Cp Curves Research Articles

Relationship between cement penetration and incidence of a radiolucent line around the tibia 2 years after total knee arthroplasty: A retrospective study

ObjectivesCement penetration (CP) plays a key role in implant stability for cemented total knee arthroplasty (TKA), and the radiolucent line (RLL) >2 ​mm is a preliminary sign for loosening of components. However, the direct relationship between CP and the frequency of RLL >2 ​mm is unclear, and the best cut-off value for CP to prevent RLL >2 ​mm also remains unclear. This study aimed to investigate this relationship between CP and RLL and to determine the clinical cut-off value for tibial CP in patients 2 years after TKA. MethodsThis retrospective study investigated 157 knees from 123 patients with osteoarthritis who underwent cemented TKA. The CP and RLL immediately after TKA and the RLL 2 years after TKA were measured for the medial, lateral, anterior, and posterior tibial baseplate zones. Receiver operating characteristic (ROC) curves were constructed to determine the best cut-off values for CP. ResultsRLL >2 ​mm was not observed just after TKA. An RLL >2 ​mm was observed in any tibial baseplate zone in 22 knees from 20 patients (RLL+ group) and was not observed in the remaining (RLL− group) 2 years after TKA. The mean CP for all zones was significantly higher in the RLL− group (2.5 ​± ​1.1 ​mm) than in the RLL+ group (1.7 ​± ​0.6 ​mm; P ​< ​0.001). An RLL >2 ​mm was seen in 21 knees in the medial zone, 9 knees in the lateral zone, 8 knees in the anterior zone, and 3 knees in the posterior zone. CP values with RLL >2 ​mm were significantly lower than those without the RLL at the medial, anterior, and posterior tibial baseplate zones. The best cut-off values from the ROC curve of CP in each zone were between 1.1 ​mm and 2.1 ​mm. ConclusionsThe depth of the CP directly affects the incidence of an RLL >2 ​mm. The best cut-off value for tibial CP to prevent an RLL >2 ​mm is 2.1 ​mm.

Synthesis, crystal structure, and thermodynamic properties of two new selenate chlorides: M2Cu(SeO4)Cl2 with M = K and Rb

Two new selenate chlorides have been prepared for the first time by hydrothermal method. Their crystal structures have been determined. Both compounds are related to the chlorothionite mineral structure type but not isostructural to each other. K2Cu(SeO4)Cl2 crystallize in the orthorhombic system with the space group Pnma (#62) and unit cell parameters a = 7.7941(2)Å, b = 6.1297(2) Å, c = 16.6644(5) Å, V = 796.15(4) Å3, Z = 4 whereas Rb2Cu(SeO4)Cl2 crystallize in monoclinic system, P21/n (#14), and parameters a = 8.0701(3), b = 12.9474(5), c = 16.9354(7), β = 103.657(2)°, V = 1719.49(12) Å3, Z = 8. Potassium compound are isostructural to the related sulfate chloride, while rubidium selenate is differ from their sulfate analogue and from prototype compound K2Cu(SO4)Cl2. Both examined crystal structures feature copper ions in planar coordination CuO2Cl2 which form isolated magnetic chains along ⟨0 1 0⟩ direction in the structure. The study of M2Cu(SeO4)Cl2 was carried out in measurements of magnetic susceptibility χ(T) = M/B in the temperature range 2–350 K, magnetization M(B) at 2 K and specific heat Cp(T) in the range 2–120 K. At lowering temperature, the magnetic susceptibility exhibits no anomalies and follows by Curie law. An increase of the Cp(T) curve below 3 ÷ 8 K indicates the release of magnetic entropy. The study of thermodynamic properties unexpectedly shows that the investigated selenates M2Cu(SeO4)Cl2 (M = K and Rb) behave like paramagnets and the interaction between copper ions in the structural chains is negligible, opposite related sulfates demonstrating 1D magnetic behavior for Cu2+ magnetic ions.

