Dependent Loss Research Articles

Re-evaluation of the impact of wall retention on Tritium-self-sufficiency in fusion reactors

Abstract In recent years several publications have claimed that the retention of tritium (T) in the first wall armor material poses a limitation on when a fusion reactor becomes T-self-sufficient. While the prediction on wall retention therein are correct, the model applied to assess the T-self-sufficiency is based on wrong assumptions and thus, the importance of T-retention in the first wall is greatly overestimated. In this publication the predictions on T-retention in the first wall armor components are included in state of the art residence time models of the entire T-cycle. These calculations show that T-wall-retention only affects T-self-sufficiency when the T-breeding ratio (TBR) is so low that the power plant is only marginally T-self-sufficient. For TBR values that allow for a finite T-doubling time and maintain a T-reserve inventory, the T-production must be so high, that the T-wall-retention is insignificant. The paper will explain the error in the previous T-self-sufficiency estimates, how to correct them and what this means for the conclusions drawn by previous publications. Then an augmented residence time model will be presented, that can include diffusion/trapping model based, time dependent wall loss data. This augmented model results in orders of magnitude higher T-retention in the first wall compared to current assumptions in residence time models. Still, it is negligible compared to the T-content in the entire T-cycle. Thus it can be concluded that based on current material data T-retention in the first wall armor will not affect T-self-sufficiency.

Dielectric Properties of Pristine and Green‐Synthesized Hematite Nanomaterials Vis‐À‐Vis Their Dependence on Porosity and Particle Size

ABSTRACTHematite is obtained using different concentrations of P. tuberosa flower extract. XRD and Raman studies confirm the formation of nanometric size (20–30 nm) and the corundum structure. Particle size depends on the extent of flower extract used for synthesis. Frequency and temperature dependent dielectric constant, dielectric loss, ac/dc conductivity and electric modulus have been explored. Large dielectric constant values (6 × 103−40 × 103) at low frequency under room temperature are observed. Dielectric constant () depends on frequency, temperature, particle size and porosity. The nature of the frequency dependence of can be explained with the help of the Maxwell‐Wagner‐Koop's theory. Correlation between particle size and dielectric constant is attributed to significant lattice distortion resulting from reduced grain size. AC conductivity is analyzed with Jonscher's power law, and correlated‐barrier‐hopping type of conduction mechanism is proposed in these nanomaterials. Temperature dependence of DC conductivity confirms semiconducting behavior of hematite. Investigation into the electric modulus reveals that both electrical conduction and dielectric polarization are governed by a common mechanism. Present study explores into the process of crystal growth influenced by the plant extract and examines its impact on the dielectric property.

Condition‐based maintenance policy for a multi‐component system considering stochastic dependence and quality loss

AbstractThe reliability evaluation of multi‐component systems has attracted increasing concern in academic and industrial circles. However, the research maintenance optimization for multi‐component systems is still underexplored due to the curse of dimensionality. This paper makes a novel contribution to the existing literature by proposing a condition‐based maintenance (CBM) policy for multi‐component systems with joint consideration of stochastic dependence and quality loss. The system is composed of critical and auxiliary components. The deterioration process of the critical component can be accelerated when the auxiliary one degrades to a certain state. Based on the states of the components, the operation cost of the system owing to quality loss is analyzed, and the operation cost is used as the threshold for the preventive maintenance (PM) decision. Semi‐regenerative technology is used to model the evolution process of the system, and the long‐run average cost is calculated. The optimal inspection period and PM threshold are derived by minimizing the long‐run average cost, and the stationary distribution of the system state under the optimal long‐run average cost is derived with a proposed algorithm. Sensitivity analysis is conducted to reveal the most sensitive parameter. Finally, an illustrative example is presented, and a comparison experiment with other maintenance policies is conducted to demonstrate the effectiveness of the proposed policy.

