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Methane Production from Farmed Rainbow Trout Byproducts by Anaerobic Digestion in Morocco

Essalhi Fatima, Bengueddour Rachid

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 2

45--54

EN

Fish are a staple in human nutrition because of their great nutritional and dietetic value. The processing stages of these fish before being sold generates an important quantity of byproducts (head, viscera, skeleton, fins, scales, tail, and skin). This study aims to determine the methane production, methanogenic potential and the percentage of volatile solids removed by the anaerobic digestion process. The experiment was carried out at mesophilic conditions in a Continuous Stirred-Tank Reactor (CSTR) with a discontinuous feeding mode (batch). The results obtained showed that the byproducts of farmed rainbow trout have a maximum methane production 1176 Nml whose methanogenic potential is 206.68 Nml/gVS with a biodegradability equal to 57.95%. For the kinetic modeling, four models were applied for an adequate fit of the experimental results (first order, MGompertz, transfererence function, and logistic function). The production of methane closest to the experimental results is that estimated by the logistic function with a methanogenic potential of 212.21 Nml/gVS whose correlation coefficient R2= 0.9870 and a very low percentage of error (1.18%), also the MGompertz model presented results adapted to those of the experiment with a methanogenic potential equal to 223.61 Nml/gVS (R2= 0.9889 and %error = 2.95); This confirms that these two kinetic models are the most suitable for this type of substrate.

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Modeling of insulin secretion and insulin mass balance during hemodialysis in patients with and without type 2 diabetes

Schneditz Daniel, Niemczyk Longin, Niemczyk Stanislaw

Biocybernetics and Biomedical Engineering

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2021

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Vol. 41, no. 2

391--401

EN

Background: The secretion, distribution, and elimination of insulin in response to a bolus of glucose injected during regular hemodialysis was modeled to quantify the intra-dialytic mass balance of glucose and insulin in patients without (D0) and with type 2 diabetes (D1). Methods: A two-compartment regional blood flow model with shared compartments and dynamics for glucose, insulin and c-peptide was used to identify parameters of insulin and c-peptide co-secretion, first- and second-pass hepatic insulin extraction, as well as insulin-independent and insulin-dependent glucose utilization. Experimental data from a previous study obtained in 21 D0 and 14 D1 were used to identify kinetic model parameters and the fractions of glucose and insulin removed by dialysis. Results: Modeled gains for insulin secretion (ß1 = 0.015 vs. 0.084 L/min, ß2 = 0.004 vs. 0.666 L) were lower in D1, resulting in a lower total insulin secretion (Mi = 6.40 vs. 38.0 nmol). Hepatic insulin extraction was high (Eihep = 0.558 vs. 0.638) and only slightly smaller in D1. The fraction of insulin removed by dialysis (Fid = 0.07 vs. 0.05) was small and comparable between D1 and D0. Modeled gains for insulin-dependent glucose uptake (γ = 0.38 vs. 1.34 L2/nmol/min) were lower whereas those for insulin-independent glucose uptake (λ = 0.14 vs. 0.067 L/min) were higher in D1. The fraction of glucose removed by dialysis (Fgd = 0.31 vs. 0.28) was higher in D1. Conclusion: Apart from expected differences in modeled secretion and glucose utilization in patients with and without diabetes an intravenous bolus of glucose causes only small differences in overall glucose and insulin balance during a typical hemodialysis treatment.

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Poliuretany - Przegląd 60-letniego rozwoju ich syntezy i zastosowań

Król P.