Static and resonant properties of decorated square kagomé lattice KCu[formula omitted](TeO[formula omitted])(SO[formula omitted])[formula omitted]Cl

The magnetic subsystem of nabokoite, KCu7(TeO4)(SO4)5Cl, is constituted by copper ions forming a buckled square kagomé lattice decorated by quasi-isolated ions. This combination determines peculiar physical properties of this compound evidenced in electron spin resonance (ESR) spectroscopy, dielectric permittivity ɛ, magnetization M and specific heat Cp measurements. At lowering temperature, the magnetic susceptibility χ=M/H passes through a broad hump inherent for low-dimensional magnetic systems at about 150 K and a sharp peak at antiferromagnetic phase transition at TN=3.2 K. The Cp(T,H) curves demonstrate additional peak-like anomaly at Tpeak=5.7 K robust to magnetic field. The latter can be ascribed to low-lying singlet excitations filling the singlet-triplet gap in magnetic excitation spectrum of the square kagomé lattice (Richter et al., 2022). ESR spectroscopy provides indications that antiferromagnetic structure below TN is non-collinear. Separate issue is the observation of antiferroelectric-type behavior in ɛ at low temperatures, which tentatively reduces the symmetry and partially lifts frustration of magnetic interactions of decorating copper ions with buckled square kagomé lattice. These complex thermodynamic and resonant properties signal the presence of two weakly coupled magnetic subsystems in nabokoite, namely a spin-liquid in square kagomé lattice layers and an antiferromagnet represented by decorating ions.

Crystal structure and thermodynamic properties of the new compound Sc4Sb2.52 in the Sc-Sb system

The new compound Sc4Sb2.52 was first discovered, which was synthesized by the arc-melting under high purity argon. The composition of the new compound was examined by energy dispersive X-ray spectroscopy (EDS). Its crystal structure was first determined using X-ray powder diffraction data by Rietveld method. In order to further verify its structure, it was also observed by transmission electron microscope (TEM). The compound crystallized in a cubic Th3P4-type structure with the space group I4¯3d (No. 220) and the lattice parameter is a = 8.65454(9) Å. Its atomic positions are Sc at 16c (0.0736(3), 0.0736(3), 0.0736(3)), and Sb at 12a (0.375, 0, 0.25). The heat capacity (Cp) of the new compound Sc4Sb2.52 was reported for the first time, which were measured using differential scanning calorimetry (DSC) in a temperature range from 105 K to 450 K. The curve of Cp shows the normal sigmoidal temperature dependence with no evidence of transitions and other anomalies, and which was fitted using Debye function from 0 K to 77 K and using Maier-Kelley type expression from 77 K to 450 K. The entropy, enthalpy and free-energy values were derived with integration of the heat capacities based on the relations of thermodynamic properties with Cp.

Fast Power Coefficient vs. Tip–Speed Ratio Curves for Small Wind Turbines with Single-Variable Measurements following a Single Test Run

Small wind turbines (SWTs) face tremendous challenges in being developed into a more reliable and widespread energy solution, with a number of efficiency, reliability, and cost issues that are yet to be resolved. As part of the development stages of an SWT, testing the resulting efficiency and determining appropriate working ranges are of high importance. In this paper, a methodology is presented for testing SWTs to obtain characteristic performance curves such as Cp (power coefficient) vs. TSR (tip–speed ratio), and torque vs. ω, in a simpler and faster yet accurate manner as an alternative energy solution when a wind tunnel is not available. The performance curves are obtained with the SWT mounted on a platform moving along a runway, requiring only a few minutes of data acquisition. Furthermore, it is only required to measure a single variable, i.e., the generator output voltage. A suitable physics-based mathematical model for the system allows for deriving the desired performance curves from this set of minimal data. The methodology was demonstrated by testing a prototype SWT developed by the authors. The tested prototype had a permanent magnet synchronous generator, but the methodology can be applied to any type of generator with a suitable mathematical model. Given its level of simplicity, accuracy, low cost, and ease of implementation, the proposed testing method has advantages that are helpful in the development process of SWTs, especially if access to a proper wind tunnel is prevented for any reason. To validate the methodology, Cp vs. TSR curves were obtained for an SWT prototype tested under different test conditions, arriving always at the same curve as would be expected. In this case, the test prototype reached a maximum power coefficient (Cp) of 0.35 for wind velocities from 20 to 50 km/h for a TSR of 5.5.

Electrophysical Properties and Heat Capacity of Activated Carbon Obtained from Coke Fines.

