Large Gain Research Articles

Enhanced 2 μm emission behavior and energy transfer in Ho3+/Yb3+ co-doped bismuth-tellurite fiber-core glasses by CeO2

Ho3+/Yb3+ co-doped and Ho3+/Yb3+/Ce3+ tri-doped 85TeO2–5Bi2O3–10ZnO glasses were synthesized by the melt-quenching method. The structural and spectral properties were investigated comprehensively according to Raman, absorption, and fluorescence spectra. By evaluating the energy transfer process, the 2 μm emission behavior has been enhanced effectively with the introduction of a glass network modifier (CeO2), which can be ascribed to the population of Ho3+: 5I7 accelerated by cross-relaxation (CR) between Ho3+ and Ce3+. A large emission cross-section (1.11 × 10−20 cm2) and gain coefficient (2.12 cm−1) have been obtained of Ho3+ at around 2 μm band in TBZHYC2 glass, where a significant advancement has been achieved compared with the glass fiber core without CeO2. Moreover, the energy transfer mechanisms between Ho3+/Yb3+ and Ho3+/Ce3+ were quantitatively analyzed based on a spectral overlap method. As mentioned above, Ho3+/Yb3+/Ce3+ tri-doped bismuth-tellurite glasses are potentially competitive and applicable in the field of 2 μm band infrared fiber lasers as a kind of novel laser glass.

Abstract PD12-01: PD12-01 Impact of obesity and post-diagnosis weight change on survival in women with breast cancer diagnosed at Smilow Cancer Hospital from 2013-2019

Abstract Background: The association between obesity and breast cancer risk is well documented, but fewer studies have explored the impact of post diagnosis weight changes on survival especially in more contemporary contexts. The existing evidence has mainly focused on weight gain, been limited by small sample sizes and has evaluated prospective cohorts with restrictive eligibility criteria rather than population-based samples. Our study uniquely contributes to the literature by using a population-based approach and recent clinically measured weight data from the electronic health record (EHR) to explore the impact of weight change following a breast cancer diagnosis on survival. Methods: EHR weight measurements were extracted for women diagnosed with stages I-IV breast cancer at CT’s Smilow Cancer Hospital and Care Network between 2013-2019 (N=6,934). During the follow-up period through April 26, 2020 (mean=3.2 years, standard deviation=1.8), there were 497 deaths. We used multivariable Cox regression models, adjusting for age at diagnosis, race/ethnicity, chemotherapy, radiation therapy, ER/PR subtype, to estimate the association between body mass index (BMI) at diagnosis and all-cause mortality from time since first post-diagnosis clinic visit (within 6 months of diagnosis). Percent weight change at 1-year post-diagnosis was categorized as a 5-level variable (weight stable – change within 5% of weight at diagnosis, moderate weight loss – 5% to < 10% change, large weight loss – ≥10% change, moderate weight gain – 5% to < 10% change, and large weight gain – ≥10% change) and evaluated in relation to all-cause mortality. A non-linear relationship between percent weight change at 1-year post-diagnosis and mortality was evaluated by comparing linear and cubic spline models. Results: Among these 6,934 breast cancer cases, the mean age was 61±13 years, BMI at diagnosis was 29±7 kg/m2 and weight change from diagnosis to 1-year post-diagnosis was -0.47±5.4 kg. Being underweight (BMI< 18.5) or having class II obesity (BMI>35) at diagnosis were statistically significantly independently associated with higher all-cause mortality compared with normal BMI (Hazard Ratio [HR]=1.43, 95% Confidence Interval [CI]=1.11-1.85 and HR=3.32, 95% CI=1.90-5.80, respectively). At 1-year post-diagnosis, 64% of women remained weight stable since diagnosis, 12% gained moderate body weight, 5% had large weight gain, 12% lost moderate weight and 7% experienced a large weight loss. Compared with the weight stable group, there was a positive, non-significant association between moderate weight gain at 1-year post-diagnosis and overall mortality (HR=1.24, 95% CI=0.84-1.81). Greater than 10% weight loss at 1-year post-diagnosis was statistically significantly associated with higher mortality (HR=2.87, 95% CI=2.13-3.87). The test for curvature suggested a non-linear relationship between percent weight change at 1-year and mortality (p< 0.001). Conclusion: In this contemporary, population-based study of women with breast cancer from one large academic medical center, underweight and obesity at diagnosis were associated with poorer survival. Weight loss during the first-year post-diagnosis was also strongly associated with an increased risk of mortality. To further inform weight management strategies and future interventions for breast cancer survivors, we need to better understand changes in body composition in the post-diagnosis period. Citation Format: Leah Puklin, Fangyong Li, Brenda Cartmel, Tara B. Sanft, Alexa Lisevick, Eric Winer, Maryam Lustberg, Mona Sharifi, Melinda L. Irwin, Leah Ferrucci. PD12-01 Impact of obesity and post-diagnosis weight change on survival in women with breast cancer diagnosed at Smilow Cancer Hospital from 2013-2019 [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD12-01.

