Glycerolysis of Fatty Acid Methyl Esters: 1. Investigations in a Batch Reactor

The present work focused on the glycerolysis of fatty acid methyl esters. The aim was to develop and test a kinetic model that could be used to reliably simulate different process alternatives for this reaction. A prerequisite was the identification and characterization of the factors that affect the reaction kinetics. Experiments were carried out in a batch reactor with and without forced removal of methanol, which is one of the reaction products. Concentrations of all components in the two-phase system were measured. It was found that the methanol concentration has a strong effect on the reaction rate and equilibrium conversion. Near-complete conversions were obtained by stripping methanol with an inert gas. The glycerol concentration in the ester phase was found to increase as the reaction proceeds, which also accelerates the reaction. Effects of mass transfer on the reaction rate were not found to control the reaction rate under well-agitated conditions. A semi-empirical model was used to simulate the reaction. The results from the semi-empirical model show good agreement with experimental results.     

Validation of Tuba1a as Appropriate Internal Control for Normalization of Gene Expression Analysis during Mouse Lung Development

The expression ratio between the analysed gene and an internal control gene is the most widely used normalization method for quantitative RT-PCR (qRT-PCR) expression analysis. The ideal reference gene for a specific experiment is the one whose expression is not affected by the different experimental conditions tested. In this study, we validate the applicability of five commonly used reference genes during different stages of mouse lung development. The stability of expression of five different reference genes (Tuba1a, Actb Gapdh, Rn18S and Hist4h4) was calculated within five experimental groups using the statistical algorithm of geNorm software. Overall, Tuba1a showed the least variability in expression among the different stages of lung development, while Hist4h4 and Rn18S showed the maximum variability in their expression. Expression analysis of two lung specific markers, surfactant protein C (SftpC) and Clara cell-specific 10 kDA protein (Scgb1a1), normalized to each of the five reference genes tested here, confirmed our results and showed that incorrect reference gene choice can lead to artefacts. Moreover, a combination of two internal controls for normalization of expression analysis during lung development will increase the accuracy and reliability of results.     

40 GHz Vertical Transition with a Dual‐Mode Cavity for a Low‐Temperature Co‐fired Ceramic Transceiver Module

A new vertical transition between a substrate integrated waveguide in a low‐temperature co‐fired ceramic substrate and an air‐filled standard waveguide is proposed in this paper. A rectangular cavity resonator with closely spaced metallic vias is designed to connect the substrate integrated waveguide to the standard air‐filled waveguide. Physical characteristics of an air‐filled WR‐22 to WR‐22 transition are compared with those of the proposed transition. Simulation and experiment demonstrate that the proposed transition shows a ?1.3 dB insertion loss and 6.2 GHz bandwidth with a 10 dB return loss for the back‐to‐back module. A 40 GHz low‐temperature co‐fired ceramic module with the proposed vertical transition is also implemented. The implemented module is very compact, measuring 57 mm × 28 mm × 3.3 mm.     

A numerical model for fluid injection induced seismicity at Soultz-sous-Forêts

During fluid injection experiments at the geothermal site of Soultz-sous-Forêts (France), more than 114,000 induced seismic events with magnitudes between ?2.0 and +2.9 were detected by a local downhole monitoring network. Of these, 35,039 events are sufficiently constrained to be located. Hypocenters align along a sub-vertical, planar structure with the apparent width being dominated by data scattering indicating that seismic activity predominantly occurs along a (pre-existing) larger scale fault structure. For this scenario, we present a numerical model to simulate hydraulic overpressures and induced seismicity during hydraulic injection. The numerical model is based on the physical processes of fluid pressure and stress diffusion with triggering of the induced seismicity being controlled by Coulomb friction.Even in its simplest form of a fault zone without any structural heterogeneity, the numerical model reproduces typical observations at Soultz-sous-Forêts, such as number and magnitude of induced events, hypocenter locations (including the Kaiser effect), occurrence of post-injection seismicity, and the largest magnitude event occurring several days after shut-in.     

