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Conducting polymers offer the ability to create electronic devices that are lightweight with relatively simple processing compared to their inorganic counterparts. They have recently gained attention in the wearable electronics field due their ability to exhibit flexibility and low stiffness while conducting electricity. However, conducting polymers are not intrinsically flexible and must be modified, usually at the expense of electrical performance, or through the use of expensive and toxic additives. Here, we explore the use of architected materials to tune a conductive polymer's mechanical properties without chemical modification. To do so, a reliable and high-throughput 3D printing system for a conducting polymer-based hydrogel was established. The system utilizes a stereolithography apparatus (SLA) to 3D print a hydrogel of almost any 3D shape. The hydrogel acts as a dopant and structural component for a subsequently grown conducting polymer. This means a conducting polymer, which is usually limited to being a thin film or a stochastic foam, can be made into specific and complex geometries, enabling the tailoring of its mechanical properties through architecture, without compositing or chemical modification. When architected into a lattice, the conducting polymers can withstand compressive strain up to 80% without failure, whereas their bulk counterpart reaches just 25% strain before undergoing brittle fracture. The architected conducting polymers also exhibit a strain rate invariant stress-strain curve, suggesting that a potential strain rate invariant electrical resistance behavior may exist, but further investigation is required.

We employ the Stroh octet formalism to develop a real-form expression of the Coulomb force acting on a line charge in an anisotropic piezoelectric bimaterial. The Coulomb force is derived using two different approaches and is expressed in terms of the generalized Barnett–Lothe tensors for the two piezoelectric half-spaces. Interestingly, we find that the Coulomb force is independent of the orientation of the bimaterial interface provided that the interface is parallel to the $$x_{3}$$ -axis and the distance between the charge and the interface remains unchanged. The Coulomb force on a line charge in a piezoelectric half-space with a rigid conducting surface or a traction-free insulating surface is deduced from the Coulomb force for two jointed piezoelectric half-spaces. In the case of a rigid conducting surface, we find that the Coulomb force always tends to attract the line charge to the surface. This is in contract to the case of a traction-free insulating surface for which we find that the Coulomb force can be either repulsive or attractive due to the piezoelectric effect.

Koncentracijo monoklonskih protiteles (mAb) in fuzijskih proteinov lahko določamo z različnimi bioanalitskimi metodami in napravami. Med slednjimi afinitetna tekočinska kromatografija visoke ločljivosti (HPLC) velja za zlati standard. Ker je pridobivanje rezultatov s HPLC zelo zamudno, so se na trgu začele pojavljati številne alternativne visokozmogljive bioanalitske metode in naprave. Mednje lahko uvrstimo naprave družine Cedex, kjer določanje koncentracije produkta poteka z metodo imunske turbidimetrije, in Octet, ki temelji na interferometriji bioloških plasti, ter metodo ValitaTiter, s katero koncentracijo mAb in fuzijskih proteinov določamo na podlagi sprememb v polarizaciji svetlobe. Namen magistrske naloge je bil raziskati odstopanja med meritvami na HPLC in preostalimi visokozmogljivimi metodami oziroma napravami. Poleg tega smo želeli preveriti, ali proces ločevanja produktov od večjih nečistoč in zamrzovanje vzorcev vplivata na meritve naprav Cedex Bio HT. Za proučevanje potencialnega vpliva strukture molekul rekombinantnih proteinov na razlike med meritvami naprav, smo v eksperiment vključili štiri celične linije CHO, ki proizvajajo IgG1, IgG2, IgG4 in Fc-fuzijski protein. Tekom 14-dnevne produkcijske faze je potekalo dnevno vzorčenje bioprocesnih brozg. Ugotovili smo, da zamrzovanje vzorcev in postopek primarnega ločevanja nimata vplivata na meritve koncentracije produktov in da je odstopanje meritev na preučevanih visokozmogljivih napravah od meritev na HPLC predvsem odvisno od koncentracije produkta v vzorcu, umeritvenih krivulj ter od strukture rekombinantnega proteina. Med vsemi preučevanimi napravami oziroma metodami smo največje ujemanje s HPLC zabeležili pri analizatorju Octet QK. The concentration of monoclonal antibodies (mAbs) and fusion proteins can be determined by various bioanalytical methods and devices. Among these, affinity high-performance liquid chromatography (HPLC) is considered as the gold standard. As obtaining HPLC results can be very time-consuming, many high-performance alternatives have started to appear on the market. These include the Cedex family of analysers, where product concentration measurements are based on immunoturbidimetry, Octet analysis systems, which are based on bio-layer interferometry, and ValitaTiter IgG quantification assay, which detects changes in light polarization. The purpose of the master’s thesis was to investigate possible discrepancies in measurements between the before-mentioned high-throughput alternatives and HPLC. In addition, we wanted to check whether the separation of the product from larger impurities and whether the freezing of samples affects the measurements of Cedex Bio HT devices. To study the potential influence of recombinant protein molecule structures on device measurements, four CHO cell lines producing IgG1, IgG2, IgG4, and Fc-fusion protein were included in the experiment. During the 14-day production phase, daily sampling of bioprocess slurries took place. We found that the primary separation process and the freezing of the samples prior to analysis does not affect product concentration measurements and that deviations between measurements mainly depend on product concentration, calibration curves, and the structure of the recombinant protein. Among all studied devices or methods, the lowest discrepancies from HPLC were observed on the Octet QK analyser.

