid angle to the beta particle and the recoiling ion. We describe here the methods which were used for the potential optimization, and we present the measured performances in terms of trapping time, cloud size and temperature, and space charge related limits. The properties of the ion cloud at equilibrium are investigated by a simple numerical simulation using hard sphere collisions, which additionally gives insights on the trapping loss mechanism. The interpretation for the observed trapping lifetimes is further corroborated by a model recently developed for ion clouds in Paul traps. The open trap shall serve other projects. It is currently used for commissioning purpose in the TRAPSENSOR experiment and is also considered in tests of the Standard Model involving the beta decay of polarized 〈sup〉23〈/sup〉Mg and 〈sup〉39〈/sup〉Ca ion in the frame of the MORA experiment. The latter tests require in-trap polarization of the ions and further optimization of the trapping and detection setup. Based on the results of the simulations and of their interpretation, different improvements of the trapping setup are discussed.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We have discussed the dynamical instability of a collapsing spherical object in the Einstein Gauss-Bonnet gravity. The linear perturbation method is used to construct the collapse equation from the field equations and conservation equations. The instability range for adiabatic index 〈span〉 〈span〉\( \Gamma\)〈/span〉 〈/span〉 has been investigated by considering Newtonian and Post-Newtonian limits. The relativistic correction of dissipation reduces instability, while the Newtonian and post-Newtonian approximations due to dissipation increase the instability range of adiabatic index 〈span〉 〈span〉\( \Gamma\)〈/span〉 〈/span〉. The Gauss-Bonnet term 〈span〉 〈span〉\( \alpha\)〈/span〉 〈/span〉 plays a dominant role in increasing the instability of the spherical object.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The intensification of energy claim and inadequate fossil fuel wealth instruct the way to renewable-based energy development that is to say vegetable oils, seed oils, plants oil and animal fats and etc. The experimental study investigated the significance of biodiesel replaced for diesel. The biodiesel is obtained by two intrinsic methods from 〈em〉Citrullus colocynthis〈/em〉, one with methyl ester and other with enzymatic lipase-based methyl ester transesterification process. The process involves Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉+ thermomyces lanuginosus lipase as a catalyst for transesterification. The fuel extruded from these methods is tested with a single cylinder four stroke DI diesel engine to investigate the performance emission and combustion parameters. Initially, Novel immobilization-based lipase transesterification method was involved in the extrusion of oil from 〈em〉Citrullus colocynthis〈/em〉 seed and a yield of 90% with a time frame of 0 to 73 h, the extrusion was also escalated with conventional transesterification. The investigation shows that the fuel undergoes good combustion and the performance parameters were improved which in turns reflects the reduction of emission. The brake thermal efficiency of lipase immobilized biodiesel (Blend-L) is 29.86% at full load condition which is fairly less than diesel (31.33%) followed by a value of 28.93% at full load condition for conventional transesterified biodiesel. When the fuels are combusted the heat release rate and peak pressure is quite less than diesel fuel for Blend-L. The emission parameters such as PM and NO〈sub〉x〈/sub〉 are comparatively high than diesel and the remaining emission showed significantly reduced values.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Structuring of surfaces increases the efficiency of heat exchangers, but influences the deposition of particles suspended in the fluid. It is assumed, that spherical dimples suppress the deposition of particles or even induce a permanent cleaning of the occupied surface. In this study the self-cleaning mechanism of dimpled surfaces in heat exchangers is investigated to describe the influencing factors and mechanisms of particulate fouling. To get a detailed insight into fundamental deposition mechanisms, experiments on different dimpled surfaces have been carried out. According to conditions of industriell problems, e.g. cooling water fouling using river or sea water, concentrations of particles (spherical glas, d〈sub〉p,50〈/sub〉 = 3 μm) of c = 2 g/l to c = 10 g/l were used. Influences of enforced turbulence due to structuring of surface with dimples or increasing fluid velocity were investigated and visualialized with μPIV technique. Furthermore, different test durations and number as well as the geometry of the dimples were considered and evaluated with specially developed analytical methods. In extension of preceding studies on the effect of a single dimple the influencing parameters were quantified and the effect of multiple dimples in a row were investigated experimentally. A repeatable fouling pattern was observed for the different structured surfaces. The quantitative results show that the surface coverage is generally decreased downstream of the dimples. Therefore, the results confirm earlier findings suggesting an advantage of dimpled surfaces against other surface structures with respect to thermo-hydraulic efficiency as well as reduced fouling propensit. Thus, this study has shown the occurrence of self-cleaning mechanisms of the surface downstream of the dimple and provides the possibility to estimate values for the reduction of particulate depositions on dimpled surfaces. All results presented were obtained by analyzing the surface around the dimple.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉New experimental prompt fission neutron and fragment data for 〈sup〉235〈/sup〉U(n, f ) measured at JRC-Geel offer the possibility of a detailed validation of the PbP and sequential emission modelings. The very good agreement of the prompt neutron multiplicity matrices 〈span〉 〈span〉\(\nu (A,\mathrm{TKE})\)〈/span〉 〈/span〉 with these data constitutes a primary and valuable validation of the models themselves. Other data from this experiment are also well described by both model results obtained by averaging the corresponding multi-parametric matrices over an 〈span〉 〈span〉\(Y(A,\mathrm{TKE})\)〈/span〉 〈/span〉 distribution measured at JRC-Geel. This is considered as a secondary validation (〈em〉i.e.