Effect of Height Difference on The Performance of Two-phase Thermosyphon Loop Used in Air-conditioning System

Two-phase thermosyphon loops (TPTLs) are highly effective devices for spontaneously transferring heat through a relatively long distance. Therefore, TPTLs are extensively used in various fields, such as cooling of electronic components, light water reactors, etc. Recently, the TPTL has also been found to be an effective way to recover or transfer heat in air-conditioning systems for energy saving. A typical TPTL consists of an evaporator, a riser (gas tube), a condenser, and a downcomer (liquid tube), and the condenser is higher than the evaporator by a certain vertical distance. The TPTL is powered by the natural force --- gravity, which means the pressure drop in the cycle always equals to the liquid head caused by the density difference of the liquid in the downcomer and the vapor or vapor/liquid mixture in the riser. Therefore, the liquid head is a key factor affecting the circulation flow rate and energy performance of TPTLs. In the traditional applications, the liquid head is considered to be proportional to the height difference between the condenser and the evaporator based on the underlying assumption: the downcomer is fully liquid filled. According to that, the TPTL will perform better with a larger height difference. The conclusion may be correct in the cases with large temperature difference and heat flux, such as in the field of cooling of electronic and light water reactors. However, when the TPTL is used in air-conditioning system, which has quite small temperature difference and small heat flux, some special phenomena were observed: the liquid heat is lower than the height difference and the downcomer is partially liquid filled. That is largely different from the thermosyphons in traditional applications. What’s the thermodynamic mechanism of partially liquid filled in the downcomer? How to determine the liquid head and the height difference? These are the fundamental questions that required answers before using two-phase thermosyphon in air conditioner field. In this study, the thermodynamic mechanism of partially liquid filled in the downcomer is researched and the effect of height difference on the performance of TPTL is investigated theoretically and experimentally. Firstly, a visual experimental setup is established, and the performance of a water-water TPTL is measured when the height difference ranges from 0 m to 2.4 m. Based on it, the basic phenomena are observed and the thermodynamic mechanism is investigated. Secondly, a generalized distributed-parameter model is developed based on the conservations of momentum, energy, and mass, which can determine liquid head and overall performance simultaneously according to external conditions. The model is verified by experiments. Then the model is used to analyze the variation of liquid head, circulation flow rate, heat transfer rate, system pressure under different height differences. The results show that with the increase of the height difference, the liquid head rises continuously until remain stable. Therefore, the liquid head is less than the height difference in some cases. Consequently, with the increase of height difference, the circulation flow rate and thermal performance firstly increases then remains constant

Implementasi Algoritma K-Nearest Neighbour Untuk Menentukan Nomor Klasifikasi Buku Studi Kasus: Perpustakaan Universitas Katolik Musi Charitas)

Classification of library books is important to allow visitors in search of a book. The classification system in the library of the Catholic University of Charity Musi using guide books dewey decimal classification (DDC). The problem in this research is the difficulty in determining the classification number of new books. By utilizing the methods of Information Retrieval (IR) or retrieval of information, so in this study will build an application program for classification of library books. The method will be used to classify the book library is a method of k-nearest neighbor (k-NN). The application program classification of library books is built with training data from library books Musi-Caritas Catholic University and the test data is a new book. Applications are made capable of classifying new library book

Screening of potentially active compounds against rheumatoid arthritis in the Juan-Bi decoction using systems pharmacology and animal experiments

