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Partitioning behavior and interfacial activity of phenolic acid derivatives and their impact on β-Lactoglobulin at the oil-water interface

Partitioning behavior and interfacial activity of phenolic acid derivatives and their impact on β-Lactoglobulin at the oil-water interface

emulsifying constituent – as well as the oil-water partitioning and interfacial activity of other constituents – are of major importance. Emulsifiers are either naturally present in the sys- tem or added to it in order to facilitate emulsification and increase kinetic stability. In food systems, proteins, and/or low molecular weight emulsifiers are used to stabilize emul- sions. The behavior of proteins at the oil-water interface has frequently been investigated [ 1 – 5 ]. Briefly, proteins migrate through the aqueous phase to the interface, where unfolding takes place. Patches with predominating hydrophobic proper- ties are exposed to the hydrophobic oil phase, while sequences with a predominance of hydrophilic amino acids remain in the aqueous phase. Rearrangement of the proteins and intermo- lecular interactions may result in a viscoelastic interfacial film that resists mechanical forces and provides electrostatic and steric stabilization [ 4 , 6 ]. However, this process may be influ- enced by other ingredients in the dispersed system. A wide range of other food constituents shows interfacial activity and thus may be present at the interface together with the protein. These constituents may also interact with proteins when they are in the same (oil or water) phase and change their interfacial behavior. In recent years, research has focused on tailoring more complex structures at the oil-water interface to Highlights • Phenolic acid derivatives could be interfacial-active
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Interfacial properties of β-Lactoglobulin at the oil/water interface: influence of starch conversion products with varying dextrose equivalents

Interfacial properties of β-Lactoglobulin at the oil/water interface: influence of starch conversion products with varying dextrose equivalents

In spray dried emulsions, frequently milk proteins are used as interfacial active components and starch conversion products are added as matrix material at high concentrations. To characterize interfacial properties at the oil/water interface by commonly applied methods, low protein, and carbohydrate concentrations from 1 to 2% are usually analyzed. The impact of a higher concentration of starch conversion products was not investigated so far. Therefore, the formation and rheological properties of β- lactoglobulin (β-LG) stabilized films at the oil/water interface were investigated via short and long-time adsorption behavior using pendant drop tensiometry as well as dilatational and interfacial shear rheology. Suitability of the applied methods to the chosen samples with higher concentrations >1–2% was verified by calculation of selected key numbers like capillary number and by detailed reviewing of the results which is summarized further on as key indicators. It is hypothesized, that the increase in concentration via presence of starch conversion products will delay interfacial stabilization as a result of increased bulk viscosity with decreasing degree of degradation (dextrose equivalent) of the starch. Furthermore, this increase in concentration leads to more stable interfacial films due to thermodynamic incompatibility effects between protein and starch conversion products which results in increases of local protein concentration. Key indicators proved a general suitability of applied methods for the evaluation of the investigated samples. Moreover, results showed an increase in interfacial film stability and elastic properties alongside a decreased interfacial tension if starch conversion products were present in a high concentration.
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Microgels at oil-water interfaces

Microgels at oil-water interfaces

Particle stabilized emulsions are well known since the beginning of the last century. Ramsden (1903) 1 , and Pickering (1907) 2 were the first to discover that particles are able to stabilize foams and emulsions by adsorbing to the interface. The rigid layer of particles residing at the oil-water interface prevents the coalescence of oil droplets. Usually this stabilization is very effective and leads to very stable emulsions due to the combination of sterical and electrostatic repulsion of the oil droplets and viscoelastic behaviour of the o/w interfaces. In the current literature these emulsion are called “Pickering emulsions” although Ramsden was the first to describe them. Most systems published in the literature are concerned with inorganic particles, e.g. from modified silica, clay, or metal. 3,4 In recent years there has been increasing interest in the use of organic latex particles to stabilize emulsions. 5,6 For big particles the adsorption at the interface is effectively irreversible 7,8 , however, controlled breaking of such Pickering emulsions is desirable in some applications, like e.g. extraction processes. To attain this goal much work has been done to modify particles to make them stimuli sensitive and a variety of particles have been tested for their intended use as stabilizers for emulsions. Stimuli responsive or switchable surfactants were the subject of a recent study by Liu et al.. 9 They described a surfactant system in which they could change the ability of an amidine – alkyl to act as a stabilizer for their emulsion by changing the gas atmosphere from N 2 to CO 2 . Magnetic
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Microgels at Oil-Water Interfaces : Deformation, Assembly and Compression

