Passive Regime Research Articles

Infl uence of the exercise regime on the quality indicators of sperm production in breeding boars

In the pig breeding industry, the quality of sperm obtained from breeding boars plays an important role in the issue of reproduction. The purpose of the research was to investigate the eff ect of exercise regime on the quality indicators of sperm production in breeding boars. The research was carried out at the Tyumensky Pig Complex LLC in the Tyumen Region. For the research 3 groups of boars were formed with 10 heads in each. The control group did not receive exercise, the 1st experimental group received passive exercise, the 2nd experimental group received active exercise. It was found that the rectilinear motility of sperm, which aff ects the fertilizing ability of semen was in the 1st experimental group of boars 87.0 %, which was by 2.8 abs.% higher than in other groups. Also, more sperm doses were obtained from semen with high rectilinear motility with the same volume and concentration indicators In the groups of boars without exercise and with active exercise, 5.7 % of dead sperm were found, which was by 0.8 abs.% more than in the analogs that received passive exercise (p < 0,05). In the 1st experimental group of boars with passive exercise, the lowest percentage of sperm with defects was found, which aff ects the efficiency of insemination and the quality of the off spring. It was found that passive exercise had a more favorable eff ect on the qualitative indicators of sperm of the breeding boars of the 1st experimental group compared to active exercise (2nd experimental group) and its absence (control group). The use of passive exercise regime for breeding boars had a positive eff ect not only on the quantitative indicators of semen, but also on the quality of sperm and can be recommended at the enterprise when housing breeding boars.

Magmatic underplating associated with Proterozoic basin formation: insights from gravity study over the southern margin of the Bundelkhand Craton, India

Abstract. Extension tectonics responsible for intracratonic rift basin formation are often the consequences of active or passive tectonic regimes. The present work puts forth a plume-related rifting mechanism for the creation and evolution of two Proterozoic sedimentary basins outlining the Bundelkhand Craton, namely the Bijawar and Vindhyan basins. Using global gravity data, a regional-scale study is performed over the region encompassing the southern boundary of the Bundelkhand Craton consisting of the Bijawar Basin, Vindhyan Basin, and Deccan basalt outcrops. The gravity highs in the central part of the complete Bouguer anomaly and the upward-continued regional anomaly, derived from global gravity grid data, suggest that the Vindhyan sedimentary basin overlies a deeper high-density crustal source. The deepest interface as obtained from the radially averaged power spectrum analysis is observed to occur at a depth of ∼30.3 km, indicating that the sources responsible for the observed gravity signatures occur at larger depths. The 3D inversion of complete Bouguer anomaly data based on Parker–Oldenburg's algorithm revealed the Moho depth of ∼32 km below the Vindhyan Basin, i.e., south of the craton. The 2D crustal models along two selected profiles showcase a thick underplated layer with a maximum thickness of ∼12 km beneath the southern part of the Bundelkhand Craton. The inferred large E–W-trending underplating and deciphered shallower Moho beneath the regions south of the exposed Bundelkhand Craton point to crustal thinning compensated for magmatic emplacement due to a Paleoproterozoic plume activity below the craton margin.

Made in Europe: Monetary–Fiscal policy mix with financial frictions

We study the role of fiscal and monetary policies in a financially constrained economy. An active monetary–passive fiscal regime amplifies technology shocks, mitigates preference shocks, and neutralizes the expansionary effects of fiscal shocks through “debt deflation” and “real interest rate” channels, compared to an active fiscal–passive monetary policy regime. Several features of the data suggest that in the aftermath of the 2007 Financial crisis, the monetary policy in the United States was more dovish than in the Euro Area while fiscal policy seemed less concerned about the dynamics of sovereign debt, implying that the distinct post-crisis dynamics of the United States and the Euro area can be rationalized through different fiscal and monetary policy mixes.

