Critical Point In Terms Research Articles

European DEMO Fusion Reactor: Design and Integration of the Breeding Blanket Feeding Pipes

This article describes the design and configuration of the DEMO Breeding Blanket (BB) feeding pipes inside the upper port. As large BB segments require periodic replacement via the upper vertical ports, the space inside the upper port needs to be maximized. At the same time, the size of the upper port is constrained by the available space in between the toroidal field coils and the required space to integrate a thermal shield between the vacuum vessel (VV) port and the coils. The BB feeding pipes inside the vertical port need to be removed prior to BB maintenance, as they obstruct the removal kinematics. Since they are connected to the BB segments on the top and far from their vertical support on the bottom, the pipes need to be sufficiently flexible to allow for the thermal expansion of the BB segments and the pipes themselves. The optimization and verification of these BB pipes inside the upper port design are critical aspects in the development of DEMO. This article presents the chosen pipe configuration for both BB concepts considered for DEMO (helium- and water-cooled) and their structural verification for some of the most relevant thermal conditions. A 3D model of the pipes forest, both for the Helium-Cooled Pebble Bed (HCPB) and Water-Cooled Lithium Lead (WCLL) concepts, has been developed and integrated inside the DEMO Upper Port (UP), Upper Port Ring Channel, and Upper Port Annex (UPA). A preliminary structural analysis of the pipeline was carried out to check the structural integrity of the pipes, their flexibility against the thermal load, their internal pressure, and the deflection induced by the thermal expansion of the BB segments. The results showed that the secondary stress on the hot leg of the HCPB pipeline was above the limit, suggesting future improvements in its shape to increase the flexibility. Moreover, the WCLL concept did not have a critical point in terms of the secondary stress on the pipeline, since the thicknesses and the diameters of these pipes were smaller than the HCPB ones.

Maximum Entropy Freeze-Out of Hydrodynamic Fluctuations.

We propose a general approach to freezing out fluctuations in heavy-ion collisions using the principle of maximum entropy. We find the results naturally expressed as a direct relationship between the irreducible relative correlators quantifying the deviations of hydrodynamic as well as hadron gas fluctuations from the ideal hadron gas baseline. The method also allows us to determine heretofore unknown parameters crucial for the freeze-out of fluctuations near the QCD critical point in terms of the QCD equation of state.

Assessing the deteriorating water quality in wards of Jaipur city through GIS interpolation

Abstract Poor management of water sources is one of the major challenge for developing nations to provide safe water to increasing population. The Central Ground Water Board, India 2019 reports that all 13 zones of Jaipur city are in the dark zone. Dark zones are those area where the ground water exploitation is extremely high and are notified for protection by the State Government. With a population of 4.1 million, Jaipur city has a water demand deficit of around 125 MLD with dependence on ground water is increasing tremendously. The city's water table has gone down 25 metres in the last decade. Higher concentrations of fluoride, nitrate, and total dissolved solids, is a common problem in the city's ground water. Presently the city gets its water from Bisalpur dam which is 120 km away, proved to be a very costly arrangement. This paper analyses the various contaminants present in ground water. A detailed survey and data collection was done, which was further analysed through GIS spatial distribution, predicting the concentration in all 91 wards of the city. Results show that some wards are at a critical point in terms of deteriorating water quality to be addressed by city planners and urban local bodies.

Superradiant phase transition induced by the indirect Rabi interaction

We theoretically study the superradiant phase transition (SPT) in an indirect Rabi model, where both a two-level system and a single-mode bosonic field couple to an auxiliary bosonic field. We find that the indirect spin-field coupling induced by the virtual excitation of the auxiliary field can allow the occurrence of a SPT at a critical point, and the influence of the so-called ${A}^{2}$ term in the normal Rabi model is naturally avoided. In the large detuning regime, we present the analytical expression of quantum critical point in terms of the original system parameters. The critical atom-field coupling strength is tunable, which will loosen the conditions on realizing the SPT. Considering a hybrid magnon-cavity-qubit system, we predict the squeezed cat state of magnon generated with feasible experimental parameters, which has potential applications in quantum metrology and quantum information processing.