Microgels at Oil-Water Interfaces : Deformation, Assembly and Compression

C OMPRESSION I SOTHERMS (pH 3) and d i = 534 ± 14 nm (pH 9) for the P(NiPAm-co-MAA) microgel and d i = 642 ± 66 (pH 3) and d i = 671 ± 22 nm (pH 9) for the second microgel. [26] FreSCa Cryo-SEM. The sample preparation for FreSCA cryo-SEM is analogous to the one already described. [26] 0.5 µL of an aqueous microgel suspension at 0.1 wt% were placed inside a custom-made copper holder with a 200 µm deep central cavity. Prior to filling, the sample holders were roughened, ultrasonicated in 95% sulphuric acid and ethanol for several minutes and finally exposed to a negative glow discharge to improve hydrophilicity and adhesion during freezing. Successively, a 3.0 µL droplet of heptane was carefully placed on top to create the liquid-liquid interface and then the holder was closed with a flat copper plate (also roughened and cleaned but not exposed to the glow discharge). The closed holder was vitrified in a liquid propane jet freezer (Bal-Tec/Leica JFD 030, Balzers/Vienna) with a cooling rate of 30000 Ks -1 to avoid water crystallization. After freezing, the samples were mounted under liquid nitrogen onto a double fracture cryo-stage and transferred under inert gas in a cryo-high vacuum airlock (< 5×10 -7 mbar Bal-Tec/Leica VCT010) to a pre-cooled freeze-fracture device at -140°C (Bal-Tec/Leica BAF060 device). The samples were then fractured and partially freeze-dried at -100°C for 1 min to remove deposited residual water condensation and ice crystals, followed by unidirectional tungsten deposition at an elevation angle α = 30° to a total thickness δ = 2 nm at -120°C and by additional 2 nm with a continuously varying angle between 90° and 30°. The second deposition is needed in order to avoid charging of the shadow during imaging which may compromise image stability at high magnifications. The presence of a macroscopic flat oil-water interface covered by particles promotes the fracture at the interface itself and allows for inspection of the particle arrangement. Freeze-fractured and metal-coated samples were then transferred for imaging under high vacuum (< 5×10 -7 mbar) at -120°C to a pre-cooled (-120°C) cryo-SEM (Zeiss Gemini 1530, Oberkochen) for imaging either with an in-lens or secondary electron detector.
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Microgels at Oil-Water Interfaces : Deformation, Assembly and Compression

Microgels at Oil-Water Interfaces : Deformation, Assembly and Compression

become more apparent and the role played by the interface becomes more important. Numerical studies on gold nanoparticles passivated by alkythiols of different lengths (and therefore different softness) have shown that the ligand shell can be severely deformed at the interface and that two effective contact angles can develop: one measured from water side and one measured from the oil side. The particle in that case assumes a lens-like shape, with two curvatures which are determined by the solubility of the ligands in the two phases and by their surface activity at the oil-water interface. [36] Substantial deformation of soft polymer shells at interfaces has also been described theoretically and experimentally for polymer-capped iron oxide nanoparticles. In particular, lower solvation of poly(ethylene glycol) chains in non-polar solvents has been found to induce partial collapse of the stabilizing shell exposed to the oil. Solvation of the ligand shell thus plays a central role in the energy balance which determines the contact angle of the particles at liquid interfaces. [37] X-ray reflectivity studies at the water-air interface have also highlighted that in the case of high interfacial activity, polymer chains preferentially adsorb and stretch out at the interface, deforming and flattening the polymer shell. [38] Compared to these cases where the soft ligand shell is anchored on a rigid core, our microgel particles can fully deform and therefore have different constraints on the shape they can take at the interface. The equilibrium shape of the microgel particles is given by the balance between the solvation of the hydrogel in the two liquid phases, its interfacial activity and the internal elasticity of the particle. Given the complex interplay between the hydrogel cross-linking profile across the particle, its internal architecture, elasticity, solubility and interfacial activity, a detailed quantitative description is beyond the scope of this work, but we provide here an intuitive description which accounts for our observations. Figure 20 gives a schematic representation of the proposed configuration of the microgels at the oil-water interface.
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Expanding oil palm cultivation in Indonesia: changing local water cycles raises risks of droughts and floods

