Fluid Operations (Germany)

Accurate pH measurement in High-Weight, Salt Saturated Water-Based Mud (>20 kPa/m) is frequently compromised by extreme salinity and high solids content, which interfere with conventional measurement techniques, presenting significant technical challenges at rig sites, in high-pressure salt formation sections in the Middle East. Extreme salinity typical of regional deep well operation (approximately 190 kg/m3) masks pH paper response, while high barite solids (∼ 40%) rapidly coat pH meter electrodes, resulting in falsely low pH readings. This paper presents a pH correction framework based on fundamental dilution principles and logarithmic relationships between ion concentration and pH. The theoretical approach is supported by laboratory datasets. A 1:1 dilution combined with a +0.3 correction factor is proposed for practical field application. This framework is suitable for technical discussion and future experimental validation.

A produção de alimentos é geralmente praticada em todas as regiões do Brasil, e o maior desafio de todas as empresas é fabricar alimentos saudáveis com o menor risco de contaminação possível. A pasteurização é um dos procedimentos utilizados para diminuição de micro-organismos presentes nos alimentos. Com tudo, o presente estudo teve como objetivo a realização de cálculos mecânicos para o aumento da vazão de um pasteurizador na empresa de suco e polpas Britvic Ebba situada na cidade de Astolfo Dutra - MG, passando sua vazão de 7860L/h para 9000L/h. Foram coletadas informações de tempo, pressão e velocidade decorrentes do processo, todos os dados foram apurados no processo em tempo real de produção. Os resultados encontrados demonstraram que com a pressão do fluido, a velocidade de saída será menor que a velocidade de início, de acordo com a altura que os tubos de envase do pasteurizador se encontram.
 Conclui-se que os métodos mecânicos de análises foram efetivos para a verificação do aumento da vazão do pasteurizador realizado pela empresa.

When a pure droplet evaporates inside an elastic medium, two instabilities are typically observed. As the droplet shrinks, the elastic medium needs to deform and elastic tension builds up. At a critical strain, accumulated tension at the gel-droplet interface is released by developing creases. The droplet keeps shrinking beyond this point, pulling the elastic network and therefore decreasing the pressure in the liquid phase. This drives the liquid phase into a metastable state, and leads to the second instability: the nucleation of a vapour bubble in the liquid phase by cavitation. These instabilities consistently occur in the described order whenever a pure liquid (water, in this case) is used. The presence of colloidal particles inside droplets is common both in vitro and in natural environments, and they can change such phenomenology significantly by stimulating cavitation events before any creasing instability. In this work, we study the role of colloidal particle size and concentration on the early inception of cavitation in water droplets in an elastic medium. Our results reveal an unexpected dependence with the particle size and with the size distribution of the colloidal particles. Given the simplicity and reliability of the system and preparation, the method described here could be eventually used to measure tensile strengths of particle solutions with accuracy.

Flow transport in confined spaces is ubiquitous in technological processes, ranging from separation and purification of pharmaceutical ingredients by microporous membranes and drug delivery in biomedical treatment to chemical and biomass conversion in catalyst-packed reactors and carbon dioxide sequestration. In this work, we suggest a distinct pathway for enhanced liquid transport in a confined space via propelling microdroplets. These microdroplets can form spontaneously from localized liquid-liquid phase separation as a ternary mixture is diluted by a diffusing poor solvent. High speed images reveal how the microdroplets grow, break up and propel rapidly along the solid surface, with a maximal velocity up to ∼160 μm s-1, in response to a sharp concentration gradient resulting from phase separation. The microdroplet propulsion induces a replenishing flow between the walls of the confined space towards the location of phase separation, which in turn drives the mixture out of equilibrium and leads to a repeating cascade of events. Our findings on the complex and rich phenomena of propelling droplets suggest an effective approach to enhanced flow motion of multicomponent liquid mixtures within confined spaces for time effective separation and smart transport processes.

In the field of fluid power, accurate knowledge of fluid properties is vital for reasonable prediction of component behaviour and system performance. In general, these properties depend on the pressure and temperature levels that the respective medium is exposed to. The properties and their respective dependencies are not publicly accessible for many fluids commonly used in fluid power. If measured values -typically published in the form of mathematical fluid property models -are available at all, their quality is typically unknown. The paper aims to provide tools to objectively ascertain the quality of measured fluid properties. For this purpose, an equation is derived which establishes a relationship between the thermodynamic parameters of density, bulk modulus, heat capacity and thermal expansion coefficient. The presented equation is always satisfied by liquids as well as gases as long as they can be treated as a continuum. Based on this relationship, the degree of thermodynamic consistency of measured properties is evaluated: The less the equation is fulfilled by experimentally determined fluid properties, the more the measured values violate physical laws. The procedure of assessing the thermodynamic consistency is demonstrated by evaluating published fluid property models with the method outlined above. To aid engineers in judging which degree of thermodynamic inconsistency is acceptable, a cut-off value is suggested.

Knowledge of the deformation mechanisms of (Mg,Fe)2SiO4 olivine is important for the understanding of flow and seismic anisotropy in the Earth’s upper mantle. We report here a numerical modelling at the atomic scale of dislocation structures and slip system properties in Mg2SiO4 forsterite. Our study focuses on screw dislocations of [100] and [001] Burgers vectors. Computations are performed using the so-called THB1 empirical potential set for Mg2SiO4. Results of dislocation core structures highlight the primary importance of the (010) plane for [100] slip dislocations. For [001] dislocations, we confirm the occurrence of a stable narrow core that evolves into transient planar configurations to glide in (100) and (010). Such configurations suggest a locking–unlocking mechanism.

The NewProt protein engineering portal is a one-stop-shop for in silico protein engineering. It gives access to a large number of servers that compute a wide variety of protein structure characteristics supporting work on the modification of proteins through the introduction of (multiple) point mutations. The results can be inspected through multiple visualizers. The HOPE software is included to indicate mutations with possible undesired side effects. The Hotspot Wizard software is embedded for the design of mutations that modify a proteins' activity, specificity, or stability. The NewProt portal is freely accessible at http://newprot.cmbi.umcn.nl/ and http://newprot.fluidops.net/.

A water-filled differentially heated rotating annulus with initially prepared stable vertical salinity profiles is studied in the laboratory. Based on two-dimensional horizontal particle image velocimetry data and infrared camera visualizations, we describe the appearance and the characteristics of the baroclinic instability in this original configuration. First, we show that when the salinity profile is linear and confined between two non-stratified layers at top and bottom, only two separate shallow fluid layers can be destabilized. These unstable layers appear nearby the top and the bottom of the tank with a stratified motionless zone between them. This laboratory arrangement is thus particularly interesting to model geophysical or astrophysical situations where stratified regions are often juxtaposed to convective ones. Then, for more general but stable initial density profiles, statistical measures are introduced to quantify the extent of the baroclinic instability at given depths and to analyze the connections between this depth-dependence and the vertical salinity profiles. We find that, although the presence of stable stratification generally hinders full-depth overturning, double-diffusive convection can lead to development of multicellular sideways convection in shallow layers and subsequently to a multilayered baroclinic instability. Therefore we conclude that by decreasing the characteristic vertical scale of the flow, stratification may even enhance the formation of cyclonic and anticyclonic eddies (and thus, mixing) in a local sense.