Performance Comparison of Control Strategies for Plant-Wide Produced Water Treatment

Offshore produced water treatment (PWT) accounts for cleaning the largest waste stream in the offshore oil and gas industry. If this separation process is not properly executed, large amounts of oil are often directly discharged into the ocean. This work extends two grey-box models of a three-phase gravity separator and a deoiling hydrocyclone, and combines them into a single plant-wide model for testing PWT control solutions in a typical process configuration. In simulations, three known control solutions—proportional-integral-derivative (PID) control, H∞ control, and model predictive control (MPC)—are compared on the combined model to evaluate the separation performance. The results of the simulations clearly show what performance metrics each controller excels at, such as valve wear, oil discharge, oil-in-water (OiW) concentration variance, and constraint violations. The work incentivizes future control to be based on operational policy, such as defining boundary constraints and weights on oil discharge, rather than maintaining conventional intermediate performance metrics, such as water level in the separation and pressure drop ratio (PDR) over the hydrocyclone.

An unsteady analysis of two-phase binding of drug in an asymmetric stenosed vessel

In this paper, we investigate endovascular delivery to get a step ahead of the pharmacological limitations it has due to the complexity of dealing with a patient-specific vessel through a mathematical model. We divide the domain of computation into four sub-domains: the lumen, the lumen-tissue interface, the upper tissue and the lower tissue which are extracted from an asymmetric atherosclerotic image derived by the intravascular ultrasound (IVUS) technique. The injected drug at the luminal inlet is transported with the streaming blood which is considered Newtonian. An irreversible uptake kinetics of the injected drug at the lumen-tissue interface from the luminal side to the tissue domains is assumed. Subsequently, the drug is dispersed within the tissue followed by its retention in the extracellular matrix (ECM) and by receptor-mediated binding. The Marker and Cell (MAC) method has been leveraged to get a quantitative insight into the model considered. The effect of the wall absorption parameter on the concentration of all drug forms (free as well as two-phase bound) has been thoroughly investigated, and some other important factors, such as the averaged concentration, the tissue content, the fractional effect, the concentration variance and the effectiveness of drug have been graphically analyzed to gain a clear understanding of endovascular delivery. The simulated results predict that with increasing values of the absorption parameter, the averaged concentrations of all drug forms do decrease. An early saturation of binding sites takes place for smaller values of the absorption parameter, and also rapid saturation of ECM binding sites occurs as compared to receptor binding sites. Results also predict the influence of surface roughness as well as asymmetry of the domain about the centerline on the distribution and retention of drug. A thorough sensitivity analysis has been carried out to determine the influence of some parameters involved.

Electrical Signatures of Diffusion-Limited Mixing: Insights from a Milli-fluidic Tracer Experiment

We investigate how diffusion-limited mixing of a layered solute concentration distribution within a porous medium impacts bulk electrical conductivity. To do so, we perform a milli-fluidic tracer test by injecting a fluorescent and electrically conductive tracer in a quasi two-dimensional (2D) water-saturated porous medium. High resolution optical- and geoelectrical monitoring of the tracer is achieved by using a fluorimetry technique and equipping the flow cell with a resistivity meter, respectively. We find that optical and geoelectrical outputs can be related by a temporal re-scaling that accounts for the different diffusion rates of the optical and electrical tracers. Mixing-driven perturbations of the electrical equipotential field lines cause apparent electrical conductivity time-series, measured perpendicularly to the layering, to peak at times that are in agreement with the diffusion transport time-scale associated with the layer width. Numerical simulations highlight high sensitivity of such electrical data to the layers’ degree of mixing and their distance to the injection electrodes. Furthermore, the electrical data correlate well with time-series of two commonly used solute mixing descriptors: the concentration variance and the scalar dissipation rate.