This paper studies the dependence of the specific heat capacity (Cp) of activated carbon obtained by the activation of coke fines on temperature (T, K) and the dependence of electrical resistance (R, Om) on temperature (T, K). In the course of the work, it was found that in the temperature range of 298.15-448 K on the curve of dependence Cp - f(T) at 323 K there is a jump in heat capacity, associated with a phase transition of the second kind. Measurements of the temperature dependence of electrical resistance on temperature were also carried out, which showed that activated carbon in the temperature range of 293-343 K exhibits metallic conductivity, turning into a semiconductor in the temperature range of 343-463 K. The calculation of the band gap showed that the resulting activated carbon is a semiconductor with a moderately narrow band gap. The satisfactory agreement of the phase transition temperatures on the curves of the temperature dependences of the heat capacity on temperature (323 K) and on the curves of the dependences of electrical resistance and the relative permittivity on temperature (343 K) indicates the nature of this phase transition, i.e., at a temperature of 323 K, the change in heat capacity is associated with the transition from semiconductor conductivity to metallic.

Experimental heat capacity of 1D chains of Xe atoms adsorbed in the grooves of c-SWCNTs bundles: Contributions of vibrations and spatial redistribution of atoms

In the temperature range of 2−75 K, the analysis and comparison were performed: (i) experimental CP,Xe(T) and theoretical CV,Xe(T) heat capacity of 1D chains of xenon atoms adsorbed in grooves on the outer surface of bundles of single-walled carbon nanotubes with closed ends (c-SWCNTs); (ii) the experimental heat capacity CP,Xe(T) and the experimental contribution to the radial thermal expansion of the c-SWNTs-Xe sample of Xe that adsorbed the grooves of c-SWCNTs [αXe(T)]. There is an anomaly near 60 K on the CP,Xe(T) and αXe(T) curves due to the contribution of the spatial redistribution of Xe atoms between the chains and the outer surface of c-SWNTs. It was found that the dependencies of CP,Xe(T) and αXe(T) are qualitatively similar below 60 K. The anomaly near 60 K in the CP,Xe(T) curve indicates the complete of fragmentation of 1D Xe atomic chains. The obtained result is important for understanding the kinetics of gas impurity sorption/desorption processes in c-SWNTs.

An Intelligent Method for Predicting the Pressure Coefficient Curve of Airfoil-Based Conditional Generative Adversarial Networks.

Recently, extensive studies have focused on analyzing aerodynamic performance due to its important impact on aircraft design. Most of these works compute the aerodynamic coefficient of the airfoil through computational fluid dynamics (CFD) simulation, which is too time-consuming. To reduce the computational time required, some intelligence-based methods have been presented. However, these methods also suffer from certain issues. First, most of them directly implement existing machine learning methods used to predict the aerodynamic coefficient without adding any improvements. Second, some methods convert the airfoil shape and aerodynamic curves into images, which may lead to curve distortion and the introduction of noise. Third, some methods learn the relationship between the airfoil shape and aerodynamic coefficients but ignore the influence of initial inflow conditions. Accordingly, to address these issues, we propose an intelligent method for predicting the pressure coefficients (Cp) of airfoil based on a conditional generative adversarial network (cGAN). More specifically, we first present a two-step data augmentation strategy designed to expand the original airfoil dataset. Subsequently, we design a novel cGAN-based neural network to predict the Cp curve. To the best of our knowledge, this is the first work to apply generative adversarial network (GAN) to aerodynamic coefficient prediction. Moreover, we design a new loss function to train our network. Extensive experimental results demonstrate that the Cp curve predicted by our method is very close to that generated via CFD simulation. More importantly, our method achieves a speedup close to 1000x compared with CFD simulation.

Performance of an Archimedes screw turbine with spiral configuration for hydrokinetic applications

The performance of an Archimedes spiral turbine (AST) for hydrokinetic applications was examined using a three-dimensional unsteady numerical model utilizing the six degrees of freedom (6-DOF) solver that is available in ANSYs Fluent software. From the computational fluid dynamics (CFD) simulations, the power coefficient (Cp) curve was estimated. This curve was compared with the curve of an Archimedes screw hydrokinetic turbine (ASHT) reported in the literature. The ASHT was found to be more efficient than the AST for electricity generation. The highest value of Cp for the AST was 0.337, which is a relatively high value in comparison with that of other types of hydrokinetic turbines. The results calculated from the CFD for the AST were compared with an experimental study reported for wind applications.