Dual-Mode Based Sliding Mode Control Approach for Nonlinear Chemical Processes.

This paper synthesizes a new sliding mode controller (SMC) approach to enhance tracking and regulation tasks by following dual-mode concepts. The new control law consists of two distinct types of operation, using the combination of higher gain to large error signals (transient) and lower gain to small error signals (the region around the set point). The design is presented from a dual-mode (PD-PID) sliding surface operating in concert, fulfilling desired control objectives to ensure stability and performance. Therefore, a new controller was established, and we called it a dual-mode based SMC. The proposed controller is tested by computer simulations applied to two nonlinear processes, a continuous stirred-tank reactor (CSTR) and a mixing tank with a variable dead time. The results are compared with two different alternatives of SMC. In addition, the merits and drawbacks of the control schemes are analyzed using radial graphs, comparing the control methods with various performance measures for set points and disturbances changes. The ITSE (integral of time multiplied by the squared error), TVu (total variation of control effort) indices, Mp (maximum overshoot), and ts (settling time) were the indices used for performance analysis and comparisons.

Mode-Locked Fiber Laser Sensors with Orthogonally Polarized Pulses Circulating in the Cavity

Intracavity phase interferometry is a powerful phase sensing technique using two correlated, counter-propagating frequency combs (pulse trains) in mode-locked lasers. Generating dual frequency combs of the same repetition rate in fiber lasers is a new field with hitherto unanticipated challenges. The large intensity in the fiber core, coupled with the nonlinear index of glass, result in a cumulative nonlinear index on axis that dwarfs the signal to be measured. The large saturable gain changes in an unpredictable way the repetition rate of the laser impeding the creation of frequency combs with identical repetition rate. The huge amount of phase coupling between pulses crossing at the saturable absorber eliminates the small signal response (deadband). Although there have been prior observation of gyroscopic response in mode-locked ring lasers, to our knowledge this is the first time that orthogonally polarized pulses were used to successfully eliminate the deadband and obtain a beat note.

Improved Operation of the Step-Up Converter with Large Voltage Gain and Low Voltage on Capacitors

This work proposes an improvement for a recently proposed converter. The discussed converter is the so-called low-voltage in capacitors (LVC). It offers a larger voltage gain compared to the standard step-up or boost converter while operating with a relatively low voltage in their capacitors (lower than the voltage at the output port). The improvement consists of a modification in the pulse width modulation (PWM) scheme. The new modulation scheme allows for a reduction in the voltage ripple at the output port, which means an improvement in the power quality. The LVC converter contains two transistors, but it was proposed to operate with a single switching signal. The new PWM scheme is based on two switching signals with the same duty cycle (same waveform and same average time in high) but 180° of phase shift among them. The PWM scheme significantly affects the voltage ripple at the converter’s output port. The voltage ripple reduction at the converter’s output port is achieved without increasing the transistor switching frequency and without modifying the circuit parameters (capacitance in capacitors or inductance in inductors). The article starts by introducing the converter. Then, it presents its mathematical model, including the calculation of the voltage ripple at its output port. The experimental results performed on the LCV in both the former and the proposed operation prove the reduction in the voltage ripple, and the comparison also includes the traditional boost converter.