A Numerical Assessment of the Effect of Concatenating Arbitrary Uncoupled Multicore Fiber Segments on Intercore Crosstalk in Long-Haul Communication Links

Random core dependent loss (CDL) has been shown to increase the direct average intercore crosstalk (ICXT) power in long-haul uncoupled multicore fiber (MCF) links. Longer links are composed of multiple MCF segments, and random CDL may arise on these links from manufacturing imperfections. During link implementation, other random effects may arise and enhance the ICXT power. In this work, the effect of concatenating MCF segments with random characteristics on the direct average ICXT power in long-haul links is assessed numerically by studying the influence of the randomness of segment length, coupling coefficient, and random CDL on the mean, standard deviation, relative spread, and excess kurtosis of the ICXT power. The numerical results show that the segment length randomness marginally affects the ICXT power. For 2000 km long links and a 6 dB maximum random variation of the coupling coefficients, the mean almost doubles and the standard deviation almost triples, relative to considering only random CDL. However, the effect of the coupling coefficients randomness on the relative spread and excess kurtosis is reduced, not affecting significantly the nearly Gaussian distribution of the direct average ICXT power and the excess of direct average ICXT power (less than a 0.26 dB increase relative to considering only random CDL).

All-fiber spatial and wavelength gain-flattening of few-mode EDFA via mode selective coupler

The mode division multiplexing (MDM) technique together with wavelength division multiplexing (WDM) shows the great prospect to solve the capacity crunch of current standard single mode fiber (SSMF) transmission system. However, the modal and wavelength gain fluctuation fundamentally limit both the capacity and the reach of hybrid MDM-WDM transmission system. Here, we propose an all-fiber few-mode gain-flattening filter (FM-GFF) based on mode selective coupler (MSC), to effectively mitigate the gain fluctuation of few-mode erbium doped fiber amplifier (FM-EDFA) in both spatial and wavelength dimensions. With the help of genetic algorithm (GA), variable mode dependent loss spectra of cascaded MSCs can be efficiently obtained, according to the gain profile of the used FM-EDFA. Consequently, gain-flattening among all guided linearly polarized (LP) mode groups over the C-band can be realized. Simulation results reveal that, as for the spatial and wavelength gain flattening among 4/6-LP mode groups, only 5/7 cascaded MSCs are good enough to mitigate the modal and wavelength gain fluctuation from 9.89 dB and 11.79-dB to less than 0.38 dB and 0.46 dB over the C-band. Finally, we carry out experimental verification based on 2-LP mode groups gain flattening over C-band. When 3 cascaded MSCs are involved, the gain fluctuation of FM-EDFA over the C-band can be flattened from 2.46 dB to less than 0.96 dB.

Asymmetric bi-level dual-core mode converter for high-efficiency and polarization-insensitive O-band fiber-chip edge coupling: breaking the critical size limitation.

Efficient coupling between optical fibers and on-chip photonic waveguides has long been a crucial issue for photonic chips used in various applications. Edge couplers (ECs) based on an inverse taper have seen widespread utilization due to their intrinsic broadband operation. However, it still remains a big challenge to realize polarization-insensitive low-loss ECs working at the O-band (1,260-1,360 nm), mainly due to the strong polarization dependence of the mode coupling/conversion and the difficulty to fabricate the taper tip with an ultra-small feature size. In this paper, a high-efficiency and polarization-insensitive O-band EC is proposed and demonstrated with great advantages that is fully compatible with the current 130-nm-node fabrication processes. By introducing an asymmetric bi-level dual-core mode converter, the fundamental mode confined in the thick core is evanescently coupled to that in the thin core, which has an expanded mode size matched well with the fiber and works well for both TE/TM-polarizations. Particularly, no bi-level junction in the propagation direction is introduced between the thick and thin waveguide sections, thereby breaking the critical limitation of ultra-small feature sizes. The calculated coupling loss is 0.44-0.56/0.48-0.61 dB across the O-band, while achieving 1-dB bandwidths exceeding 340/230 nm for the TE/TM-polarization modes. For the fabricated ECs, the peak coupling loss is ∼0.82 dB with a polarization dependent loss of ∼0.31 dB at the O-band when coupled to a fiber with a mode field diameter of 4 μm. It is expected that this coupling scheme promisingly provides a general solution even for other material platforms, e.g., lithium niobate, silicon nitride and so on.

