Internal Manifold Research Articles

(Invited) Shunt-currents in Alkaline Water-Electrolyzers and Renewable Energy

Shunt-currents in bipolar cell stack design with a common electrolyte-feed and -outlet is an inevitable physical phenomenon governed by Ohms law that causes some extra challenges when alkaline water-electrolysers shall operate on renewable energy that is both dynamic and intermittent. Shunt-currents are also referred to as bypass-current or creep-current. The shunt-currents are to much degree governed by the electrolyte inside the cell stack manifold system that transports lye in and out of the cells. The electrolyte inside the manifold system also electrically connects the individual cells together and enables transport of ions/electricity in parallel to the cell stack. Thus, a small portion of the rectifier current is being shunted outside the cells and does not contribute to any production. Previous work on shunt-current modelling brought new insight on how to design the manifolds and raised the awareness on shunt-current and the use of metallic manifolds which both reduced the ohmic resistivity of the manifold system and was a source of secondary electrolysis.Classic alkaline water-electrolysers are typically using an internal manifold system where the inlet ports are located at the bottom of the cell stack and the outlet ports are located at the top, and where the ports connecting the cell-interior and the common manifold channel are short and straight. Such design has in the past worked satisfactory for alkaline water-electrolysers that have been working on a high nominal load and only being shut-down for maintenance a few times over the stack-lifetime, mainly causing a modest reduction in the current efficiency. Membrane-chlorine electrolysers on the other hand, are designed for very small shunt-currents by using an external manifold system, which enables a current protection system that protects electrodes from corrosion under shutdown conditions.Shunt-currents bypassing the cell stack does not contribute to any product and therefore constitutes a loss in current efficiency and, hence, an accordingly loss in the energy efficiency (the shunt-currents still adds to the electricity bill). The atmospheric alkaline electrolyser has a modest loss in current efficiency at nominal load where the high gas volume blocks much of the current path in the rather open outlet ports. The high-pressure alkaline electrolysers on the other hand, where the gas volumes are much smaller, the current efficiency can be as low as 89% at nominal load due to shunt-currents when using simple internal manifold system. For an electrolyser with already low current efficiency at the nominal load, the current efficiency will drop dramatically as the electrolyser is taken to lower load, severely compromising the energy efficiency. The impact on shunt-currents also dramatically increases for increased number of cells in a cell stack, and eventually limits the number of cells that can be assembled in one single cell stack operating on the same common lye system.Shutdown and discharge of the electrodes may further lead to corrosion and degradation of the electrodes, strongly influenced by the shunt-currents and the manifold system. Large cell stacks will discharge faster and deeper, eventually causing corrosion of the electrodes. As the cell stack is discharged the current in the cell stack is reversed where the hydrogen electrode is being polarized to anodic potentials, and the oxygen electrode is polarized to low cathodic potentials which eventually may challenging the material stability. Thus, evaluation of electrode potentials must be an integral part of development of industrial electrodes [LeRoy] and especially in intermittent operation where frequent shutdown will occur. A good integration of the manifold system into the cell stack can potentially mitigate both the loss of current efficiency under dynamic operation and the electrode corrosion under intermittent operation.

D-terms in generalised complex geometry

Generalised Complex Geometry provides a natural interpretation of the N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 1 supersymmetry conditions for warped solutions of type II supergravity as differential equations on polyforms on the internal manifold. Written in this language the supersymmetry conditions correspond to calibration conditions for probe D-branes: D-string, domain-wall or space-filling branes, depending on the directions they span in the non-compact four-dimensional space. The BPS condition corresponding to the calibration of space-filling D-branes has been reformulated by Tomasiello, eliminating the explicit dependence on the metric. We generalise this derivation to the case of non-supersymmetric backgrounds violating the domain-wall and D-string calibration conditions. We use this reformulation to derive constraints that the ten-dimensional solutions with BPS space-filling sources must respect in order to dimensionally reduce to solutions of four-dimensional N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 1 supergravity with non-vanishing F-terms and potentially non-vanishing D-terms. We give the equations of motion for the class of type II vacua satisfying these constraints in the language of pure spinors. We investigate how restrictive these constraints are for the class of type IIB SU(3) backgrounds with BPS space-filling O5-planes.