Octet-truss lattice materials have excellent potential for use as lightweight structures due to their high strength and stiffness, but low relative density. Octet-truss lattice specimens fabricated...

Herein new lattice unit cells with buckling load 261–308% higher than the classical octet unit cell were reported. Lattice structures have been widely used in sandwich structures as lightweight core. While stretching dominated and bending dominated cells such as octahedron, tetrahedron and octet have been designed for lightweight structures, it is plausible that other cells exist which might perform better than the existing counterparts. Machine learning technique was used to discover new optimal unit cells. An 8-node cube containing a maximum of 27 elements, which extended into an eightfold unit cell, was taken as representative volume element (RVE). Numerous possible unit cells within the RVE were generated using permutations and combinations through MATLAB coding. Uniaxial compression tests using ANSYS were performed to form a dataset, which was used to train machine learning algorithms and form predictive model. The model was then used to further optimize the unit cells. A total of 20 optimal symmetric unit cells were predicted which showed 51–57% higher capacity than octet cell. Particularly, if the solid rods were replaced by porous biomimetic rods, an additional 130–160% increase in buckling resistance was achieved. Sandwich structures made of these 3D printed optimal symmetric unit cells showed 13–35% higher flexural strength than octet cell cored counterpart. This study opens up new opportunities to design high-performance sandwich structures.

In the past, the axion-nucleon coupling has been calculated in the framework of SU(2) heavy baryon chiral perturbation theory up to third order in the chiral power counting. Here, we extend these earlier studies to the case of heavy baryon chiral perturbation theory with SU(3) flavor symmetry and derive the axion coupling to the full SU(3) baryon octet, showing that the axion also significantly couples to hyperons. As studies on dense nuclear matter suggest the possible existence of hyperons in stellar objects such as neutron stars, our results should have phenomenological implications related to the so-called axion window., Comment: 45 pages, 1 figure

LHC provides a chance to study the physical processes of γγ collision and γ p collision mode by adding a forward detector. In this paper, we investigate J/ψ-pair photoproduction in NRQCD framework at the LHC with γγ collision mode. We calculate the contributions from ${~}^{3}S_{1}^{1}$ , ${~}^{3}S_{1}^{(8)}$ , ${{~}^{1}}S_{0}^{(8)}$ , ${~}^{3}P_{J}^{(8)}$ Fock states, and find that contribution from the colour octet ${{~}^{1}}{S_{0}^{8}}$ ${~}^{3}P_{J}^{(8)}$ and ${~}^{3} P_{J}^{(8)}{~}^{3}P_{J}^{(8)}$ channels dominates this process with forward detector acceptance 0.0015 < ξ

Designing crashworthy components requires a special structural configuration that provides effective crushing deformation to absorb crash impact energy. Recent developments in crash impact energy absorption for crashworthy components include thin wall structures, honeycomb structures, and metallic foam sandwich structures. The honeycomb and metallic foam structures appear to have high specific energy absorption capability. However, both structural configurations have a shortcoming, i.e. honeycomb structures only have the unidirectional capability, while the metallic foam structures have highly irregular (random) three-dimensional cell configuration. The advanced development of additive manufacturing has paved the way for the developments of complicated geometry that will support the development of crashworthy components in the form of lattice structures. The lattice structures provide both three-dimensional and regular structural configurations that are able to absorb crash impact energy efficiently. Therefore, lattice structures have excellent potential to be used for energy management of crash impact structures. Eleven types of lattice configurations were examined to determine the highest specific energy absorption capability, i.e. kagome, tetrahedron, pyramid, cube, truncated-pyramid, octahedron, rhombicuboctahedron, rhombic dodecahedron, open-cell, and octet lattice structures. Numerical analysis and design optimization were performed on a single cell unit of each lattice configuration. It was found that the optimum lattice configuration for crashworthy components was the octet lattice structure. Further topology optimization of the octet lattice configuration resulted in an optimum solution of the octet structure in the form of a twisted octet lattice structure. The twisted lattice structure with 20% relative density was able to generate the highest specific energy absorption. A case study on an aircraft subfloor surface structures showed that the twisted lattice structure was able to absorb aircraft grounding impact energy efficiently. General buckling failure in the twisted lattice structure can be avoided by using a tapered configuration. This tapered lattice structure has a high potential to provide specific energy absorption of up to 127 kJ/kg. These results show the potential applicability of the lattice structure for aircraft crashworthy components.