5G NOMA Defense Application Environment and Stacked LSTM Network Architectures

In 5G and beyond 5G wireless communication networks, the NOMA scheme is widely considered a major non-orthogonal access technique for improving system capacity and data rates. The main challenges in current NOMA systems are limited channel feedback and the difficulty of integrating it with advanced adaptive coding and modulation algorithms. This study analyses S-LSTM-based DL NOMA receivers in i.i.d. Nakagami-m fading channel circumstances as opposed to previously presented solutions. The LSTM has the advantage of responding dynamically to changing channel conditions. When compared to a typical NOMA system, a typical NOMA system has a 12% lower outage probability, a 39% increase in net throughput, and a maximum SER reduction of 48%. Complex modulated M-ary PSK and M-ary QAM data symbols are employed in D/L NOMA transmission. Classic receivers such as LS and MMSE are outperformed by the S-LSTM-based DL-NOMA receiver. The CP and non-linear clipping noise simulation curves compare the performance of the MMSE and LS receivers with that of the DL NOMA receiver in real-time propagation circumstances. The DL-based detector outperforms the MMSE for SNRs greater than 15 dB because the S-LSTM method is more robust than the clipping noise.

Lethal diquat poisoning manifests as acute central nervous system injury and circulatory failure: A retrospective cohort study of 50 cases

SummaryBackgroundThe mortality rate of patients with diquat (DQ) poisoning is extremely high due to insufficient understanding of DQ-induced injury. This study aimed to summarize the characteristics of DQ poisoning as well as analyse the correlation between plasma DQ concentration and patient outcomes, thus providing a new strategy for diagnosis and treatment.MethodsThis single-centre retrospective cohort study was conducted at the Emergency Department of the First Affiliated Hospital, Zhejiang University School of Medicine, China, between Oct 9, 2019 and March 10, 2022. 50 patients, whose plasma or urine samples tested positive for diquat and negative for paraquat by high performance liquid chromatography-tandem mass spectrometry, were included in the study.FindingsThe mortality rate of acute DQ poisoning was 25 (50%) of 50. Compared with the survival group, the death group presented significantly higher initial plasma DQ concentration (Cp1), aspartate aminotransferase, alanine aminotransferase, serum creatinine, and creatine kinase-MB (P < 0.05). We found that six (24.0%) patients died of central nervous system injury, six (24.0%) patients died of refractory circulatory failure, and 13 (52.0%) patients died of central nervous system injury combined with circulatory failure. Receiver operator characteristic curve analysis showed that the area under the curve of Cp1 was 0.967 (95% CI: 0.911, 1.000), and the cut-off value was 3516.885 ng/mL (sensitivity, 90.9%; specificity, 96.0%).InterpretationLethal DQ poisoning is primarily associated with serious brain and vascular injury, as well as a high rate of mortality. Further research into the mechanisms of refractory circulatory failure and central nerve system damage could help reduce mortality.FundingThere are no funding sources to declare.

Pressure-Induced Intermetallic Charge Transfer and Semiconductor-Metal Transition in Two-Dimensional AgRuO 3

Pressure-Induced Intermetallic Charge Transfer and Semiconductor-Metal Transition in Two-Dimensional AgRuO ₃

Metal-organic framework (MOF-5) incorporated on NiCo2O4 as electrode material for supercapacitor application

In this article, we incorporated the Metal-organic framework (MOF-5) on NiCo2O4. First, we synthesized the Nickel cobaltite nanoparticles by combustion method. Then incorporated the MOF-5 on NiCo2O4 via the hydrothermal method. NiCo2O4/MOF-5 supported more active sites for ion transportation and storage, improving the specific capacitance of electrode materials. Prepared NiCo2O4/MOF-5 electrode exhibit a good specific capacitance of CP curves shown 357.69F/g at 1A/g and CV curves shown 557.50F/g at 5 mV/s. Thus, the as-prepared NiCo2O4/MOF-5 has a definite advantage for supercapacitor electrode materials. Which proven their promising implications in next-generation high-performance supercapacitors.