Subleading analysis for S3 partition functions of N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 2 holographic SCFTs

We investigate the 3-sphere partition functions of various 3d N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 2 holographic SCFTs arising from the N stack of M2-branes in the ’t Hooft limit both analytically and numerically. We first employ a saddle point approximation to evaluate the free energy F = – log Z at the planar level, tracking the first subleading corrections in the large ’t Hooft coupling λ expansion. Subsequently, we improve these results by determining the planar free energy to all orders in the large λ expansion via numerical analysis. Remarkably, the resulting planar free energies turn out to take a universal form, supporting a prediction that these S3 partition functions are all given in terms of an Airy function even beyond the special cases where the Airy formulae were derived analytically in the literature; in this context we also present new Airy conjectures in several examples. The subleading behaviors we captured encode a part of quantum corrections to the M-theory path integrals around dual asymptotically Euclidean AdS4 backgrounds with the corresponding internal manifolds through holographic duality.

Development and calibration of a fast flow model for solid oxide cell stack internal manifolds

Due to the commercialization of solid oxide cells (SOC) progressing at an accelerated pace, computationally inexpensive SOC models adapted to the iterative nature of the engineering process are in increasing demand. Flow simulation in the stack is especially challenging in this regard because detailed computational fluid mechanic models are computationally demanding, while simplified models rely on pressure loss coefficients and friction factors not readily available in the literature. In this study, a computationally inexpensive algebraic model of an SOC stack internal manifold is developed and calibrated for laminar flow conditions. Thereby, pressure loss coefficients and Darcy friction factors are determined for a broad range of operating conditions through symbolic regression of Navier–Stokes flow simulation results of stacks of 20 to 40 cells. The derived Darcy friction factors for the inlet and outlet manifolds prove to be of particular importance, as they deviate strongly from the expressions assumed in similar modeling studies. The predictive power of the developed model is demonstrated by providing accurate predictions of the flow distribution in the stack, even outside of the calibration window.

G-structures for black hole near-horizon geometries

We derive necessary and sufficient conditions for warped AdS2 solutions of Type II supergravity to preserve N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 1 supersymmetry, in terms of bispinors. Such solutions generically support an SU(3)-structure on their internal manifold M8, which can experience an enhancement to a G2-structure. We perform an SU(3)-structure torsion classes analysis and express the fluxes and other physical fields in terms of these, in general. We use our results to derive two new classes of AdS2 solutions. In (massive) Type IIA supergravity we derive an N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 1 supersymmetric class for which M8 decomposes as a weak G2-manifold foliated over an interval and which is locally defined in terms of a degree three polynomial. In Type IIB supergravity we find a class of AdS2 × S2 × CY2 × Σ2 solutions preserving small N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 4 supersymmetry, governed by a harmonic function on Σ2 and partial differential equations reminiscent of D3-D7-brane configurations.

Cobordism and bubbles of anything in the string landscape

We study bubble of nothing decays and their reverse processes, the creation of vacua through ‘bubbles of something’, in models of the Universe based on string theory. From the four-dimensional perspective, the corresponding gravitational instantons contain an end-of-the-world (ETW) boundary or brane, realized by the internal manifold shrinking to zero size. The existence of such ETW branes is predicted by the Cobordism Conjecture. We develop the 4d EFT description of such boundaries at three levels: first, by generalizing the Witten bubble through an additional defect. Second, by replacing the compact S1 with a Calabi-Yau orientifold and allowing it to shrink and disappear through a postulated defect. Third, we describe an ETW brane construction for type IIB Calabi-Yau orientifold compactifications with O3/O7 planes through an appropriate additional O5 orientifolding. Our 4d EFT formalism allows us to compute the decay/creation rates for bubbles of anything depending on two parameters: the size of the relevant defect and its tension a.k.a. the induced (generalized) deficit angle.

