Reciprocal System Research Articles

Semi-empirical Density Estimations for Binary, Ternary and Multicomponent Alkali Nitrate–Nitrite Molten Salt Mixtures

For sensible thermal energy storage in Concentrating Solar Power (CSP) plants, a molten salt mixture of 60 wt% sodium nitrate (NaNO3) and 40 wt% potassium nitrate (KNO3), known as Solar Salt, is commonly utilized. The paper presents semi-empirical estimation results of the density of Solar Salt and alternative molten salt mixtures with low melting temperatures in a range from 70 °C to 140 °C. These mixtures are Hitec, HitecXL, LiNO3–KNO3–NaNO3 and a multicomponent mixture. The paper shows that density values of mixtures can be closely predicted from single salt densities. The paper examines different estimation rules for mixtures. The quasilinear volumetric additivity rule (QVAR) is known for ternary reciprocal systems. For the first time, the presented work extends the QVAR to multicomponent mixtures. Temperature-dependent densities of selected salt mixtures of the system Ca,Li,K,Na//NO2,NO3 were estimated. Estimations are motivated by a fast and reliable method compared to time-consuming and error-prone measurements of several mixtures.

Metastable Phase Equilibrium in the Reciprocal Quaternary System LiCl+MgCl2+Li2SO4+MgSO4+H2O at 348.15 K and 0.1 MPa

The metastable solubilities and the physicochemical properties including density and pH of the reciprocal quaternary system(LiCl+MgCl2+Li2SO4+MgSO4+H2O) at 348.15 K and 0.1 MPa were determined using the isother-mal evaporation method. The dry-salt diagram and water-phase diagram were plotted based on the experimental data. There are five invariant points, eleven univariant curves, and seven crystallization zones corresponding to hexahy-drite, tetrahydrite, kieserite, bischofite, lithium sulfate monohydrate, lithium chloride monohydrate and lithium car-nallite. Comparison between the stable and metastable diagrams at 348.15 K indicates that the metastable phenome-non of magnesium sulfate is obvious, and the crystallization regions of hexahydrite and tetrahydrite disappear in the stable phase diagram. A comparison of the metastable dry-salt phase diagrams at 308.15, 323.15 and 348.15 K shows that with the increasing of temperature the epsomite crystallization zone disappears from the dry-salt phase diagram of 303.15 K, and a new kieserite crystallization zone is presented at 348.15 K. The density and pH in the metastable equilibrium solution present regular change with the increasing of Janecke index J(2Li+), and the calculated densities using the empirical equation agree well with the experimental values.

Stable Triangle LiF–NaF–CsI of the Quaternary Reciprocal System Li, Na, Cs∥F, I

The quaternary reciprocal system Li, Na, Cs∥F, I was partitioned into simplexes, and the tree of phases was constructed. By differential thermal analysis, the stable triangle LiF–NaF–CsI was studied, and the characteristics of a ternary eutectic were determined.

A friend in need is a friend indeed: Need-based sharing, rather than cooperative assortment, predicts experimental resource transfers among Agta hunter-gatherers

Despite much theorizing, the evolutionary reasons why humans cooperate extensively with unrelated individuals are still largely unknown. While reciprocity explains many instances of non-kin cooperation, much remains to be understood. A recent suite of models based upon ‘cooperative assortativity’ suggest that non-kin cooperation can evolve if individuals preferentially assort with certain cooperative phenotypes, such as helping those who help others. Here, we test these assortative hypotheses among the Agta, a population of Filipino hunter-gatherers, using an experimental resource allocation game in which individuals divide resources between themselves and camp-mates. Individuals preferentially shared with less cooperative individuals, arguing against cooperative assortativity as a mechanism sustaining resource transfers in this population. Rather, sharing was often based on the recipient's level of need, in addition to kin-based transfers and reciprocal sharing. Contrary to several recent theoretical accounts, in this real-world setting we find no evidence for cooperative assortativity influencing patterns of cooperation. These results may reflect the demands of living in a foraging ecology characterized by high resource stochasticity, necessitating need-based sharing as a system of long-term reciprocity to mitigate repeated subsistence shortfalls.

Safe pseudoelastic limit range under torsional loading with Reciproc Blue.