Photorefractive flexoelectric liquid crystal mixtures and their application to laser ultrasonics

A photorefractive effect of mixtures of flexoelectric liquid-crystal (flex LC) was investigated and applied to laser ultrasonics. Mixtures of flex LC, composed of smectic-C liquid crystals, photoconductive chiral compounds, and a sensitizer, are demonstrated to exhibit a large photorefractive effect. The experiments of a two-beam mixing with a photorefractive flexoelectric liquid crystal (PR-flex LC) show that a gain coefficient was measured as 1400 cm–1 and a response time was 960 microseconds, both with an applied electric field of 2.0 V/µm. The large gain and fast response are advantageous for remote ultrasound detection by using two-beam mixing with PR-flex LC. This remote sensing method can be used to probe the internal structure of an object or to measure the thickness of a plate object. The experimental results of acoustic time-of-flight in an aluminum (Al) plate are presented by using an adaptive two-beam interferometer with a PR-flex LC. A 3-D surface topology is shown by using laser ultrasonics with 2-D scanning of a test Al plate. With a fast response time in PR-flex LC, the system is not affected by vibrations in an industrial environment.

Where to begin? A flexible framework to prioritize caribou habitat restoration

Habitat loss is a leading threat to many species at risk, and as such, the need for habitat restoration is widespread. In the boreal forests of Western Canada, habitat restoration is a key habitat management action needed to achieve self‐sustaining populations of woodland caribou, a federally threatened species in decline. Hundreds of thousands of kilometers of linear features were created during the exploration or extraction of oil and gas that are no longer used, yet natural regeneration remains stagnated. Only a fraction of these linear features is restored each year, sparking the need for managers to prioritize efforts. We developed an algorithm to prioritize habitat restoration and demonstrate how it can be used to predict and monitor progress towards restoration goals. Our approach is based on the idea of maximizing the gain in unaltered caribou habitat per unit cost, while allowing for the inclusion of different goals, costs, and weighting criteria. Our algorithm ranked landscape units into five zones of restoration priority. The largest gain in unaltered habitat occurred following restoration of the highest priority zones, with diminishing returns as restoration proceeded. None of the caribou ranges reached habitat management targets when not considering restoration within energy project boundaries, even after all candidate linear features were restored. Our results highlight the need for ambitious, coordinated restoration, and the need for improved land‐use planning to minimize alteration within caribou range. We demonstrate the flexibility of our algorithm by applying the framework to a case study in a mountain ecosystem.

A fast simulation model of 2-D photoelectron track images for gaseous X-ray polarimetry

Gaseous polarimetry applies in soft X-ray polarization detection, typically like the Gas Pixel detector (GPD) and the micropattern time projection chamber (TPC). The polarization phase angles resolve from photoelectron track trajectories for both of them. The photoelectron track images derived from read-out pixels or strips are the key to determining the performance of the polarimetry. Gaseous X-ray polarimetry is regularly optimized and diagnosed by the Geant4 associated with Garfield++ and finite element analysis software (full simulation). Although the results are more realistic by the full simulation, the sample generation is low efficiency, especially for large gain values of the multiplier stage. The 2-D photoelectron track images regularly generate by a gaussian smear of initial ionization electrons at present. However, discrepancies exist in the modulation curves, resulting in fuzzy diagnoses and optimization of polarimetry. In this study, a fast simulation framework is constructed, the reconstruction of polarization phase angles and energy spectrum of the samples obtained from the fast simulation are consistent with those from experiments and the full simulation, and the deviation of modulation factor is within 2% for both situations of the GPD and TPC. In addition, the fast simulation greatly improves the sample generation efficiency. These results illustrate the fast simulation model is relative accuracy and high efficiency, which provides a useful tool for gaseous X-ray polarimetry.

