Wear dependent virtual flow rate sensor for progressing cavity pumps with deformable stator

This contribution presents a novel wear dependent virtual flow rate sensor for single stage single lobe progressing cavity pumps. We study the wear-induced material loss of the pump components and the impact of this material loss on the volumetric efficiency. The results are combined with an established backflow model to implement a backflow calculation procedure that is adaptive to wear. We use a laboratory test setup with a highly abrasive fluid and operate a pump from new to worn condition to validate our approach. The obtained measurement data show that the presented virtual sensor is capable of calculating the flow rate of a pump being subject to wear during its regular operation.

Optimal Design of High-Speed Partial Flow Pumps using Orthogonal Tests and Numerical Simulations

To investigate the influence of structural parameters on the performances and internal flow characteristics of partial flow pumps at a low specific speed of 10000 rpm,special attention was paid to the first and second stage impeller guide vanes.Moreover,the impeller blade outlet width,impeller inlet diameter,blade inclination angle,and number of blades were considered for orthogonal tests.Accordingly,nine groups of design solutions were formed,and then used as a basis for the execution of numerical simulations(CFD)aimed at obtaining the efficiency values and heads for each design solution group.The influence of impeller geometric parameters on the efficiency and head was explored,and the“weight”of each factor was obtained via a range analysis.Optimal structural parameters were finally chosen on the basis of the numerical simulation results,and the performances of the optimized model were verified accordingly(yet by means of CFD).Evidence is provided that the increase in the efficiency and head of the optimized model was 12.11%and 23.5 m,respectively,compared with those of the original model.

Low-intensity pulsed ultrasound reduces alveolar bone resorption during orthodontic treatment via Lamin A/C-Yes-associated protein axis in stem cells

BACKGROUND The bone remodeling during orthodontic treatment for malocclusion often requires a long duration of around two to three years,which also may lead to some complications such as alveolar bone resorption or tooth root resorption.Low-intensity pulsed ultrasound(LIPUS),a noninvasive physical therapy,has been shown to promote bone fracture healing.It is also reported that LIPUS could reduce the duration of orthodontic treatment;however,how LIPUS regulates the bone metabolism during the orthodontic treatment process is still unclear.AIM To investigate the effects of LIPUS on bone remodeling in an orthodontic tooth movement(OTM)model and explore the underlying mechanisms.METHODS A rat model of OTM was established,and alveolar bone remodeling and tooth movement rate were evaluated via micro-computed tomography and staining of tissue sections.In vitro,human bone marrow mesenchymal stem cells(hBMSCs)were isolated to detect their osteogenic differentiation potential under compression and LIPUS stimulation by quantitative reverse transcription-polymerase chain reaction,Western blot,alkaline phosphatase(ALP)staining,and Alizarin red staining.The expression of Yes-associated protein(YAP1),the actin cytoskeleton,and the Lamin A/C nucleoskeleton were detected with or without YAP1 small interfering RNA(siRNA)application via immunofluorescence.RESULTS The force treatment inhibited the osteogenic differentiation potential of hBMSCs;moreover,the expression of osteogenesis markers,such as type 1 collagen(COL1),runt-related transcription factor 2,ALP,and osteocalcin(OCN),decreased.LIPUS could rescue the osteogenic differentiation of hBMSCs with increased expression of osteogenic marker inhibited by force.Mechanically,the expression of LaminA/C,F-actin,and YAP1 was downregulated after force treatment,which could be rescued by LIPUS.Moreover,the osteogenic differentiation of hBMSCs increased by LIPUS could be attenuated by YAP siRNA treatment.Consistently,LIPUS increased alveolar bone density and decreased vertical bone absorption in vivo.The decreased expression of COL1,OCN,and YAP1 on the compression side of the alveolar bone was partially rescued by LIPUS.CONCLUSION LIPUS can accelerate tooth movement and reduce alveolar bone resorption by modulating the cytoskeleton-Lamin A/C-YAP axis,which may be a promising strategy to reduce the orthodontic treatment process.