To determine the distortional angle and torsional load at the pseudoelastic limit of Reciproc Blue instruments and to verify the safety of using pre-set dedicated motors designed for use with the original Reciproc instruments. Two torsional conditions of Reciproc R25 and Reciproc Blue R25 were tested using a custom device. The first condition fixed the file tips at 3mm and repetitively rotated them, with gradually increasing angles, from 10° to 270°, and the resulting torque was recorded (n=15). The second test involved a single continuous rotation until fracture (n=15). The pseudoelastic limits of the instruments were determined from their torque-rotation curves. For statistical analysis, two-way analysis of variance and t-tests were used, at a 95% significance level. Tested specimens were examined using field-emission scanning electron microscopy (FE-SEM). The angle at the pseudoelastic limit was significantly greater for Reciproc Blue than Reciproc, regardless of test mode (P<0.05). When torsional loading was repeated, using gradually increasing rotational angles, the torsional resistance was significantly lower than for a single rotation (P<0.05). However, under all test conditions, the pseudoelastic limit was below the pre-set 170° of the dedicated reciprocating motor. FE-SEM evaluation of the lateral aspects of the instruments revealed numerous longitudinal microcracks running along their long axis. For Reciproc Blue groups, the file shaft machining grooves were distorted after repetitive and continuous torsional tests. The 170° pre-set angle of the dedicated endodontic motors for the Reciproc system was safe for Reciproc Blue in single or time-restricted use.

First measurements of a scintillator based fast-ion loss detector near the ASDEX Upgrade divertor.

A new reciprocating scintillator based fast-ion loss detector has been installed a few centimeters above the outer divertor of the ASDEX Upgrade tokamak and between two of its lower Edge Localized Modes (ELM) mitigation coils. The detector head containing the scintillator screen, Faraday cup, calibration lamp, and collimator systems are installed on a motorized reciprocating system that can adjust its position via remote control in between plasma discharges. Orbit simulations are used to optimize the detector geometry and velocity-space coverage. The scintillator image is transferred to the light acquisition systems outside of the vacuum via a lens relay (embedded in a 3D-printed titanium holder) and an in-vacuum image guide. A charge coupled device camera, for high velocity-space resolution, and an 8 × 8 channel avalanche photo diode camera, for high temporal resolution (up to 2 MHz), are used as light acquisition systems. Initial results showing velocity-space of neutral beam injection prompt losses and fast-ion losses induced by a (2, 1) neoclassical tearing mode are presented.

Solubility of the Copper(II) Salt–Sodium Formate–Water Systems at 25°C

Solubilities in the CuSO4 (CuCl2, Cu(NO3)2)–NaHCOO–H2O systems are studied at 25°C using the isothermal sections method. Crystallization regions of copper(II) formate mono- and dihydrate are elucidated. It is proved that copper(II) formate can be synthesized in CuAn2 + 2NaHCOO ⇆ Cu(HCOO)2 + 2NaAn–H2O quaternary reciprocal systems using the conversion method.

Fracture incidence of instruments from a single-file reciprocating system by students in an endodontic graduate programme: a cross-sectional retrospective study.

To assess the fracture incidence of instruments from single-file reciprocating systems when used by students in an endodontic graduate programme. Dental records and periapical radiographs of patients treated by students on an endodontic graduate programme using reciprocating systems were assessed. Data on tooth type, number of treated root canals, number of fractured instruments, fragment size, angle, radius, arc length and position of root canal curvature where fractures occurred were tabulated for analysis. The risk of fracture was calculated for each group of teeth, root canal and root thirds, whilst the incidence of fractures reported for the reciprocating systems was compared using the chi-squared test at 5% significance level. Overall, 2056 root canals (826 teeth) from 810 patients were included. The incidence of fractured files from single-file reciprocating systems in relation to a number of instrumented canals was 0.92%. Fracture rates of 0.84% and 0.93% were found in 830 and 1226 root canals instrumented with WaveOne and Reciproc systems, respectively. No significant differences were observed between the systems. The highest fracture rate was 52.6% in the mesiobuccal root of mandibular molars. The central angle, radius and arc length of the curvature of root canals where the instruments fractured ranged from 58° to 84°, from 1.7 to 7.2mm and from 2.4 to 7.6mm, respectively. The use of WaveOne and Reciproc single-file reciprocating systems in an endodontic graduate programme was associated with a low incidence of instrument fractures.