Polimery

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2009

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T. 54, nr 7-8

489-500

PL

W artykule stanowiącym przegląd literatury dotyczący rozwoju technologii z dziedziny poliuretanów (PUR) w ciągu 60. ostatnich lat omówiono zagadnienia, już dziś historyczne, związane z otrzymywaniem surowców - diizocyjanianów i dioli - oraz klasycznych wielkocząsteczkowych związków poliuretanowych, takich jak elastomery i pianki. Przedstawiono syntezę PUR metodą stopniowej poliaddycji wraz z jej modelowaniem kinetycznym a także proces reaktywnego formowania elastomerów poliuretanowych. Zaprezentowano najnowsze technologie obejmujące wytwarzanie ekologicznych wodnych klejów i lakierów PUR opartych na dyspersjach wodnych typu jonomerów oraz sposoby otrzymywania kopolimerów uretanowo-akrylowych i uretanowo-siloksanowych typu core-shell. Podano także kilka przykładów najnowszych zastosowań PUR (wytrzymałe mechanicznie nanokompozyty, biozgodne materiały medyczne lub ciekłokrystaliczne materiały dla elektroniki i optyki). Zasygnalizowano problem zagospodarowania odpadów poliuretanowych.

EN

The article is a review of development of polyurethanes (PUR) technologies during past 60 years. The problems, now being historical, concerning the preparation of raw materials: diisocyanates and diols (Scheme A) and classical macromolecular polyurethane compounds such as elastomers or foams (Fig. 1, 6) were discussed. PUR synthesis via gradual polyaddition (Fig. 2, 3), its kinetic modeling (Fig. 4, Table 1) and the process of reactive molding of polyurethane elastomers (Fig. 5) were presented. The newest technologies concerning the preparation of ecological PUR adhesives and varnishes based on ionomer type aqueous dispersions and the methods of production of core-shell type urethane-acrylic or urethane-siloxane copolymers are described. Selected examples of new applications of PUR are given: mechanically stable nanocomposites, biocompatible materials for medicine, liquid crystalline materials for electronics and optics. The problem of PUR waste management was mentioned (Fig. 7).

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Uproszczony przepływowy model hemodializy - porównanie z klasycznym modelem dwuprzedziałowym

Korohoda P.

Automatyka / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie

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2009

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T. 13, z. 3/1

1129-1140

PL

W artykule zaproponowano uproszczoną strukturę modelu przepływowego hemodializy, zbliżoną do klasycznego modelu dwuprzedziałowego. W celu przeprowadzenia obliczeń porównawczych umożliwiających ocenę przydatności nowego modelu opracowano metodykę pseudolosowego generowania danych symulujących zabieg dializy. Dla wytworzonego w ten sposób zbioru danych testowych, N — 1000 wykazano, iż oba modele - proponowany i klasyczny - wykazują podobną zdolność odtwarzania zadanych przebiegów stężeń. Dla opisanych wyżej danych wyznaczono zależność między najważniejszymi parametrami obu modeli, wykazując możliwość ich łatwego przeliczania. Wskazano jednak także na pewne różnice w przebiegach uzyskanych za pomocą obu modeli, co stanowi uzasadnienie dalszego badania modeli przepływowych.

EN

In the paper a simplified blood flow model of hemodialysis is sugested, being a modified version of the classical two-compartment model. A method of pseudorandom hemodialysis data generation has been designed to enable relevant comparative study of both models. For such test data, N = 1000, it has been shown that the flow model has very similar capability of modeling the concentration runs, as the classical two-compartment model. For the randomly generated data, the mutual relationship between the crucial model parameters has been shown. Such property makes the convertion between discussed models very simple. However, some differences in the runs obtained from both models were also indicated, which encourages further investigation of the blood-flow models.

5

Mathematical models for evaluation, optimization, and control of artificial kidney therapy

Waniewski J.

Journal of Medical Informatics & Technologies

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2002

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Vol. 3

IP27--39

EN

Renal replacement therapy involves the control of body pools of water and electrolytes, and removal of small metabolites (urea, creatinine). The correct estimation of "the dose of therapy" and optimisation of the procedure needs quantification of fluid and solute transport during dialysis as well as evaluation of the distribution and exchange of water and solutes within the body. Mathematical models can combine the general physiological knowledge with information about individual patients yielded by clinical measurements. Many of these models (urea model, sodium model, models of peritoneal transport) have been presented to the community of clinical nephrologists in the form of computer programs often supplemented with on-line measuring devices. However, the debate about their meaning and the search for better methods of their application are still vivid.