Wire rope isolator identification and dynamic modeling for small amplitude vibrations

Wire rope isolators are used in variety of applications to protect sensitive equipment from vibration. The nonlinear hysteretic behavior of steel wires provides advantages when compared to linear vibration isolators. This study proposes an amplitude dependent stiffness and damping model for low amplitude vibrations under axial loading, where the parameters can be determined with an experimental procedure. Comprehensive experimental results of forced vibration tests with varying loading, frequency and preload were considered in the model identification. Amplitude dependent stiffness and loss energy models were determined from the test data, and the effect of the preload and loading frequency on the model parameters were studied. It is shown, that the effect of preload and frequency is not evidently clear, while the effect of vibration amplitude is more significant. The mathematical model was further verified against measurements from base excitation loading. The proposed model can be used to study the effectiveness of the selected wire rope isolator configurations in chosen application, and to effectively perform dynamic design studies.

Design of high-efficiency InP/InGaAsP diluted waveguide for edge couplers

To transition integrated optical communication devices from laboratory settings to practical applications, efficient coupling between optical fibers and chip waveguides remains pivotal. This paper presents a systematic design of a diluted waveguide, a key component in the edge couplers of photonic integrated circuits. The primary purpose of the diluted waveguide lies in facilitating superior edge coupling with fiber waveguides, thereby seamlessly integrating external light sources into the waveguide structure. To commence, we employ the transfer matrix and effective refractive index techniques to simplify the 3-dimensional diluted waveguide into 2-dimensional multi-layer slab waveguides. By computing the field distribution of the fundamental mode within the diluted waveguide, the fiber-to-waveguide coupling efficiency can be derived using a simplified overlap equation and optimized diluted waveguide structure through particle swarm optimization algorithms. Consequently, we achieve a remarkable fiber-to-waveguide coupling efficiency exceeding 95% for TE-mode and 92% for TM-mode, with a polarization dependent loss (PDL) of merely 0.13 dB. Interestingly, the optimized diluted waveguide exhibits quasi-single mode behavior, as the fundamental mode containing 98% of the total energy propagates within it. Additionally, the diluted waveguide edge coupler demonstrates favorable alignment tolerance, with 1-dB excess losses of ±2.3 μm and (−2.5, +3) μm along the horizontal and vertical directions, respectively. Notably, our approach offers a versatile methodology for designing multi-layer waveguides across various materials. This method has the potential to be universally applied.

O-band and C-band dual-polarization SMF-28 edge coupler with SiON taper cladding based on silicon nitride platform.

Optical communication is progressing towards low power consumption and lightweight solutions, necessitating the integration of multispectral output capabilities within a single optical module. We demonstrate a SiN photonic platform-based edge coupler for a standard single mode fiber (SMF) that enables operation in both the O-band and C-band simultaneously. The device is composed of a multi-segment SiN inverse taper and SiON taper cladding with specific refractive index. The measured edge coupler exhibits a coupling loss of less than 1 dB/facet, 0.5 dB bandwidth exceeding 100 nm from 1260 nm to 1360 nm; and a coupling loss of less than 2 dB/facet, 1 dB bandwidth exceeding 100 nm from 1500 nm to 1600 nm. Furthermore, the polarization dependent loss (PDL) remained less than 0.3 dB throughout the measurement range.

Activated SKN-1 alters the aging trajectories of long-lived C. elegans mutants.

In the presence of stressful environments, the SKN-1 cytoprotective transcription factor is activated to induce the expression of gene targets that can restore homeostasis. However, chronic activation of SKN-1 results in diminished health and a reduction of lifespan. Here we demonstrate the necessity of modulating SKN-1 activity to maintain the longevity-promoting effects associated with genetic mutations that impair daf-2/insulin receptor signaling, the eat-2 model of caloric restriction, and glp-1-dependent loss of germ cell proliferation. A hallmark of animals with constitutive SKN-1 activation is the age-dependent loss of somatic lipids and this phenotype is linked to a general reduction in survival in animals harboring the skn-1gf allele, but surprisingly, daf-2lf; skn-1gf double mutant animals do not redistribute somatic lipids which suggests the insulin signaling pathway functions downstream of SKN-1 in the maintenance of lipid distribution. As expected, the eat-2lf allele, which independently activates SKN-1, continues to display somatic lipid depletion in older ages with and without the skn-1gf activating mutation. In contrast, the presence of the skn-1gf allele does not lead to somatic lipid redistribution in glp-1lf animals that lack a proliferating germline. Taken together, these studies support a genetic model where SKN-1 activity is an important regulator of lipid mobilization in response to nutrient availability that fuels the developing germline by engaging the daf-2/insulin receptor pathway.