Comparison of the effectiveness of various rotary and reciprocating systems with different surface treatments to remove gutta-percha and an epoxy resin-based sealer from straight root canals.

To compare the Reciproc Blue, Reciproc and ProTaper Universal Retreatment systems with regard to the effective removal of epoxy resin-based sealer and gutta-percha during the retreatment of oval, straight root canals. Forty-five extracted, human mandibular first premolars with single straight oval canals were selected on the basis of cone beam computed tomography evaluations. The root canals were instrumented with the ProTaper Next system up to the X2 file, and filled with gutta-percha and epoxy resin-based sealer using the cold lateral condensation technique. After 1month, the samples were randomly divided into three groups (n=15) according to the retreatment system used: Reciproc Blue R40, Reciproc R40 and ProTaper Universal. The specimens were scanned at the resolution of 1.2μm by a microcomputed tomography device after the root filling and retreatment procedures, and the decrease in the volume of filling material after each retreatment protocol was measured. The results were analysed using the Kruskal-Wallis test and additional box-and-whisker plots. Although the volume of the filling material decreased significantly in all three groups (P<0.05), none of the systems removed the material completely. The Reciproc system removed significantly more material than the ProTaper Universal (P<0.001) and Reciproc Blue (P=0.005) systems, with the latter two exhibiting equal volumes of remaining material (P=0.068). The Reciproc system was more effective than the Reciproc Blue and ProTaper Universal Retreatment systems during the removal of filling material from oval, straight canals, although none of the systems completely removed the filling material.

On the internal signature and minimal electric network realizations of reciprocal behaviors

In a recent paper, it was shown that (i) any reciprocal system with a proper transfer function possesses a signature-symmetric realization in which each state has either even or odd parity; and (ii) any reciprocal and passive behavior can be realized as the driving-point behavior of an electric network comprising resistors, inductors, capacitors and transformers. These results extended classical results to include uncontrollable systems. In this paper, we establish new lower bounds on the number of states with even parity (capacitors) and odd parity (inductors) for reciprocal systems that need not be controllable.

Phase Equilibria in the System LiF–KI–KF–K2CrO4

Phase equilibria were experimentally studied in the system LiF–KI–KF–K2CrO4, which is the stable tetrahedron of the quaternary reciprocal system Li, K∥F, I, CrO4. Differential thermal analysis revealed the compositions and transformation temperatures at the eutectic point E□ 488 (L ⇄ LiF + KF + KI + α-K2CrO4) and the peritectic point P□ 510 (L + K3FCrO4 ⇄ KI + α-K2CrO4 + KF). A computer model of the phase complex of the system was built, which can predict phase transformations at an arbitrary composition in the system. Isothermal sections of the systems were constructed, using which the phase composition at the temperature of the section can be calculated.

Ternary Reciprocal System K, Pb∥Cl, WO4

The phase diagram of the ternary reciprocal system K, Pb∥Cl, WO4 was studied for the first time by the calculation–experimental method and differential thermal and X-ray powder diffraction analyses. Chemical interactions between components were described, metathesis and complexation reactions were revealed, and the coordinates of binary and ternary eutectics were found (mol %): e4(410°C, 48% KCl, 52% PbCl2), e5(424°C, 23% KCl, 77% PbCl2), P(490°C, 63.5% KCl, 36.5% PbCl2), e6(487°C, 91% PbCl2, 9% PbWO4), e7(428°C, 30.5% KCl, 60.5% PbCl2, 9% PbWO4) (eutectic in the stable section D2–PbWO4), e8(650°C, 80% KCl, 20% PbWO4), e9(650°C, 70% KCl, 15% K2WO4, 15% PbWO4) (binary eutectic in the stable section D1–KCl), E1(620°C, 59% KCl, 34% K2WO4, 7% PbWO4), E2(640°C, 75% KCl, 5% K2WO4, 20% PbWO4), E3(400°C, 46% KCl, 6% PbWO4, 48% PbCl2), E4(410°C, 21% KCl, 9% PbWO4, 70% PbCl2), and Pо(468°C, 56% KCl, 10% PbWO4, 34% PbCl2).

