Shape Optimisation of Curved Interconnecting Ducts

Practical ducting layout in process plants needs to satisfy a number of on-site constraints. The search for an optimal flow path around the obstructions is a multi-parameter problem and is computationally prohibitively expensive. In this study, authors proposed a rapid and efficient methodology for the optimal linkage of arbitrarily oriented fluid flow ducts using a single-parameter quadratic/cubic Bézier curves in two/three dimensions to describe the centreline of the curved duct. A smooth interconnecting duct can then be generated by extruding the duct face along the curve. By varying the parameter either along the angular bisector or along the axes of the ducts, a family of Bézier curves is generated. Computational fluid dynamics simulations show that the relationship between pressure drop and the adjustable parameter is a unimodal curve and the optimal connecting duct is the one which has the least pressure drop while satisfying on-site constraints can be used for linking the ducts. The efficacy of the method is demonstrated by applying it to some cases of practical interest.Defence Science Journal, Vol. 65, No. 4, July 2015, pp. 300-306, DOI: http://dx.doi.org/10.14429/dsj.65.8353

Numerical study of on-board fuel reforming in a catalytic plate reactor for solid-oxide fuel cells

A pseudo-transient numerical model is used for the simulation of a multi-functional catalytic plate reactor (CPR). The work mainly addresses the problems associated with on-board reforming for solid-oxide fuel cells. Heat management is achieved by indirectly coupling partial oxidation with reforming. Water management is achieved by partially recycling the anode stream from a solid-oxide fuel cell. The model uses detailed heterogeneous chemistry for reforming and oxidation reactions occurring on the catalyst beds

Deactivation and regeneration of Ni catalyst during steam reforming of model biogas: An experimental investigation

his paper presents detailed study of biogas reforming. Model biogas with different levels of H2S is subjected to reforming reaction over supported Ni catalyst in a fixed bed reactor at 700 °C and 800 °C. In order to understand the poisoning effects of H2S the reactions have been initially carried out without H2S in the feed stream. Three different H2S concentrations (20, 50 and 100 ppm) have been considered in the study. The H2O to CH4 ratio is maintained in such as way that CO2 also participates in the reforming reaction. After performing the poisoning studies, regeneration of the catalyst has been studied using three different techniques i) removal of H2S from the feed stream ii) temperature enhancement and iii) steam treatment. Poisoning at low temperature is not recoverable just by removal of H 2S from the feed stream. However, poisoning at high temperature is easily reversed just by removal of H2S from the feed stream. Unlike some previous reports by Li et al. (2010) and Rostrup-nielsen (1971) [1,2], catalyst regeneration is achieved in shorter time frames for all the regeneration techniques attempte

A detailed kinetic model for biogas steam reforming on Ni and catalyst deactivation due to sulfur poisoning

This paper deals with the development and validation of a detailed kinetic model for steam reforming of biogas with and without H2S. The model has 68 reactions among 8 gasphase species and 18 surface adsorbed species including the catalytic surface. The activation energies for various reactions are calculated based on unity bond index-quadratic exponential potential (UBI-QEP) method. The whole mechanism is made thermodynamically consistent by using a previously published algorithm. Sensitivity analysis is carried out to understand the influence of reaction parameters on surface coverage of sulfur. The parameters describing sticking and desorption reactions of H2S are the most sensitive ones for the formation of adsorbed sulfur. The mechanism is validated in the temperature range of 873-1200 K for biogas free from H 2S and 973-1173 K for biogas containing 20-108 ppm H2S. The model predicts that during the initial stages of poisoning sulfur coverages are high near the reactor inlet; however, as the reaction proceeds further sulfur coverages increase towards the reactor exit. In the absence of sulfur, CO and elemental hydrogen are the dominant surface adsorbed species. High temperature operation can significantly mitigate sulfur adsorption and hence the saturation sulfur coverages are lower compared to low temperature operation. Low temperature operation can lead to full deactivation of the catalyst. The model predicts saturation coverages that are comparable to experimental observatio

Hubungan Tingkat Pengetahuan dan Praktik Perawat Mengenai Keselamatan Pasien (Patient Safety) di Instalasi Gawat Darurat RS X Semarang