Heat capacity measurements of the Fe2Nb and Fe7Nb6 intermetallic compounds

The molar heat capacities of the Fe2Nb and Fe7Nb6 intermetallic compounds are reported here for the first time. The results were obtained via Differential Scanning Calorimetry (DSC) measurements, performed in a temperature range between 348 and 1038 K. The alloys were prepared by arc-melting high purity metals under argon flux and later heat-treated at 1200 ∘C for 336 h encapsulated in quartz tubes under argon to ensure thermodynamic equilibrium. The resulting samples were then characterized using X-Ray Diffractometry (XRD) and Scanning Electron Microscopy (SEM). The heat-capacity DSC measurements were carried out using an alternating step method with 20 and 50 K steps, with the resulting Cp associated with the midpoint of each temperature interval. A fit to a simplified Cp(T) curve was employed, due to the scatter in the data. Quasi-Harmonic Approximation (QHA) calculations were also performed, showing a good agreement with the measured values. Experimental results of heat capacity, along with other thermodynamic properties and phase equilibria, are key information for binary and ternary systems, specially for CALPHAD-type assessments. The results were therefore compared with the Kopp-Neumann approximation, used in recent assessments, showing that the parameters of both compounds can be improved in current CALPHAD databases, which motivates future work on the Fe-Nb system.

Indirect Speed Control Strategy for Maximum Power Point Tracking of the DFIG Wind Turbine System

In this In this article, a control strategy for Maximum Power Point Tracking (MPPT) of a wind turbine system based on a Doubly Fed Induction Generator (DFIG) is presented. The proposed strategy consists of the Indirect Speed Control (ISC) taking the Low Speed Shaft (LSS) as variable input. This implementation allows the MPPT to optimize the Power coefficient (Cp). The controller has been designed in order to allow the wind turbine to reach the MPPT along the partial load operation. For these experiments, a 1.5 MW wind turbine was modeled and simulated by using Matlab and Fatigue, Aerodynamic, Structure and Turbulence (FAST) software. In order to present the achieved results, a comparison between the ISC and a classical PI controller is made. The Cp curves as well as the output power display an important improvement in terms of stability. These results are possible because the appropriate values of optimal Tip Speed Ratio (TSR) and maximum Cp have been properly established. article, a control strategy for Maximum Power Point Tracking (MPPT) of a wind turbine system based on a Doubly Fed Induction Generator (DFIG) is presented. The proposed strategy consists of the Indirect Speed Control (ISC) taking the Low Speed Shaft (LSS) as variable input. This implementation allows the MPPT to optimize the Power coefficient (Cp). The controller has been designed in order to allow the wind turbine to reach the MPPT along the partial load operation. For these experiments, a 1.5 MW wind turbine was modeled and simulated by using Matlab and Fatigue, Aerodynamic, Structure and Turbulence (FAST) software. In order to present the achieved results, a comparison between the ISC and a classical PI controller is made. The Cp curves as well as the output power display an important improvement in terms of stability. These results are possible because the appropriate values of optimal Tip Speed Ratio (TSR) and maximum Cp have been properly established.

Liquid Thermo-Responsive Smart Window Derived from Hydrogel

Summary Buildings account for 40% of global energy consumption, while windows are the least energy-efficient part of buildings. Conventional smart windows only regulate solar transmission. For the first time, we developed high thermal energy storage thermo-responsive smart window (HTEST smart window) by trapping the hydrogel-derived liquid within glasses. The excellent thermo-responsive optical property (90% of luminous transmittance and 68.1% solar modulation) together with outstanding specific heat capacity of liquid gives the HTEST smart window excellent energy conservation performance. Simulations suggested that HTEST window can cut off 44.6% heating, ventilation, and air-conditioning (HVAC) energy consumption compared with the normal glass in Singapore. In outdoor demonstrations, the HTEST smart window showed promising energy-saving performance in summer daytime. Compared with conventional energy-saving glasses, which need expensive equipment, the thermo-responsive liquid-trapped structure offers a disruptive strategy of easy fabrication, good uniformity, and scalability, together with soundproof functionality that opens an avenue for energy-saving buildings and greenhouses.