Thermo-Hydrodynamic Performance Evaluation of a Mini-Channel Inserted With TPMS-Based Porous Lattice

Abstract The coupled pore-scale and Darcy-scale numerical simulations are used in this work to investigate heat transport and hydrodynamic characteristics within a porous channel constructed by using a primitive lattice based on triply-periodic-minimal-surface. The pore-scale simulation is used in void subdomain, whereas the microporous-solid subdomain is simulated by Darcy-scale simulation for a range of mass transfer rates 4×10−7 to 2×10−3 kg/s (corresponding Reynolds numbers 0.1<Re<500). The liquid-water (Pr=7) is used as the working fluid. The Darcy number and inertial drag coefficient are calculated using the pressure drop in the channel along with the heat transfer coefficient (Nusselt number) on both internal and external walls. The quantifiable deviation from local thermal equilibrium (LTE) is also established. The results reveal two distinct, namely passive and active regimes, depending upon the permeability of the microporous-solid subdomain. It is found that the Nusselt number is almost constant for permeability values Kμ<10−11m2(passive regime). However, significant variation is observed in the Nu for higher value of permeability Kμ≥10−11m2(active regime). The Darcy number and effective Nusselt number are found to be increasing, while the inertial drag coefficient and deviation from LTE are found to be decreasing with the permeability in the active regime only.

The ALMaQUEST Survey. XIII. Understanding Radial Trends in Star Formation Quenching via the Relative Roles of Gas Availability and Star Formation Efficiency

Star formation quenching is one of the key processes that shape the evolution of galaxies. In this study, we investigate the changes in molecular gas and star formation properties as galaxies transit from the star-forming main sequence to the passive regime. Our analysis reveals that as galaxies move away from the main sequence toward the green valley the radial profile of specific star formation rate surface density (ΣsSFR) is suppressed compared with main-sequence galaxies out to a galactocentric radius of 1.5 R e(∼7 kpc for our sample). By combining radial profiles of gas fraction (f gas) and star formation efficiency (SFE), we can discern the underlying mechanism that determines ΣsSFR at different galactocentric radii. Analysis of relative contributions of f gas and SFE to ΣsSFR uncovers a diverse range of quenching modes. Star formation in approximately half of our quenching galaxies is primarily driven by a single mode (i.e., either f gas or SFE), or a combination of both. A collective analysis of all galaxies reveals that the reduction in star formation within the central regions (R < 0.5 R e) is primarily attributable to a decrease in SFE. Conversely, in the disk regions (R > 0.5 R e), both f gas and SFE contribute to the suppression of star formation. Our findings suggest that multiple quenching mechanisms may be at play in our sample galaxies, and even within a single galaxy. We also compare our observational outcomes with those from galaxy simulations and discuss the implications of our data.

SiCf/SiC composites tolerance to high temperature combustion atmosphere and post ageing mechanical and microstructural characterisation

This article reports the activities carried out under WP4, coordinated by ENEA, within the CEM-WAVE European project, about experimental study on SiCf/SiC composites tolerance to high temperature combustion atmosphere. Water corrosion phenomena are known to affect mechanical properties of SiC-based CMC, due to the formation of a silica, volatile in certain condition. The study will simulate combustion conditions, aiming at using more environmentally friendly alternatives to methane, such as hydrogen, coke oven gas or biomethane, in steel production. It is essential to determine, in each case, if corrosion happens in active (that means continuous degradation) or passive (silica forms a protective “scale” on the component) regime. Since fibre-to-matrix interface can also be degraded, it is important to determine post-ageing mechanical flexural strength (by 4point bending tests). Water corrosion ageing was performed by means of direct flame exposure. When the oxidizing species becomes CO2, instead of O2, the formation rate of silica passivating layer is expected to be lower than the volatilization rate, and consequently active oxidation results in continuous weight loss. Ageing tests of SiCf/SiC composites were carried out at high temperature in a CO2/H2O/N2 gaseous environment at atmospheric pressure (reference conditions: 1200°C, 10/20/70 v/v). Bending tests up to failure are carried out at room temperature on these aged samples after different exposure times. Relationships are established between the evolution of mechanical properties, the ageing conditions, and the rates of oxidation reactions.

