25 research outputs found
Bounds on the Hermite spectral projection operator
We study - bounds on the spectral projection operator
associated to the Hermite operator in . We are
mainly concerned with a localized operator for a
subset and undertake the task of characterizing the sharp
-- bounds. We obtain sharp bounds in extended ranges of . First,
we provide a complete characterization of the sharp -- bounds when
is away from . Secondly, we obtain the sharp
bounds as the set gets close to . Thirdly, we
extend the range of for which the operator is uniformly
bounded from to .Comment: The paper is a modified version of a part of the paper Hermite
spectral projection operator (arXiv:2006.11762v3). The previous paper will
remain unpublishe
Bochner-Riesz mean for the twisted Laplacian in
We study the Bochner-Riesz problem for the twisted Laplacian on
. For , it has been conjectured
that the Bochner-Riesz means of order
converges in for every if and only if . We prove the conjecture by obtaining uniform
bounds on up to the sharp summability indices.Comment: 15 page
THE EFFECT OF GAS TEMPERATURE AND VELOCITY ON COAL DRYING IN FLUIDIZED BED DRYER
The objective of this research work is to develop fluidized bed coal dryer to overcome the disadvantages of low rank coal with high moisture such as low calorific values, costly transportation, high emissions of pollutants, and operational problem. In this paper, laboratory scale bubbling fluidized bed was used to dry high moisture, low-rank Indonesian coal to produce low moisture, high-rank coal. The effects of temperature, gas velocity and bed height to diameter ratio (L/D) on drying rate were studied to obtain information relating to optimum operating conditions. Coal characterizations (proximate analysis, ultimate analysis, Thermogravimetric Analysis (TGA), BET, Higher Heating Value (HHV), Lower Heating Value (LHV)) were performed to identify the effect of the change of moisture content. This investigation aims to study the drying process under moderated heating conditions.
As a result of the experiments the conclusion is that the thermal fluidized bed process can be successfully applied to reducing moisture in Indonesian coal. Results also indicate that about 80~90% of total moisture could be reduced, including some of the inherent moisture, yielding high heating value product. The drying rate of coal in a fluidized bed is increased by increasing the temperature and velocity of the drying gas. However gas temperature had limitations causing from the spontaneous combustion and gas velocity has to be decided considering energy efficiency
Analysis of virulence profiles in clinical isolates of Klebsiella pneumoniae from renal abscesses: clinical significance of hypervirulent isolates
IntroductionKlebsiella pneumoniae can cause a wide range of infections. Hypervirulent K. pneumoniae (hvKp), particularly associated with the K1 and K2 capsular types, is an increasingly significant microorganism with the potential to cause invasive infections, including renal abscesses. Despite the rising prevalence of hvKp infections, information on renal abscesses caused by K. pneumoniae is limited, and the clinical significance of hvKp associated with specific virulence genes remains elusive.MethodsThis study performed at a 1200-bed tertiary hospital sought to identify the clinical and microbiological characteristics of renal abscesses caused by K. pneumoniae, focusing on various virulence genes, including capsular serotypes and multilocus sequence typing (MLST).ResultsOver an 8-year period, 64 patients with suspected renal abscesses were reviewed. Ten patients diagnosed with K. pneumoniae-related renal abscesses were ultimately enrolled in the study. Among the isolates from the 10 patients, capsular serotype K2 was predominant (40.0%), followed by K1 (30.0%). The most common sequence type by MLST was 23 (40.0%). In particular, six patients (60.0%) harbored specific genes indicative of hvKp: iucA, peg-344, rmpA, and rmpA2.ConclusionsOur findings highlight the importance of hvKp as a pathogen in renal abscesses. Although the nature of hvKp is relatively unknown, it is widely recognized as a highly virulent pathogen that can infect relatively healthy individuals of various ages and simultaneously cause infections at multiple anatomical sites. Therefore, when treating patients with K. pneumoniae-related renal abscesses, caution is necessary when considering the characteristics of hvKp, such as potential bacteremia, multi-organ abscess formation, and metastatic spread
Sharp Lp-Lq estimate for the spectral projection associated with the twisted Laplacian
In this note we are concerned with estimates for the spectral projection operator Pµ associated with the twisted Laplacian L. We completely characterize the optimal bounds on the operator norm of Pµ from Lp to Lq when 1 ≤ p ≤ 2 ≤ q ≤ ∞. As an application, we obtain a uniform resolvent estimate for L
Endpoint eigenfunction bounds for the Hermite operator
We establish the optimal , eigenfunction bound for the
Hermite operator on . Let
denote the projection operator to the vector space spanned by the
eigenfunctions of with eigenvalue . The optimal
-- bounds on , , have been known by
the works of Karadzhov and Koch-Tataru except . For ,
we prove the optimal bound for the missing endpoint case. Our result is built
on a new phenomenon: improvement of the bound due to asymmetric localization
near the sphere .Comment: The paper is an extended revision of a part of the paper Hermite
spectral projection operator (arXiv:2006.11762) where the endpoint results
were established for . The earlier paper will remain unpublishe