Ruin probability for heavy-tailed and dependent losses under reinsurance strategies

The frequency and severity of extreme events have increased in recent years in many areas. In the context of risk management for insurance companies, reinsurance provides a safe solution as it offers coverage for large claims. This paper investigates the impact of dependent extreme losses on ruin probabilities under four types of reinsurance: excess of loss, quota share, largest claims, and ecomor. To achieve this, we use the dynamic GARCH-EVT-Copula combined model to fit the specific features of claim data and provide more accurate estimates compared to classical models. We derive the surplus processes and asymptotic ruin probabilities under the Cramér–Lundberg risk process. Using a numerical example with real-life data, we illustrate the effects of dependence and the behavior of reinsurance strategies for both insurers and reinsurers. This comparison includes risk premiums, surplus processes, risk measures, and ruin probabilities. The findings show that the GARCH-EVT-Copula model mitigates the over- and under-estimation of risk associated with extremes and lowers the ruin probability for heavy-tailed distributions.

Multimode interference coupler based on general interference for integrated optical and quantum optic devices: a review

Integrated optics play important role in the development for optical network devices, optical processing, instrumentation and quantum information device. Here, multimode interference (MMI) coupler is one of basic component preferred for these integrated optic devices in which MMI coupler based on general interference (GIMMI) has been focused for large scale integrated optic devices because of compact size in comparison to MMI coupler based restricted interference (RIMMI). In this paper, we have reviewed different GIMMI structures reported previously. Different waveguide materials are mentioned and compared for fabrication of GIMMI device. The coupling behaviors and modal analysis of GIMMI couplers and their different tapered structures are estimated by using simple model based on sinusoidal modes showing reduced coupling lengths in down tapered structures in comparison to other structures. The excess loss, polarization dependence loss and crosstalk versus fabrication tolerances are obtained to compare their performances revealing almost same losses and fabrication tolerance. The paper reports the use of the GIMMI coupler in wavelength multiplexing, power splitting, switching, optical processing. Finally, Quantum optic application of GIMMI coupler is shown indicating high quantum fidelity of 50:50 coupling ratio.

Statistical characterization of the effect of random core loss on the intercore crosstalk in long-haul uncoupled multicore fiber links.

We characterize the statistical properties of direct average intercore crosstalk (ICXT) in long-haul uncoupled multicore fiber (MCF) links consisting of concatenated MCF segments, where core dependent loss (CDL) in each segment varies randomly. Numerical simulation results show that the direct average ICXT power at the output of long-haul MCF links with random CDL is well described by a Gaussian distribution. A statistical distribution, which accounts for only two values of core loss (the highest and lowest core loss) with equal probability, is proposed as the worst-case distribution of core loss resulting in the maximum excess of direct average ICXT power. With this distribution, practical values of random CDL, 20 MCF segments per span and 2000 km-long links, analytical and simulation results show the maximum excess of direct average ICXT power does not exceed 0.25 dB, being further lower for a higher number of segments. An analytical approximation for the maximum excess of direct average ICXT power in long-haul uncoupled MCF links with similar spans is presented. Demonstrating high accuracy (with less than 0.02 dB discrepancy relative to simulation results in all cases evaluated), this approximation provides a simple and efficient means for estimating the worst-case impact of random CDL on ICXT power in long-haul MCF links.

Forecasting reserve risk for temporal dependent losses in insurance

Forecasting reserve risk for temporal dependent losses in insurance

Comments on the dielectric spectroscopy results on a new series of fluorinated hydrogen-bonded liquid crystals

Recently, a work entitled “Synthesis, thermal, dielectric and electro-optic properties of new series of fluorinated hydrogen-bonded liquid crystals” is published by M. Derbali et al., in J Mol Liq, 367 (2022) 120510. Authors reported SmA and SmC mesophases in the synthesised liquid crystalline materials. However, dielectric data reported here are erroneous when tested even from some fundamental aspects. Inadvertent omissions by the authors in presenting and explaining the dielectric results in terms of frequency dependent permittivity and loss are discussed here so that appropriate precautions may be taken by the readers to avoid such fundamental gross mistakes. Some problems related to other studies are also discussed in brief.