A soft switched high step‐up DC‐DC converter based on VMC and coupled inductor for photovoltaic energy applications

AbstractIn this paper a new topology of non‐isolated high step‐up DC‐DC is proposed for renewable applications like photovoltaic (PV) power generation. This converter is designed based on coupled inductor and VMC techniques. The main benefits of the presented topology are: (1) Continues input current with low ripple, (2) low voltage stress across semiconductors, (3) soft switching of diodes (ZVS and ZCS), (4) high voltage gain with low duty cycle, (5) low volume and cost, and (6) high power efficiency. To obtain a high output voltage, the secondary side of the coupled inductor is integrated with VMC, resulting in a large voltage gain with low duty cycles and reduced conduction loss of power switches. Additionally, diodes' zero voltage switching (ZVS) and zero current switching (ZCS) improve the efficiency of the proposed converter. The used VMCs act as a voltage clamp, and the peak voltages across power switches are reduced. The presented converter's operational modes, steady‐state, and efficiency analysis are discussed. Additionally, to indicate the performance of the suggested structure, a 200 W prototype with Vin = 33 V and Vo = 403 V voltage conversion is built, and the experimental results are presented. The experimental efficiency at Po = 200 W is measured 95.29%. Also, efficiency is measured more than 95 % for Po = 20 W to 200 W.

Quantitative Genetics of a Hybrid Population of Eucalyptus nitens × Eucalyptus globulus: Estimation of Genetic Parameters and Implications for Breeding Strategies

In Chile, interspecific hybrids between Eucalyptus nitens × Eucalyptus globulus (GloNi) were developed by Arauco Forestry to capture specific traits from each parental species: growth rate and cold resistance from E. nitens (NIT) and wood properties from E. globulus (GLO). Field tests of E. nitens × E. globulus were distributed in two geographic zones: Arauco (12 tests) and Valdivia (15 tests), where growth and wood properties measurements were recorded at different ages. The hybrid population is composed of clones from 28 full-sib families, being the result of crossing 12 E. nitens females and 8 E. globulus males. Progeny from each of these families were vegetatively propagated and tested on each growth zone, with a total of 1214 clones developed. The quantitative genetic parameter estimates reveal high genetic variation in hybrid volume gain and wood properties, which make possible large genetic gain in all traits analyzed. Additionally, E. nitens has a considerable impact on the volume gain of the hybrid, making it important to test more parents in future interspecific crosses in both hybrid zones. In contrast, E. globulus demonstrated zero impact in volume. In wood traits, E. globulus in Arauco zone demonstrates a large effect on the genetic variability of these traits; meanwhile, in the Valdivia zone, E. nitens and E. globulus parents contributed roughly similar amounts of genetic variation. The high General Hybridizing Ability (GHA) and General Combining Ability (GCA) relationship between hybrid progeny and pure species progeny performance indicates that parents could be selected for interspecific crosses based on pure species test results for volume and wood properties.

Spatiotemporal mode-locked fiber laser based on dual-resonance coupling long-period fiber grating.

Spatiotemporal mode-locked (STML) fiber lasers have become an excellent platform in nonlinear optics research due to the rich nonlinear evolution process. In order to overcome modal walk-off and realize phase locking of different transverse modes, it is usually crucial to reduce the modal group delay difference in the cavity. In this paper, we use long-period fiber grating (LPFG) to compensate the large modal dispersion and differential modal gain in the cavity, realizing the spatiotemporal mode-locking in step-index fibers cavity. The LPFG inscribed in few-mode fiber could induce strong mode coupling, which has wide operation bandwidth based on dual-resonance coupling mechanism. By using dispersive Fourier transform involved intermodal interference, we show that there is a stable phase difference between the transverse modes constituting the spatiotemporal soliton. These results would be beneficial for the study of spatiotemporal mode-locked fiber lasers.