PERFORMANCE SIMULATION AND ANALYSIS OF AQUA AMMONIA ABSORPTION－RESORPTION HEAT PUMP

An investigation of an aqua ammonia atherption-resorption heat pump(ARHP) is made on the basis of experimental analysis and research. The results ofcomputer simulation are compared with the experimental data , and the relations be-tween the coefficient of performance (COP) of an aqua ammonia ARHP and its mainoperatins parameters, such as temperature and pressure,are obtained by means ofcomputer simulation.

Cavitation recognition of axial piston pumps in noisy environment based on Grad-CAM visualization technique

The cavitation in axial piston pumps threatens the reliability and safety of the overall hydraulic system.Vibration signal can reflect the cavitation conditions in axial piston pumps and it has been combined with machine learning to detect the pump cavitation.However,the vibration signal usually contains noise in real working conditions,which raises concerns about accurate recognition of cavitation in noisy environment.This paper presents an intelligent method to recognise the cavitation in axial piston pumps in noisy environment.First,we train a convolutional neural network(CNN)using the spectrogram images transformed from raw vibration data under different cavitation conditions.Second,we employ the technique of gradient-weighted class activation mapping(Grad-CAM)to visualise class-discriminative regions in the spectrogram image.Finally,we propose a novel image processing method based on Grad-CAM heatmap to automatically remove entrained noise and enhance class features in the spectrogram image.The experimental results show that the proposed method greatly improves the diagnostic performance of the CNN model in noisy environments.The classification accuracy of cavitation conditions increases from 0.50 to 0.89 and from 0.80 to 0.92 at signal-to-noise ratios of 4 and 6 dB,respectively.

Nutrient resorption and its influencing factors of typical desert plants in different habitats on the northern margin of the Tarim Basin, China

The resorption of nutrients from senescent leaves allows plants to conserve and recycle nutrients. To explore the adaptation strategies of desert plants to nutrient-limited environments, we selected four typical desert plants(Populus euphratica Oliv., Tamarix ramosissima Ledeb., Glycyrrhiza inflata Batal., and Alhagi camelorum Fisch.) growing in the desert area of the northern margin of the Tarim Basin,China. The contents of nitrogen(N), phosphorus(P), potassium(K), calcium(Ca), magnesium(Mg), and Ferrum(Fe) in the leaves of these four typical desert plants and their resorption characteristics were analyzed. The relationship of nutrient resorption efficiency with leaf functional traits and soil physical-chemical properties in two different habitats(saline-alkali land and sandy land) was discussed.The results showed that the four plants resorbed most of the elements. Ca was enriched in the leaves of P.euphratica, G. inflate, and A. camelorum;Mg was enriched in the leaves of G. inflata;and Fe was enriched in the leaves of the four plants. The results of the redundancy analysis showed that leaf thickness, soil electrical conductivity, and soil P content were the major factors affecting the nutrient resorption efficiency of the four plants. Leaf thickness was negatively correlated with N resorption efficiency(NRE),P resorption efficiency, and Fe resorption efficiency;soil electrical conductivity was positively correlated with the resorption efficiency of most elements;and soil P content was negatively correlated with the resorption efficiency of most elements in the plant leaves. The results showed that soil physical-chemical properties and soil nutrient contents had an important impact on the nutrient resorption of plant leaves.The same species growing in different habitats also differed in their resorption of different elements. The soil environment of plants and the biological characteristics of plant leaves affected the resorption of nutrient elements in different plants. The purpose of this study is to provide small-scale data support for the protection of ecosystems in nutrient-deficient areas by studying leaf functional strategies and nutrient conservation mechanisms of several typical desert plants.

