Cavity Radiation Research Articles

Effective Thermal Conductivity and Heat Transfer Characteristics of a Series of Ceramic Triply Periodic Minimal Surface Lattice Structure

Triply periodic minimal surface (TPMS) structures with high surface area, high porosity, complex pore channels, and pore size distribution have great potential for application in thermal metamaterials and thermal engineering applications. To demonstrate the possibility of the use of TPMS structures as thermal metamaterials, the thermal insulation properties and heat transfer mechanisms of TPMS structures are investigated in detail. The results show that modulation of the volume fraction to within 15% by a rational geometric design indicates the possibility to obtain excellent lightweight properties. The effective thermal conductivity is within 0.25 W m−1 K−1, which is much lower than this component, indicating that the TPMS structure is designed to reduce the effective thermal conductivity and provide a lightweight design. However, in a high‐temperature environment, reasonable structural parameters can shield the cavity radiation in the TPMS structure and play an effective role to provide high‐temperature thermal insulation. Finally, based on the relationship between structural parameters and thermal insulation performance, a dynamic density TPMS‐graded structure is proposed, which exhibits a better thermal insulation performance than the conventional TPMS structure both at room temperature and at high temperature.

Entanglement Dynamics Induced by a Three-Level Laser Coupled to the Squeezed Vacuum Reservoir

We have studied the squeezing and entanglement properties of the light induced by a three-level laser coupled to the squeezed vacuum reservoir. Applying the pertinent master equation, we have obtained the evolution equations for the cavity mode variables. Using the solutions of the resulting equations, the squeezing properties, entanglement amplification, and the normalized second-order correlation function of the cavity radiation are described. We have seen that the light generated by a three-level laser is in a squeezed state, and the squeezing occurs in the plus quadrature. In addition, we have also established that the effect of the squeezed parameter increases the mean and variance of the photon number. It is found that the squeezing and entanglement in the two-mode light are directly related. As a result, an increase in the degree of squeezing directly leads to an increase in the degree of entanglement and vice versa. This shows that, whenever there is squeezing in the two-mode light, there exists an entanglement in the system.

A study of the quasi-probability distributions of the Tavis–Cummings model under different quantum channels

We study the dynamics of the spin and cavity field of the Tavis–Cummings model using quasi-probability distribution functions and the second-order coherence function, respectively. The effects of (non)-Markovian noise are considered. The relationship between the evolution of the cavity photon number and spin excitation under different quantum channels is observed. The equal-time second-order coherence function is used to study the sub-Poissonian behavior of light and is compared with the two-time second-order coherence function in order to highlight the (anti)-bunching properties of the cavity radiation.

Investigating Predictive Factors of Dysphagia and Treatment Prolongation in Patients with Oral Cavity or Oropharyngeal Cancer Receiving Radiation Therapy Concurrently with Chemotherapy

Radiation therapy (RT) treatment for head and neck cancer has been associated with dysphagia manifestation leading to worse outcomes and decrease in life quality. In this study, we investigated factors leading to dysphagia and treatment prolongation in patients with primaries arising from oral cavity or oropharynx that were submitted to radiation therapy concurrently with chemotherapy. The records of patients with oral cavity or oropharyngeal cancer that received RT treatment to the primary and bilateral neck lymph nodes concurrently with chemotherapy were retrospectively reviewed. Logistic regression models were used to analyze the potential correlation between explanatory variables and the primary (dysphagia ≥ 2) and secondary (prolongation of total treatment duration ≥ 7 days) outcomes of interest. The Toxicity Criteria of the Radiation Therapy Oncology Group (RTOG) and the European Organization for Research and Treatment of Cancer (EORTC) were used to evaluate dysphagia. A total of 160 patients were included in the study. Age mean was 63.31 (SD = 8.24). Dysphagia grade ≥ 2 was observed in 76 (47.5%) patients, while 32 (20%) experienced treatment prolongation ≥ 7 days. The logistic regression analysis showed that the volume in the primary site of disease that received dose ≥ 60 Gy (≥118.75 cc, p < 0.001, (OR = 8.43, 95% CI [3.51-20.26]) and mean dose to the pharyngeal constrictor muscles > 40.6 Gy (p < 0.001, OR = 11.58, 95% CI [4.84-27.71]) were significantly associated with dysphagia grade ≥ 2. Treatment prolongation ≥ 7 days was predicted by higher age (p = 0.007, OR = 1.079, 95% CI [1.021-1.140]) and development of grade ≥ 2 dysphagia (p = 0.005, OR = 4.02, 95% CI [1.53-10.53]). In patients with oral cavity or oropharyngeal cancer that receive bilateral neck irradiation concurrently with chemotherapy, constrictors mean dose and the volume in the primary site receiving ≥ 60 Gy should be kept below 40.6 Gy and 118.75 cc, respectively, whenever possible. Elderly patients or those that are considered at high risk for dysphagia manifestation are more likely to experience treatment prolongation ≥ 7 days and they should be closely monitored during treatment course for nutritional support and pain management.