A non-invasive measurement approach of boric acid concentration for anticipating reactivity excursion in light water integrated small modular reactors

This article presents a viability study about a non-invasive and a higher accurate experimental approach to measure boric acid concentration in water under a vast combination of pressure and temperature conditions. This novel approach has been developed to be used in a test facility simulating integral Pressurized Water Reactor - Small Modular Reactors (iPWR-SMRs), that is under development and will be operated by the Brazilian Nuclear Energy National Commission. Besides, the passive acting of the main systems is one of the most important requirements that characterize Generations III + and IV nuclear reactors. The integration of such systems in a unique hermetic enclosure has brought new technological challenges to the nuclear engineering. Among such challenges is the need for adequate and efficient instrumentation for assessing operating conditions and phenomena present in iPWR-SMRs. The boric acid solution has been used in conventional PWRs as an important option to core reactivity control, demanding the need to characterize boric acid concentrations in reactor vessels any time, justifying the interest of this research. However, in an iPWR-SMR, water flow (with boron) between the pressurizer and the nuclear core occurs under passive convection regime and is invariably very slow and small. This situation may require a non-invasive measurement approach. The objective of this work is to analyze the viability of using ultrasonic technique to characterize the concentration of boric acid in a liquid medium non-invasively under experimental conditions of a specific test facility. Ultrasonic tests were performed relating different boric acid concentrations with the path time of the ultrasonic wave. Factors able to mask the characterization of these concentrations by ultrasonic technique were also evaluated. The results showed that this technique allows the characterization of boric acid concentrations in liquid medium under very simple conditions, requiring further studies for complex conditions like those found in nuclear reactors.

Corrosion Performance of Ti6Al7Nb Alloy in Simulated Body Fluid for Implant Application Characterized Using Macro- and Microelectrochemical Techniques

In this paper, the applicability of Ti6Al7Nb as a more biocompatible alternative for bone and dental implants than Ti6Al4V and pure titanium in terms of corrosion resistance and electrochemical inertness is investigated. The chemical inertness and corrosion resistance of the Ti6Al7Nb biomaterial were characterized by a multi-scale electrochemical approach during immersion in simulated physiological environments at 37 °C comparing its behavior to that of c.p. Ti, Ti6Al4V, and stainless steel. The establishment of a passive regime for Ti6Al7Nb results from the formation of a thin layer of metal oxide on the surface of the material which prevents the action of aggressive species in the physiological medium from direct reaction with the bulk of the alloy. Conventional electrochemical methods such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) provide quantified information on the surface film resistance and its stability domain that encompasses the potential range experienced in the human body; unfortunately, these methods only provide an average estimate of the exposed surface because they lack spatial resolution. Although local physiological environments of the human body are usually simulated using different artificial physiological solutions, and changes in the electrochemical response of a metallic material are observed in each case, similar corrosion resistances have been obtained for Ti6Al7Nb in Hank’s and Ringer’s solutions after one week of immersion (with a corrosion resistance of the order of MΩ cm2). Additionally, scanning electrochemical microscopy (SECM) provides in situ chemical images of reactive metal and passive dielectric surfaces to assess localized corrosion phenomena. In this way, it was observed that Ti6Al7Nb exhibits a high corrosion resistance consistent with a fairly stable passive regime that prevents the electron transfer reactions necessary to sustain the metal dissolution of the bulk biomaterial. Our results support the proposition of this alloy as an efficient alternative to Ti6Al4V for biomaterial applications.

Birth Brachial Plexus Palsy: An Indian Perspective.

Birth brachial plexus palsy (BBPP) is an unfortunate outcome of a difficult labor, which can often lead to long-lasting upper limb impairments. Spontaneous recovery may or may not occur. Timely diagnosis of the condition and initiation of the appropriate treatment can be instrumental in decreasing the functional impact. The management begins right from the day the child presents first and ranges from physiotherapy to surgical intervention such as nerve repair/transfer or grafts. The sequelae of the condition are also quite common and need to be detected preemptively with initiation of appropriate treatment. However, prevention is the key to reducing the incidence of secondary deformities. In this study, the team of authors, based on their considerable experience, discuss their approach to the management of BBPP. This is done in the background of Indian cultural practices and social constraints. A detailed discussion has been done on importance of preoperative passive joint mobilization regime and role of botulinum toxin in the authors' preferred ways of surgical correction of primary as well as secondary deformities. An extensive review of peer-reviewed publications has been done in this study, including clinical papers, review articles, and systematic review of the subject. Good results are possible with early and appropriate intervention even in severe cases.