Rh2O n + (n = 2-10) species are prepared by the reaction of the laser-ablated rhodium atoms with oxygen; furthermore, they are characterized by employing time-of-flight mass spectroscopy. To reveal the stable electronic structure, in this study, we performed the density functional theory calculations for the possible isomers of Rh2O7 +. A total of 29 geometries were obtained including cyclic Rh2O3, cyclic Rh2O2, and ring-opening structures with doublet, quartet, sextet, and octet states. It is noteworthy that no Rh-Rh bond was observed for all the optimized Rh2O7 + isomers including oxides, peroxides, superoxides, and oxygen groups. The optimized geometries were also confirmed to exhibit minimum structural energies by employing harmonic frequency analysis at the same energy level. Generally, two types of oxygen-bridged geometries were discovered with cyclic and pseudo-linear Rh2O7 +, which contained one or more than one O2 groups. It is concluded that the cyclic structure comprises a lower energy than that observed in pseudo-linear structures. In addition, Rh2O7 + tends to be unstable when the coordination groups change from O2 to O2 - unit. Finally, the localized orbital bonding analysis indicates that Rh has oxidation states of 1 or 2 in cyclic Rh2O7 + structures; this is true even in the presence of O2-, O2 -, and O2 2- groups.

The remarkable progress in additive manufacturing has promoted the design of architected materials with mechanical properties that go beyond those of conventional solids. Their realization, however, leads to architectures with process-induced defects that can jeopardize mechanical and functional performance. In this work, we investigate experimentally and numerically as-manufactured defects in Ti–6Al–4V octet truss lattice materials fabricated with selective laser melting. Four sets of as-manufactured defects, including surface, microstructural, morphological, and material property imperfections, are characterized experimentally at given locations and orientations. Within the characterized defects, material property and morphological defects are quantified statistically using a combination of atomic force microscopy and micro–computed tomography to generate representative models that incorporate individual defects and their combination. The models are used to assess the sensitivity to as-manufactured defects. Then, the study is expanded by tuning defects amplitude to elucidate the role of the magnitude of as-designed defects on the mechanical properties of the lattice material.

Cellular materials, often called lattice materials, are increasingly receiving attention for their ultralight structures with high specific strength, excellent impact absorption, acoustic i...

The present work exemplifies complementary perspectives offered by the band and bond pictures of solids, with an emphasis on the chemical intuition pertaining to the latter, especially in the presence of interfaces. The modern computational method of constructing a unique set of maximally localized Wannier functions from delocalized band states imparts new interpretations to the familiar concept of chemical bonds in the context of crystalline solids. By bridging the band and bond pictures using advanced computational tools, we reveal for the first time the unusual bond characters of a long-predicted fivefold coordinated structure of binary octet compounds ANB8−N consisting of AA′ stacked planar AB honeycombs. While the isolated monolayer retains the familiar pz–π bonding in a honeycomb framework as in graphene and hexagonal boron nitride, the bulk foregoes in-plane π bonding and embraces out-of-plane ⋯A–B–A–B⋯ chain bonding via overlapping pz orbitals. Not only does the chemical intuition gained by invoking the bond picture clarify the chemical nature of the fivefold coordination, but it also facilely explains a salient discrepancy in theoretical predictions in otherwise sound ample experimental evidence in the form of epitaxial thin films, paving the way towards rational synthesis of such thin films for optoelectronic applications. On the other hand, we show that the conduction band minimum, important in determining the electrical and optical properties, is a distinctly extended state that can only be properly described within the band picture., A refreshed view of chemical bonds in solids unveils unusual bonding in fivefold coordinated bulk crystals of octet compounds: out-of-plane cation–anion chain bonding via overlapping pz orbitals replaces in-plane π bonding of the isolated monolayer.