Long-term outcomes of modern multidisciplinary management of sinonasal cancers: The M. D. Anderson experience.

To report long-term outcomes of modern radiotherapy for sinonasal cancers. A retrospective analysis of patients with sinonasal tumors treated with intensity-modulated radiotherapy or proton therapy. Multivariate analysis was used to determine predictive variables of progression free survival (PFS) and overall survival (OS). Three hundred and eleven patients were included, with median follow-up of 75 months. The most common histologies were squamous cell (42%), adenoid cystic (15%), and sinonasal undifferentiated carcinoma (15%). Induction chemotherapy was administered to 47% of patients; 68% had adjuvant radiotherapy. Ten-year local control, regional control, distant metastasis free survival, PFS, and overall survival rates were 73%, 88%, 47%, 32%, and 51%, respectively. Age, non-nasal cavity tumor site, T3-4 stage, neck dissection, and radiation dose were predictive of PFS, while age, non-nasal cavity tumor site, T3-4 stage, positive margins, neck dissection, and use of neoadjuvant chemotherapy were predictive of OS. There was a 13% rate of late grade ≥3 toxicities. This cohort of patients with sinonasal cancer treated with modern radiotherapy demonstrates favorable disease control rate and acceptable toxicity profile.

Conjugate Radiation and Convection Heat Transfer Analysis in Solar Cooker Cavity Using a Computational Approach

The heat loss caused by radiation and persistently laminar natural convection in a solar cooker cavity that has a rectangular cavity or a trapezoidal cavity are computationally explored in this paper. The hot bottom and the adiabatic side wall are both taken into account. Two possibilities are considered for the top wall: first, a cold wall, and, second, losses from wind-induced convection and radiation. The parameters of heat loss in various depth cavities have been investigated along with a variety of external heat transfer coefficient values above the glass surface were simulated. The emissivity of the bottom surface, the absolute temperature ratio, on heat loss from the considered geometries, are also calculated. Analysis of the cavity’s flow pattern and isotherms at different depths has been conducted, and it is discovered that the total rate of heat transfer from the top wall increases as the bottom wall’s emissivity, the absolute temperature ratio, the Rayleigh number, and the external Nusselt number all increase. While radiation heat transfer increases monotonically, convective heat transfer rates shift slightly as these values rise at different emissivities of the bottom, and the opposite occurs when Ra increases at the same emissivity. Furthermore, it has been discovered that as the aspect ratio of the cavity increases, the overall Nusselt number decreases. A trapezoidal cavity has a faster rate of heat transfer than a rectangular cavity for the same parameters. Generic empirical correlations were developed for the total average Nusselt number concerning all influencing parameters.