Trajectory pattern of serially measured acute kidney injury biomarkers in critically ill patients: a prospective observational study

BackgroundThe clinical value of the trajectory of temporal changes in acute kidney injury (AKI) biomarkers has not been well established among intensive care unit (ICU) patients.MethodsThis is a single-center, prospective observational study, performed at a mixed ICU in a teaching medical institute in Tokyo, Japan. Adult ICU patients with an arterial line and urethral catheter were enrolled from September 2014 to March 2015. Patients who stayed in the ICU for less than 48 h and patients with known end-stage renal disease were excluded from the study. Blood and urine samples were collected for measurement of AKI biomarkers at 0, 12, 24, and 48 h after ICU admission. The primary outcome was major adverse kidney events (MAKE) at discharge, defined as a composite of death, dialysis dependency, and persistent loss of kidney function (≥ 25% decline in eGFR).ResultsThe study included 156 patients. Serum creatinine-based estimated glomerular filtration rate (eGFR), plasma neutrophil gelatinase-associated lipocalin (NGAL), and urinary liver-type fatty acid-binding protein (uL-FABP) were serially measured and each variable was classified into three groups based on group-based trajectory modeling analysis. While the trajectory curves moved parallel to each other (i.e., “low,” “middle,” and “high”) for eGFR and plasma NGAL, the uL-FABP curves showed distinct trajectory patterns and moved in different directions (“low and constant,” “high and exponential decrease,” and “high and exponential increase”). These trajectory patterns were significantly associated with MAKE. MAKE occurred in 16 (18%), 16 (40%), and 9 (100%) patients in the “low and constant,” “high and exponential decrease,” and “high and exponential increase” groups, respectively, based on uL-FABP levels (p-value < 0.001). The initial value and the 12-h change in uL-FABP were both significantly associated with MAKE, even after adjusting for eGFR [Odds ratio (95% confidence interval): 1.45 (1.17–1.83) and 1.43 (1.12–1.88) for increase of initial value and 12-h change of log-transformed uL-FABP by 1 point, respectively].ConclusionsTrajectory pattern of serially measured urinary L-FABP was significantly associated with MAKE in ICU patients.

Synthetic photonic lantern characterization and power regulation with intensity superposition mode decomposition.

Photonic lanterns (PLs) enable to convert the spatial modes, making it possible to simply add/drop modes in multimode division multiplexing (MDM) systems. The parameters of PLs have a significant impact on the modal purity, signal quality, transmission distance, and efficiency. This paper proposes a method for the synthetic characterization and power regulation of PLs with multi-channel intensity superposition mode decomposition (MD). The observation reveals that the single channel on the charge-coupled device (CCD) comprises a combination of the fundamental and higher mode fields. However, when the multi-channel is input together, the intensity of each few-mode spot is superimposed on the CCD, and the parameters that cannot be acquired by a single channel can be obtained through the detection of multi-channel input. This offers a novel avenue for optimizing the PLs. Thus, the insertion loss (IL), modal dependent loss (MDL), mode conversion efficiency (MCE), crosstalk, and mode multiplexing power ratio difference (MMPRD) can be obtained. Furthermore, the power regulation is implemented based on the multi-channel intensity superposition MD. The difference between the two modes before power control at the output of the PL is 0.28 dB. However, after implementing power control measurements, this difference was reduced to 0.05 dB, facilitating power equalization throughout the entire communication system.

Free-standing microscale photonic lantern spatial mode (De-)multiplexer fabricated using 3D nanoprinting

Photonic lantern (PL) spatial multiplexers show great promise for a range of applications, such as future high-capacity mode division multiplexing (MDM) optical communication networks and free-space optical communication. They enable efficient conversion between multiple single-mode (SM) sources and a multimode (MM) waveguide of the same dimension. PL multiplexers operate by facilitating adiabatic transitions between the SM arrayed space and the single MM space. However, current fabrication methods are forcing the size of these devices to multi-millimeters, making integration with micro-scale photonic systems quite challenging. The advent of 3D micro and nano printing techniques enables the fabrication of freestanding photonic structures with a high refractive index contrast (photopolymer-air). In this work we present the design, fabrication, and characterization of a 6-mode mixing, 375 µm long PL that enables the conversion between six single-mode inputs and a single six-mode waveguide. The PL was designed using a genetic algorithm based inverse design approach and fabricated directly on a 7-core fiber using a commercial two-photon polymerization-based 3D printer and a photopolymer. Although the waveguides exhibit high index contrast, low insertion loss (−2.6 dB), polarization dependent (−0.2 dB) and mode dependent loss (−4.4 dB) were measured.