The Active and Passive Fiscal-Monetary Policy Regimes and India’s Government Expenditure Shocks: Which Stand Matters the Most?

The Active and Passive Fiscal-Monetary Policy Regimes and India’s Government Expenditure Shocks: Which Stand Matters the Most?

Hypoxic Conditioning in Rehabilitation and Secondary Prevention Programs in Cardiac Patients with Multimorbidity: a Review

INTORDUCTION. Patients with multiple chronic diseases are at higher risk of premature death, hospitalization, longer hospital stays, and reduced health-related quality of life compared to patients with a single disease. On the other hand, the presence of comorbid conditions limits the enrolment of traditional exercise-based cardiac rehabilitation programs. It is predicted that as life expectancy increases, the level of multimorbidity will increase, making it even more important to find new additional methods and technologies for the rehabilitation of cardiac patients with comorbidities. AIM. To analyze the data from the current publications or to define the validity and effectiveness of using different hypoxic conditioning regimens in cardiac patients with concomitant chronic pathology (arterial hypertension, obesity, diabetes mellitus, and chronic bronchopulmonary diseases) as well as in multimorbid elderly patients. MATERIAL AND METHODS. The search for relevant papers was carried out using the Medline, e-library, and Web of Science Core Collection databases, as well as the following keywords: “hypoxic conditioning”, “hypoxic training”, “hypoxic therapy”, “interval hypoxic therapy”, “intermittent hypoxia”, “hypoxic conditioning”, “interval hypoxia training”, and “hypoxic exposure”. The analysis included publications regarding the use of the hypoxic conditioning method in cardiac and elderly patients with multimorbid pathology, as well as publications on the use of the method in the rehabilitation of patients with certain nosologies to identify potential mechanisms in correcting bronchopulmonary violations and lipid and carbohydrate metabolism disorders. The last search date was April 05, 2022. RESULTS. Most of the analyzed studies proved that the hypoxic conditioning technology in passive interval exposure regimes is an effective method for non-pharmacological correction of cardiometabolic risks in cardiac patients with multimorbid pathology and can increase exercise tolerance, optimize hemodynamic parameters (HR, SBP and DBP), reduce the manifestations of bronchial obstruction and respiratory failure, and improve cognitive function and metabolic indicators. Personalized physical activity doses in oxygen-depleted ambient air appear to be promising, but require additional studies to establish optimal application protocols. CONCLUSION. The data presented may recommend hypoxic conditioning technologies for wider implementation in cardiac rehabilitation programs for patients with multimorbid pathologies.

Experimental Evaluation of Modified Groundhook Car Suspension with Fast Magnetorheological Damper

The car suspension setting is always a trade-off between comfort and handling. The semi-active damper system seems to be an option for reducing the compromise between the two demands. This paper deals with the effect of the magnetorheological damper setting on a car’s suspension performance, especially tire grip, which was directly measured. A unique test rig was developed, and an experimental trolley with a fast magnetorheological damper (response time of 3 µs) was used in the paper. The damper was controlled by a modified Groundhook algorithm. Compared with the passive regime, the experiments showed a 30% improvement when using the Groundhook algorithm and when the damper was adequately set. The experiments proved the trends that were set by simulations.

Coherence Recovery in a Hybrid Partially Mode Locked III-V-on-Silicon Laser

We analyse the spectral properties of an optical frequency comb emitted by a III-V-on-silicon ring laser operated in the hybrid mode-locking regime. We demonstrate that the mode-locked laser has disparate responses to an external RF modulation depending on the saturable absorber bias and pump current. Firstly, we show that, when the mode-locking is fully achieved, the hybrid operation maintains the full mode-locking characteristics across the whole locking region. Secondly, starting from an incomplete passive mode-locking regime, and using the modulation frequency as a control parameter, we demonstrate the gradual improvement of the mode-locking characteristics within the locking tongue. This effect is maximized at the RF locking tongue boundary and manifests in an increase of the spectral width and a diminution of the modal linewidth dispersion.