Microscopic Theory of Multimode Polariton Dispersion in Multilayered Materials

We develop a microscopic theory for the multimode polariton dispersion in materials coupled to cavity radiation modes. Starting from a microscopic light-matter Hamiltonian, we devise a general strategy for obtaining simple matrix models of polariton dispersion curves based on the structure and spatial location of multilayered 2D materials inside the optical cavity. Our theory exposes the connections between seemingly distinct models that have been employed in the literature and resolves an ambiguity that has arisen concerning the experimental description of the polaritonic band structure. We demonstrate the applicability of our theoretical formalism by fabricating various geometries of multilayered perovskite materials coupled to cavities and demonstrating that our theoretical predictions agree with the experimental results presented here.

The Quantum Features of Correlated Photons with the Effect of Phase Fluctuation

We theoretically investigate the effect of phase fluctuations on correlated photons resulting from nondegenerate three-level atoms under the cavity radiation. The photon statistics, photon number correlation, and entanglement properties of the system have been calculated employing the dynamical equation of the system. It is shown that, for the sub-Poissonian photon statistics, the degree of correlation increases with the atomic pumping rate, and the entanglement varies with phase fluctuations, rather than with the atomic pumping rate. The proposed system is well suitable for the quantum information processing.

Turbulent Free Convection and Thermal Radiation in an Air-Filled Cabinet with Partition on the Bottom Wall

Computational analysis is performed for turbulent free convection and surface thermal radiation in an air-filled cavity with solid obstacle on the bottom wall. A partition of finite thickness is considered, the position, length, and heat conductivity of which vary for certain values of the Rayleigh number. The coupled heat transmission by thermal radiation, free convection and heat conduction through the solid obstacle and walls is studied. The governing equations are solved by the finite difference method. This work also contains a detailed description of the computational grid thickening procedure. Temperature patterns and airflow field are scrutinized for some specific conditions using streamlines and isotherms. The overall heat transfer within the cavity is analyzed in terms of the mean convective and radiative Nusselt numbers, and many of the data are presented in detail for various partition positions, heat conductivities of the partition and walls of the cavity, and Rayleigh numbers. The results report that the participation of partitions within the cavities in the heat exchange processes decreases the overall heat transfer rate compared to the simpler case of cavities without partitions.

Assessment of cavitation noise in a centrifugal pump using acoustic finite element method and spherical cavity radiation theory

To examine the cavitation noise characteristics of centrifugal pumps, the combination of test and simulation was applied in this study. The numerical method is based on spherical cavity radiation theory and the acoustic finite element method. A multi-field synchronized test-rig was built to study and validate the numerical results under cavitating flow and cavitation noise conditions. The three-dimensional unsteady flow-field simulation was carried out inside the centrifugal pump based on DES and the improved-RZGB cavitation model. The constructed numerical method for cavitation noise was used to solve the acoustic-field based on the flow-field solutions. The test–simulation comparison reveal that the numerical simulation results are consistent and reliable. The development of cavitation has a stronger influence on the strong vorticity regions in the impeller flow channel, and the vortex has a promotional-effect on the formation of cavitation. With the same cavitation number, the acoustic-power on the blade suction-side is greater than the pressure-side of the blade. As the cavitation number decreases, the pulsating radiated noise of cavitation volume is the primary noise-source for the increased acoustic-power value. At this stage, the SPL and total SPL at the model pump inlet show a decreasing trend during the severe cavitation-stage.

Entanglement of mechanical modes in a doubly resonant optomechanical cavity of a correlated emission laser

We explore the extent of the induced entanglement of the mechanical modes that can be attributed to the transfer of coherence from two-mode cavity radiation in a doubly resonant optomechanical cavity. It is expected that this scheme can support a generation of mechanical oscillations with a robust degree of entanglement combined with significant controllability. The entanglement is found to be sensitive to the specific choices of the frequencies of the bichromatic drive laser. It also turns out that the degree of entanglement would be enhanced with increasing rates of injection of the atoms but with decreasing initial lengths of a doubly resonant cavity and atomic decay rates. In addition, the entanglement is found to behave qualitatively in the same way for the measures of entanglement we have applied. Since the scheme we considered can possibly be implemented with current technology and allows the quantum features of cavity radiation to be accessible for application, we anticipate that it can be utilized in the realization of continuous-variable quantum information processing.