Unlike the octet baryons for $N_f=3$, there is no skyrmion coming from the $\eta^\prime$ meson. It is instead described as a fractional quantum Hall droplet, a pancake or a pita involving a singular $\eta^\prime$ ring in which Chern-Simons fields live. By incorporating hidden local symmetry and hidden scale symmetry in nuclear dynamics, I describe how to access baryon-charged quantum Hall droplets in dense nuclear matter in terms of the nuclear scale-chiral effective field theory approach ``G$n$EFT" with the $U_A(1)$ anomaly taken into account. I discuss how the single-flavor baryon that I will call ${\cal B}^s$ could be exposed in superdense baryonic matter, figuring, perhaps, in ``quark stars" associated with the baryon-quark continuity involving CFL or phase transitions., Comment: 8 pages, no figures

Additively manufactured lattice truss structures, often referred to as architected cellular materials, present significant advantages over conventional structures due to their unique characteristics such as high strength-to-weight ratios and surface area-to-volume ratios. These geometrically complex structures, however, come with concomitant challenges for qualification and inspection. In this study, compression testing interrupted with micro-computed tomography inspection was conducted to monitor the evolution of global and local deformation throughout the loading process of 304 L stainless steel octet truss lattice structures. Both two- and three-dimensional image analysis techniques were leveraged to characterize geometric heterogeneities resulting from the laser powder bed fusion manufacturing process as well as track the structure throughout deformation. Variations from model-predicted behavior resulting from these heterogeneities are considered relative to the predicted and actual responses of the structures during compression to better understand, model, and predict the octet truss lattice structure compression response.

We present a calculation of the $\mathrm{cos}(2{\ensuremath{\phi}}_{h})$ asymmetry in $J/\ensuremath{\psi}$ production in electron-proton collisions at the future electron-ion collider (EIC), a useful channel to probe the transverse momentum dependent gluon distribution functions also known as gluon transverse momentum dependent parton distributions (TMDs). The dominant subprocess for the $J/\ensuremath{\psi}$ production is the virtual-photon-gluon fusion process ${\ensuremath{\gamma}}^{*}+g\ensuremath{\rightarrow}J/\ensuremath{\psi}+g$. The production of $J/\ensuremath{\psi}$ is calculated in the nonrelativistic quantum chromodynamics framework with the inclusion of both color singlet and color octet contributions. Numerical estimates of the $\mathrm{cos}(2{\ensuremath{\phi}}_{h})$ asymmetry are given in the kinematical region to be accessed by the future EIC. The asymmetry depends on the parametrization of the gluon TMDs, as well as on the long distance matrix elements. We use both Gaussian-type parametrization and the McLerran-Venugopalan model for the TMDs in the kinematical region of small $x$, where the gluons play a dominant role. The asymmetry may be useful to probe the ratio of the linearly-polarized and the unpolarized gluon distribution in the proton.

Designing a suitable scaffold matching the mechanical properties of natural bones to optimize the bone regeneration is required in bone tissue engineering. The present work developed a single-parameter design method for the octet truss topological scaffold to achieve the accurate prediction and flexible adjustment of its Young’s modulus and strength. A theoretical model that formulated the normalized Young’s modulus and normalized yield strength of the octet truss scaffold by the single parameter (d/O) was proposed and further validated by uniaxial compression tests and FEA simulations. On the basis of the proposed model, the Young's modulus and yield strength of the octet truss scaffold made of different polymers with different d/O were mapped, and the ranges of suitable d/O that match the different natural cancellous bones were suggested. The results showed that the design method could accurately predict the porosity, specific area, normalized Young’s modulus and normalized yield strength, and adjust the mechanical properties of the scaffold in a wide range. The present work can be used for the design of scaffolds and the selection of constituent materials to obtain a suitable scaffold with desired mechanical properties, and has application prospects in the fields of bone tissue engineering and regenerative medicine.