CoupleNet: Paying Attention to Couples with Coupled Attention for Relationship Recommendation

Dating and romantic relationships not only play a huge role in our personal lives but also collectively influence and shape society. Today, many romantic partnerships originate from the Internet, signifying the importance of technology and the web in modern dating. In this paper, we present a text-based computational approach for estimating the relationship compatibility of two users on social media. Unlike many previous works that propose reciprocal recommender systems for online dating websites, we devise a distant supervision heuristic to obtain real world couples from social platforms such as Twitter. Our approach, the CoupleNet is an end-to-end deep learning basedestimator that analyzes the social profiles of two users and subsequently performs a similarity match between the users. Intuitively, our approach performs both user profiling and match-making within a unified end-to-end framework. CoupleNet utilizes hierarchical recurrent neural models for learning representations of user profiles and subsequently coupled attention mechanisms to fuse information aggregated from two users.To the best of our knowledge, our approach is the first data-driven deep learning approach for our novel relationship recommendation problem. We benchmarkour CoupleNet against several machine learning and deep learning baselines. Experimental results show that our approach outperformsall approaches significantly in terms of precision. Qualitative analysis shows that our model is capable of also producing explainable results to users.

New Directions for Preventing Dating Violence in Adolescence: The Study of Gender Models.

Dating violence is a huge transcultural and alarming phenomenon, directly linked with endless discrimination against women. The latest research on dating violence in adolescence shows how dating violence is persistent and common in the adolescent period as well and pinpoints the origin of gender violence from first adolescent relationships. This element takes us to considerate how recent gender violence studies and policies, increased also thanks to international efforts on this issue, are not bringing expected results, especially among young people. This mini-review aims to analyze the main characteristics of current gender studies and policies on dating violence, focusing on percentages with a woman-centered approach, which stresses the consequences of gender violence. Other gender studies, that consider gender as a relational product, stress the importance of integrating the analysis of gender models as a key instrument to understand the main causes of dating violence, providing new elements to develop effective policies against dating violence. Indeed, gender models of femininity and masculinity are based on a binary system, which is also a reciprocal recognition and identity system: gender models define female and male characteristics, roles, stereotypes, and expectation, being complementary and foreclosing at the same time. Recent studies on gender relationships, especially among the youth, allows us to propose a new dialog between dating violence studies and gender model studies, underling the need of a complete and complex understanding of gender structure, and of its tensions and contradictions, to put an end to gender and dating violence, through effective programs.

Can the delta-wye transformation convert an ordinary passive reciprocal three-phase impedance system into another with negative resistors?

Can the delta-wye transformation convert an ordinary passive reciprocal three-phase impedance system into another with negative resistors?

Theoretical Analysis of the Li, Ca, Ba∥F, WO4 System: Thermal Analysis of the Quaternary System LiF–BaF2–CaF2–BaWO4

The differentiation of the quaternary reciprocal system Li, Ca, Ba∥F, WO4 was performed based on graph theory using special software. Stable and metastable secant complexes of the system were found using a matrix of reciprocal pairs of salts. For the first time, by a set of physicochemical analysis methods (differential thermal, visual polythermal, and X-ray powder diffraction analyses), based on the method of thermal analysis of successive projections of the composition polytope, the quaternary system LiF–BaF2–CaF2–BaWO4, which is a stable complex of the quaternary reciprocal system Li, Ca, Ba∥F, WO4, was studied and the coordinates of invariant points were determined.

Longevity of bond strength of resin cements to root dentine after radiation therapy.