Finite Element Analysis and Investigation of Critical Impact Point of Steel Guardrails Affecting Safety and Structural Performance

After the guardrails are designed, the structural adequacy and safety criteria are determined by the relevant standards and full-scale crash tests. One of the widely used standards is European Norm 1317 (EN1317). Guardrail systems generally consist of rails and posts. The guardrails are more rigid around the posts, which are mounted on the ground or embedded in soil at certain intervals. Therefore, it is important for driver/passenger and roadside safety to determine the most critical point in terms of structural and safety performance and design according to the most unfavourable situation. With this motivation, in this study, the effect of different impact points on the structural and safety performance of the H1W4 guardrail was investigated by finite element (FE) analysis. For this purpose, first of all, the finite element models of the H1W4-A system were calibrated and validated with real crash test data. Then, with the help of the validated models, analyses were completed for different impact points as 0.5, 1.0, 1.5 and 2.0 meters with a half-meter difference for the standard 2-meter post spacing. In the light of the measured safety parameters such as Acceleration Severity Index (ASI), Theoretical Head Impact Velocity (THIV) and structural performance criteria such as working width (W) and exit angle (α), the critical impact point for the guardrail was determined. Contrary to what is generally known, crashing vehicles into flexible points (0.5 and 1.0 m) rather than impacting rigid points (1.5 and 2.0 m) creates a more negative situation in crash tests.

Soil Organic Matter and Nutrient Levels in Outdoor Runs in Organic Laying Farms.

To evaluate the nutrient load due to the grazing of laying hens in outdoor runs, monitoring of soil characteristics was conducted in three Italian organic farms. For each farm, soil samples were taken from three increasing distances from the hen house and two depths, and different chemical parameters were evaluated. The comparison among the results from the different distances shows that N-NO3 and Olsen P are the most affected parameters by hen feces: both present high values with a statistically significant difference in the area close to the poultry house and for the most superficial layer. Even TKN and TOC show significant differences between the concentrations of the first layer (more concentrated) and those of the second layer (less concentrated). In general, the surface soil layer closest to the chicken house is the portion of the outdoor run most affected by chicken droppings and represents the most critical point in terms of potential environmental impact. Therefore, it is necessary to intensify the management of the outdoor run with tools that can facilitate the grazing of animals and with vegetation that can absorb nutrients by limiting leaching and runoff.

Thermo-economic analysis of a combined cooling, heating and power system based on self-evaporating liquid carbon dioxide energy storage

Renewable energy will play the hard core in the future energy consumption structure. However, presently, the penetration rate of renewable electricity in power grid is put to limit by the nature of intermittent and volatile. Compressed carbon dioxide energy storage is a promising way to smoothen the fluctuations. In order to realize the evaporation process without heat source in charging process and satisfy the diversified energy demands, a combined cooling, heating and power system based on liquid carbon dioxide energy storage system was proposed in this paper. An ejector refrigeration cycle was coupled to recycle the waste heat, and a self-evaporating method was presented on the basis of flash distillation. Parametric analysis was carried out to evaluate the influence of several key parameters on system’s thermal and economic performances. Results indicated that the roundtrip efficiency and energy density of the system were 64.97% and 17.46 kWh/m3 under design conditions. Besides, increasing the turbine inlet parameters improved the system efficiencies and amplified the system storage capacity prominently, but it had negative effect on the cooling power. The optimum value of low pressure storage tank was around critical point in terms of system thermal efficiency and heating power, while entrainment ratio dominated the behavior of the cooling power. Moreover, economic performance of the proposed system was advantageous in the large-scale energy storage systems.

