Modelling and dynamic simulation of struvite precipitation from source-separated urine

A model of a mixed-mode nutrient recovery reactor is developed for a urine feed, incorporating complex solution thermodynamics, dynamic conservation relations and a power-law kinetic expression for crystal growth from seed crystals. Simulations at nominal operating conditions predict phosphorus recoveries greater than 99%, based on existing process kinetic parameters and operating conditions employed in previously published studies. The overall rate of nutrient recovery depends on the saturation index of the precipitating solid, the available surface area for mass transfer and the feed rate of the limiting constituent ion. Under the conditions considered, the nutrient feed rate appears to be the limiting factor for precipitation. Simulations demonstrate that diurnal feed flow variations of ±50% have a small effect on the rate of nutrient recovery. Overall, the study shows that valuable insights are gained in relation to process performance predictions, which should lead to more confident process design, operation and control

Mechanical properties and cytotoxic evaluation of the Ti-3Nb-13Zr alloy

Ti-13Nb-13Zr is a new titanium alloy that was originally developed for medical implant applications. This alloy combines a low elastic modulus, high strength, excellent hot and cold workability, and superior corrosion resistance. Research on this alloy has shown that the mechanical properties can be controlled over a significant range through hot working, heat treatment and cold-working. The present study describes the mechanical properties and cytotoxic evaluation of the Ti-13Nb-13Zr alloy, which was produced by furnace arc melting in argon atmosphere. The elemental constituents were unalloyed Ti, Nb and Zr sheets. The obtained ingots, which initial diameter were about 15 mm, have undergone sequences of cold-working and heat treatments in order to achieve a final diameter of 6 mm. The tensile strength of Ti-13Nb-13Zr achieved 1270 MPa (cold-worked – 60% reduction in area) and 860 MPa after heat treatment (60% reduction in area + 1000 o C/1h + water quenched). The elastic module were 52 GPa and 60 GPa respectively. Furthermore, the toxic effect of this alloy on cells was evaluated by a cytotoxicity test, a quantitative method of colony suppression assay using Chinese Hamster Ovary (CHO) cultured cells in contact with diluted extracts of the biomaterials. The results showed that Ti-13Nb-13Zr alloy obtained by furnace arc melting isn’t cytotoxic.Peer Reviewe

Prime ideals in nilpotent Iwasawa algebras

Let G be a nilpotent complete p-valued group of finite rank and let k be a field of characteristic p. We prove that every faithful prime ideal of the Iwasawa algebra kG is controlled by the centre of G, and use this to show that the prime spectrum of kG is a disjoint union of commutative strata. We also show that every prime ideal of kG is completely prime. The key ingredient in the proof is the construction of a non-commutative valuation on certain filtered simple Artinian rings

The Effects of Milk Protein Polymorphisms on Milk Components and Cheese-Producing Ability

Abstract A Total of 2005 first lactation Holstein-Friesian cows with known 305-d lactation yield for milk, fat, and protein were available. For each cow, genotypes for α s1 -casein, β-casein, κ-casein, and β-lactoglobulin were known. It appears that the milk protein variants α s1 -casein, β-casein, and κ-casein may not be segregating independently. Effects of genetic variants of milk proteins on estimated individual Parmesan cheese yields were investigated. The relationships of the genetic variants of milk proteins to total lactation milk yield, fat yield, protein yield, fat percentage, and protein percentage were also investigated. Least squares analysis of the data indicated that α s1 -casein genotype significantly influenced milk yield, fat yield, and protein yield with the highest yields obtained for the genotype BB . Cheese yield on a fixed amount of milk and fat percentage were significantly related to β-lactoglobulin genotype with the highest estimates obtained for BB . Protein percentage was influenced by α s1 -casein and κ-casein, with the genotypes BC and BB , respectively, having the highest percentages. Significantly higher lactation cheese yields were estimated with α s1 -casein genotype BB . Using the prediction equation to estimate cheese yield (on data from another study), it was found that differences in Parmesan cheese yield from milk of either κ-casein genotype AA or BB were greater than expected based on composition. Differences in salted curd yield from another study using milk of either β-lactoglobulin genotype AA or BB were also greater than expected