Concentration Fluctuations of Single Particle Stochastic Lagrangian Model Assessment with Experimental Field Data

A single particle Lagrangian Stochastic model has been developed and applied with the purpose of simulating the concentration fluctuations dispersion. This model treats concentration variance as a quantity whose motion is driven by an advection-diffusion process so that it can be studied by a single particle model. A parameterization for both velocity standard deviations and Lagrangian time-scales is required as input to the model. The paper is focused on the estimation of the best parameterization needed to simulate both mean and standard deviation concentrations in a case study. We consider the FFT-07 field experiment. The trials took place at Dugway Proving Ground, UTAH (USA) and consist of a dispersion analysis of a gas emitted from a point-like source in different atmospheric conditions with a continuous emission technique. The very small spatial scales (a few hundred meters) and short duration (about 10 minutes) that characterize the trials make the comparison with model results very challenging, since traditional boundary layer parameterizations fail in correctly reproducing the turbulent field and, as a consequence, the dispersion simulation yields unsatisfactorily results. We vary the coefficients of the turbulence parameterization to match the small-scale turbulence. Furthermore, we show that the parameterization for the variance dissipation time-scale, already tested in neutral conditions, can be used also in stable and unstable conditions and in low-wind speed conditions. The model gives good results as far as mean concentration is concerned and rather satisfactory results for the concentration standard deviations. Comparison between model results and observation is shown through both statistical and graphical analyses.

A Statistical Method for Generating Temporally Downscaled Geochemical Tracers in Precipitation

Sampling intervals of precipitation geochemistry measurements are often coarser than those required by fine-scale hydrometeorological models. This study presents a statistical method to temporally downscale geochemical tracer signals in precipitation so that they can be used in high-resolution, tracer-enabled applications. In this method, we separated the deterministic component of the time series and the remaining daily stochastic component, which was approximated by a conditional multivariate Gaussian distribution. Specifically, statistics of the stochastic component could be explained from coarser data using a newly identified power-law decay function, which relates data aggregation intervals to changes in tracer concentration variance and correlations with precipitation amounts. These statistics were used within a copula framework to generate synthetic tracer values from the deterministic and stochastic time series components based on daily precipitation amounts. The method was evaluated at 27 sites located worldwide using daily precipitation isotope ratios, which were aggregated in time to provide low resolution testing datasets with known daily values. At each site, the downscaling method was applied on weekly, biweekly and monthly aggregated series to yield an ensemble of daily tracer realizations. Daily tracer concentrations downscaled from a biweekly series had average (+/- standard deviation) absolute errors of 1.69‰ (1.61‰) for δ2H and 0.23‰ (0.24‰) for δ18O relative to observations. The results suggest coarsely sampled precipitation tracers can be accurately downscaled to daily values. This method may be extended to other geochemical tracers in order to generate downscaled datasets needed to drive complex, fine-scale models of hydrometeorological processes.

EKSTRAKSI GELATIN DARI TULANG IKAN KAKAP PUTIH (Lates calcarifer) DENGAN ASAM HCl

Extraction of Gelatin from Fish White Bone (Lates Calcarifer) with HCl Concentration Variance Gelatin is a food added ingredient used in emulsifiers, thickeners, food stabilizers. Gelatin is a type of protein in the form of gel obtained from the denaturation of skin, bone and fish tissue collagen denaturation. The process of making gelatin from the bones of white snapper (Lates calcarifer) uses the HCl acid method with the parameters of yield, water content, ash content, and protein content. The immersion process carried out with varoius of HCl acid concentration 3%, 7% and 11%.The results show that the best value of% yield at a concentration of 7% of 1.90%, 10.16% water content. Ash content 3%. Protein content is 3.25%. FTIR spectrum revealed the presence of amida group at wave number 3269 cm-1, amide I; II; and Amida III sequentially at wave number 1656 cm-1; 1525.69 cm-1; 1161.15 cm-1.Keywords : Gelatin ; collagen ; Lates calcarifer ; FTIRABSTRAK Gelatin merupakan bahan tambah pangan yang digunakan dalam pengemulsi, pengental, penstabil makanan. Gelatin merupakan salah satu jenis protein yang berbentuk gel yang didapatkan dari hasil denaturasi kolagen kulit, tulang dan jaringan ikan. Proses ekstrak gelatin dari bahan tulang ikan kakap putih (Lates calcarifer) menggunakan asam HCl dengan parameter rendemen, kadar air, kadar abu, kadar protein dan analisis FTIR. Proses perendaman dilakukan variasi asam HCl 3%, 7% dan 11%. Dari hasil penelitian didapatkan nilai % rendemen tertinggi pada konsentrasi 7% sebesar 1,90%, dengan nilai kadar air 10,16%, kadar abu 3,00%, kadar protein 3,25%. Dari spektrum FTIR didapatkan gugus Amida A pada bilangan gelombang 3269 cm-1, amida I ; II ; dan amida III secara berturut-turut pada bilangan gelombang 1656 cm-1 ; 1525,69 cm-1 ; 1161,15 cm-1.Kata kunci : Gelatin ; ikan kakap putih ; FTIR