Expanding oil palm cultivation in Indonesia: changing local water cycles raises risks of droughts and floods

In 2011, the Indonesian government created its own certification scheme – the Indonesian Sustainable Palm Oil System (ISPO). A major point of criticism about ISPO is that the system only certifies the compliance with existing Indonesian laws. In 2011, the Indonesian government signed the Forest Moratorium. It banned any further plantation establishment on primary natural forest areas and peatlands. Critics of both the ISPO and the Moratorium point out a much greater problem in Indonesia: the lack of law enforcement. National laws do protect water resources, for example, riparian buffer zones and upstream conservation forests must be maintained and water pollution controlled. Yet many riparian sites and forest areas are still being illegally converted to oil palm plantations. To this day, too many loopholes remain in the monitoring and auditing of environmental laws and certification standards. Amnesty International recently accused Wilmar International Ltd., the largest producer of palm oil worldwide and a member of RSPO since 2005, of employing children on their oil palm plantations; the IOI Group, a major Malaysian palm oil company, was suspended from RSPO in April 2016. Although IOI was accused of major violations such as illegal plantation activities, encroaching on community land, felling protected forests and clearing forests with deep peat soils, its sustainability certification was restored after only four months, even though it is doubtful that such severe violations could be corrected in such a short time.
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Experimental investigation of sulfate-modified water and polymer flooding for enhanced oil recovery

Experimental investigation of sulfate-modified water and polymer flooding for enhanced oil recovery

Abstract Modified/smart water flooding is a low-cost enhanced oil recovery (EOR) technique that works through the manipulation of injected water chemistry to disturb the es- tablished ionic equilibrium in a reservoir system. Chemical manipulation is achieved by the addition/removal of active/non-active ions, respectively. Added active ions are known as potential determining ions (PDI) while removed non-active ions are known as non-potential determining ions (non-PDI). The focus of this study is to investigate the role of sulfate ions as PDI to select an optimum injection scheme and initiation time. This work investigates the combination of two EOR methods (also known as the hybrid method)—modified water flooding in the secondary mode and low-concentration poly- mer flooding in the tertiary mode—to enhance the capability of the flooding process. Modified water triggered fluid-fluid and rock-fluid interactions, and follow-up polymer flood improved the macroscopic sweep efficiency due to a favourable displacement mo- bility ratio. Hence, the hybrid EOR method is expected to be low-cost (as low poly- mer concentrations are required) and to provide the combined benefits of both EOR processes. This research work is focusing on experimental work. Evaluations were per- formed through comprehensive laboratory evaluations that included measurements of rheological behaviour, contact angle, interfacial tension, oil drop snap-off volume, and wettability alteration. Furthermore, the synergetic effects of modified water and poly- mer flooding were defined by flooding experiments using two types of micromodels with modified-wettability and complemented with core flooding in Bentheimer outcrops.
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Physical-biological interactions controlling the variability of oxygen fluxes across the sediment-water interface

Physical-biological interactions controlling the variability of oxygen fluxes across the sediment-water interface