Evaluating the impacts of membrane type, coating, fouling, chemical properties and water chemistry on reverse osmosis rejection of seven nitrosoalklyamines, including NDMA

Reverse osmosis (RO) treatment has been found to be effective for a wide range of organics but generally small, polar, uncharged molecules such as N-nitrosodimethylamine (NDMA) can be poorly rejected. The rejection of seven N-nitrosoalkylamines with molecular masses in the range of 78-158Da, including NDMA, N-nitrosodiethylamine (NDEA), N-nitrosomethylethylamine (NMEA), N-nitrosodipropylamine (NDPA), N-nitrosodibutylamine (NDBA), N-nitrosopyrrolidine (NPyr), N-nitrosopiperidine (NPip) by three commercial brackish-water reverse osmosis membranes was studied in flat-sheet cells under cross-flow conditions. The membranes used were ESPA3 (Hydranautics), LFC3 (Hydranautics) and BW-30 (Dow/Filmtec), commonly used in water reuse applications. The effects of varying ionic strength and pH, dip-coating membranes with PEBAX 1657, a hydrophilic polymer, and artificial fouling with alginate on nitrosamine rejection were quantified. Rejection in deionized (DI) water increased with molecular mass from 56 to 70% for NDMA, to 80-91% for NMEA, 89-97% for NPyr, 92-98% for NDEA, and to beyond the detection limits for NPip, NDPA and NDBA. For the nitrosamines with quantifiable transmission, linear correlations (r(2)>0.97) were found between the number of methyl groups and the log(transmission), with factor 0.35 to 0.55 decreases in transmission per added methyl group. A PEBAX coating lowered the ESPA3 rejection of NDMA by 11% but increased the LFC3 and BW30 rejection by 6% and 15%, respectively. Artificially fouling ESPA3 membrane coupons with 170g/m(2) alginate decreased the rejection of NDMA by 18%. A feed concentration of 100mM NaCl decreased rejection of NDMA by 15% and acidifying the DI water feed to pH=3 decreased the rejection by 5%, whereas increasing the pH to 10 did not have a significant (p<0.05) effect.     

iFlash:80℃活化漂白与新型皂洗

加工技术与设备的发展通常会使加工时间缩短.但是新型助剂的应用也可减少加工时间,大大降低成本.随着iFlash系统的应用,漂白温度可降至80℃,活性染料染色后皂洗的时间也大大缩短.因此,织物间歇式染色得到优化,在不增加额外投资的情况下运行更经济.     

Zum einfluß des borat-anions auf die elektrochemischen eigenschaften des eisens in Wäßrigen Lösungen

Measurements of potential—time and current density—potential curves of iron were carried out in air-saturated and argon-flushed sodium borate solutions of different concentrations and pH to determine whether borate anions possibly influence the electrochemical behaviour of iron even in the absence of oxygen. The critical minimum pH necessary for passivating iron in air-saturated borate solutions has been established. Using these results and those taken from the literature we discuss the role of the borate anion in possibly stimulating the process of oxygen reduction and/or in influencing the process of metal oxydation, respectively. The latter influence, leading to a decrease of the critical current density, does not absolutely require the presence of oxygen. However, with the formation of hydrogen as the cathodic reaction it cannot give rise to the passive state of iron. The relation between the potential of the passive iron electrode in air-saturated borate solutions and the pH is explained by Fe(III)-borohydroxo-complexes possibly being formed on the solution side of the passive layer.     

Assessment of the technological development and economic potential of photobioreactors

In this paper, we investigate the development and economic potential of the photobioreactor (PBR) technology for energy purposes, i.e. production of hydrogen or biofuels. The approach adopted is to consider the technology, its expected costs and revenues, and related risks from an investor perspective. To this end we develop an investment model that is used to calculate the economic feasibility of PBRs for different scenarios, including a best-case scenario, with plenty of sunlight and water, inexpensive nutrients, high prices for hydrogen and biomass, and low other costs. The best-case scenario is compared to a scenario with less favorable boundary conditions. We find that PBR efficiencies will likely be less than 10%, with typical values between 1.8% and 5.6%. We also find that hydrogen production costs would be lower than those for biodiesel or biogas from solid biomass produced in PBRs. Compared to biofuels from traditional agriculture there is a great advantage for the PBR technology if land is scarce, because land is used more efficiently. Since PBRs can be designed as a closed system they can be applied in very dry regions. In the long term this might enable this promising concept to penetrate the energy supply market.     

Offshore wind power grid connection—The impact of shallow versus super-shallow charging on the cost-effectiveness of public support

Public support for electricity generation from renewable energy sources is commonly funded by non-voluntary transfers from electricity consumers to producers. Apparently, the cost-effective disposition of funds in terms of induced capacity deployment has to be regarded a key criterion for the success of renewable energy policy.