Hierarchical lattices are structures composed of self-similar or dissimilar architected metamaterials that span multiple length scales. Hierarchical lattices have superior and tunable properties when compared to conventional lattices, and thus, open the door for a wide range of material property manipulation and optimization. Using finite element analysis, we investigate the energy absorption capabilities of 3D hierarchical lattices for various unit cells under low strain rates and loads. In this study, we use fused deposition modeling (FDM) 3D printing to fabricate a dog bone specimen and extract the mechanical properties of thermoplastic polyurethane (TPU) 85A with a hundred percent infill printed along the direction of tensile loading. With the numerical results, we observed that the energy absorption performance of the octet lattice can be enhanced four to five times by introducing a hierarchy in the structure. Conventional energy absorption structures such as foams and lattices have demonstrated their effectiveness and strengths, this research aims at expanding the design domain of energy absorption structures by exploiting 3D hierarchical lattices. The result of introducing a hierarchy to a lattice on the energy absorption performance is investigated by varying the hierarchical order from a first-order octet to a second-order octet. In addition, the effect of relative density on the energy absorption is isolated by creating a comparison between a first-order octet lattice with an equivalent relative density as a second-order octet lattice. The compression behaviors for the second order octet, dodecahedron, and truncated octahedron are studied. The effect of changing the cross-sectional geometry of the lattice members with respect to the energy absorption performance is investigated. Changing the orientation of the second-order cells from 0 to 45 degrees has a considerable impact on the force–displacement curve, providing a 20% increase in energy absorption for the second-order octet. Analytical solutions of the effective elasticity modulus for the first- and second-order octet lattices are compared to validate the simulations. The findings of this paper and the provided understanding will aid future works in lattice design optimization for energy absorption.

We perform an analysis of $J/\psi$ decays into octet baryons using the QCD factorisation framework. All decay amplitudes are calculated within the effective field theory approach. The subleading amplitude, which describes the decay of longitudinally polarised charmonia, is obtained for the first time using higher twist three-quark distribution amplitudes. A qualitative analysis of the experimental data is performed. It is found that the polarisation parameter $\alpha_B$ can be described with an accuracy $10-30\%$, which indicates that the pQCD contribution provides the dominant part for this observable.

Capture-to-translocation dynamics control is an important issue for single-particle and -molecule analyses by resistive pulse waveforms. Here, we report on regulated motions for accurate zeta-potential assessments of single nanoscale objects passing through an octet-nanochannel. We observed ionic spike signals consisting of eight consecutive sub-pulses signifying the ion blockage at the eight sensing zones in series upon electrophoretic translocation of individual nanoparticles. We find an exponential decrease to saturation of the channel-to-channel translocation duration as a nanobead moves forward, reflecting the more restricted radial motion degrees of freedom via inertial effects at the downstream side of the octet channel. This finding enabled a protocol for single-nanoparticle zeta potential estimation impervious to the uncertainty stemming from the stochastic nature of the translocation dynamics. The multi-channel approach presented in this study may be used as a useful tool for analyzing particles and molecules of variable sizes.

Purpose This paper aims to present a multiscale fuzzy optimization (FO) method to optimize both the density distribution and macrotopology of a uniform octet-truss lattice structure. Design/methodology/approach The design formulae for the strut radii are presented based on the effective mechanical properties obtained from the representative volume element. The proposed basic lattice material is applied in a normalization process to determine the material model with penalization. The solid isotropic material with penalization (SIMP) method is extended to solve the minimum compliance problem using the optimality criteria. The evolutionary deletion process is proposed to delete elements corresponding to thin-strut unit cells and to obtain the optimal macrotopology. Findings Both numerical cases indicate that the FO results significantly improved in structural performance compared with the results of the conventional SIMP. The deleting threshold controls the macrotopology of the graded-density lattice structures with negligible effects on the mechanical properties. Originality/value This paper presents one of the first multiscale optimization methods to optimize both the relative density and macrotopology of uniform octet-truss lattices. The material model and corresponding optimality criteria of octet-truss lattices are proposed and implemented in the optimization.

This article contrasts the normal method for drawing Lewis structures with a two-step systematic approach. The latter approach uses a known molecular connectivity and a knowledge of the number of valence electrons that each atom possesses to visualize bonds that are formed by pairing electrons, one from each atom. This process is repeated until at least one of the non-hydrogen atoms in each bond has an octet. Donor bonds are added when atoms with six and eight electrons are adjacent. In forming donor bonds charges are added to the atoms involved to maintain electron accounting and there is no need to use a formula to calculate formal charges. The general importance of adhering to the octet rule for p-block compounds is stressed and the difference between covalent and donor bonds and the use of the recent IUPAC definition of oxidation state which is based on Lewis structures is included in the discussion. When students are able to draw Lewis structures they can be given access to PC software, available on an academic free basis, which will draw rotatable Lewis structures in 3D for p-block compounds. The software allows the user to move electron pairs in a bow and arrow fashion within the structures and atoms are highlighted when the octet is exceeded.