Background: The Juan-Bi decoction (JBD) is a classic traditional Chinese medicines (TCMs) prescription for the treatment of rheumatoid arthritis (RA). However, the active compounds of the JBD in RA treatment remain unclear.Aim: The aim of this study is to screen effective compounds in the JBD for RA treatment using systems pharmacology and experimental approaches.Method: Botanical drugs and compounds in the JBD were acquired from multiple public TCM databases. All compounds were initially screened using absorption, distribution, metabolism, excretion, and toxicity (ADMET) and physicochemical properties, and then a target prediction was performed. RA pathological genes were acquired from the DisGeNet database. Potential active compounds were screened by constructing a compound–target–pathogenic gene (C-T-P) network and calculating the cumulative interaction intensity of the compounds on pathogenic genes. The effectiveness of the compounds was verified using lipopolysaccharide (LPS)-induced RAW.264.7 cells and collagen-induced arthritis (CIA) mouse models.Results: We screened 15 potentially active compounds in the JBD for RA treatment. These compounds primarily act on multiple metabolic pathways, immune pathways, and signaling transduction pathways. Furthermore, in vivo and in vitro experiments showed that bornyl acetate (BAC) alleviated joint damage, and inflammatory cells infiltrated and facilitated a smooth cartilage surface via the suppression of the steroid hormone biosynthesis.Conclusion: We screened potential compounds in the JBD for the treatment of RA using systems pharmacology approaches. In particular, BAC had an anti-rheumatic effect, and future studies are required to elucidate the underlying mechanisms

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

Measurement of B-c(2S)(+) and B-c*(2S)(+) cross section ratios in proton-proton collisions at root s=13 TeV

Peer reviewe

Development and validation of HERWIG 7 tunes from CMS underlying-event measurements

This paper presents new sets of parameters (“tunes”) for the underlying-event model of the HERWIG7 event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in HERWIG7, and are obtained from a fit to minimum-bias data collected by the CMS experiment at s=0.9, 7, and 13Te. The tunes are based on the NNPDF 3.1 next-to-next-to-leading-order parton distribution function (PDF) set for the parton shower, and either a leading-order or next-to-next-to-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event shape observables in electron-positron collisions, and for minimum-bias, inclusive jet, top quark pair, and Z and W boson events in proton-proton collisions, and are compared with data. Each of the new tunes describes the data at a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI provide the best description of the dat

Reconstruction of signal amplitudes in the CMS electromagnetic calorimeter in the presence of overlapping proton-proton interactions

A template fitting technique for reconstructing the amplitude of signals produced by the lead tungstate crystals of the CMS electromagnetic calorimeter is described. This novel approach is designed to suppress the contribution to the signal of the increased number of out-of-time interactions per beam crossing following the reduction of the accelerator bunch spacing from 50 to 25 ns at the start of Run 2 of the LHC. Execution of the algorithm is sufficiently fast for it to be employed in the CMS high-level trigger. It is also used in the offline event reconstruction. Results obtained from simulations and from Run 2 collision data (2015-2018) demonstrate a substantial improvement in the energy resolution of the calorimeter over a range of energies extending from a few GeV to several tens of GeV.Peer reviewe

Observation of the Production of Three Massive Gauge Bosons at root s=13 TeV

The first observation is reported of the combined production of three massive gauge bosons (VVV with V = W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV. The analysis is based on a data sample recorded by the CMS experiment at the CERN LHC corresponding to an integrated luminosity of 137 fb(-1). The searches for individualWWW, WWZ, WZZ, and ZZZ production are performed in final states with three, four, five, and six leptons (electrons or muons), or with two same-sign leptons plus one or two jets. The observed (expected) significance of the combinedVVV production signal is 5.7 (5.9) standard deviations and the corresponding measured cross section relative to the standard model prediction is 1.02(-0.23)(+0.26). The significances of the individual WWW and WWZ production are 3.3 and 3.4 standard deviations, respectively. Measured production cross sections for the individual triboson processes are also reported

Measurement of the W gamma Production Cross Section in Proton-Proton Collisions at root s=13 TeV and Constraints on Effective Field Theory Coefficients

A fiducial cross section for W gamma production in proton-proton collisions is measured at a center-of-mass energy of 13 TeV in 137 fb(-1) of data collected using the CMS detector at the LHC. The W -> e nu and mu nu decay modes are used in a maximum-likelihood fit to the lepton-photon invariant mass distribution to extract the combined cross section. The measured cross section is compared with theoretical expectations at next-to-leading order in quantum chromodynamics. In addition, 95% confidence level intervals are reported for anomalous triple-gauge couplings within the framework of effective field theory.Peer reviewe