Study on the Effect of Radiant Insulation Panel in Cavity on the Thermal Performance of Broken-Bridge Aluminum Window Frame

Windows have a great impact on building energy consumption, and the thermal performance of window frames directly affects its energy-saving potential. In this paper, a novel method is proposed to optimize the thermal performance of commercially available broken-bridge aluminum window frames, by incorporating radiant insulation panels (RIPs) into the window frame cavity. A typical aluminum alloy window frame heat transfer model is theoretically analyzed and validated, and the effects of key design parameters on the equivalent thermal conductivity (ETC) of the cavity radiation heat transfer and the heat transfer coefficient (U-factor) of window frames are quantitatively analyzed by a finite element simulation method using the THERM software. Moreover, the RIP, the insulation material filling, and low surface emissivity on the thermal performance of the window frame are compared and analyzed. The results show that the RIP is better placed in the middle, the width and quantity of RIPs are negatively correlated with the U-factor, while the surface emissivity of RIPs is positively correlated with the U-factor. Adding RIPs in the cavity can reduce the U-factor of the window frame by more than 7.43%, slightly lower than 8.97% for the filling type, but significantly higher than 0.81% for the low-emissivity type. Inserting RIPs is a simple and effective way to reduce the U-factor of the window frame and have a great potential of use.

High-temperature two-layer integrated receiver storage for concentrating solar power systems

Abstract An integrated receiver storage for a beam-down concentrating solar power (CSP) plant enables simplifying the system layout and reducing the costs. Here a two-layer integrated receiver storage (TLIRS) system design is proposed consisting of a cavity receiver and a two-layer packed-bed storage. The first layer is a porous ceramic and the second one is rocks. To enable performance optimization of the system, models for cavity radiation, two-phase transient heat transfer and local thermal nonequilibrium were derived and validated. The thermal performance of the TLIRS system was assessed and characterized by the absorbing, charging, discharging and overall efficiencies and by the solar-to-exergy conversion ratio. The results indicate that the porous ceramic layer significantly enhances the absorption of solar irradiance and thus improves the thermal efficiencies. For CSP applications, the TLIRS system potentially achieves high thermal performance in repetitive charging and discharging cycles.

Study of banana preservation extension by UVC radiation in precise monitoring LED irradiation cavity.

Ultraviolet C (UVC) radiation has been considered a possible option to alleviate the seriousness of black spots on bananas during preservation which help increase economic efficiency. In this study, using 275nm UVC light-emitting diodes (LEDs), a preliminary cavity with dimensions of 30 × 30 × 30cm was designed and fabricated to aid in reducing black spots on bananas with the aim of application in the factory conveyor belts. The UVC irradiance distribution was thoroughly monitored for many sections at different box heights in both simulation and measurement, with a dominant range of 6-9W/m2 in the middle. Afterward, trials were conducted in vitro and in vivo at different selected UVC doses. The results in vitro revealed that a dose of over 0.36kJ/m2 has an excellent effect on inhibiting the colonial germination of fungal Colletotrichum musae, a common species of fungi causing black spot disease on bananas. In vivo conditions, with a short exposure time of around 5s, the black spots on UVC-irradiated banana peel significantly reduced with minimal sensory damage compared to a control banana via observation after seven days from treatment. Finally, the optimal UVC dose is proposed from 0.030 to 0.045kJ/m2 for the one-time treatment when considering the upper surface of the banana. With flexibility advantage and short exposure time, the fabricated cavity (box) promises to bring a lot of application potential to aid banana preservation in factories and households.

