Developmental Competence of Oocytes Derived from Seasonally Anovulatory Mares Treated with Estradiol and Sulpiride

Over the course of two years (2021-2022), two experiments were conducted during the nonbreeding seasons to evaluate the in vitro developmental potential of oocytes derived from seasonally anovulatory mares treated with ECP-sulpiride. The objective of experiments 1 and 2 were to compare pooled recovery and maturation rates of oocytes from mares treated with estradiol cypionate (ECP) and sulpiride with oocytes collected from naturally transitional mares (controls). Cleavage rates of oocytes subjected to intracytoplasmic sperm injection (ICSI) were compared only in experiment 2. In experiments 1 and 2, a total of 36 light horse and pony-cross anovulatory mares were used. Treatment was administered intramuscularly and consisted of 50 mg ECP followed by 3 g sulpiride (n = 18) in sucrose acetate isobutyrate (SAIB), while controls received vehicle only (n = 18). Jugular blood samples were collected prior to treatment and continued daily for 12 days in order to characterize plasma LH and prolactin concentrations. All mares were subjected to ovum pick up (OPU) when the first 30 mm follicle of the season was detected. All follicles ≥ 8 mm were targeted for OPU and aspirates from three follicle diameter categories (8-19 mm, 20-29 mm, and \u3e 30 mm) were pooled within treatment groups. In experiments 1 and 2, 7/7 and 10/11 ECP-sulpiride treated mares responded within 15 days of treatment. Mean day to first 30 mm follicle of ECP-sulpiride treated mares was advanced in experiments 1 (P = 0.005) and 2 (P = 0.0007) by 23 and 19 days, respectively. In both experiments, plasma prolactin and LH increased (P ≤ 0.0001) in all mares treated with ECP-sulpiride for at least 7-10 days after treatment. The recovery and maturation rates of oocytes from ECP-sulpiride and vehicle only treated mares did not differ (41.6 vs 45%; P = 0.77 and 55.6 vs 65.4%; P = 0.47, respectively) and there was no significant effect on follicle diameter. Cleavage rates of oocytes subjected to ICSI did not differ between ECP-sulpiride and vehicle only treated mares (71.4 vs 61.3%; P = 0.99, respectively)

A new open-source PEMFC simulation tool for easy assessment of material parameterizations

After almost three decades of PEM fuel cell modelling, there is a large need for standardization and establishment of a common basis in the development of PEMFC models, not only for numerical simulation purposes, but also to test and validate MEA material parameterizations from experimental measurements. Until recently, there were only two open-source codes capable of simulating the state of the art in PEMFC modeling at the scale of single cells or MEAs: OpenFCST, a rather heavy FEM package consisting of more than 120 000 lines of C++ code (not counting library dependencies), and FAST-FC, a finite volume tool built on top of OpenFOAM, consisting of about 12 000 lines of code (not counting the required OpenFOAM). Albeit highly capable, these tools require significant effort and programming know-how to be set up and modified, and they are not well suited for easy substitution of material parameterizations or extensive parameter studies in sufficiently short computation times. We have recently developed the first open standalone MATLAB implementation of a full-blown, steady-state, non-isothermal, macro-homogeneous two-phase MEA model for low-temperature PEM fuel cells. It implements the most dominant through-plane transport processes in a 5-layer membrane electrode assembly: the transport of charge, energy, gas species and water. With a focus on code simplicity, compactness, portability, transparency, accessibility and free availability, our program is an ideal candidate for the assessment of new material parameterizations that may originate e.g. from experimental data. Thanks to the very short runtime of just a few seconds on an ordinary PC, extensive parameter studies and quick substitution of modeling assumptions or material properties are now possible with our tool without requiring deep programming knowledge or compilation of large software libraries. We demonstrate how the program may be used to quantitatively understand and evaluate PEM fuel cell material properties or measurement data

Experimental parameter uncertainty in PEM fuel cell modeling. Part I: Scatter in material parameterization

Ever since modeling has become a mature part of proton exchange membrane fuel cell (PEMFC) research and development, it has been plagued by significant uncertainty lying in the detailed knowledge of material properties required. Experimental data published on several transport coefficients are scattered over orders of magnitude, even for the most extensively studied materials such as Nafion membranes, for instance. For PEMFC performance models to become predictive, high-quality input data is essential. In this bipartite paper series, we determine the most critical transport parameters for which accurate experimental characterization is required in order to enable performance prediction with sufficient confidence from small to large current densities. In the first part, a macro-homogeneous two-phase membrane-electrode assembly model is furnished with a comprehensive set of material parameterizations from the experimental and modeling literature. The computational model is applied to demonstrate the large spread in performance prediction resulting from experimentally measured or validated material parameterizations alone. The result of this is a ranking list of material properties, sorted by induced spread in the fuel cell performance curve. The three most influential parameters in this list stem from membrane properties: The Fickean diffusivity of dissolved water, the protonic conductivity and the electro-osmotic drag coefficient.Comment: 19 pages, 8 figures, 10 table