Dose Analysis of BNCT Treatment Method for Rhabdomyosarcoma in the Head and Neck Regions Based on PHITS Code

The objectives of this research were to ?nd (1) the optimum boron dose for treating rhab- domyosarcoma in the head and neck regions and (2) the effective irradiation time to treat rhab- domyosarcoma in the head and neck regions. This research used the particle and heavy ions transport code system (PHITS) to simulate the neutron source and BNCT doses. The neutron source used was Kartini Reactor. The simulation was carried out by creating the geometry of cancer tissue in the head and neck regions. Boron concentration variance was 30, 35, 40, 45, and 50 µg/g tissue. The output of PHITS was a neutron ?ux and neutron dose. The neutron ?ux value was used to acquire the alpha dose, proton dose, and gamma dose inside the tissue. The results showed that (1) the optimum boron dose for treating rhabdomyosarcoma in the head and neck regions was 50 µg/g tissue and (2) the effective irradiation time was 7 hours and 4 minutes, which was acquired with a boron concentration of 50 µg/g tissue. The higher the boron concentration level, the higher the dose rate, the quicker the irradiation time, and the lower the radiation dose received by healthy tissues.

Indoor Comfort and Symptomatology in Non-University Educational Buildings: Occupants’ Perception

The indoor environment in non-university classrooms is one of the most analyzed problems in the thermal comfort and indoor air quality (IAQ) areas. Traditional schools in southern Europe are usually equipped with heating-only systems and naturally ventilated, but climate change processes are both progressively increasing average temperatures and lengthening the warm periods. In addition, air renewal is relayed in these buildings to uncontrolled infiltration and windows’ operation, but urban environmental pollution is exacerbating allergies and respiratory conditions among the youth population. In this way, this exposure has a significant effect on both the academic performance and the general health of the users. Thus, the analysis of the occupants’ noticed symptoms and their perception of the indoor environment is identified as a potential complementary tool to a more comprehensive indoor comfort assessment. The research presents an analysis based on environmental sensation votes, perception, and indoor-related symptoms described by students during lessons contrasted with physical and measured parameters and operational scenarios. This methodology is applied to 47 case studies in naturally ventilated classrooms in southern Europe. The main conclusions are related to the direct influence of windows’ operation on symptoms like tiredness, as well as the low impact of CO2 concentration variance on symptomatology because they usually exceeded recommended levels. In addition, this work found a relationship between symptoms under study with temperature values and the environmental perception votes, and the special impact of the lack of suitable ventilation and air purifier systems together with the inadequacy of current thermal systems.