Event-triggered bipartite consensus control algorithm design for nonlinear second-order multi-agent systems

Bipartite consensus of nonlinear second-order multi-agent systems with directed communication topology is investigated in this article. A kind of novel event-triggered control protocol is proposed, which based on relative information sensing. Different from some conventional event-triggered control for second-order multi-agent systems, the event-triggered control in distributed way for second-order multi-agent systems is studied in this article, which imply that the controller of each follower only needs to collect the local information. To eliminate too large control gain, the control gain of control protocol is further designed based on adaptive way. Moreover, these control algorithms prove that Zeno behavior can be avoided. Finally, the performance of the proposed control protocols is presented by virtue of two simulation examples.

Structure and fluorescence characteristics in highly Dy3+ doped tellurite-fluoride glass for white light fiber lasers

High concentration Dy3+ doped 75TeO2-25YF3-xDyF3 (where x = 8, 10, 12, 14 mo1%) were synthesized by a melt-quenching method. Raman spectra and oscillator strength were utilized to evaluate the structural of glass and radiation properties with differing DyF3 concentrations. The maximum phonon energy of the glass is about 770 cm-1. Ω6 and χ are 3.5 and 0.51 when DyF3 concentration reaches 10 mol%, indicating that the activated ions in the glass material system have a wide fluorescence bandwidth and excellent stimulated emission characteristics. The yellow/blue value enhance with the addition of high concentrations of DyF3, which may be due to the depolymerization of [TeO4], gradually converting into [TeO3+1] and [TeO3], destroying with the local coordination environment and inverting Dy3+ symmetry. Furthermore, under the excitation wavelength of 350 nm, the TYDF2 glass obtained relatively large emission cross-section (35.53 × 10−22 cm2) and gain coefficient (5.88 cm−1) at 4F9/2 → 6H13/2. The CIE coordinates are in the range of white light, and the CCT values are between 4200 and 4400 K. The results show that highly Dy3+ doped tellurite-fluoride glasses prepared in this way have the potential as a gain materials for white light fiber lasers.

In Vivo Plant Bio-Electrochemical Sensor Using Redox Cycling.

This work presents an in vivo stem-mounted sensor for Nicotiana tabacum plants and an in situ cell suspension sensor for Solanum lycopersicum cells. Stem-mounted sensors are mechanically stable and less sensitive to plant and air movements than the previously demonstrated leaf-mounted sensors. Interdigitated-electrode-arrays with a dual working electrode configuration were used with an auxiliary electrode and an Ag/AgCl quasi-reference electrode. Signal amplification by redox cycling is demonstrated for a plant-based sensor responding to enzyme expression induced by different cues in the plants. Functional biosensing is demonstrated, first for constitutive enzyme expression and later, for heat-shock-induced enzyme expression in plants. In the cell suspension with redox cycling, positive detection of the enzyme β-glucuronidase (GUS) was observed within a few minutes after applying the substrate (pNPG, 4-Nitrophenyl β-D-glucopyranoside), following redox reactions of the product (p-nitrophenol (pNP)). It is assumed that the initial reaction is the irreversible reduction of pNP to p-hydroxylaminophenol. Next, it can be either oxidized to p-nitrosophenol or dehydrated and oxidized to aminophenol. Both last reactions are reversible and can be used for redox cycling. The dual-electrode redox-cycling electrochemical signal was an order of magnitude larger than that of conventional single-working electrode transducers. A simple model for the gain is presented, predicting that an even larger gain is possible for sub-micron electrodes. In summary, this work demonstrates, for the first time, a redox cycling-based in vivo plant sensor, where diffusion-based amplification occurs inside a tobacco plant's tissue. The technique can be applied to other plants as well as to medical and environmental monitoring systems.

Integrating Parental Phenotypic Data Enhances Prediction Accuracy of Hybrids in Wheat Traits.