〈/em〉, of the models together with the 〈span〉 〈span〉\(Y(A,\mathrm{TKE})\)〈/span〉 〈/span〉 distribution).〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We study the partial decay widths of the charmonium states ( 〈span〉 〈span〉\( J/\psi\)〈/span〉 〈/span〉, 〈span〉 〈span〉\( \psi (3686)\)〈/span〉 〈/span〉, 〈span〉 〈span〉\( \psi (3770)\)〈/span〉 〈/span〉, 〈span〉 〈span〉\( \chi_{c0}\)〈/span〉 〈/span〉, 〈span〉 〈span〉\( \chi_{c2}\)〈/span〉 〈/span〉 to 〈span〉 〈span〉\( D\bar{D}\)〈/span〉 〈/span〉 (〈span〉 〈span〉\( D^+D^-\)〈/span〉 〈/span〉 or 〈span〉 〈span〉\( D^0\bar{D^0}\)〈/span〉 〈/span〉) in isospin asymmetric nuclear matter, in the presence of strong magnetic fields. The in-medium partial decay widths of charmonium states to 〈span〉 〈span〉\( D\bar{D}\)〈/span〉 〈/span〉 are calculated within a light quark-antiquark pair creation model, namely the 〈sup〉3〈/sup〉〈em〉P〈/em〉〈sub〉0〈/sub〉 model, using the in-medium masses of the charmonia as well as 〈em〉D〈/em〉 and 〈span〉 〈span〉\( \bar{D}\)〈/span〉 〈/span〉 mesons in the magnetized nuclear matter, obtained within a chiral effective model. The presence of a magnetic field leads to Landau quantization of the energy levels of the proton in the nuclear medium. The effects of magnetic field and isospin asymmetry on the charmonium decay widths to 〈span〉 〈span〉\( D\bar{D}\)〈/span〉 〈/span〉 are found to be quite prominent. The effects of the anomalous magnetic moments have also been taken into consideration for obtaining the in-medium masses of these heavy flavour mesons, used to calculate the partial decay widths of the charmonium states. The medium modifications of the charmonium decay widths can have observable consequences on the production of the charmed mesons in high energy asymmetric heavy ion collision experiments.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Subcooled boiling of alcohol flowing through micro-cylinder-groups with different heights in aligned arrangement was investigated. Meanwhile, the outlet temperature and Nusselt number of the working fluid were obtained when the heating power was 80 W, 60 W and 40 W respectively. Subcooled boiling is divided into two parts: the partially developed stage and fully developed stage. The result showed that the outlet temperature of the fully developed stage in subcooled boiling changed rarely as the Reynolds number decreased. At the same heating power, the heights of the micro-cylinders had little effects on the outlet temperature of working fluid in the fully developed stage. However, for the same height of micro-cylinder, the fully developed stage of subcooled boiling came earlier as the heating power increased. And the Nusselt number in the fully developed stage was greater than that in the partially developed stage. Based on the regression analysis of experimental data, a correlation formula of Nusselt number for subcooled boiling in micro-cylinder-groups was established and made comparison with existing correlation.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The sorption isotherms of di-calcium phosphate (DCP) were determined using the gravimetric method at four temperatures. The sorption curves were fitted by the Guggenheim-Anderson-deBoer (GAB) model. The dehydration process was studied by means of X-ray diffraction. Thermo-gravimetric /differential thermal analyses (TGA / DTA) were used to record the loss of water and the nature of the products was studied by Fourier Transform Infrared Spectroscopy. The morphology of DCP was tested using the electronic scanning morphology (SEM). The thermal conductivity was determined using Hot Disk method. DCP convective drying kinetics modeling was conducted by the experimental study of the aero-thermal condition effects. The drying characteristic curves were then modeled using the nonlinear regression functions of MATLABR2013a. The curves predicted by the GAB model coincide well with the majority of the experimental points of the sorption isotherms. The net isosteric heat is mathematically expressed by second-order exponential function of the water content. SEM shows the presence of anhydrate and di-hydrate forms of DCP. DCP loses molecules of water when heated in two stages. Hot Disk method shows that the thermal conductivity depends heavily on the drying temperature and the product moisture. Midilli-kucuk is considered the most suitable model for the experimental results.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In order to investigate the flow characteristics and film cooling performance of novel merged holes cooling method, merged cylindrical holes structures have been applied on a flat plate with three merging ratios under three blowing ratios. Single cylindrical hole film cooling structure is also established as a benchmark structure. The numerical results of the single cylindrical hole are validated with the experimental results available in open literatures. The discharge coefficient, aerodynamic loss, tangential velocity vectors and total vorticity distributions are studied and compared. The spanwise averaged film cooling effectiveness and adiabatic temperature contours are studied and compared. Results show that the development of the kidney vortex is impeded and the film cooling performance is promoted in merged holes cooling cases. The blowing ratio and merging ratio both affect the cooling performance of merged holes cooling cases. In this paper, the best film cooling performance is obtained at the biggest merging ratio.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉High-precision mass measurements of stable and beta-decaying nuclides 〈sup〉52-57〈/sup〉Cr, 〈sup〉55〈/sup〉Mn, 〈sup〉56,59〈/sup〉Fe, 〈sup〉59〈/sup〉Co, 〈sup〉75, 77-79〈/sup〉Ga, and the lanthanide nuclides 〈sup〉140〈/sup〉Ce, 〈sup〉140〈/sup〉Nd, 〈sup〉160〈/sup〉Yb, 〈sup〉168〈/sup〉Lu, 〈sup〉178〈/sup〉Yb have been performed with the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The new data are entered into the Atomic Mass Evaluation and improve the accuracy of masses along the valley of stability, strengthening the so-called backbone. The mass of neutron-deficient 〈sup〉168〈/sup〉Lu in its isomeric state has been measured directly. The mass of neutron-rich 〈sup〉178〈/sup〉Yb indicates a change of nuclear structure approaching the double harmonic-oscillator shell closure for 〈span〉 〈span〉\( Z=70\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( N=112\)〈/span〉 〈/span〉.〈/p〉