Numerical simulation of contact vacuum drying of potato slices

• A mathematical model for contact vacuum drying is numerically solved. • The simulations predict the drying kinetics coupled to the pressure changes in the chamber. • The frequency of active/passive phases depends on the mass flux, which is linked to the free moisture content of the samples. • Vacuum drying reveals to have a larger impact in the first period of drying. In this work, a mathematical model is proposed to simulate the Contact Vacuum Drying of potato slices. Three temperatures were analyzed: 55, 65, and 75 °C with three levels of vacuum pressure: 60, 40, and 20 mmHg. In the macroscopic model, the boundary condition for the moisture conservation is written in terms of water vapor pressure, and it considers the dynamics of the vapor pressure in the chamber. The simulations predict the evolution of gas pressure and the drying kinetics. As drying occurs, the passive regime is prolonged as a result of a decrease in the moisture content. The maximum drying rate (1.4 E-3 kg. water/kg. dry solid·s) corresponds to the drying condition at 75 °C and 20 mmHg, which is the most intensive drying condition. The comparison between the predicted and experimental values showed acceptable agreement. The simulations correctly represent the drying kinetics and the evolution of the gas pressure in the drying chamber.

On the role of elasticity in focal adhesion stability within the passive regime

Within a purely mechanical setting, we investigate the behavior, up to full decohesion, of a system modeling the interactions exchanged between focal adhesions and extra-cellular matrix in the passive regime. In our work, decohesion is described as a homogenized effect of low scales events leading to the rupture of the molecular bonds between integrin receptors and the extra-cellular matrix ligands. We propose a simple three-layers scheme of this mechanical system and, based on a Griffith-like approach, we analytically describe the transition from an elastic regime to the nucleation of a decohesion front, up to full decohesion. We focus our attention on the important role played by elasticity and deduce how the relative stiffness of the layers modulates the decohesion behavior, with the system undergoing a ductile–fragile detachment transition. The comparison with known experimental results on focal adhesions and DNA shear denaturation supports the effectiveness of the proposed model in predicting the mechanical behavior of decohesion phenomena in biological systems. Interestingly, we show the possibility of predicting focal adhesion lengths distribution based on the obtained force saturation as the focal adhesion dimension is increased theoretically deduced.

The passive Q-switching Tm, Ho co-doped GAGG state laser operating near 2.1 μm

In this letter, we report on a diode pumped passive Q-switching Tm, Ho:GAGG laser at 2090.8 nm with a graphene saturable absorber mirror. In continuous wave operation, a maximum output power of 297 mW at 2114.1 nm is achieved, corresponding to a slope efficiency of 8%. In the passive Q-switching regime, stable pulses are obtained with a shortest pulse width of 576.9 ns and pulse repetition rate of 69.46 kHz. The single pulse energy is 0.3 μJ, corresponding to a pulse peak power of 0.52 W. To the best of our knowledge, this is the first report on the passive Q-switching Tm, Ho:GAGG laser.

Electrochemical Corrosion Behavior of Explosively Welded Ti/Type 304L Stainless Steel in Nitric Acid

Two metallurgically incompatible materials, titanium grade 2 and Type 304L stainless steel (SS), were joined through explosive welding for applications in nitric acid service. The morphology and microstructure of the bonded interface were examined using a scanning electron microscope (SEM) and an optical microscope. Typical wavy interfaces along with solidified melted zones at wave vortexes were observed. Various intermetallic phases, having high hardness, were shown to be formed in these solidified melted zones. Elemental distribution in these intermetallic phases was established using SEM coupled with energy dispersive spectroscopy (EDS). Low corrosion rates were observed after exposure of the weld specimens in boiling 14.5 M and 4 M HNO3 solutions. In addition, potentiodynamic polarization tests in 4 M HNO3 solution have been performed at different surfaces at the plane of the welded interface by successive material removal by grinding from 304L SS through weld to titanium. Despite the presence of different intermetallic phases at the test surfaces, it was found that the current densities in the passive regime of potentials were low. The morphological examination of the tested surfaces revealed that corrosion attack was mainly along the boundaries between SS/intermetallic phases, Ti/SS, and along the pre-existing cracks in the intermetallic phases. No corrosion attack was observed along the boundaries between Ti and intermetallic phases.

