Transvaginal natural orifice transluminal endoscopic surgery (vNOTES) adnexectomy for benign pathology compared with laparoscopic excision (NOTABLE) : A protocol for a randomised controlled trial

M1 - 018059 Acknowledgments We thank the vNOTES investigators’ team for taking care of the study participants. We also thank Amanda McPhail for language correction and editing of the manuscript.Peer reviewedPublisher PD

HALON-hysterectomy by transabdominal laparoscopy or natural orifice transluminal endoscopic surgery : a randomised controlled trial (study protocol)

Acknowledgments The authors acknowledge the NOTES Investigators' team for taking care of the study participants; and Amanda McPhail for language correction and editing of the manuscript.Peer reviewedPublisher PD

An analytical algorithm of porosity–permeability for porous and fractured media: extension to reactive transport conditions and fitting via flow-through experiments within limestone and dolomite

Accurate prediction of permeability evolution is essential for forecasting the long-term performance and lifetime of hydrothermal reservoirs, an important goal in the geothermal, ore, and petroleum industries. Erol et al. (Transp Porous Media 120(2):327–358, 2017. https://doi.org/10.1007/s11242-017-0923-z) introduced a general (non-empirical) analytical Kozeny–Carman type equation for predicting matrix and fracture permeability during single-phase, non-reactive flow. Here we incorporate the equation into an algorithm for addressing the influence on porous and fractured media permeability of the transient reactive processes of mineral dissolution and precipitation. Analytical algorithm predictions are identical to permeability values measured during fluid circulation through limestone and dolomite core samples from the Campine Basin deep geothermal system in Belgium. Benchmarking used identical values for initial hydraulic aperture dimension and porosity, measured during fluid circulation based on nondestructive micro-CT imaging. Analytical algorithm predictions of reactive surface area and fracture porosity are similar to results based on the TOUGHREACT reactive transport code. TOUGHREACT implements several well- established power-law models for predicting permeability, notably Civan (AIChE J 47(2):1167–1197, 2001. https://doi.org/10.1002/aic.690470206) and Verma and Pruess (J Geophys Res Solid Earth 93:1159–1173, 1988. https://doi.org/10.1029/jb093ib02p01159). However, these models rely on specification of empirical exponents, which are not straightforward to measure. Our results suggest that a more general, computationally inexpensive analytical method can lead to accurate permeability calculation

Adnexectomy by vaginal Natural Orifice Transluminal Endoscopic Surgery versus laparoscopy : results of a first randomised controlled trial (NOTABLE trial)

Peer reviewedPostprin

RG-improved single-particle inclusive cross sections and forward-backward asymmetry in ttˉt\bar t production at hadron colliders

We use techniques from soft-collinear effective theory (SCET) to derive renormalization-group improved predictions for single-particle inclusive (1PI) observables in top-quark pair production at hadron colliders. In particular, we study the top-quark transverse-momentum and rapidity distributions, the forward-backward asymmetry at the Tevatron, and the total cross section at NLO+NNLL order in resummed perturbation theory and at approximate NNLO in fixed order. We also perform a detailed analysis of power corrections to the leading terms in the threshold expansion of the partonic hard-scattering kernels. We conclude that, although the threshold expansion in 1PI kinematics is susceptible to numerically significant power corrections, its predictions for the total cross section are in good agreement with those obtained by integrating the top-pair invariant-mass distribution in pair invariant-mass kinematics, as long as a certain set of subleading terms appearing naturally within the SCET formalism is included.Comment: 55 pages, 14 figures, 6 table

Ultrafast Vibrational Spectroscopy of Aqueous Solution of Methylamine from First Principles MD Simulations

We performed Car-Parrinello molecular dynamics (CPMD) simulations of deuterated aqueous solution of methylamine (MA) to investigate the structure, dynamics and time dependent vibrational spectra of water molecules in the first solvation shell. Our results show that the hydrogen bond of DOD…ND2 is the dominant interaction between ND2 and D2O as compared to the D2O…D2N. The hydrogen bond involving DOD…ND2 has longer lifetime (2.6 ps) than both D2O…D2N (1.1 ps) and water-water hydrogen bonds. The residence time of water molecule inside the first solvation shell of ND2 is 5.72 ps. The vibrational spectral diffusion of water molecules in the first hydration shell of the amine nitrogen of methylamine proceeds with three time scales. A short-time relaxation originates from dynamics of amine-water hydrogen bonds without breaking (90 fs), and a slower relaxation (∼1.8 ps) is due to the breaking of amine-water hydrogen bonds. Another longer time constant (∼7 ps) is due to the escape dynamics of water molecules from the first hydration shell of the amine group

Naar een hernieuwbaar energielandschap

status: publishe

Influence of the configuration of heat exchangers on the performance of ORCs: a first step to a system optimization

An ORC can be split into two levels. The first level contains the cycle parameters (temperatures and pressures) and the second level contains the components (heat exchangers, turbine, etc.). Often, both levels are optimized seperately and the interconnection between these two levels is chosen, based on experience. Pinch point temperature differences, pressure drops, etc. are assumed. This design process will in general not lead to the optimum system configuration. In a system optimization, the two levels of the ORC are optimized together and no assumptions have to be made about the interconnecting parameters. In this presentation, a simple version of a system optimization is explained. For a given heating and cooling source and for a fixed pump and turbine efficiency, the configuration of the heat exchangers is optimized together with the cycle parameters. Plate heat exchangers with chevron-type corrugations and shell-and-tube heat exchangers are modeled and can be used in the cycle. Single- and double-pressure cycles are investigated and both cycles can be a standard or a recuperated one. The developed model is based on a previous developed code and this code is extended with heat exchanger models which are taken from the literature. The Bell-Delaware model is used for the shell-and-tube heat exchangers. For single-phase plate heat exchanger the method of Martin is used while the models of Han, Lee and Kim are used for plate-type condensers and evaporators. The results show that plate-type heat exchangers are, as expected, more efficient than shell-and-tube heat exchangers. It is also shown that adding a second pressure level is useful, but the effect is less than in the case with ideal components. This is because adding an extra pressure level improves the fit between the heat source cooling curve and the working fluid heating curve, but this will also increase the heat transfer surface. So, the pinch point temperature difference has to increase to keep the heat transfer surface constant. A similar effect is seen in the recuperator. The average temperature difference in the desuperheater is often relatively high, so replacing it partly with a recuperator, in which the average temperature difference is mostly lower, will also increase the heat transfer surface. This model will be further extended with a turbine model, a model for air cooled condensers and a model for mechanical draft water cooling towers. Economics will also be taken into account.status: publishe

Optimization of subcritical and transcritical ORC's for low-temperature heat sources

status: publishe