Experimental study of multiple magnetic transitions in micrometer and nano-grain sized Ni3TeO6-type oxide

We report the experimental results of dc and ac magnetic susceptibility (χdc and χac) and specific heat (CP) measurements of the powdered Ni3TeO6-type oxide. Upon decreasing the grain size from micrometer (bulk) to nanometer range, the magnetic measurements have indicated multiple transitions, viz., a cusp at paramagnetic to ferrimagnetic (FIM) transition temperature (TC) ∼ 78 K, an antiferromagnetic (AFM) transition temperature (TN) ∼ 52 K, and a re-entrant spin glass (RSG) transition at Tm2 ∼ 7.49 K. The ferrimagnetic transition temperature TC is found to be highly sensitive to dc magnetic fields, where superposition of a small dc field (10 Oe) in the ac susceptibility measurement or the application of a dc magnetic field of up to 100 Oe in the dc magnetic measurement is enough to suppress the observed TC at 78 K. The CP(T) measurement also revealed a RSG state at lower temperatures for the sample with nano-sized grains. The absence of any sharp peak at TC in the CP(T) curves implies the absence of a true long-range FIM spin order in the samples. The coexistence of a RSG state with multiple magnetic transitions is understood as an effect of competitive AFM and FIM phases in the Ni3TeO6-type structure.

Heat Capacity of Compounds in the Bi2O3–TiO2 System

The Bi12TiO20, Bi4Ti3O12, and Bi2Ti4O11 bismuth titanates have been prepared by solid-state reactions, via multistep firing of stoichiometric mixtures of their constituent oxides in air at temperatures from 1003 to 1273 K (Bi12TiO20, to 1123 K). The heat capacity of polycrystalline samples of the synthesized compounds has been determined by differential scanning calorimetry in the temperature range 330–1050 K. The Cp(T) curves of Bi4Ti3O12 and Bi2Ti4O11 show peaks at temperatures of 943 and 509 K, respectively, due to ferroelectric phase transitions. The experimental data have been used to evaluate the enthalpy increment, entropy change, and reduced Gibbs energy change of the bismuth titanates.

Breakdown of One-to-One Correspondence in Energy and Volume in a High-Pressure Heat-Treated Zr-Based Metallic Glass During Annealing

The glassy state of a high-pressure heat-treated Zr50Cu40Al10 metallic glass was investigated from energetic and volumetric perspectives. The specific heat (Cp) data of initial heating and subsequent cooling from the supercooled liquid region indicates that the sample behaviour cannot be explained simply by the derivative of the well-known enthalpy (H)–temperature (T) curve. Unlike the Cp data, the thermal-expansion coefficient (α) value increased monotonically during the first heating step, which suggests the collapse of a one-to-one correspondence between the energy and volume during the process. The α data of the cooling process follow almost the same path as those of the as-cast process, whereas the corresponding Cp curves do not. This result implies that the volume appears to be more sensitive to obeying external heat compared with energy, which highlights the different time scale for achieving an equilibrium state in energy and volume. The second heating data of the Cp and α exhibit an inverse relationship against the corresponding first heating set, which confirms the breakdown of a one-to-one correspondence during annealing. The newly constructed energy–density diagram shows that the treated sample is rejuvenated volumetrically but is relaxed energetically during aging, which has never been observed experimentally previously.

Investigation of Power Coefficient Behaviors of the Parabolic Wind Rotor Due to its Variable Geometry Parameters

In this work, the effect of changing the diameter of the rotor (2R), the height of the rotor (H), the number of blades (N) and the length of the blade section (C) on the power factor (Cp) were studied. The results were presented in the form of power factor (Cp) curves as a function of tip speed ratio (l 0 ). The aerodynamic mathematical model Multi Streamtube was implemented by a computer program that was designed using Microsoft Visual Basic. A total of 57 configurations were utilized for the investigation of the effects of the various rotor design parameters on the Cp of the rotor. The results indicated that increasing rotor height to diameter ratio (H/R) leads to a decrease in Cp over low tip speed ratio range for all values of solidity,s, (NC/R) investigated. However, higher values of (H/R) result in a raise in Cp over high tip speed ratio range for values of (NC/R) less than 0.2 approximately. Thus, it seems that higher (H/R) values constitute an advantage for fast rotating rotors (low (NC/R) and high tip speed ratio).