On exceptional QP-manifolds

The connection between two recent descriptions of tensor hierarchies — namely, infinity-enhanced Leibniz algebroids, given by Bonezzi & Hohm and Lavau & Palmkvist, and the p-brane QP-manifolds constructed by Arvanitakis — is made precise. This is done by presenting a duality-covariant version of latter.The construction is based on the QP-manifold T⋆[n]T[1]M × ℋ[n], where M corresponds to the internal manifold of a supergravity compactification and ℋ[n] to a degree-shifted version of the infinity-enhanced Leibniz algebroid. Imposing that the canonical Q-structure on T⋆[n]T[1]M is the derivative operator on ℋ leads to a set of constraints. Solutions to these constraints correspond to 12\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\frac{1}{2} $$\\end{document}-BPS p-branes, suggesting that this is a new incarnation of a brane scan. Reduction w.r.t. to these constraints reproduces the known p-brane QP-manifolds. This is shown explicitly for the SL(3)×SL(2)- and SL(5)-theories.Furthermore, this setting is used to speculate about exceptional ‘extended spaces’ and QP-manifolds associated to Leibniz algebras. A proposal is made to realise differential graded manifolds associated to Leibniz algebras as non-Poisson subspaces (i.e. not Poisson reductions) of QP-manifolds similar to the above. Two examples for this proposal are discussed: generalised fluxes (including the dilaton flux) of O(d, d) and the 3-bracket flux for the SL(5)-theory.

A 4D IIB flux vacuum and supersymmetry breaking. Part II. Bosonic spectrum and stability

We recently constructed type-IIB compactifications to four dimensions depending on a single additional coordinate, where a five-form flux Φ on an internal torus leads to a constant string coupling. Supersymmetry is fully broken when the internal manifold includes a finite interval of length ℓ, which is spanned by a conformal coordinate in a finite range 0 < z < zm. Here we examine the low-lying bosonic spectra and their classical stability, paying special attention to self-adjoint boundary conditions. Special boundary conditions result in the emergence of zero modes, which are determined exactly by first-order equations. The different sectors of the spectrum can be related to Schrödinger operators on a finite interval, characterized by pairs of real constants μ and μ~\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\overset{\\sim }{\\mu } $$\\end{document}, with μ equal to 1/3 or 2/3 in all cases and different values of μ~\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\overset{\\sim }{\\mu } $$\\end{document}. The potentials behave as μ2−1/4z2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\frac{\\mu^2-1/4}{z^2} $$\\end{document} and μ~2−1/4zm−z2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\frac{{\\overset{\\sim }{\\mu}}^2-1/4}{{\\left({z}_m-z\\right)}^2} $$\\end{document} near the ends and can be closely approximated by exactly solvable trigonometric ones. With vanishing internal momenta, one can thus identify a wide range of boundary conditions granting perturbative stability, despite the intricacies that emerge in some sectors. For the Kaluza-Klein excitations of non-singlet vectors and scalars the Schrödinger systems couple pairs of fields, and the stability regions, which depend on the background, widen as the ratio Φ/ℓ4 decreases.

Neutralizing topological obstructions to bubbles of nothing

Theories with compact extra dimensions can exhibit a vacuum instability known as a bubble of nothing. These decay modes can be obstructed if the internal manifold is stabilized by fluxes, or if it carries Wilson lines for background gauge fields, or if the instanton is incompatible with the spin structure. In each of these cases the decay can proceed by adding dynamical charged membranes or gauge fields. We give a general, bottom-up procedure for constructing approximate bubble of nothing solutions in models with internal spheres stabilized by flux and study the influence of the brane tension on the tunneling exponent, finding two branches of solutions that merge at a minimal superextremal value of the tension. In the case of Wilson operators and incompatible fermions, the relevant bubble is shown to be the Euclidean Reissner-Nordstrom black hole, and the ordinary decay exponent is modified by 1/g2 effects. We examine the Dirac operator on this background and comment on the relevance for models of supergravity with gauged R-symmetry.