The benthic oxygen flux can be considered as a proxy for mineralization rate (Glud, R.N. et al., 2016; Granéli, 1979a; Gudasz et al., 2010) thus for estimating the global carbon budgets (Seiter et al., 2005). The benthic oxygen flux has been investigated by estimating the oxygen transport rate (e.g. Lorke et al. (2003)) or by estimating the sediment oxygen uptake rate (e.g. Cai and Reimers (1995)). As mentioned before, from transport phenomena point of view, the benthic oxygen flux is predominantly controlled by boundary-layer turbulence driven by large-scale flows, while from the sediment oxygen uptake rate point of view, the benthic oxygen flux is controlled by availability of organic matters for decomposition. For both processes, the benthic oxygen flux has been correlated to various controlling factors, e.g. organic content, water depth, bottom water oxygen concentration, thickness of the diffusive boundary layers, fauna activity, light, temperature, sedimentation rates, trophic level and sediment permeability (Glud, R.N., 2008 and references therein). Some of those controlling factors are coupled, such as temperature, which influences both the transport processes and the sediment oxygen uptake rate. In our study, we collected measured and derived physical variables, such as discharge, wind-speed, bottom water temperature, near-bed flow velocity, bottom oxygen concentration, turbulent kinetic energy dissipation rate and friction velocity as well as benthic oxygen fluxes. We observed short- (hourly) and long-term (seasonal) flux variations covering a wide range of those environmental conditions. The measured fluxes were varied both in short- and long-term scales.
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Friendship and money, oil and water? Credit constraints and "Family and Friends" finance

Friendship and money, oil and water? Credit constraints and "Family and Friends" finance

Notes: The table shows results for OLS estimations in a sample of all credit negotiations of all firms since 2008; the dependent variable in all estimations is the dummy variable indicat[r]

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Structure and Stability of Ultrathin Polymer and Nanocomposite Films at the Air-Water Interface

Structure and Stability of Ultrathin Polymer and Nanocomposite Films at the Air-Water Interface

The results for the electron density profiles are shown in the bottom right panel of the figure. For the first two positions in the isotherm the density profile resembles a gaussian shaped function for the thick disks. For the second position the electron density increases to almost two times of the one from water which has been similarly observed for FeNP10 in a highly compressed film. Compared to the profile for the spherical shaped particles in figure 7.11, the maximum is broadened while the density decreases quite fast on both flanks. The profile resembles the expected structure of thick disks oriented parallel to the water surface. The bulk scattering provided a thickness of 3 nm. With an oleic acid shell on both sides with a total thickness of roughly 2.5 nm, the overall thickness used in the model appears reasonable for this orientation. The second position illustrates a denser packed film, however the orientation of the particles is still the same. The model used for the last position in the isotherm had to change which can also be seen in the density profile. The overall thickness of the layer is around 11.2 nm and the density profile shows a broad plateau with the two flanks being similar to the ones for the lower surface pressure. The form of the profile indicates that the thick disks flip their orientation by 90 ◦ for high surface pressures. The overall thickness agrees with the diameter of 8 nm adding the oleic acid shell of roughly 2.5 nm. The transition is illustrated as a sketch in figure 7.13 in an idealized way. It is very interesting that the phase transition leads to a dense layer of flipped disks without a collapse of the layer. If multilayer structures would be formed, the density profile should not have such a broad maximum. It is also unlikely that the nanoparticle form a perfect double layer when the film breaks and its regions are pushed over each other. All results indicate that particles indeed perform a flipping process similar to the one illustrated in figure 7.13.
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Gutenberg Open Science: Vibrational Dynamics of Water at Interfaces : Study of vibrational dynamics of water with interface specific time resolved vibrational spectroscopy

Gutenberg Open Science: Vibrational Dynamics of Water at Interfaces : Study of vibrational dynamics of water with interface specific time resolved vibrational spectroscopy