We study the semileptonic decays ${\bf B_c} \to {\bf B_n} \ell^+ \nu_{\ell}$ where ${\bf B_{c(n)}}$ is the anti-triplet-charmed (octet) baryon with the $SU(3)_f$ flavor symmetry and helicity formalism. In particular, we present the decay branching ratios of $ {\bf B_c} \to {\bf B_n}\ell^+ \nu_\ell$ in three scenarios: (a) an exact $SU(3)_f$ symmetry with equal masses for the anti-triplet-charmed (octet) baryon states of ${\bf B_c}$ (${\bf B_n}$), (b) $SU(3)_f$ parameters without the baryonic momentum-transfer dependence, and (c) $SU(3)_f$ with baryonic transition form factors in the heavy quark limit. We show that our results are all consistent with the existing data. Explicitly, we predict that ${\cal B}( \Xi_c^+ \to \Xi^0 e^+ \nu_{e})=(11.9\pm1.3, 9.8\pm 1.1, 10.7\pm 0.9)\times 10^{-2}$ and ${\cal B}( \Xi_c^0 \to \Xi^- e^+ \nu_{e})=(3.0\pm0.3, 2.4\pm 0.3, 2.7\pm 0.2)\times 10^{-2}$ in the scenarios (a), (b) and (c) agree with the data of $(14.0^{+8.3}_{-8.7})\times 10^{-2}$ and $(5.6\pm2.6)\times 10^{-2}$ from the CLEO Collaboration, respectively. In addition, we obtain that ${\cal B}(\Lambda_c^+\to n e^+ \nu_e)=(2.8\pm 0.4, 4.9\pm0.4, 5.1\pm0.4)\times 10^{-3}$ in (a), (b) and (c). We also examine the longitudinal asymmetry parameters of $\alpha({\bf B_c} \to {\bf B_n} \ell^+ \nu_{\ell})$, which are sensitive to the different scenarios with $SU(3)_f$. Some of the decay branching ratios and asymmetries can be observed by the ongoing experiments at BESIII and LHCb as well as the future searches by BELLEII., Comment: 11 pages, 1 figure, revised version accepted by PLB

We analyze the weak processes of anti-triplet charmed baryons decaying to octet baryons and mesons with the SU(3) flavor symmetry and topological quark diagram scheme. We study the decay branching ratios without neglecting the contributions from O ( 15 ‾ ) for the first time in the SU(3) flavor symmetry approach. The fitting results for the Cabibbo allowed and suppressed decays of Λ c + are all consistent with the experimental data. We predict all singly Cabibbo suppressed decays. In particular, we find that B ( Λ c + → p π 0 ) = ( 1.3 ± 0.7 ) × 10 − 4 , which is slightly below the current experimental upper limit of 2.7 × 10 − 4 and can be tested by the ongoing experiment at BESIII as well as the future one at Belle-II.

Octet truss lattice structures are a potential candidate for developing multifunctional heat exchangers/sinks owing to their superior structural characteristics compared against stochastic open-cellular metal foams. Structural efficiency is achieved primarily due to increased nodal connectivity in octet-truss lattices. Designed octet trusses and periodic cellular materials, in general, lend themselves well to topology optimization and integration of multiple functions enabling a high degree of tailorability and superior performance benefits. Specific to heat transfer design, octet truss lattices can be tailored to achieve optimal strand cross-sectional area-to-length ratio for improved effective thermal conductivity while meeting surface-area per volume requirements for convective transport. In this work, we explore the heat and fluid flow characteristics using direct numerical simulations of a periodic unit-cell. Effective thermal conductivity, permeability, inertial coefficient, friction factor and Nusselt number for octet truss lattice structures are predicted and compared against stochastic foam experimental data. A range of porosities and pore densities are simulated and heat transfer and fluid flow characteristics are correlated using a single length scale in the form of Brinkman screening length, √K, as against existing literature where different geometric length scales are used. Further, octet truss lattice geometry is compared against existing stochastic metal foam heat and fluid flow empirical data. Normalized permeability of octet lattices were found to be 20–80% higher than stochastic foam for a given porosity. Similarly, for a fixed porosity, inertial coefficients of octet lattices were 50% of stochastic experimental measurements. For the range of Reynolds number considered, octet truss lattices show similar fluid and heat flow characteristics if not better performance than stochastic foams and thus making them ideally suited for tailored multifunctional heat sinks and exchangers.