Unambiguous 1-Uniform Morphisms

A morphism h is unambiguous with respect to a word w if there is no other morphism g that maps w to the same image as h. In the present paper we study the question of whether, for any given word, there exists an unambiguous 1-uniform morphism, i.e., a morphism that maps every letter in the word to an image of length 1.Comment: In Proceedings WORDS 2011, arXiv:1108.341

Physical and chemical properties of the groundwater of the Santo Domingo-Salinas ranges, South Central Pyrenees

The Santo Domingo-Salinas ranges represent a unique Natural Area in the south-central Pyrenees, and they were declarationas a Protected Landscape in 2015. Available biological and geological knowledge is extensive but lacks of information on groundwater quality. In this work we provide new hydrogeological results and integrate them with previously available hydrogeological data. To do so, we have: (i) compiled existing hydrogeological information, (ii) exhaustively developed an inventory of water points, (iii) sampled, analyzed and interpreted the hydrochemical facies detected, and (iv) developed a preliminary conceptual model for the hydrogeological functioning of the area. These information has been integrated in an map that displays the chemical analyses of the two new campaigns (Stiff diagrams), the flow rates and the three aquifer systems defined. This new information improves and synthetizes the knowledge of the hidrogeology of the Santo Domingo-Salinas ranges Protected Landscape and it will help in its future management and planning

Differential Effects of the Mitochondria-Active Tetrapeptide SS-31 (D-Arg-dimethylTyr-Lys-Phe-NH₂) and Its Peptidase-Targeted Prodrugs in Experimental Acute Kidney Injury.

The mitochondria-active tetrapeptide SS-31 can control oxidative tissue damage in kidney diseases. To investigate other potential beneficial nephroprotective effects of SS-31, in vivo murine models of acute tubular injury and glomerular damage were developed. Reduction of acute kidney injury was demonstrated in mice treated with SS-31. The expression of mRNAs involved in acute inflammatory and oxidative stress responses in the diseased kidneys confirmed that SS-31 could regulate these pathways in our in vivo models. Furthermore, ex vivo histoenzymography of mouse kidneys showed that aminopeptidase A (APA), the enzyme involved in the processing of angiotensin (Ang) II to Ang III, was induced in the diseased kidneys, and its activity was inhibited by SS-31. As the renin-angiotensin system (RAS) is a main regulator of kidney functions, the modulation of Ang receptors (ATR) and APA by SS-31 was further investigated using mRNAs extracted from diseased kidneys. Following acute tubular and/or glomerular damage, the expression of the AT <sub>1</sub> R mRNA was upregulated, which could be selectively downregulated upon SS-31 administration to the animals. At the same time, SS-31 was able to increase the expression of the AT <sub>2</sub> R, which may contribute to limit renal damage. Consequently, SS-31-based prodrugs were developed as substrates and/or inhibitors for APA and were screened using cells expressing high levels of APA, showing its selective regulation by α-Glu-SS-31. Thus, a link between SS-31 and the RAS opens new therapeutic implications for SS-31 in kidney diseases

Coherent states for Hopf algebras

Families of Perelomov coherent states are defined axiomatically in the context of unitary representations of Hopf algebras possessing a Haar integral. A global geometric picture involving locally trivial noncommutative fibre bundles is involved in the construction. A noncommutative resolution of identity formula is proved in that setup. Examples come from quantum groups.Comment: 19 pages, uses kluwer.cls; the exposition much improved; an example of deriving the resolution of identity via coherent states for SUq(2) added; the result differs from the proposals in literatur

Justification of the coupled-mode approximation for a nonlinear elliptic problem with a periodic potential

Coupled-mode systems are used in physical literature to simplify the nonlinear Maxwell and Gross-Pitaevskii equations with a small periodic potential and to approximate localized solutions called gap solitons by analytical expressions involving hyperbolic functions. We justify the use of the one-dimensional stationary coupled-mode system for a relevant elliptic problem by employing the method of Lyapunov--Schmidt reductions in Fourier space. In particular, existence of periodic/anti-periodic and decaying solutions is proved and the error terms are controlled in suitable norms. The use of multi-dimensional stationary coupled-mode systems is justified for analysis of bifurcations of periodic/anti-periodic solutions in a small multi-dimensional periodic potential.Comment: 18 pages, no figure