Criticality from Einstein-Maxwell-dilaton holography at finite temperature and density

We investigate consistent charged black hole solutions to the Einstein-Maxwell-Dilaton (EMD) equations that are asymptotically AdS. The solutions are gravity duals to phases of a non-conformal plasma at finite temperature and density. For the dilaton we take a quadratic ansatz leading to linear confinement at zero temperature and density. We consider a grand canonical ensemble, where the chemical potential is fixed, and find a rich phase diagram involving the competition of small and large black holes. The phase diagram contains a critical line and a critical point similar to the van der Waals-Maxwell liquid-gas transition. As the critical point is approached, we show that the trace anomaly in the plasma phases vanishes signifying the restoration of conformal symmetry in the fluid. We find that the heat capacity and charge susceptibility diverge as $C_V \propto (T-T^c)^{-\alpha}$ and $\chi \propto (T-T^c)^{-\gamma}$ at the critical point with universal critical exponents $\alpha=\gamma=2/3$. Our results suggest a description of the thermodynamics near the critical point in terms of catastrophe theories. In the limit $\mu \to 0$ we compare our results with lattice results for $SU(N_c)$ Yang-Mills theories.

Critical behavior of charged dilaton black holes in AdS space

We revisit critical behaviour and phase structure of charged anti-deSitter (AdS) dilaton black holes for arbitrary values of dilaton coupling $\alpha$, and realize several novel phase behaviour for this system. We adopt the viewpoint that cosmological constant (pressure) is fixed and treat the charge of the black hole as a thermodynamical variable. We study critical behaviour and phase structure by analyzing the phase diagrams in $T-S$ and $ q-T$ planes. We numerically derive the critical point in terms of $\alpha$ and observe that for $\alpha =1$ and $\alpha \geq \sqrt{3}$, the system does not admit any critical point, while for $0<\alpha <1$, the critical quantities are not significantly affected by $\alpha$. We find that unstable behavior of the Gibbs free energy for $q<q_{c}$ exhibits a \textit{first order} (discontinuous) phase transition between small and large black holes for $0\leq\alpha<1$. For $1<\alpha <\sqrt{3}$ and $q>q_{c}$, however, a novel first order phase transition occurs between small and large black hole, which has not been observed in the previous studies on phase transition of charged AdS black holes.

Core annular flow theory as applied to the adiabatic section of heat pipes

Core annular flow theory is used to model the parallel flow of fluids of different phases and has been used to describe drag reduction in the context of internal flows bounded by superhydrophobic surfaces. The work presented here is an extension of core annular flow theory to the study of the adiabatic section of heat pipes. Our aim is to develop a first-principles estimate of the conditions necessary to maximize the (counter) flow of liquid and vapor and, by extension, the axial flow of heat. The planar and axisymmetric geometries are examined as are heat pipes containing vs being devoid of a wick. In the wick vs no-wick cases, the peripheral return flow of liquid is, respectively, driven by capillarity and by gravity. Our model is used to predict velocity profiles and the flux-maximizing pressure gradient ratio (vapor-to-liquid). We further obtain estimates for the optimum thickness of the liquid layer. Note finally that when the liquid flow occurs via capillary pumping, there is a minimum surface tension below which the wick cannot supply a sufficient flow of liquid. We characterize this critical point in terms of the properties of the working fluid and of the wick.

The reverse Yang–Mills–Higgs flow in a neighbourhood of a critical point

The main result of this paper is a construction of solutions to the reverse Yang–Mills–Higgs flow converging in the $C^{\infty}$ topology to a critical point. The construction uses only the complex gauge group action, which leads to an algebraic classification of the isomorphism classes of points in the unstable set of a critical point in terms of a filtration of the underlying Higgs bundle. Analysing the compatibility this filtration with the canonical Harder–Narasimhan–Seshadri double filtration gives an algebraic criterion for two critical points to be connected by a flow line. As an application, we use this to construct Hecke modifications of Higgs bundles via the Yang–Mills–Higgs flow. When the Higgs field is zero (corresponding to the Yang–Mills flow), this criterion has a geometric interpretation in terms of secant varieties of the projectivisation of the underlying bundle inside the unstable manifold of a critical point, which gives a precise description of broken and unbroken flow lines connecting two critical points. For non-zero Higgs field, at generic critical points the analogous interpretation involves the secant varieties of the spectral curve of the Higgs bundle.