A Case of Multiple Idiopathic Root Resorption

Tooth root resorption is multifactorial, and its etiology and pathogenesis are poorly understood. Tooth root resorption is often incidentally revealed on radiographic examination. Here, we report a case of root resorption in multiple teeth of unknown etiology. Radiographic examination revealed root resorption in the cervical region of the left lateral incisor, canine, first and second premolars, and first and second molars of the mandible. Panoramic radiographs revealed no mandibular lesions that could cause tooth resorption. The patient did not wish to undergo any treatment and is currently under observation. Tooth root resorption with unknown etiology is rare, and further case collection is needed to determine the cause and treatment.

As Planet Warms,Heat Pumps Get Hotter

The heat pump,an old device dating back to the early 1850s[1],has captured new attention for its potential to help meet climate change goals.Driven in large part by legislated incentives and bans on fossil-fuel heating in a growing number of countries,the heightened interest has also spawned improvements in the technology’s efficiency and cost.Another unique benefit is for one device to provide,depending on seasonal needs,both heating and cooling.

Research progress of bone sialoprotein in osteoclast differentiation and bone resorption

Bone sialoprotein(BSP)is an important non-collagen extracellular matrix protein(EMC)that promotes bone formation and induces bone resorption.BSP is secreted by odontoblasts,it plays an important role in cementum,alveolar bone formation and mineralization,and periodontal function.Bone resorption is controlled by a complex molecular network,and BSP can promote osteoclast differentiation and bone resorption.It is also associated with the metastasis of a range of malignancies.Osteoclasts(OC)are thought to be the only cells involved in bone resorption and play an important role in bone formation and late developmental remodeling.Osteoporosis and periodontal disease are caused by excessive bone resorption.This article will summarize the osteoclasts differentiation,the biological function of bone resorption,and explore the progress of the prevention and treatment of the related bone resorption diseases such as osteoporosis and periodontal disease through the regulation of osteoclasts.

Factors of Pumping Capacity in Some Different Types of Channel Brownian Pumps

The motion of particles in different channel Brownian pumps can be described by Langevin equations,and the pumping capacity is a useful indicator to demonstrate the strength of a pump’s transportation ability.Via the simulation,there is always an optimal value of temperature and unbiased external force for different pumps which make the concentration ratio between the right tube and left tube derive its maximum and minimum in two asymmetric tubes respectively.Besides,the concentration ratio will keep 1 regardless of radius,temperature or magnitude of force in the tube in a symmetric tube.To obtain more information about pumping capacity,exploring the average probability current(APC) of tubes in different conditions is necessary.Results indicate that as the concentration ratio is 1,the change of the APC when x_(0)=0 is similar to that when x_(0)=π.Also,when the concentration ratio is more than 1,there are optimal values of temperature,radius and magnitude of force where the APC gains a maximum,and the maximum decreases as the concentration in the right tube increases when x_(0)=0.

Root Resorption in Anterior Open Bite Malocclusions Due to Vertical Correction: A Radiometric Pilot Study

Introduction: One of the most common risks of fixed orthodontic therapy is the evidence of root resorption post orthodontic treatment ranging from mild root blunting to severe root resorption of significant portions of the root structure. The etiology of apical root resorption is multifactorial but largely depends upon the type of orthodontic tooth movement and treatment duration. Study Objective: The primary aim of this study is to examine the association of external apical root resorption and vertical correction in anterior open bite malocclusions using panoramic radiographs for evaluation. Materials and Methods: Pre-treatment and post-treatment panoramic radiographs of 16 patients with anterior open bite malocclusions were scored to assess root resorption of anterior teeth (U/L 3-3). Initial and final root length and total tooth length for U/L 3-3 were measured on panoramic radiographs in Dolphin imaging. Results: Of the 24 pairs of measurements, 7 had a significant p-value (p Conclusions: A statistically significant amount of root resorption was observed, from pre-treatment to post-treatment radiographs. All mandibular anterior teeth except the mandibular right lateral incisors showed evidence of root resorption.