The baryon axial vector current is computed in heavy baryon chiral perturbation theory in the large-${N}_{c}$ limit, where ${N}_{c}$ is the number of color charges. One-loop nonanalytic corrections of the order ${m}_{q}\mathrm{ln}{m}_{q}$ are comprised in the analysis, with contributions of both intermediate octet and decuplet baryon states, to all orders in the $1/{N}_{c}$ expansion of the axial vector current relevant for ${N}_{c}=3$. Theoretical expressions are obtained in the limit of vanishing decuplet-octet mass difference only, which allows one to carry out a full comparison with conventional heavy baryon chiral perturbation theory results for three flavors of light quarks and at the physical value ${N}_{c}=3$. Both approaches perfectly agree to all orders considered. Furthermore, a numerical analysis via a least-squares fit is performed in order to extract the values of the free parameters of the theory, using the experimental data available. The predictions of formalism are in good agreement with the experimental data.

The self-energies of the full set of flavor SU(3) octet and decuplet baryons are computed within a relativistic chiral effective theory framework. The leading nonanalytic chiral behavior is derived for the octet and decuplet masses, and a finite-range regularization consistent with Lorentz and gauge invariance is applied to account for the finite size of the baryons. Using a four-dimensional dipole form factor, the relative importance of various meson-baryon loop contributions to the self-energies is studied numerically as a function of the dipole range parameter and meson mass, and comparison is made between the relativistic results and earlier approximations within the heavy baryon limit., 42 pages, 7 figures

In this work we study the collider phenomenology of color-octet scalars (sgluons) in supersymmetric models with Dirac gaugino masses that feature an explicitly broken $R$ symmetry ($R$-broken models). We construct such models by augmenting minimal $R$-symmetric models with a fairly general set of supersymmetric and softly supersymmetry-breaking operators that explicitly break $R$ symmetry. We then compute the rates of all significant two-body decays and highlight new features that appear as a result of $R$ symmetry breaking, including enhancements to extant decay rates, novel tree- and loop-level decays, and improved cross sections of single sgluon production. We demonstrate in some detail how the familiar results from minimal $R$-symmetric models can be obtained by restoring $R$ symmetry. In parallel to this discussion, we explore constraints on these models from the Large Hadron Collider. We find that, in general, $R$ symmetry breaking quantitatively affects existing limits on color-octet scalars, perhaps closing loopholes for light CP-odd (pseudoscalar) sgluons while opening one for a light CP-even (scalar) particle. Qualitatively, however, we find that -- much as for minimal $R$-symmetric models, despite stark differences in phenomenology -- scenarios with broken $R$ symmetry and two sgluons below the TeV scale can be accommodated by existing searches., Comment: 69 pages, 14 figures. Updated to resemble JHEP Version of Record

We propose a new model for a homogeneous description of hadron-hadron and hadron-nucleus collisions, the Gluon Exchange Model, fundamentally based on color octet (gluon) exchange. In proton-proton collisions we provide an exact description of the final state proton and neutron spectrum including the proton diffractive peak. In proton-nucleus reactions we find that the projectile proton diquark cannot survive in more than about half of multiple proton-nucleon processes and consequently must be very frequently disintegrated, leading to long transfers of baryon number over rapidity space., 10 pages, 4 figures

Recently unpolarized and polarized $J/\psi \,(\Upsilon)$ production at the Electron-Ion Collider (EIC) has been proposed as a new way to extract two poorly known color-octet NRQCD long-distance matrix elements: $\langle0\vert{\cal O}_{8}^{J/\psi}(^{1}S_{0})\vert0\rangle$ and $\langle0\vert{\cal O}_{8}^{J/\psi}(^{3}P_{0})\vert0\rangle$. The proposed method is based on a comparison to open heavy-quark pair production ideally performed at the same kinematics. In this paper we analyze this proposal in more detail and provide predictions for the EIC based on the available determinations of the color-octet matrix elements. We also propose two additional methods that do not require comparison to open heavy-quark pair production., Comment: 10 pages, 9 figures; some small additions to the text, corrections to eqs. 37-38, conclusions unchanged, matches version accepted by Physical Review D