Thermal performance and airflow analysis of a new type of Double Skin Façade for warm climates: An experimental study

Double Skin Facades (DSF) integrated with shading devices are increasingly implemented in tall buildings to protect the building from excessive solar radiation. However, the potential overheating of DSF in warm climates leads to lower DSF performance in hot seasons. In this study, a new type of DSF named Interstitial Slat-blind DSF (IS-DSF) has been introduced featuring wind-induced ventilation and insulated shading devices. This research aims to highlight the capabilities of the proposed DSF in a warm climate and identify contributing environmental and geometrical factors for overheating risk reduction of IS-DSF. To this end, an experimental study was conducted in a scaled room located in an outdoor environment on summer days in Brisbane, Australia. First, the test room with and without IS-DSF was studied to assess the performance of IS-DSF for controlling indoor temperature. Next, a parametric evaluation was conducted including geometrical variables (cavity width, slat blind angle) and environmental factors (approaching wind speed and direction, air velocity in the cavity and solar radiation). It was found that the most influential factor for controlling the cavity overheating risk is the air velocity inside the cavity while the effect of blind slats angle is negligible. A cavity airflow velocity threshold was estimated beyond which the overheating of the IS-DSF cavity becomes negligible. Correlations were established to predict cavity airflow velocity from approaching wind speed for IS-DSF with different lateral openings. Overall, IS-DSF showed a reduction in surface temperature of the cavity as a potential advantage compared to conventional DSF to reduce the overheating risk of the DSF's cavity in a warm climate. • Addressing the overheating risk of Double Skin Facade (DSF) in warm climates. • IS-DSF is introduced featuring vertical openings and insulated shading devices. • An air velocity threshold for overheating estimation is experimentally identified. • Correlations are established to predict the air velocity in DSF's cavity.

The Effect of Microchannel Cavity on the Bulk Acoustic Wave-Induced Acoustofluidics: Numerical Investigation

Acoustofluidics is emerging as an effective approach to manipulating microparticles and cells no matter their optical, electrical, and magnetic properties and no requirement of pre-processing. Standing field in a microfluidic channel produced by a bulk acoustic wave (BAW) could accumulate the microparticles at the plane of the pressure node. In order to further accumulate them from a plane (2D) to a line (1D), a new strategy without significant change of the systematic setup (i.e., adding another orthogonal standing field) was proposed and evaluated numerically in a full-sized model. Concave cavity on the conventional rectangular microchannel leads to a slight increase of the maximum acoustic pressure and distortion of the wavefront, but two more vortexes close to the edge of the bottom cavity and directional acoustic radiation forces in the middle line of the microchannel (the upper part pointing downwards while the lower part upwards). Subsequently, most of the microparticles are accumulated in a very small region in the middle line of the microchannel. The effect of the cavity geometry on such a novel phenomenon was investigated. With the increase of the diameter of the cavity from 170 μm to 260 μm, the resonant frequency of the microchannel, the maximum acoustic pressure, and the maximum acoustic streaming velocity increased by 13%, 78%, and 7.1 fold, respectively. When shifting the center of the cavity, the position of 1D accumulated microparticles could be changed correspondingly. In summary, the characteristics of acoustofluidics are highly dependent on the microchannel geometry. Microparticle accumulation with a significant reduction to one dimension using only one acoustic standing field is theoretically possible by introducing an appropriate concave cavity in the conventional rectangular microchannel.

Patterns of Failure after Stereotactic Radiosurgery vs. Whole Brain Radiotherapy for Resected Brain Metastases: Central Imaging Review of the N107C/CEC.3 (Alliance) Phase III Clinical Trial