Abstract A015: Novel genetic driver for the genesis of muscle invasion in bladder cancer

Abstract Non-muscle invasive bladder cancer (NMIBC) is a heterogeneous type of urothelial carcinoma with a substantial risk (&amp;gt;50%) of tumor progression and muscle invasion. Our sequential studies uniquely unveiled the availability of Retinal Degeneration Protein 3 (RD3) in human adult/fetal tissues and recognized its functional significance in tumor evolution. Herein, we investigated the relevance of RD3 in coordinating de novo MIBC from NMIBC. Compared to the low-grade tumor, RD3 is significantly lost (mRNA, qPCR; protein, ELISA) in grade III and IV patient derived NMIBC cells. In a cohort of (n=55) NMIBC patients, RD3-loss associated with increased tumor invasive potential (complete loss in highly invasive T4), metastasis (vs. primary tumors), therapy pressure (insignificant levels in progressive disease that defies therapy), disease recurrence, and death (custom archived TMA with automated RD3 IHC).Crucially, we observed a significant low-is-worse association to overall survival (p=7.30E-03, hazard ratio (HR) of 5.161), relapse-free survival (p=4.464E-02, HR = 2.328), and progression-free survival (p=7.00E-0.4, HR = 3.264). Further, radio-resistant cells exposed to fractionated irradiation (FIR, 2Gy/Day for 5 days) to a total dose of 10 or 20Gy displayed a dose dependent loss of RD3 recognizing an ongoing acquisition of RD3-loss with therapy pressure. More interestingly, Grade I or III bystander cells (BSE) co-cultured with FIR-exposed cells displayed anew acquisition of RD3-loss and displayed tumor grade-dependent increase (vs. mock-irradiated) in NFkB transcriptional activity (EMSA) and the activation of NFkB trans-activated pro-survival molecules (QPCR profiling of 89 NFkB targets). Together, these results clearly depict that RD3 regulates NMIBC disease pathogenesis, dissemination, acquired loss of RD3 with therapy pressure and further implies its role in the evolution of de novo MIBC from NMIBC. Funding: DOD CA-210339, OCAST-HR19-045, NIH-P20GM103639, NIH-NCI-P30CA225520 and TSET-R23-03. Citation Format: Sreenidhi Mohanvelu, Poorvi Subramanian, Sabir Salim, Dinesh Babu Somasundaram, Sheeja Aravindan, Natarajan Aravindan. Novel genetic driver for the genesis of muscle invasion in bladder cancer [abstract]. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2024 May 17-20; Charlotte, NC. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(10_Suppl):Abstract nr A015.

Crystal structure and dielectric properties of Ln2Ti2SiO9 (Ln = Pr and Nd)

Low loss and high dielectric constant materials are essentially desired for wide varieties of applications in electronics and communication technology. Herein the structure and dielectric properties of two titanosilicates, Ln2Ti2SiO9, for Ln = Pr3+ and Nd3+ are reported. Both materials are isostructural and have layered structure with layers of [LnTi2SiO9]3- and Ln3+ ions. Electrical properties of both have been analyzed by using the temperature and frequency dependent permittivity, loss, conductivity and modulus data. At room temperature, appreciable relative permittivity (35 for Nd2Ti2SiO9 and 22 for Pr2Ti2SiO9 over the frequency range of 100 Hz to 5 MHz) and low dielectric loss (like 0.007–0.03 at 100 Hz and 10−4-10−3 at 1 MHz). Analysis of dc-conductivity data of both compounds indicate that the conduction in both materials is due to the correlated barrier hopping (CBH) of polarons. The relaxation peak of modulus spectra indicates more non-Debye like relaxation in Pr2Ti2SiO9 than that in Nd2Ti2SiO9, and that is possibly due to increased correlation in the dynamics of hopping polarons in Pr2Ti2SiO9.