In Chapter 3 , the interfacial structure of water in contact with the negatively surface charged muscovite mica is investigated. By exchanging surface cations on muscovite mica, the heterogeneous ice nucleation temperature can be altered. The lowest ice nucleation temperature of −26 °C is observed for Na-Mica, while the highest ice nucleation temperature of −20 °C is observed on H-Mica. By using SFG spectroscopy, it is revealed that the average water alignment depends on the mica surface cation. The highest average water alignment is found for Na-Mica, and the lowest for H-Mica. This indicates that the water hydrogen bond network is aligned in the Na-Mica case hindering the formation of ice crystals. The opposite happens for the H-Mica interface, where the formation of ice crystals is not hindered. With this ordering mechanism both, the SFG and the ice nucleation temperature results can be explained. However, there also remain some issues, as, e.g., the ice nucleation temperature of Cs-Mica and K-Mica are significantly different with −23 °C and −25 °C, but the average SFG intensity, and thus probably the average water alignment, is indistinguishable for these two interfaces. Most likely heterogeneous ice nucleation is affected by multiple molecular mechanisms, and water alignment is one amongst others. E.g., the distortion of the interfacial crystal structure due to surface cations could play an important role in all of the mentioned cases as well.
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Spacewire Interface Simulation

Spacewire Interface Simulation

Complex systems have often several functional modes based on special parameter pre-configuration or internal conditions. That means it must be possible to influence an interface behaviour in real time initiated by command requests. A proper function or handling of failure cases have to be simulated, e.g. a sensor system sends different sensor data in two different modes depending on a special parameter configuration. The “condition controlled simulation” supports such behaviour. That means a command request packet can set SWIS internal conditions which influence the simulation protocol, response packet content and/or timing. In the same way a simulation of interface or system failures can be performed if needed. The SWIS supports simulation functions by generic actions like “SetCondition()”, “ResetCondition()” or “WaitCondition()”.
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publish.UP Model membrane interactions with ions and peptides at the air/water interface

publish.UP Model membrane interactions with ions and peptides at the air/water interface

the concentration dependent random coil – β-structure transition by a cooperative aggregation model with an association constant of approximately 1x10 4 M -1 . One can calculate that for this system essentially all Aβ is present in the bound form. In the IRRAS experiments we use a fixed lipid concentration, i.e. a certain area of the water surface is covered with lipid. The Aβ concentration was varied between 0.2 – 0.4 µM. Thus we are in the range of a 1/1 L/P ratio. Therefore, a large excess of lipid molecules to induce the β-sheet - α-helix transition as observed in bulk with vesicle systems is never reached in equilibrium. Because the lipid concentration at the air-water interface is essentially fixed, the only possibility to obtain large L/P ratios is to decrease the Aβ concentration. For a peptide concentration 100-fold lower (0.002 µM) and a L/P ratio of approximately 100, the concentration of bound peptide would be however very small, namely 0.5 nM (only 0.2% of the binding sites are occupied). Such a small amount of peptide cannot be detected using IRRAS or any other technique. It is therefore not surprising that the β- sheet - α-helix transition cannot be observed in the IRRAS experiments after reaching the adsorption equilibrium. However, at the beginning of the adsorption process one can expect high enough L/P ratios. But then the question arises what is the minimum peptide concentration to be detected by IRRAS. Assuming that this minimum peptide concentration at the interface has to be around 0.7 nm 2 per amino acid residue as observed for another model peptide (Kerth et al., 2004), then Aβ occupies an area of less than 30 nm 2 . Such an area corresponds to approximately 60 DPPG molecules in the condensed state. Therefore, the L/P ratio would be 60 and one would expect a conformational
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Exploring the Interface of Skin‐Layered Titanium Fibers for Electrochemical Water Splitting

Exploring the Interface of Skin‐Layered Titanium Fibers for Electrochemical Water Splitting

Another plausible explanation is related to the strong ten- dency of both Ir and Ti to form bonds with oxygen. Thus, the uncoated titanium PTL will oxidize at high potentials taking the oxygen not only from the evolved gas but also from IrO 2 catalyst as well, which is reported that it continuously forms unstable species during OER that will eventually recombine again with oxygen, [40,41] and this oxygen can be found at the interface with the uncoated titanium PTL. After the long-term operation, more and more of this unstable Ir will bond strongly with the oxygen at the interface with the uncoated titanium PTL from the passivation. It is worth noting that TiO x is widely used in the thin-film industry as a prelayer to improve the bonding of a desired coating to a substrate. Lastly, one must not discard the tendency of polymers to adhere stronger to oxidized sur- faces than metal ones, [42] which could be the case for the Nafion in the catalysts layer. Future investigation will be done to design an experiment in which we insert microtemperature sensors in the PTLs or perform adhesion tests on the catalyst layers directly deposited on the PTLs.
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Insights into Water Interaction at the Interface of Nitrogen-Functionalized Hydrothermal Carbons