Genomic selection (GS) is a methodology that is revolutionizing plant breeding because it can select candidate genotypes without phenotypic evaluation in the field. However, its practical implementation in hybrid prediction remains challenging since many factors affect its accuracy. The main objective of this study was to research the genomic prediction accuracy of wheat hybrids by adding covariates with the hybrid parental phenotypic information to the model. Four types of different models (MA, MB, MC, and MD) with one covariate (same trait to be predicted) (MA_C, MB_C, MC_C, and MD_C) or several covariates (of the same trait and other correlated traits) (MA_AC, MB_AC, MC_AC, and MD_AC) were studied. We found that the four models with parental information outperformed models without parental information in terms of mean square error by at least 14.1% (MA vs. MA_C), 5.5% (MB vs. MB_C), 51.4% (MC vs. MC_C), and 6.4% (MD vs. MD_C) when parental information of the same trait was used and by at least 13.7% (MA vs. MA_AC), 5.3% (MB vs. MB_AC), 55.1% (MC vs. MC_AC), and 6.0% (MD vs. MD_AC) when parental information of the same trait and other correlated traits were used. Our results also show a large gain in prediction accuracy when covariates were considered using the parental phenotypic information, as opposed to marker information. Finally, our results empirically demonstrate that a significant improvement in prediction accuracy was gained by adding parental phenotypic information as covariates; however, this is expensive since, in many breeding programs, the parental phenotypic information is unavailable.

Adult BMI change over time and risk of colorectal adenoma.

68 Background: Obesity and adult weigh gain are established risk factors for colorectal cancer (CRC). Few studies have investigated the association between adult body weight change over time and risk of colorectal adenoma. We hypothesize adult BMI change over time is associated with risk in the development of colorectal adenomas. Methods: We tested this hypothesis in 2,993 patients undergoing screening colonoscopy from 2007–2017. Weight at age 20, 30, 40, and 50 were self-reported via computer assisted personal interviews. Height and weight at recruitment were measured at the time of colonoscopy exam. BMI (kg/m2) change was calculated as the difference of BMI at recruitment from the BMI estimate for each of the age periods. Results: Of the 2,993 patients, 984 had pathologically confirmed diagnosis of colon adenoma. Multivariate logistic regression adjusted for potential confounders and BMI at recruitment showed statistically significant increase of risk of adenoma with increase of BMI since age 30, age 40, and age 50. Compared to those with BMI change of less than 5, the ORs for those with BMI gain of 5-10 and ≥10 were: 1) 1.16 (0.92-1.46) and 1.48 (1.08-2.03) respectively for change from age 30 (ptrend = 0.05); 2) 1.11 (0.87-1.43) and 1.60 (1.09-2.35) respectively for change from age 40 (ptrend = 0.05); and 3) 1.36 (0.95-1.94) and 2.95 (1.33-6.90) respectively for change from age 50 (ptrend = 0.01). Stratified analysis did not reveal noticeable gender differences. Conclusions: Large adult weight gain over time is an independent risk factor for colorectal adenoma. Our results suggest maintaining healthy body weight throughout adulthood is an important preventive measure against the development of early colorectal neoplasia. [Table: see text]

Extremely low excess noise avalanche photodiode with GaAsSb absorption region and AlGaAsSb avalanche region

An extremely low noise Separate Absorption and Multiplication Avalanche Photodiode (SAM-APD), consisting of a GaAs0.52Sb0.48 absorption region and an Al0.85Ga0.15As0.56Sb0.44 avalanche region, is reported. The device incorporated an appropriate doping profile to suppress tunneling current from the absorption region, achieving a large avalanche gain, ∼130 at room temperature. It exhibits extremely low excess noise factors of 1.52 and 2.48 at the gain of 10 and 20, respectively. At the gain of 20, our measured excess noise factor of 2.48 is more than three times lower than that in the commercial InGaAs/InP SAM-APD. These results are corroborated by a Simple Monte Carlo simulation. Our results demonstrate the potential of low excess noise performance from GaAs0.52Sb0.48/Al0.85Ga0.15As0.56Sb0.44 avalanche photodiodes.