“Nada les hemos cumplido”: negociaciones de paz entre apaches y españoles en la Nueva Vizcaya en 1787

Desde fines del siglo XVI, distintas fuentes de primera mano registraron la presencia de grupos identificados como apaches a lo largo de la frontera norte novohispana. Conforme el poblamiento español avanzó hacia el norte en el siglo XVII y conforme estos grupos clasificados como apaches fueron desplazados hacia el sur, las confrontaciones violentas entre ambos bandos se hicieron recurrentes. Los estudios clásicos sobre estos temas, producidos por autores estadounidenses y españoles, han mostrado que la corona española transitó de manera errática entre las políticas de guerra y negociación para hacer frente a la amenaza apache, y que el punto crítico en la definición de una política firme con respecto de estos grupos indígenas se daría hacia 1786, en la época del virrey Bernardo de Gálvez. Como argumenta este artículo, las mudanzas entre la guerra (ofensiva o defensiva) y los tratados de paz (mediante regalos y el establecimiento de apaches cerca de los presidios) no solamente obedecieron a los cambios en la diplomacia española a gran escala, sino que también estuvieron relacionadas con la distancia que separaba a los altos mandos militares de las experiencias que apaches y españoles vivían en el ámbito local. El caso del fallido intento de pactar la paz con los mezcaleros en 1787 en la Nueva Vizcaya muestra la forma en que las fisuras en las líneas de mando españolas, y la distancia cultural entre los apaches y la jerarquía militar, dificultaron la construcción de una paz duradera entre ambosbandos a fines del siglo XVIII.

Core Annular Flow Theory as Applied to the Adiabatic Section of Heat Pipes

Core annular flow theory is used to model the parallel flow of fluids of different phases and has been used to describe drag reduction in the context of internal flows bounded by superhydrophobic surfaces. The work presented here is an extension of core annular flow theory to the study of the adiabatic section of heat pipes. Our aim is to develop a first-principles estimate of the conditions necessary to maximize the (counter) flow of liquid and vapor and, by extension, the axial flow of heat. The planar and axisymmetric geometries are examined as are heat pipes containing vs being devoid of a wick. In the wick vs no-wick cases, the peripheral return flow of liquid is, respectively, driven by capillarity and by gravity. Our model is used to predict velocity profiles and the flux-maximizing pressure gradient ratio (vapor-to-liquid). We further obtain estimates for the optimum thickness of the liquid layer. Note finally that when the liquid flow occurs via capillary pumping, there is a minimum surface tension below which the wick cannot supply a sufficient flow of liquid. We characterize this critical point in terms of the properties of the working fluid and of the wick.

Structural behavior of fluids from the vapor and liquid region to the supercritical phase.

A metric (χ) is introduced to quantify the relative proportion of particles having a specified number of near neighbors that are characteristic of liquid-phase properties. It can be used as a simple alternative to other methods for the investigation of some aspects of percolation behavior. Values of χ are obtained from molecular-dynamics simulations spanning the heterogeneous vapor and liquid region and the supercritical phase of the Lennard-Jones fluid. The supercritical phase can be delineated into regions of different structural properties. At different isochoric subcritical conditions, the temperature versus χ behavior shows evidence of inflections, which are associated with the onset of transitions from the vapor and liquid region to the supercritical phase. The analysis suggests a phenomenological requirement for the critical point in terms of a near-equal proportion of near neighbors with gaslike and liquidlike characteristics.

Tools for generation and results analysis of SOC performance tests

To ensure that the SoC project complies with the requirements for efficiency on applied tasks, the entire route of developing SoC, starting with architectural design and ending with qualification tests of the topological list of chains, should be focused on early localization of performance problems. A critical point in terms of performance is the interconnect subsystem of the So C. As part of this work, a tool for generating tests, aimed at verifying the compliance of the system with the stated requirements, was proposed. This tool implements the generation of test scenarios based on the description of data streams and their interdependencies, taking constraints into account. Describing data streams at a high level of abstraction and considering constraints allows you to automatically generate both simple load tests and complex tests based on usage scenarios that require consideration of data dependencies. To automate the analysis of test results, an error analysis tool was developed, the task of which is to scan the test logs and find the reasons for their unsuccessful completion. This module helps to automate the decision to match the current state of the project with the test plan, thus helping to decide on the allocation of resources to the project.