An NMOS output-capacitorless low-dropout regulator with dynamic-strength event-driven charge pump

In this paper,an NMOS output-capacitorless low-dropout regulator(OCL-LDO)featuring dual-loop regulation has been proposed,achieving fast transient response with low power consumption.An event-driven charge pump(CP)loop with the dynamic strength control(DSC),is proposed in this paper,which overcomes trade-offs inherent in conventional structures.The presented design addresses and resolves the large signal stability issue,which has been previously overlooked in the event-driven charge pump structure.This breakthrough allows for the full exploitation of the charge-pump structure's poten-tial,particularly in enhancing transient recovery.Moreover,a dynamic error amplifier is utilized to attain precise regulation of the steady-state output voltage,leading to favorable static characteristics.A prototype chip has been fabricated in 65 nm CMOS technology.The measurement results show that the proposed OCL-LDO achieves a 410 nA low quiescent current(IQ)and can recover within 30 ns under 200 mA/10 ns loading change.

Experimental and Numerical Investigation on High-Pressure Centrifugal Pumps:Ultimate Pressure Formulation,Fatigue Life Assessment and Topological Optimization of Discharge Section

A high percentage of failure in pump elements originates from fatigue.This study focuses on the discharge section behavior,made of ductile iron,under dynamic load.An experimental protocol is established to collect the strain under pressurization and depressurization tests at specific locations.These experimental results are used to formulate the ultimate pressure expression function of the strain and the lateral surface of the discharge section and to validate finite element modeling.Fe-Safe is then used to assess the fatigue life cycle using different types of fatigue criteria(Coffin-Manson,Morrow,Goodman,and Soderberg).When the pressure is under 3000 PSI,pumps have an unlimited service life of 107 cycles,regardless of the criterion.However,for a pressure of 3555 PSI,only the Morrow criterion denotes a significant decrease in fatigue life cycles,as it considers the average stress.The topological optimization is then applied to the most critical pump model(with the lowest fatigue life cycle)to increase its fatigue life.Using the solid isotropic material with a penalization approach,the Abaqus Topology OptimizationModule is employed.The goal is to reduce the strain energy density while keeping the volume within bounds.According to the findings,a 5%volume reduction causes the strain energy density to decrease from 1.06 to 0.66106 J/m^(3).According to Morrow,the fatigue life cycle at 3,555 PSI is 782,425 longer than the initial 309,742 cycles.

Influence of specific speed on hydraulic performances and pressure fluctuations in mixed-flow pumps

A series of steady and unsteady numerical calculations of the internal flow in mixed-flow pumps with three different specific speeds were carried out based on the N-S equation coupled with the standard k-εturbulence model under different operating conditions to investigate the relationship between the impeller specific speed and the pump performance as well as pressure pulsations.Meanwhile,the pump performance and pressure pulsations inside the mixed-flow pump with three different specific speeds were also analyzed and compared with the corresponding test data.From the results,the averaged deviations between the predicted and tested head among different impellers are below 5%,and with respect to the equivalent impeller specific speeds of 280 and 260,the values are 4.30%and 3.69%,respectively.For all the impeller schemes,the best efficiency point of the mixed-flow pump is found at the flow rate of 1.2 Q_(d) and the higher head deviation occurs at lower flow rates.Especially,it can be found that the specific speed has a slight effect on the pressure fluctuation in the impellers.Eventually,it is determined that the pump performance curves calculated by numerical simu-lations have good agreement with the relevant experimental results,which verifies that the numerical methods used in the present study are accurate to a certain extent.Furthermore,the results also provide some references to the pressure pulsation analysis and the performance improvement of the mixed-flow pump design.

Effects of proton pump inhibitors on inflammatory bowel disease:An updated review

Inflammatory bowel disease(IBD)is believed to be caused by various factors,including abnormalities in disease susceptibility genes,environmental factors,immune factors,and intestinal bacteria.Proton pump inhibitors(PPIs)are the primary drugs used to treat acid-related diseases.They are also commonly prescribed to patients with IBD.Recent studies have suggested a potential association between the use of certain medications,such as PPIs,and the occurrence and progression of IBD.In this review,we summarize the potential impact of PPIs on IBD and analyze the underlying mechanisms.Our findings may provide insights for conducting further investigations into the effects of PPIs on IBD and serve as an important reminder for physicians to exercise caution when prescribing PPIs to patients with IBD.