In Indonesia, reports regarding patient safety has not been noticed and concerned decently, but the arraignments toward malpractice are increasing. Nurses, are the spearhead of the health care. Emergency room is one of healthcare area that needs fast and right treatment, so that the nurses should have good knowledge and practice regarding patient safety.The purpose of this study was to determine the correlation between nurses knowledge and nurses practice or the implementation regarding patient safety at emergency room of X Hospital Semarang. This study is belong to an explanatory research with cross sectional approach. The population that used was total sampling, with 35 nurses which are working at emergency room of X Hospital Semarang. Data was collected directly used questionnaire that is based on Joint Commission International (JCI).Chi Square test was used to analyze the data. The results of statistical test showed that there is a correlation between nurses knowledge regarding patient safety with the implementation of patient safety at emergency room of X Hospital Semarang with p value=0,000. Socialization and review concerning patient safety should be given periodically by nurse supervisor

Micro-kinetic modeling of NH3 decomposition on Ni and its application to solid oxide fuel cells

This paper presents a detailed surface reaction mechanism for the decomposition of NH3 to H2 and N2 on a Ni surface. The mechanism is validated for temperatures ranging from 700 to 1500K and pressures from 5.3Pa to 100kPa. The activation energies for various elementary steps are calculated using the unity bond index-quadratic exponential potential (UBI-QEP) method. Sensitivity analysis is carried out to study the influence of various kinetic parameters on reaction rates. The NH3 decomposition mechanism is used to simulate SOFC button cell operating on NH3 fuel

FORMULATION AND EVALUATION OF SUSTAINED-RELEASE PELLETS OF LORNOXICAM

Objective: The aim of the study was to develop sustained release pellets of lornoxicam using Eudragit RLPO and Eudragit RSPO to reduce the dosing frequency. Methods: The sustained release pellets of lornoxicam were prepared by extrusion–spheronization technique using Eudragit RLPO and Eudragit RSPO as release retardant polymers and microcrystalline cellulose as spheronizing agent. A 32 Full factorial design was applied to investigate the combined effect of the two independent variables i.e. concentration of Eudragit RLPO (X1) and concentration of Eudragit RSPO (X2) on the dependent variables, In vitro drug release at 1h (Y1), In vitro drug release at 4 h (Y2) and In vitro drug release at 12 h. (Y3). Results: The optimized formulation (F0) show in vitro drug release 11.24±1.21 %, 43.69±1.28 %, 82.69±1.74 % and 100.24±1.56 % at 1 h, 4 h, 12 h and 24 h respectively. Drug excipients compatibility study by FTIR showed no interaction between drug and excipients. Eudragit RLPO and Eudragit RSPO had a significant effect on in vitro drug release. Conclusion: From all parameters and experimental design evaluation, it was concluded that the drug release rate decreased with an increase the concentration of Eudragit RLPO and Eudragit RSPO. SEM Photomicrograph of pellets revealed that the surface was rough and the pellets were spherical shaped in nature. The in vitro release kinetics revealed higuchi model is followed and drug release is by anamolous diffusion

Two-Proton Correlations near Midrapidity in p+Pb and S+Pb Collisions at the CERN SPS

Correlations of two protons emitted near midrapidity in p+Pb collisions at 450 GeV/c and S+Pb collisions at 200A GeV/c are presented, as measured by the NA44 Experiment. The correlation effect, which arises as a result of final state interactions and Fermi-Dirac statistics, is related to the space-time characteristics of proton emission. The measured source sizes are smaller than the size of the target lead nucleus but larger than the sizes of the projectiles. A dependence on the collision centrality is observed; the source size increases with decreasing impact parameter. Proton source sizes near midrapidity appear to be smaller than those of pions in the same interactions. Quantitative agreement with the results of RQMD (v1.08) simulations is found for p+Pb collisions. For S+Pb collisions the measured correlation effect is somewhat weaker than that predicted by the model simulations, implying either a larger source size or larger contribution of protons from long-lived particle decays.Comment: 10 pages (LaTeX) text, 4 (EPS) figures; accepted for publication in Phys. Lett.

Strange Meson Enhancement in PbPb Collisions

The NA44 Collaboration has measured yields and differential distributions of K+, K-, pi+, pi- in transverse kinetic energy and rapidity, around the center-of-mass rapidity in 158 A GeV/c Pb+Pb collisions at the CERN SPS. A considerable enhancement of K+ production per pi is observed, as compared to p+p collisions at this energy. To illustrate the importance of secondary hadron rescattering as an enhancement mechanism, we compare strangeness production at the SPS and AGS with predictions of the transport model RQMD.Comment: 11 pages, including 4 figures, LATE