Seasonal and Sexual Variation of the Intermediate Metabolism and Body Condition Indexes in the LizardTropidurus catalanensis(Gudynas and Skuk, 1983) (Squamata: Tropiduridae)

Throughout the life cycle of organisms, nutrient intake is necessary for the maintenance of the functions of daily life and in preparation for a variety of biological events, such as molting, migration, hibernation, and reproduction. One of the most energetically costly events is reproduction. Present study sought to elucidate the seasonal variations in the markers of intermediate metabolism (total proteins, uric acid, glucose, total lipids, triglycerides, total cholesterol, VLDL cholesterol, and glycogen) and body condition indices (gonadossomatic, hepatosomatic, and abdominal fat index) in Tropidurus catalanensis, in order to know the physiological costs of reproduction in this species, also allowing these parameters to be used as markers in studies of environmental alterations. During the study period, 38 males and 35 females were collected. Tropidurus catalanensis is a lizard that inhabits the Pampa grasslands, a biome that stretches across Argentina, Brazil, and Uruguay. Results obtained reveal that this lizard exhibits a clear pattern of seasonal variation in its metabolism, as reflected mainly in levels of plasma total protein, liver glycogen, total lipids, and triglycerides in males and females; and in blood glucose and lipid, and liver protein levels in females. It bears stressing that all body condition indices analyzed varied over the course of the year. The parameters studied can be used to evaluate the impact of changes in environmental conditions on these animals. Winter months appear to trigger a reduction in overall metabolism, most intensely in males. Reproductive period seems to be the biological event that demands greater energy demand, leading to the mobilization of energy stocks mainly in females, where the search for food may be reduced in the months of reproductive peak (spring). The response pattern observed during the reproductive period suggests that this time represents a critical point in terms of the animal's adaptation to its life cycle.

Investigation of the level of consciousness of citizens about the climate change

As of the first periods of history, the fact that human being has benefited from the natural resources and the efforts to improve life conditions has shown a continuous increase and diversification in the direction of technological developments. The fact that improving technological developments within time has provided people to intervene in the nature influentially, the usage of natural resources has reached a critical point in terms of both the environment and living creatures and it has caused to climate changes in conjunction with environmental pollution. This research has been conducted in order to investigate the consciousness level of native people living in different regions of Libya on climate issue. The universe of the research consisted of native people living in Libya, while the sample consisted of 300 Libyans. The scanning method was used in the research. A questionnaire was carried out in order that the levels of consciousness of participants on climate change could be investigated. The information that was obtained from the questionnaires were analyzed in computer environment by using SPSS 20.0 program. As a result, in this research, which was conducted with the aim of determining the level of consciousness about the climate change of Libyan people, there were significant differences about age, gender and education variables, and the people of Libya participating in the survey have been informed about climate change.

Environmental impact assessment of different cropping systems of home-grown feed for milk production