Robust Exponential Graph Regularization Non-Negative Matrix Factorization Technology for Feature Extraction

Graph regularized non-negative matrix factorization (GNMF) is widely used in feature extraction. In the process of dimensionality reduction, GNMF can retain the internal manifold structure of data by adding a regularizer to non-negative matrix factorization (NMF). Because Ga NMF regularizer is implemented by local preserving projections (LPP), there are small sample size problems (SSS). In view of the above problems, a new algorithm named robust exponential graph regularized non-negative matrix factorization (REGNMF) is proposed in this paper. By adding a matrix exponent to the regularizer of GNMF, the possible existing singular matrix will change into a non-singular matrix. This model successfully solves the problems in the above algorithm. For the optimization problem of the REGNMF algorithm, we use a multiplicative non-negative updating rule to iteratively solve the REGNMF method. Finally, this method is applied to AR, COIL database, Yale noise set, and AR occlusion dataset for performance test, and the experimental results are compared with some existing methods. The results indicate that the proposed method is more significant.

Spin 2 spectrum for marginal deformations of 4d mathcal{N} = 2 SCFTs

We compute spin 2 spectrum associated with massive graviton fluctuations in γ-deformed Gaiotto-Maldacena background those are holographically dual to marginal deformations of mathcal{N} = 2 SCFTs in four dimensions. Under the special circumstances, we analytically estimate the spectra both for the γ-deformed Abelian T dual (ATD) as well as the non-Abelian T dual (NATD) cases where we retain ourselves upto leading order in the deformation parameter. Our analysis reveals a continuous spectra which is associated with the breaking of the U(1) isometry (along the directions of the internal manifold) in the presence of the γ-deformation. We also comment on the effects of adding flavour branes into the picture and the nature of the associated spin 2 operators in the dual mathcal{N} = 1 SCFTs.

Smearing and unsmearing KKLT AdS vacua

Gaugino condensation on D-branes wrapping internal cycles gives a mechanism to stabilize the associated moduli. According to the effective field theory, this gives rise, when combined with fluxes, to supersymmetric AdS4 solutions. In this paper we provide a ten-dimensional description of these vacua. We first find the supersymmetry equations for type II AdS4 vacua with gaugino condensates on D-branes, in the framework of generalized complex geometry. We then solve them for type IIB compactifications with gaugino condensates on smeared D7-branes. We show that supersymmetry requires a (conformal) Calabi-Yau manifold and imaginary self-dual three-form fluxes with an additional (0,3) component. The latter is proportional to the cosmological constant, whose magnitude is determined by the expectation value of the gaugino condensate and the stabilized volume of the cycle wrapped by the branes. This confirms, qualitatively and quantitatively, the results obtained using effective field theory. We find that exponential separation between the AdS and the KK scales seems possible as long as the three-form fluxes are such that their (0,3) component is exponentially suppressed. As for the localized solution, it requires going beyond SU(3)-structure internal manifolds. Nevertheless, we show that the action can be evaluated on-shell without relying on the details of such complicated configuration. We find that no “perfect square” structure occurs, and the result is divergent. We compute the four-fermion contributions, including a counterterm, needed to cancel these divergences.