Subsurface reactivity dominates regional patterns of riverine nitrate concentration variability

<p>The mean surface water concentration and the concentration variance of nutrients are major water quality characteristics of catchments that directly relates to exported nutrient loads and ecosystems functioning. The mean concentration reflects nutrient input, discharge (Q) and retention within different compartments of the catchment. The concentration variability defines the export regime of a certain solute and can be characterized by the ratio of CV<sub>C</sub> and CV<sub>Q</sub> and the slope <em>b </em>of the logC-logQ relationship. Recent explorative modelling studies argue that the export regime is shaped by spatial variance of the solute source in the catchment and by the subsurface reactivity (Musolff et al. 2017, Zhi et al. 2019). Here, we seek large scale evidence of this hypothesis by analyzing nitrate concentration and discharge (C-Q) time series in more than 1400 catchments across France and Germany. We found a consistent relationship between mean nitrate concentrations and the fraction of cultivated area within the catchments pointing to agriculture as the dominant nitrate source. The upper boundary of this relationship follows an exponential function with catchments showing mean nitrate concentrations around this envelope function being characterized by chemostatic export regimes with low concentration variance and slope <em>b</em> near zero. In contrast, catchments deviating from this relationship i.e. with lower than expected mean nitrate concentrations are characterized by higher concentration variance and steep, positive logC-logQ slopes. We argue, that subsurface retention is the major control of this behavior: i.e., effective denitrification decreases groundwater nitrate concentration. This was mainly observed in catchments with sedimentary aquifers and low topographic slopes. Here, old water components in the catchment storage that dominate discharge under low flow conditions are low in nitrate. Under high flow conditions, young water components high in nitrate concentrations are activated. Catchments without effective nitrate retention are characterized by a low concentration gradient between younger and older water components. The observed relationship between the fraction of cultivated areas, mean nitrate concentration and export regime was found to be surprisingly consistent across the wide range of hydroclimatic conditions, geology and topography. In consequence, steeply positive logC-logQ slopes can be used as indicators of effective subsurface reactivity. Future work will further elucidate the catchment characteristics that favor effective denitrification.</p><p>References</p><p>Musolff, A., Fleckenstein, J.H., Rao, P.S.C., Jawitz, J.W., 2017. Emergent archetype patterns of coupled hydrologic and biogeochemical responses in catchments. Geophys Res Lett, 44(9): 4143-4151. DOI:10.1002/2017GL072630</p><p>Zhi, W., Li, L. Dong, W.M., Brown, W., Kaye, J., Steefel, C., Williams, K.H., 2019. Distinct Source Water Chemistry Shapes Contrasting Concentration-Discharge Patterns. Water Resour Res, 55(5): 4233-4251. DOI:10.1029/2018wr024257</p>

Effectiveness of Cocoa (Theobroma Cacao L.) Seed Extract on the Growth of in Vitro Malassezia Furfur

ABSTRACT Background: Pityriasis versicolor or Tinea versicolor is a skin disease caused by the Malassezia furfur which is often found in Indonesia. People can use anti-fungal drugs to treat this disease. However, long-term use of anti-fungal drugs is relatively more expensive and can have side effects for its users. Cocoa bean husk contains flavonoids, saponins, and alkaloids which have anti-fungal effects. This study aimed to determine the antifungal effectiveness of the cocoa bean husk extract on the growth of M. furfur. Subjects and Methods: This was an experimental study using cocoa bean husk extract with a concentration variance of 25%, 50%, 75%, 100%, with a positive control for ketoconazole 2% and a negative control using distilled water. The test was carried out by the well diffusion method using Sabouraud Dextrose Agar media. The inhibition of fungal growth was calculated by looking at the clear zone formed after 48 hours. Data were analyzed using Kruskal-Wallis and Post hoc Mann Whitney statistical tests. Results: The mean diameter of the inhibition zone at a concentration of 25%, 50%, 75% and 100% was 3.42 mm, 4.07 mm, 4.9 mm, and 7.3 mm, respectively, and it was statistically significant (p = 0.001). Conclusion: Cocoa bean husk extract has weak anti-fungal effectiveness at concentrations of 25%, 50%, and 75%, while at 100% it has moderate effectiveness. Keywords: antifungal, Pityriasis versicolor, cocoa bean shell, well diffusion, Malassezia furfur Correspondence: Yuni Setyaningsih. Department of Parasitology, Faculty of Medicine, Universitas Pembangunan Nasional “Veteran” Jakarta. DOI: https://doi.org/10.26911/the7thicph.05.01