To evaluate the bond strength and adhesive interface between several resin cements and root dentine immediately and 6months after radiotherapy. Sixty maxillary canines were selected and randomly assigned to two groups (n=30): one group was not irradiated and the other one was subjected to a cumulative radiation dose of 60Gy. The teeth were sectioned to obtain roots 16mm long and the canals were prepared with the Reciproc system (R50) and filled using a lateral condensation technique with an epoxy resin sealer. Each group was divided into three subgroups (n=10) according to the resin cement used for fibreglass fibre post cementation: RelyX-U200, Panavia-F2.0 and RelyX ARC. The posts were cemented in accordance with the manufacturer's recommendations. Three 1-mm-thick dentine slices were then obtained from each root third. The first two slices in the crown-apex direction of each third were selected for the push-out test. The failure mode after debonding was determined with a stereo microscope. The third slice from each root third was selected for scanning electron microscopy (SEM) analyses to examine the resin cement-dentine interface with 100, 1000, 2000 and 4000× magnification. Bond strength data were analysed by anova and Tukey's test (α=0.05). Significantly lower bond strength (P<0.0001) was obtained after irradiation compared to nonirradiated teeth. RelyX-U200 cemented fibre posts had the higher bond strength (15.17±5.89) compared with RelyX ARC (P<0.001) and Panavia-F2.0 (P<0.001). The evaluation after 6months revealed lower bond strength values compared to the immediate values (P<0.001) for irradiated and nonirradiated teeth. Cohesive failures occurred in the irradiated dentine. SEM revealed fractures, microfractures and fewer collagen fibres in irradiated root dentine. RelyX-U200 and Panavia-F2.0 were associated with a juxtaposed interface of the cement with the radicular dentine in irradiated and nonirradiated teeth, and for RelyX ARC, hybrid layer formation and tags were observed in both irradiated and nonirradiated teeth. Radiation was associated with a decrease in the push-out bond strength and with lower resin cement/root dentine interface adaptation. Self-adhesive resin cement was a better alternative for fibre post cementation in teeth subjected to radiation therapy. The bond strength decreased after 6months.

An Environmentally Responsive Reciprocal Replicating Network.

A reciprocal replication system is constructed from four building blocks, A, B, C, and D, which react in a pairwise manner through either a 1,3-dipolar cycloaddition or the condensation reaction between an amine and an aldehyde to create two templates, trans-TAB and TCD. These templates are equipped with complementary recognition sites-two carboxylic acids ( trans-TAB) or two 4,6-dimethylamidopyridines (TCD)-that enable each template to direct the formation of its complementary partner through two mutually reinforcing cross-catalytic pathways, in which the templates trans-TAB or TCD preorganize the appropriate building blocks within two catalytically active ternary complexes: [C•D• trans-TAB] and [A•B•TCD]. The template-directed processes within these complexes generate a heteroduplex [ trans-TAB•TCD], which is shown to possess significant stability through kinetic simulations and fitting. As a consequence, the individual cross-catalytic pathways perform more efficiently in template-directed experiments when the concentration of the template being formed is below that of the template added as instruction. Comprehensive analysis of the system in which A, B, C, and D are mixed together directly, using a series of 1H NMR spectroscopic kinetic experiments, demonstrates that the behavior of the reciprocal system is more than the simple sum of its parts-as part of the interconnected network, the product of each reaction clearly directs the fabrication of its reciprocal partner, facilitating both higher rates of formation for both templates and improved diastereoselectivity for trans-TAB. A simple change in experimental conditions (from dry to "wet" CDCl3) demonstrates the sensitivity of the replication pathways within the network to the reaction environment, which leads to a >10-fold increase in the contribution of a new minimal self-replicator, trans-TAB*, to the replication network.

Phase Equilibria of Three-Component Reciprocal System Na,K║I,MoO4

The three-component reciprocal system Na,K║I,MoO4 has been studied by differential thermal analysis (DTA). The compositions and melting temperatures have been determined, and the enthalpies of melting of eutectic mixtures measured. Phase equilibria in the system are described, and phase fields are demarcated.

The Effects of Antioxidant Application and Time Factor on Fiber Post Bonding to Root Dentin after Intracoronal Bleaching

Aim: The aim was to evaluate the effects of antioxidant application and delayed cementation on the bond strength of fiber posts after intracoronal bleaching.&#x0D; Methodology: Fifty-five maxillary central incisors were used. Root canals were enlarged using Reciproc system up to R40 instrument. Root canals were irrigated, dried with paper-points, and obturated with gutta-percha and a sealer. In 44 teeth, root canal fillings were removed 2-mm coronally and canal orificies were sealed with glass-ionomer-cement. A 37% CP gel was used to bleach the teeth. Five experimental groups were defined (n=11). G1: No bleaching, G2: Immediate FPC, G3: Immediate FPC after SA application, G4: 14-days delayed FPC, G5: 14-days delayed FPC after SA application. Push-out tests were performed. Statistical interpretations were made (α=0.05).&#x0D; Results: There was no significant difference among the groups in apical thirds (p&gt;0.05). However, significant differences were detected among the groups in middle and coronal thirds (p&lt;0.05).&#x0D; Conclusion: The 14-days delayed cementation seems to be a more reliable method than the SA application before FPC procedure after intracoronal bleaching.