Critical points of warped AdS/CFT and higher-curvature gravity

WAdS/WCFT correspondence is an interesting realization of non-AdS holography. It relates 3-dimensional Warped-Anti-de Sitter (WAdS$_3$) spaces to a special class of 2-dimensional quantum field theory with chiral scaling symmetry that acts only on right-moving modes. The latter are often called Warped Conformal Field Theories (WCFT$_2$), and their existence makes WAdS/WCFT particularly interesting as a tool to investigate a new type of 2-dimensional conformal structure. Besides, WAdS/WCFT is interesting because it enables to apply holographic techniques to the microstate counting problem of non-AdS, non-supersymmetric black holes. Asymptotically WAdS$_3$ black holes (WBH$_3$) appear as solutions of topologically massive theories, Chern-Simons theories, and many other models. Here, we explore WBH$_3\times \Sigma_{D-3}$ solutions of $D$-dimensional higher-curvature gravity, with $\Sigma_{D-3}$ being different internal manifolds, typically given by products of deformations of hyperbolic spaces, although we also consider warped products with time-dependent deformations. These geometries are solutions of the second order higher-curvature theory at special (critical) points of the parameter space, where the theory exhibits a sort of degeneracy. We argue that the dual (W)CFT at those points is actually trivial. In many respects, these critical points of WAdS$_3 \times \Sigma_{D-3}$ vacua are the squashed/stretched analogs of the AdS$_D$ Chern-Simons point of Lovelock gravity.

Introduction to Mirror Symmetry in Aspects of Topological String Theory

Under the compactification by the Calabi-Yau threefold, the string theory shows there is duality called mirror symmetry, which implies there is an isomorphism between two string theories under the compactifications of two topologically different internal manifolds. By twisting the topological string theory in two methods, the twisted theories named A-model and B-model have an isomorphism to each other under the mirror symmetry.

Light stringy states and the g − 2 of the muon

In this work, we evaluate the contributions to the anomalous magnetic moment of the muon ((g − 2)μ) coming from light stringy states in a D-brane semi-realistic configuration. A scalar which couples only to the muon can have a mass sufficiently light to provide a significant contribution to the (g − 2)μ. This scenario can arise in intersecting D-brane models, where such light scalars correspond to the first stringy excitations of an open string stretched between two D-branes intersecting with a very small angle. In this article, we show that there is a region in the space of the geometric parameters of the internal manifold where such scalar light stringy states can explain (part) of the observed discrepancy in the (g − 2)μ. In a low string scale framework with Ms ≳ 10 TeV, we show that an excited Higgs with mass mathcal{O} (250 MeV), living in an intersection with an angle of order mathcal{O} (10−10), can provide a significant contribution of one-tenth of the (g − 2)μ discrepancy. This leads to a lower bound for the compact dimension where the branes intersect of order mathcal{O} (10−8 GeV−1). We also study patterns in D-brane configurations that realize our proposal, both in three and four stacks models.

Deep manifold regularized semi-nonnegative matrix factorization for Multi-view Clustering

With the development and application of modern technology, multi-view data exists widely. The deep matrix factorization model is widely used because it mines the hierarchical information of the samples, but it lacks a geometric structure protection mechanism. Moreover, in multi-view representation learning, strong representations have consensus from multi-view data and are more likely to exist in the structural relationships of data objects. To address these issues, we propose Deep Manifold Regularized Semi-Nonnegative Matrix Factorization for Multi-view Clustering (DMRMF_MVC), which preserves the geometric structure of data objects through multi-layer embedding graph regularization. The graph regularizer combines the nearest neighbor relationship with the exclusive relationship of data objects to express the internal manifold structure of the data fully. Furthermore, to distinguish the value of each view data, the adaptive weight is associated with representation learning to maximize the complementarity between the views. Extensive experimental results show that DMRMF_MVC outperforms other state-of-the-art algorithms based on multiple indicators on various datasets.

Supersymmetric dS4 solutions in D = 11 supergravity

The necessary and sufficient conditions for warped product dS4 solutions in D = 11 supergravity to be supersymmetric are determined. The Killing spinor is associated with two possible stabilizer groups, SU(3) and G2. We show that there are no solutions to the Killing Spinor equations in the G2 stabilizer case. For the SU(3) stablilzer case, all of the conditions imposed from supersymmetry on the 4-form flux, and the geometry of the internal manifold, are determined in terms of SU(3) invariant spinor bilinears.