Insights into Water Interaction at the Interface of Nitrogen-Functionalized Hydrothermal Carbons

Figure 4 , di ffusion results are plotted as the natural logarithm of the normalized signal intensity vs the squared gradient amplitude. For the Glu/Uro-1:0 samples these curves decay linearly, while N-HTC samples show a stretched decay. A straight line in this plot is interpreted as a single component of water translational motion, and the slope becomes an e ffective di ffusion constant according to the Stejskal−Tanner equation. As in the relaxation experiments, the suitability of a linear fit on the log scale for the HTC sample does not imply the existence of a single di ffusion constant only. Instead, diffusion in the limit of fast exchange over a time scale given by the mixing time Δ of the diffusion experiment (here Δ = 50 ms) would equally result in such a decay. On the other hand, the data for the N-HTC sample do not coincide with a straight line. This is interpreted as being caused by water in two di fferent reservoirs in the intermediate or slow exchange limit, meaning that no or incomplete mixing of the reservoirs is achieved during the experiment. The PGSTE NMR experiment is sensitive to translational motion over length scales of micrometers; therefore, these results indicate not only that the two reservoirs do not mix or mix slowly but also that water moves over at least hundreds of nanometers within each of the reservoirs without exchanging. 49 Time-dependent di ffusion NMR experi- ments, 50 , 51 recorded with di fferent Δ, are also consistent with two coupled water reservoirs in the slow exchange limit in N- HTC, which is not seen in HTC ( Figure S5 ).
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Gutenberg Open Science: Structure formation of amphiphilic molecules at the air, water interface and after film transfer

Gutenberg Open Science: Structure formation of amphiphilic molecules at the air, water interface and after film transfer

dipole orientation. For SFAs at the air/water interface a surface potential differ- ence of -0.8 V has been proposed corresponding to a vertical molecular orientation with the fluorinated part of the molecules facing air (or for transferred layers -0.6 to -0.7 V relative to a Si wafer surface) [80, 84]. In our experiments it was possible to perform KPFM measurements on individual surface micelles prepared by solvent evaporation (Figure 3.9). Aim was to directly compare surface potential differences between silicon substrate and F12H12 micelles on our sample with those obtained by Magonov et al. following their experimental procedure [84]. At the film edge single surface micelles were found. The surface potential difference between silicon sub- strate and micelles was determined to be -0.6 V, which is close to the -0.8 V proposed by Magonov et al. [80, 82, 84]. In accordance, for our sample a similar orientation can be concluded, with the F-blocks of the F12H12 molecules oriented towards air (Figure 3.1 C). The divergence between the two values can be explained by taking the size of the investigated structures into account. The size of the surface micelles in our experiment (35.2 ± 7.1 nm diameter) is of the same order of magnitude as the lateral resolution of KPFM (ca. 30 nm), while the measurements from Magonov et al. were performed on structures prepared by spin-coating with a diameter of ca. 1 µm. When measuring structures at the limit of lateral resolution, as in our case, the cantilever will not only detect the surface potential of the pure F12H12 micelle, but also a contribution from the Si-wafer, which decreases the finally determined surface potential difference. Furthermore, the assumed presence of flat lying molecules on the substrate surface between the micelles has to be considered, which would also in- fluence the reference signal from the substrate and additionally alter the determined micelle height. As a consequence, it can be concluded that the F12H12 molecules inside the micelle carpet are oriented vertically with their fluorocarbon moiety facing air. This is in good agreement with literature data [62]: the molecular orientation is similar to the one confirmed by X-ray reflectivity measurements for F8H16 monolay- ers [68] which present the same lateral organization with hexagonal arrays of circular surface micelles. Also, neutron reflectivity measurements of F12H12 directly at the air/water interface have supported the theory, that the molecule is standing upright with the fluorocarbon moiety facing air [85].
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Surface Properties of Monomolecular Films of Reduced Plastocyanin at a Nitrogen-Water Interface 