Parametric study of the effectiveness of active yaw control based on large eddy simulation

Previous studies on active yaw control (hereafter, AYC) have demonstrated its potential in wind farm power optimization. However, most focus are concentrated on the amount of relative power enhancement achieved by AYC, ignoring how various parameters affect the effectiveness of AYC, let alone the mechanism behind the variation of AYC efficiency. Evidently, this is not conducive to the practical implementation of AYC. In response, a parametric study of the effectiveness of AYC is pursued in this paper, by performing a series of large eddy simulations (hereafter, LES) for the NREL 5 MW turbine array under different operating conditions. The LES results reveal that AYC is more effective in the environment with lower incoming wind speed and smaller turbulence intensity level. What is more, the AYC efficiency is found to vary greatly with the streamwise distance between consecutive wind turbines, but is not sensitive to the change of column spacing within a typical range. A large power gain is achieved at wind angles corresponding to partial-wake operating conditions. The active yaw behavior of the last wind turbine in the array also shows the potential to increase the total power production but the corresponding power gain is small. Moreover, it is shown that the yaw direction of wind turbine has nonnegligible influence on AYC, especially in the stable boundary layer. From the power production perspective, positive yaw of wind turbine is recommended in the north hemisphere.

Multiobjective optimization of free convection through a nonuniform cabinet filled with porous media

AbstractIn the current study, multiobjective optimization and numerical simulation were used to evaluate free convection through a nonuniform cabinet, which has several technical applications, such as cooling techniques, solar air collectors, and heat sinks. The new aspect of the current study is to compute the maximum free convection within an irregular L‐shaped cavity filled with porous media using both computational analysis and response surface methodology (RSM). Moreover, the impacts of constant coefficients, such as aspect ratios of the horizontal (ARh), vertical (ARv), and Darcy numbers (Da) on the Nusselt number (Nuave), Nusselt number maximization (NNM), the temperature of the surface (Ts), and entropy (S) are studied and discussed to evaluate their effect on the thermal performance. The results showed that when Da, ARh, and ARv increase, Nuave improves while the Ts and S decline and the largest desirability is achieved at ARh = 0.9, ARv = 0.9, and Da = 10−1. Additionally, when compared with the subpar design data, the largest gain in NNM was 26.7 times, while the biggest decreases in surface temperature and entropy were 59% and 97%, respectively. As a result, the combination of the numerical simulation and RSM study produces a novel strategy and insightful suggestions for the ideal cooling L‐shaped cabinet design.

The micro-RWELL detector for the phase-2 upgrade of the LHCb muon system

The micro-RWELL detector (μ-RWELL) is a single amplification stage resistive Micro Pattern Gaseous Detector (MPGD), based on a copper-clad polyimide foil patterned with a micro-well matrix coupled with the readout PCB through a DLC resistive film (10÷100MΩ/□). For the phase-2 upgrade of the LHCb experiment, proposed for the LHC Run-5, the excellent performance of the current muon detector will need to be maintained at 40 times the pile-up level experienced during Run-2. Requirements are challenging for the innermost regions of the muon stations: the detectors should exhibit a rate capability up to 1MHz/cm2 and they are supposed to integrate a charge up to ∼1C/cm2. In this framework an intense optimization program of the micro-RWELL technology has been launched in the last year, together with a technology transfer to the industry operating in the PCB field. In order to fulfill the requirements, a new layout of the detector with a very dense current evacuation grid of the DLC has been designed. The detector, co-produced by the CERN-EP-DT-MPT Workshop, lead by one of the authors, and the ELTOS Company, has been characterized in terms of rate capability exploiting a high intensity X-ray Philips 2217/20 gun with a spot size (10÷50mm diameter) larger than the DLC grounding-pitch. A rate capability exceeding 10MHz/cm2 has been achieved, in agreement with previous results obtained with m.i.p. at the Paul Scherrer Institute (PSI) in Villigen (CH). A long term stability test is in progress: a charge of about 5mC/cm2 has been integrated over a period of about 16 days. The test will continue, in harder conditions (larger gain and X-ray flux), with the goal to integrate about 1C/cm2 in one year, while a slice test of the detector is under preparation.