Refined topological amplitudes from the Ω-background in string theory

It was recently shown that the mathcal{N} = 2 string topological amplitudes in the heterotic weak coupling limit generate a six-dimensional Melvin space, providing a description of the Ω-background in string theory, where string propagation can be exactly studied. In this work, we generalise the analysis to the refined case of the Ω-background with two independent deformation parameters. The Melvin space is now ten-dimensional and is extended by an action on the internal K3 compactification manifold of the heterotic superstring, corresponding to an SU(2)R rotation in the field theory description. We identify the class of heterotic topological amplitudes realising this background as the scattering of two anti-self-dual gravitons and arbitrary numbers of anti-self-dual graviphotons, self-dual vector fields of the dilaton multiplet, together with self-dual magnetic fluxes along the K3. In the field theory limit, our result correctly reproduces the perturbative part of the Nekrasov free energy in the case where both equivariant parameters are turned on.

Defining Internal Tissue Closure: High-Resolution Ultrasound Evaluation of Interi-A Novel Internal Tissue Closure System.

Seroma remains a leading postsurgical complication in plastic surgery. Conventional drains are ineffective in clearing blood and fluid and closing down surgical spaces. The Interi (Internal Closure System, IC Surgical, Grand Rapids, MI) is comprised of a novel branching internal manifold attached to a self-contained portable pump with a higher, consistent, continuous negative pressure, may reduce this long-standing issue. In addition, high-resolution ultrasound (HRUS) has emerged as an ideal tool to visualize structures, fluid collections, and seromas internally. This study evaluates Interi in full abdominoplasty patients utilizing HRUS to evaluate Interi's ability to evacuate blood and fluid, hold internal tissues together and document, for the first time, what internal tissue healing actually looks like radiographically. An IRB approved, Contract Research Organization reviewed retrospective study evaluated consecutive patients undergoing full abdominoplasty utilizing Interi from July 2020 through March 2021 by three plastic surgeons. HRUS visualized and confirmed the presence or absence of fluid collections and healing tissue planes during the postoperative process. Study data and all adverse events were recorded, with HRUS images reviewed by investigators and confirmed by an independent radiologist. Seventy-one Interi patients were enrolled. Mean age was 43 (range: 21-74) and BMI was 28. Seroma was confirmed clinically and through HRUS in 3/71 patients, and was associated with either clot (2) or failure to activate system (1). Interi's ability to eliminate fluid and approximate/hold surgical tissue planes together was confirmed with HRUS. No other major complications, including abscess, hematomas, or flap necrosis were observed. This novel Internal Tissue Closure System effectively evacuated blood and fluid, approximated and maintained closure of internal tissue planes in abdominoplasty patients, allowing for primary tissue healing and internal wound closure to occur. Healing tissue planes and any fluid present are easily identified on HRUS visualizing actual internal tissue healing with a simple, widely available radiographic scan.

Developing Shunt-Current Minimized Soluble-Lead-Redox-Flow-Batteries

Shunt currents in membrane-less soluble-lead-redox-flow-batteries (SLRFB) are observed in open-circuit condition and found to depend on size of the stack, manifolds, flow rates and charge/discharge parameters. Ramifications of shunt currents on the performance of membrane-less SLRFB stacks with internal and external manifolds are reported. In the case of stacks with 3, 5 and 7-cells and internal manifold design, the charge current for the middle cell decreases by 3.3%, 6%, and 8.5%, while the discharge current increases by 2.6%, 5.5%, and 6.6%, respectively, for 3 A charge/discharge current. By contrast, no such adverse effect is observed for external manifold design. The current—potential studies show that while the stacks comprising 3 and 5-cells deliver a maximum power density of 35 mW cm−2, which declines to 15 mW cm−2 for the 7-cell stack with internal manifold design, while the power density remains invariant at 50 mW cm−2 for stacks with external manifold design. An 8-cell stack of 12 V, 50 mAh/cm2 specific capacity and 273 Wh energy storage capacity with 64% energy efficiency is also reported which shows good cyclability over 100 cycles with 95% coulombic efficiency when cycled at 20 mA cm−2 current density for 1 h duration.