Additive manufacturing methods allow to produce complex geometries such as lattice structures. Aim of this study is to identify octet truss lattice structure’s mechanical capabilities. Firstly, octet truss structure designed and used to fill specimens. Specimens 1, 2 and 4 with wall and lattice structure, specimen 3 only with lattice structure and also a filled specimen are modelled. Modelled tensile specimens are additively manufactured from Ti-6Al-4V with Electron Beam Melting method. A comparison between specimens having same structural design (1, 2 and 4) has been made to gain insight about consistency of EBM method. Tensile experiments have been made with all of the specimens and tensile strength difference that can be considered significant determined among specimen 1, 2&4. Specimen 3 resulted not to be a practical approach as it showed poor tensile strength values. Lastly, tensile stress results of filled specimen are shared and compared with the other types of specimens. These results are providing a good sight for assessment of both octet truss structure and EBM manufacturing technology., Katmanlı üretim yöntemleri, kafes yapıları gibi karmaşık geometrilerin üretimine izin veren yeni bir teknolojidir. Bu çalışmanın amacı sekizli kafes yapısının mekanik özelliklerini belirlemektir. İlk olarak, kafes yapısı oluşturulmamış ve tamamen dolu bir numune kullanılmıştır. 1,2 ve 4 numaralı numuneler duvar kalınlıkla kafes yapıdan modellenmiş, yalnızca 3 numaralı numune duvar kalınlıklı sekizli kafes yapısından oluşturulmuştur. Modellenen çekme numuneleri, Elektron Işını Eritme yöntemi ile Ti-6Al-4V'den malzeme kullanılarak üretilmiştir. EBM yönteminin tutarlılığı hakkında fikir edinmek için aynı yapısal tasarıma (1, 2 ve 4) sahip numuneler arasında bir karşılaştırma yapılmıştır. 1, 2 ve 4 numaralı numuneler arasında önemli sayılabilecek gerilme mukavemeti farkı belirlenmiştir. Numune 3, zayıf gerilme mukavemeti değerleri göstermiştir. Son olarak, doldurulmuş bir numunenin çekme gerilmesi sonuçları paylaşılmış ve diğer numunelerin sonuçlarıyla karşılaştırılmıştır. Bu sonuçlar hem sekizli kafes yapısı hem de EBM üretim teknolojisinin değerlendirilmesi açısından önemlidir.

In this paper, we try to reveal the structure of the $Y(4660)$ from the light-quark perspective. We study the dipion invariant mass spectrum and the helicity angular distributions of the $e^+ e^- \to Y(4660) \to \psi(2S) \pi^+\pi^-$ process. In particular, we consider the effects of different light-quark SU(3) eigenstates inside the $Y(4660)$. The strong pion-pion final-state interactions as well as the $K\bar{K}$ coupled channel in the $S$-wave are taken into account model independently by using dispersion theory. We find that the light-quark SU(3) octet state plays a significant role in this transition, implying that the $Y(4660)$ contains a large light-quark component and thus might not be a pure conventional charmonium state. In the fit scheme considering both the SU(3) singlet and SU(3) octet states, two solutions are found, and both solutions reproduce the $\pi\pi$ invariant mass spectra well. New measurement data with higher statistics in the future will be helpful to better distinguish these two solutions., Comment: 16 pages, 5 figures, discussion of the SU(3) flavor breaking effect added, calculations of the $Z$-exchange mechanism and the triangle diagrams added, version accepted for publication in PRD. arXiv admin note: substantial text overlap with arXiv:1902.10957

The interactions between two octet baryons are studied at low energies using lattice QCD (LQCD) with larger-than-physical quark masses corresponding to a pion mass of $m_{\pi}\sim 450$ MeV and a kaon mass of $m_{K}\sim 596$ MeV. The two-baryon systems that are analyzed range from strangeness $S=0$ to $S=-4$ and include the spin-singlet and triplet $NN$, $\Sigma N$ ($I=3/2$), and $\Xi\Xi$ states, the spin-singlet $\Sigma\Sigma$ ($I=2$) and $\Xi\Sigma$ ($I=3/2$) states, and the spin-triplet $\Xi N$ ($I=0$) state. The $s$-wave scattering phase shifts, low-energy scattering parameters, and binding energies when applicable, are extracted using L\"uscher's formalism. While the results are consistent with most of the systems being bound at this pion mass, the interactions in the spin-triplet $\Sigma N$ and $\Xi\Xi$ channels are found to be repulsive and do not support bound states. Using results from previous studies at a larger pion mass, an extrapolation of the binding energies to the physical point is performed and is compared with experimental values and phenomenological predictions. The low-energy coefficients in pionless EFT relevant for two-baryon interactions, including those responsible for $SU(3)$ flavor-symmetry breaking, are constrained. The $SU(3)$ symmetry is observed to hold approximately at the chosen values of the quark masses, as well as the $SU(6)$ spin-flavor symmetry, predicted at large $N_c$. A remnant of an accidental $SU(16)$ symmetry found previously at a larger pion mass is further observed. The $SU(6)$-symmetric EFT constrained by these LQCD calculations is used to make predictions for two-baryon systems for which the low-energy scattering parameters could not be determined with LQCD directly in this study, and to constrain the coefficients of all leading $SU(3)$ flavor-symmetric interactions, demonstrating the predictive power of two-baryon EFTs matched to LQCD.