Optimization of a Micromixer with Automatic Differentiation

As micromixers offer the cheap and simple mixing of fluids and suspensions, they have become a key device in microfluidics. Their mixing performance can be significantly increased by periodically varying the inlet pressure, which leads to a non-static flow and improved mixing process. In this work, a micromixer with a T-junction and a meandering channel is considered. A periodic pulse function for the inlet pressure is numerically optimized with regard to frequency, amplitude and shape. Thereunto, fluid flow and adsorptive concentration are simulated three-dimensionally with a lattice Boltzmann method (LBM) in OpenLB. Its implementation is then combined with forward automatic differentiation (AD), which allows for the generic application of fast gradient-based optimization schemes. The mixing quality is shown to be increased by 21.4% in comparison to the static, passive regime. Methodically, the results confirm the suitability of the combination of LBM and AD to solve process-scale optimization problems and the improved accuracy of AD over difference quotient approaches in this context.

Contribution of Diffusing Hydrogen to Anodic Processes and Pitting for Iron in Chloride-Bearing Bicarbonate Solutions

The effects of diffusing hydrogen atoms on anodic processes and pitting corrosion for iron in chloride-bearing bicarbonate solutions were studied with a dual cell for realizing the hydrogen diffusing and electrochemical measurements simultaneously. A high concentration of chloride in solution, precleaning, and diffusing hydrogen in iron can move the open-circuit state from a passive state to an active dissolution state. Potentodynamic anodic polarization curves show that the effect of diffusing hydrogen is strongly dependent on the chloride concentration in the solution. The diffusing hydrogen atoms enhance the anodic reaction before the oxygen evolution potential when the chloride concentration is low while they enhance the anodic reaction in the overall potential range when the chloride concentration is high. In addition, diffusing hydrogen atoms slow down the anodic reaction in the first current plateau regime while not significantly affecting the other potential regimes if the chloride concentration is sufficiently high. Comparisons of the results from the hydrogen-diffusing electrodes with those from the precleaned electrodes facilitate clarifying the roles of diffusing hydrogen atoms in anodic reactions. For the hydrogen-diffusing electrode, the occurrence of the active dissolution regime is mainly from the surface cleaning effect, and the enhanced anodic reaction in the transition regime, prepassive regime, passive film growth regime, passive regime, and in some cases, transpassive regime, is due to both the electrode kinetics and the surface cleaning effect. Diffusing hydrogen would retard the anodic reaction in a specific potential regime through its combined effect with high concentration chlorides. More severe pitting is generally observed for the precleaned electrodes and the hydrogen diffusing than for the noncharged electrode. Depending on the applied potential and time as well as the chloride concentration, the hydrogen-diffusing electrode would show more extensive or severe pitting than the precleaned electrode, with some exceptions showing less severe pitting.

Anodic behavior of nickel in sub-molten KOH and its relevance for the production of electroactive nickel oxides

This study investigated the electrochemical behavior of pure nickel in sub-molten KOH at 200 °C and the structure of surface films formed at different anodic polarization potentials. Potentiodynamic polarization measurements showed an active-to-passive transition followed by transpassivity. Unlike aqueous alkaline solutions, surface films created in active, far passive, and transpassive regions are few microns thick. Grazing-incidence x-ray diffraction (GI-XRD), Raman, and x-ray photoelectron spectroscopy (XPS) measurements revealed that a thick and defective layer of NiO forms during polarization in the active region. Polarization into the passive regime reduces the thickness and number of defects of NiO and promotes passivity. With the formation of +3 valent nickel at far passive region, a thick, flaky adlayer of potassium-intercalated γ-NiOOH is produced. At high transpassive potentials, the flake-like morphology deteriorated with the high rate of oxygen evolution reaction (OER). The micrometer thick electroactive anodic surface films formed during active, far passive, and transpassive region became a few micrometers thick because of the high dissolution rate of Ni and the high viscosity of the sub-molten KOH.