<h3>Purpose/Objective(s)</h3> Whole brain radiotherapy (WBRT) has historically been the main instrument to decrease intracranial progression after resection of brain metastases. The previously reported NCCTG N107C/CEC.3 (Alliance) randomized phase III clinical trial of WBRT vs. stereotactic radiosurgery (SRS) demonstrated that overall survival did not significantly differ between arms, while SRS was associated with less cognitive decline than WBRT. However, the initial analysis also showed that local tumor bed control (LC) was significantly worse with SRS than WBRT, with an unexpectedly low 12-month LC rate of 60.5% in patients receiving post-operative SRS. To further investigate LC, a central imaging review was performed. <h3>Materials/Methods</h3> In N107C/CEC.3, 194 patients were randomized to SRS (n=98) or WBRT (n=96). SRS dose was dependent on resection cavity volume and ranged from 12 Gy to 20 Gy all in a single fraction, and WBRT dose was 30 Gy in 10 fractions or 37.5 Gy in 15 fractions. For this analysis, patients with local failure (LF) or leptomeningeal failure that had imaging available were centrally reviewed by two radiation oncologists to verify pattern of failure. Patient and treatment characteristics were assessed for association with updated outcomes after central review using Cox proportional hazards, Pearson's chi-square, or Kruskal-Wallis tests. <h3>Results</h3> Seventy-three patients with LF or leptomeningeal failure determined by their local site were centrally reviewed. After adding patients with no LF or leptomeningeal failure, 185 (95% of total enrolled) patients were included in this analysis as 9 patients with LF did not have imaging available for central review. Of 59 patients initially determined to have LF, 20 were determined on central review to be free of LF. Accordingly, after central review post-operative SRS was no longer associated with significantly lower rates of LC than WBRT (79.2% vs. 86.5% 12-month LC, respectively, p=0.099). After central review, the interrelated variables of tumor diameter, target volume, and prescription dose were associated with risk of LF. Patients with resection cavities > 3 cm had higher rates of LF than those with smaller cavities (23.5% vs. 12.6% 12-month LF rate, respectively; p=0.010). Larger target volume was associated with increased risk of LF (HR: 1.05, 95% CI: 1.01 – 1.09, p=0.008), while higher prescription dose was associated with lower risk of LF (HR: 0.81, 95% CI: 0.67 – 0.96, p=0.018). <h3>Conclusion</h3> In contrast to the initial report, after central review SRS was not associated with significantly higher rates of LF than WBRT. Patients with larger surgical cavities had higher rates of LF, though it is unclear whether this is related to cavity size, biology, or radiation dose. Randomized data comparing single to multifraction SRS in larger surgical cavities is awaited.

Floquet Control of Optomechanical Bistability in Multimode Systems.

Cavity optomechanical systems make possible the fine manipulation of mechanical degrees of freedom with light, adding functionality and having broad appeal in photonic technologies. We show that distinct mechanical modes can be exploited with a temporally modulated Floquet drive to steer between distinct steady states induced by changes of cavity radiation pressure. We investigate the additional influence of the thermo-optic nonlinearity on these dynamics and find that it can suppress or amplify the control mechanism in contrast to its often performance-limiting character. Our results provide new techniques for the characterization of thermal properties of optomechanical systems and their control, sensing and computational applications.

Study of Fabry-Perot Cavity Design and Radiation Features of The Antenna

In this present paper we studied about the Fabry Perot cavity design and radiation features of the antenna.

Simulation of state transfer from atom to cavity radiation in atom-photon interaction in large detuning

In this research, atom-cavity entanglement in closed Jaynes – Cumming model has been used with the assumption of large detuning between atom and cavity, to simulate the state transfer from atom to cavity radiation. A two-level atom which is prepared in a half-half superposition between the ground and excited states, has been exposed to initially coherent radiation field which is far from resonance with the atom. Mixture of each subsystem, linear entropy, entanglement, Von Neumann entropy and Schmidt decomposition of composite system as a function of time, has been determined analytically, for the first time. Assuming large frequency differences between atom and radiation, the simulation is shown no energy is transferred between atom and radiation due to large detuning, even though atom-radiation entanglement took place. Also, it has been shown that a particular measurement on the atom in this composite entangled system, can project the composite system into a separable (non-entangled) state so that the radiation state is changed into a superposition of the coherent state which is called the cat state. The conditions required to transfer radiation into odd and even cat states have been particularly investigated.