Surface Properties of Monomolecular Films of Reduced Plastocyanin at a Nitrogen-Water Interface 

In a previous study were reported the properties of a monomolecular film of oxidized plastocyanin (ox. pcyan) at an air-water interface 3. It was shown that there is an interaction, possibly a complex, be­ tween chlorophyll (Chi) and ox. pcyan in a mixed monomolecular film. The surface potential and area of the mixed Chl-pcyan films are changed signifi­ cantly upon irradiation indicating a photoreaction between Chi and ox. pcyan in air. Since no special efforts were taken in the above work to insure that all the pcyan was in the oxidized state there could be some reduced plastocyanin present in the film.
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Peep durchs Interface

Peep durchs Interface

Wenn sich das Subjekt in der Perversion mit dem Objekt - mit sich selbst in seiner eigenen Gespaltenheit - identifiziert, dann gibt es keinen Entfaltungsraum für diese Fr[r]

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Iranian-oil-free zone and international oil prices

Iranian-oil-free zone and international oil prices

Where 𝑦 𝑡 is a vector of k endogenous variables, 𝑥 𝑡 is a vector of d exogenous variables, 𝐴 1 ,…, A p and B are matrices of coefficients to be estimated, p is the optimum number of lags, and 𝜀 𝑡 is a vector of innovations . These innovations should be uncorrelated both with their own lagged values and with all of the right-hand side variables. One of the major advantages of using the VAR is addressing the endogeneity issue due to strong interconnections between oil prices, oil supply and global economic growth. All variables in the VAR are endogenous which mitigate prior invalid restrictions on variables. We use impulse response (IRF) and variance decomposition (VDA) analytical tools on the basis of estimated VAR model in order to respond to our research question. By using the IRF we can measure the size and statistical significance of global oil prices to one standard deviation increase in absolute negative changes of Iranian oil exports (e.g., from -1% to -2%). The IRF shows the response of oil prices after initial negative shock in Iranian oil export in forthcoming years. To judge about statistical significance of such response we report 68% confidence intervals around the main response (see Sims and Zha, 1999 who recommend this). We employ 1000 Monte Carlo simulations to build these confidence intervals. The response is said to be statistically insignificant when the confidence intervals include the horizontal zero line.
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Cross-Linking Strategies for Fluorine-Containing Polymer Coatings for Durable Resistant Water- and Oil-Repellency

Cross-Linking Strategies for Fluorine-Containing Polymer Coatings for Durable Resistant Water- and Oil-Repellency

) was measured using the sessile-drop method with a Contact Angle System DataPhysics OCA 115 EC (Filderstadt, Germany) using 4 µL droplets of deionized water. The measurements were conducted in a controlled climatic chamber at T = 23 ± 2 ◦ C and a relative humidity of 50%. The contact angles were determined geometrically using the SCA20 software by aligning a tangent from the surficial contact point along the droplets surface in the droplet profile. The oil repellency was determined with the hydrocarbon test for oil repellency according to the American Association of Textile Chemists and Colorists AATCC test method 118 with four hydrocarbon test liquids (n-tetradecane, n-dodecane, n-decane, and n-octane) as described in the literature [ 32 , 55 , 56 ]. For the complete thermal cross-linking reaction of the polymer with the cellulose fiber, the coated samples were treated in a VTR 5022 oven (Heraeus, Hanau, Germany) at 120 or 160 ◦ C under reduced pressure for at least 4 h. For the UV-cross-linking reaction, a UVA-Cube 2000 (Dr. Hoenle AG, Gräfelfing, Germany) was used and the samples were irradiated with a mercury lamp and an output power of 1000 W for 5 min at each side of the sample. The tensile strength was determined on a ZwickRoell Z1.0 with a 1 kN X-force P load cell using the software testXpert II V3.71 (ZwickRoell, Ulm, Germany) at a tensile speed of 10 mm/min. The samples were stored for 24 h in a climate chamber at T = 23 ±
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