Prostatic Abscess Caused by <i>Klebsiella pneumoniae</i>: A 6-Year Single-Center Study
Hypervirulent Klebsiella pneumoniae (hvKp) is an important strain that can cause multiple organ infections. Although hvKp infection cases are increasing, there is limited information on the prostatic abscesses caused by K. pneumoniae. Furthermore, the clinical significance of hvKp associated with K1 or K2 capsular types or virulence genes in prostatic abscesses remains unclear. Therefore, we aimed to elucidate the clinical and microbiological characteristics of prostatic abscesses caused by K. pneumoniae in relation to various virulence genes. A retrospective study was performed at a 1200-bed tertiary hospital between January 2014 and December 2019. Patients diagnosed with prostatic abscesses with K. pneumoniae isolated from blood, urine, pus, or tissue cultures were enrolled in this study. Our results demonstrate that 30.3% (10/33) of the prostatic abscesses were caused by K. pneumoniae. All strains isolated from patients with prostatic abscesses due to K. pneumoniae were the K1 capsular type, and eight patients (80.0%) carried rmpA and iutA genes that identified hvKp. These findings suggest that hvKp is an important pathogen in prostatic abscesses. Therefore, when treating patients with K. pneumoniae prostatic abscesses, attention should be paid to the characteristics of hvKp, such as bacteremia, multiorgan abscess formation, and metastatic spread
FPGA Implementation of the Chirp-Scaling Algorithm for Real-Time Synthetic Aperture Radar Imaging
Synthetic aperture radar (SAR), which can generate images of regions or objects, is an important research area of radar. The chirp scaling algorithm (CSA) is a representative SAR imaging algorithm. The CSA has a simple structure comprising phase compensation and fast Fourier transform (FFT) operations by replacing interpolation for range cell migration correction (RCMC) with phase compensation. However, real-time processing still requires many computations and a long execution time. Therefore, it is necessary to develop a hardware accelerator to improve the speed of algorithm processing. In addition, the demand for a small SAR system that can be mounted on a small aircraft or drone and that satisfies the constraints of area and power consumption is increasing. In this study, we proposed a CSA-based SAR processor that supports FFT and phase compensation operations and presents field-programmable gate array (FPGA)-based implementation results. We also proposed a modified CSA flow that simplifies the traditional CSA flow by changing the order in which the transpose operation occurs. Therefore, the proposed CSA-based SAR processor was designed to be suitable for modified CSA flow. We designed the multiplier for FFT to be shared for phase compensation, thereby achieving area efficiency and simplifying the data flow. The proposed CSA-based SAR processor was implemented on a Xilinx UltraScale+ MPSoC FPGA device and designed using Verilog-HDL. After comparing the execution times of the proposed SAR processor and the ARM cortex-A53 microprocessor, we observed a 136.2-fold increase in speed for the 4096 × 4096-pixel image
Efficacy and Optimal Pressure of Continuous Positive Airway Pressure in Intensity-Modulated Radiotherapy for Locally Advanced Lung Cancer
We aimed to determine the optimal pressure of continuous positive airway pressure (CPAP) for radiotherapy (RT) through changes in the dosimetric parameters and lung volume according to pressure. Patients with locally advanced lung cancer, who underwent CPAP during computed tomography (CT) simulation, were included. The air pressure was raised in five steps of 4, 7, 10, 14, and 17 cmH2O and a CT scan was performed at the baseline and at each pressure step, accompanied by contouring and RT planning. Paired t- and Wilcoxon signed rank tests were used to compare the volumetric and dosimetric parameters according to pressure and interpressure. A total of 29 patients were selected, and 158 CT datasets were obtained. The lung volume increased significantly at all pressures (p 2O (p 2O with increasing pressure, and the Dmean and V5 of the heart decreased significantly from 14 cmH2O with increasing pressure. The V50 showed no significant differences at any pressure. We recommend the use of at least 7 cmH2O with 14 cmH2O as the optimal pressure to achieve the effect of heart preservation
Bimodal Control of Heat Transport at Graphene–Metal Interfaces Using Disorder in Graphene
Thermal energy transport across the interfaces of physically and chemically modified graphene
with two metals, Al and Cu, was investigated by measuring thermal conductance using the timedomain
thermoreflectance method. Graphene was processed using a He2+ ion-beam with a Gaussian
distribution or by exposure to ultraviolet/O3, which generates structural or chemical disorder,
respectively. Hereby, we could monitor changes in the thermal conductance in response to varying
degrees of disorder. We find that the measured conductance increases as the density of the physical
disorder increases, but undergoes an abrupt modulation with increasing degrees of chemical
modification, which decreases at first and then increases considerably. Moreover, we find that the
conductance varies inverse proportionally to the average distance between the structural defects in the
graphene, implying a strong in-plane influence of phonon kinetics on interfacial heat flow. We attribute
the bimodal results to an interplay between the distinct effects on graphene’s vibrational modes
exerted by graphene modification and by the scattering of modes.
© The Author(s) 20161