Animal feeding is a critical point in terms of both production efficiency and environmental impact for the livestock sector and farmer choices about home-grown feed can have great influence on environmental impact of milk production. The aim of the study was to assess the environmental performances of the most common home-grown fodder crops in Northern Italy and to analyse the impacts of different cropping system scenarios for milk production, through a Life Cycle Assessment (LCA) approach. The environmental impact of the most common home-grown feeds was calculated from cradle-to-the-animal’s mouth expressing the different categories per hectare and per unit of net energy for lactation and protein digested in the small intestine when rumen-fermentable nitrogen is the limiting factor (PDIN). Moreover four scenarios (BASE, HAY, SILAGE, PROTEIN) characterized by different cropping systems were hypothesized to assess the environmental impact of milk production from cradle to farm gate in an intensive farming system. Primary data were collected by direct interviews in 134 dairy farms located in Lombardy Region (Northern Italy).Among the most common fodder crops grown in Northern Italy, alfalfa preserved as silage and, although with a lesser extent, the double cropping system “whole plant maize silage-Italian ryegrass hay” showed the best environmental performances especially when the impact are expressed per unit of net energy for lactation or digestible protein in the intestine. Alfalfa showed also the lowest values of acidification and eutrophication when they were expressed as unit of land. The high variability of forage quality suggests a great room for improvement in terms of mitigation potentials.The analysis of alternative cropping system scenarios for milk production showed that the cropping system based on alfalfa and grass hays (HAY scenario) had the lowest self-sufficiency in terms of DM and the highest values of all impact categories per kg of fat and protein corrected milk (FPCM). The PROTEIN scenario, characterized by the introduction in the cropping system of protein rich crops (whole plant soy silage and alfalfa hay) can be considered the best one in a global perspective. In fact, the PROTEIN scenario showed the lowest potentials for acidification, eutrophication and non-renewable fossil energy use per kg FPCM and a reasonable value in terms of GWP. Moreover, the PROTEIN scenario had the higher feed self-sufficiency in terms of both DM and CP. Thanks to their capability to fix atmospheric nitrogen increasing the cultivation of legume such as alfalfa and soy in the cropping system of Northern Italy can reduce the utilization of chemical nitrogen fertilization and, consequently, the environmental impact. Moreover, considering that the main part of soybean consumed in Italy is cultivated in South America, a higher farm self-sufficiency in terms of protein feeds could decrease the emissions of CO2 linked to land use change generated by the cultivation of soybean.

Experimental and numerical evaluation of the axial stiffness of the web-to-flange adhesive connections in composite I-beams

In most full-composite structures nowadays, pultruded profiles are joined together to form more complex cross-sections that are not produced by the pultrusion process. These unconventional cross-sections represent a critical point in terms of strength and deformability of the whole structure, especially due to the presence of adhesive. This fundamental unknown aspect recently inspired the authors of the present paper to study the mechanical behavior of a glass fiber reinforced polymer (GFRP) profile with a complex cross-section shape obtained by bonding simple pultruded plates (bonded beams) by epoxy resin. The first step was to compare the behaviors of bonded beams with those of similar pultruded ones. With this aim, in a previous paper the flexural global behavior of an I-bonded beam was investigated, highlighting its better performance with respect to the pultruded I-profile in terms of failure load and stiffness. Now the authors would like to extend the study, both experimentally and numerically, to the mechanical behavior of the adhesive web–flange connections in terms of axial stiffness.Seventeen full specimens were tested by performing pull-out tests under force control. A uniformly distributed load was applied to the lower flange in order to favor the detachment of the flange from the web of the profile by using a steel device designed and realized ad hoc.The overall result of the research is that the bonded profile shows a good mechanical behavior justifying its use in technical practice. In addition, the bonded beams represents a valid alternative to the pultruded profile especially when the latter is not available on the market. In more detail, in bonded beams, the presence of the resin (instead of resin and fibers as in pultruded beams) at the web-to-flange connection does not affect the flexural global behavior but does penalize the axial behavior of their connections, as here demonstrated.

Quantum Critical Higgs

The appearance of the light Higgs boson at the LHC is difficult to explain, particularly in light of naturalness arguments in quantum field theory. However light scalars can appear in condensed matter systems when parameters (like the amount of doping) are tuned to a critical point. At zero temperature these quantum critical points are directly analogous to the finely tuned standard model. In this paper we explore a class of models with a Higgs near a quantum critical point that exhibits non-mean-field behavior. We discuss the parametrization of the effects of a Higgs emerging from such a critical point in terms of form factors, and present two simple realistic scenarios based on either generalized free fields or a 5D dual in AdS space. For both of these models we consider the processes $gg\to ZZ$ and $gg\to hh$, which can be used to gain information about the Higgs scaling dimension and IR transition scale from the experimental data.