Review:Measurement-Based Monitoring and Fault Identification in Centrifugal Pumps

Condition based maintenance(CBM) is one of the solutions to machinery maintenance requirements. Latest approaches to CBM aim at reducing human engagement in the real-time fault detection and decision making. Machine learning techniques like fuzzy-logic-based systems, neural networks, and support vector machines help to reduce human involvement. Most of these techniques provide fault information with 100% confidence. It is undeniably apparent that this area has a vast application scope. To facilitate future exploration, this review is presented describing the centrifugal pump faults, the signals they generate, their CBM based diagnostic schemes, and case studies for blockage and cavitation fault detection in centrifugal pump(CP) by performing the experiment on test rig. The classification accuracy is above 98% for fault detection. This review gives a head-start to new researchers in this field and identifies the un-touched areas pertaining to CP fault diagnosis.

Synthesis and Design of Distillation Columns for Wide-Boiling Binary Mixtures with Vapor Recompression Heat Pumps

The vapor recompression heat pump(VRHP) distillation technology offers significant improvements in energy efficiency for distillation systems with small temperature differences between the top and bottom of the column. However, the separation of wide-boiling binary mixtures leads to substantial temperature differences between the top and bottom of the column. This limits the applicability of conventional VRHP due to high capital costs and strict performance requirements of the compressor. To overcome these challenges and to accommodate compressor operating conditions, a novel synthesis and design method is introduced to integrate VRHPs with wide-boiling binary mixture distillation columns(WBMDCs). This method enables quick determination of an initial configuration for the integrated WBMDC-VRHP system and helps identify the optimum configuration with the minimum total annual cost. Two examples, namely the separation of benzene/toluene and isopropanol/chlorobenzene, are employed to derive optimum configurations of the WBMDC-VRHP and compare them with the WBMDC. A systematic comparison between the WBMDC-VRHP and WBMDC demonstrates the superior steady-state performance and economic efficiency of the WBMDC-VRHP.

Preface:Development and utilization of pumped storage in closed/abandoned mines

China has embarked on an extensive and sustained endeavor to harness its coal resources for a substantial period.However,the depletion of coal reserves in mining regions has necessitated the closure or abandonment of numerous mines,resulting in a marked increase in the number of such facilities.Parallel to this,China is vigorously advancing the development of a novel energy power system,aimed at transitioning the power sector from a high-carbon,fossil fuel-dependent paradigm to a low-carbon,clean energy footing.

An LED-Side-Pumped Intracavity Frequency-Doubled Nd,Ce:YAG Laser Producing a 2W Q-Switched Red Beam

We report a high-average-power acousto-optic(AO)Q-switched intracavity frequency-doubled red laser based on a high-efficiency light-emitting-diode(LED)pumped two-rod Nd,Ce:YAG laser module.Under quasi-continuous wave operation conditions,a maximum output power of 1319.08 nm wavelength was achieved at 11.26 W at a repetition rate of 100 Hz.

Dual-wavelength pumped latticed Fermi-Pasta-Ulam recurrences in nonlinear Schrödinger equation

We show that the nonlinear stage of the dual-wavelength pumped modulation instability(MI)in nonlinear Schrödinger equation(NLSE)can be effectively analyzed by mode truncation methods.The resulting complicated heteroclinic structure of instability unveils all possible dynamic trajectories of nonlinear waves.Significantly,the latticed-Fermi-Pasta-Ulam recurrences on the modulated-wave background in NLSE are also investigated and their dynamic trajectories run along the Hamiltonian contours of the heteroclinic structure.It is demonstrated that there has much richer dynamic behavior,in contrast to the nonlinear waves reported before.This novel nonlinear wave promises to inject new vitality into the study of MI.