Free open reference implementation of a two-phase PEM fuel cell model

In almost 30 years of PEM fuel cell modeling, countless numerical models have been developed in science and industrial applications, almost none of which have been fully disclosed to the public. There is a large need for standardization and establishing a common ground not only in experimental characterization of fuel cells, but also in the development of simulation codes, to prevent each research group from having to start anew from scratch. Here, we publish the first open standalone implementation of a full-blown, steady-state, non-isothermal two-phase model for low-temperature PEM fuel cells. It is based on macro-homogeneous modeling approaches and implements the most essential through-plane transport processes in a five-layer MEA. The focus is on code simplicity and compactness with only a few hundred lines of clearly readable code, providing a starting point for more complex model development. The model is implemented as a standalone MATLAB function, based on MATLAB's standard boundary value problem solver. The default simulation setup reflects wide-spread commercially available MEA materials. Operating conditions recommended for automotive applications by the European Commission are used to establish new fuel cell simulation base data, making our program a valuable candidate for model comparison, validation and benchmarking.Comment: 13 pages, 7 figures, 7 table

Experimental parameter uncertainty in PEM fuel cell modeling. Part II: Sensitivity analysis and importance ranking

Numerical modeling of proton exchange membrane fuel cells is at the verge of becoming predictive. A crucial requisite for this, though, is that material properties of the membrane-electrode assembly and their functional dependence on the conditions of operation are known with high precision. In this bipartite paper series we determine the most critical transport parameters for which accurate experimental characterization is required in order to enable the simulation of fuel cell operation with sufficient confidence from small to large current densities. In Part II, we employ the two-phase model developed in Part I to carry out extensive forward uncertainty propagation analyses. These include the study of local parameter sensitivity in the vicinity of a baseline parameter set, and a global sensitivity analysis in which a broad range of operating conditions and material properties is covered. A comprehensive ranking list of model parameters is presented, sorted by impact on predicted fuel cell properties such as the current-voltage characteristics and water balance. The top five in this list are, in this order: The membrane hydration isotherm, the electro-osmotic drag coefficient, the membrane thickness, the water diffusivity in the ionomer and its ionic conductivity.Comment: 9 pages, 5 figures, 4 table

Negative time delay for wave reflection from a one-dimensional semi-harmonic well

It is reported that the phase time of particles which are reflected by a one-dimensional semi-harmonic well includes a time delay term which is negative for definite intervals of the incoming energy. In this interval, the absolute value of the negative time delay becomes larger as the incident energy becomes smaller. The model is a rectangular well with zero potential energy at its right and a harmonic-like interaction at its left.Comment: 6 pages, 5 eps figures. Talk presented at the XXX Workshop on Geometric Methods in Physics, Bialowieza, Poland, 201

Integrated Geothermal Well Testing: Test Objectives and Facilities

A new and highly integrated geothermal well test program was designed for three geothermal operators in the US (MCR, RGI and Mapco Geothermal). This program required the design, construction and operation of new well test facilities. The main objectives of the test program and facilities are to investigate the critical potential and worst problems associated with the well and produced fluids in a period of approximately 30 days. Field and laboratory investigations are required to determine and quantify the problems of fluid production, utilization and reinjection. The facilities are designed to handle a flow rate from a geothermal well of one million pounds per hour at a wellhead temperature of approximately 268 C (515 F). The facilities will handle an entire spectrum of temperature and rate conditions up to these limits. All pertinent conditions for future fluid exploitations can be duplicated with these facilities, thus providing critical information at the very early stages of field development. The new well test facilities have been used to test high temperature, liquid-dominated geothermal wells in the Imperial Valley of California. The test facilities still have some problems which should be solvable. The accomplishments of this new and highly integrated geothermal well test program are described in this paper

Non-commutative desingularization of determinantal varieties, I

We show that determinantal varieties defined by maximal minors of a generic matrix have a non-commutative desingularization, in that we construct a maximal Cohen-Macaulay module over such a variety whose endomorphism ring is Cohen-Macaulay and has finite global dimension. In the case of the determinant of a square matrix, this gives a non-commutative crepant resolution.Comment: 52 pages, 3 figures, all comments welcom