Type Condensation Research Articles

Experimental study on film condensation heat transfer characteristics of R134a, R1234ze(E) and R1233zd(E) over condensation tube with enhanced surfaces

This paper presents an experimental study on the film condensation heat transfer characteristics of a horizontal smooth tube and an enhanced tube using R134a, R1233zd(E) and R1234ze(E). The objectives of this paper are to develop experimental correlations of heat transfer for enhanced tubes used in a film type condenser and to provide a guideline for design of the film type condenser. Tests are performed on a horizontally smooth tube with a 19.05 mm diameter and three enhanced tubes. The temperature of the saturated vapor inside the condenser is 38 °C. In the case of the horizontal smooth tube, the film condensation heat transfer coefficients of R1234ze(E) and R1233zd(E) were approximately 10.97% and 10.04% lower than those of R134a, respectively. The experimental values obtained from the horizontal smooth tube agreed well with the theoretical value of Nusselt’s film which were within the ±10% error range. In the enhanced tubes experiment, the film condensation heat transfer characteristics according to the number of knurling and Fin per inch were examined. The enhanced tubes E.T(C)-1 and E.T(C)-3 exhibit a fin per inch number value of 55 and 85 and 107, respectively. Moreover, the fin per inch and knurling number of E.T(C)-5 are 60 and 117, respectively. As a result, the film condensation heat transfer coefficient was found to decrease with increasing heat flux, and E.T (C) -5 showed the highest average film condensation heat transfer coefficient for all refrigerants. Based on the experimental results, the effect of the fin per inch number on the heat transfer coefficient outside the tube is greater than that of the knurling number. In this study, the equations for film condensation heat transfer coefficient for each refrigerant and each enhanced were derived tube according to the heat flux, and a total of nine correlations were observed to have an accuracy of ±10% within the experimental range.

Study on pollutant characteristics of different types of manure sludge drying condensate

In order to further study the characteristics of condensate contaminants generated during the drying of livestock manure and biogas residues, the three biogas residues were dried at different temperatures and at different time. The condensate produced in the experiment was collected and its pH, ammonia nitrogen and COD were measured. Exploring the effects of different temperatures and different times on the characteristics of condensate contaminants during the drying of manure sludge. And further comparing the characteristics of different types of biogas residue dry condensate. The results show that: the three biogas residue condensates are weakly alkaline; the three biogas residue condensates COD rises with the increase of drying temperature, the use of low temperature drying can reduce the organic content of the dry condensate; low temperature drying can significantly reduce Exhaust gas treatment load to prevent the loss of organic fertilizer efficiency; with the extension of the drying time, the NH3-N content of the dry condensate of pig manure and chicken manure biogas residues decreased, and the NH3-N content of the dry manure biogas residue dry condensate increased; comprehensive consideration of drying efficiency and drying for the characteristics of condensate. It is recommended that all three kinds of biogas residues be dried at 60°C at low temperature.

Performance of air source air conditioning water heater using trombone coil dummy condenser with different diameter and pipe length

The Air Source Air Conditioning Water Heater (ASACWH) performance as an energy source to heat water in the tank using dummy condenser type of trombone coil with different diameter and pipe length without hot water circulation has been investigated. The diameter and length of the dummy condenser pipe are intensely affected by ACWH performance. In this study, cooling capacity, Coefficient of Performance (COP), compressor power and room temperature were evaluated in three types of trombone coil (6.4 mm coil diameter with a length of 7.9 m, 6.4 mm coil diameter with a length of 5.3 m, and 9.5 mm coil diameter with a length of 5.3 m) with different cooling load variation. This study used cooling load with a variation of 0 W, 1000 W, 2000 W, and 3000 W without hot water circulation in the simulation room. It was found that the ASACWH using a pipe with a coil diameter of 6.4 mm and length of 7.9 m performed the highest cooling capacity and COP, and produced more comfortable room temperature than the other two pipes. The results indicated that when the cooling load icreased from 0 W to 3000 W, the compressor power increased by 11.3%, 6.3%, and 9.3%, using the 6.4 mm coil diameter with 7.9 m length, 6.4mm diameter of the coil with 5.3m length and 9.5mm coil diameter with 5.3m length, respectively.

Symmetry Breaking in a Condensate of Light and its Use as a Quantum Sensor

Bose-Einstein condensates (BECs) represent one of the very few manifestations of purely quantum effects on a macroscopic level. The vast majority of BECs achieved in the lab to date consist of bosonic atoms, which macroscopically populate the ground state once a threshold temperature has been reached. Recently, a new type of condensate was observed - the photon BEC, where light in a dye-filled cavity thermalises with dye molecules under the influence of an external driving laser, condensing to the lowest-energy mode. However, the precise relationship between the photon BEC and symmetry-breaking phenomena has not yet been investigated. Here we consider medium-induced symmetry breaking in a photon BEC and show that it can be used as a quantum sensor. The introduction of polarisable objects such as chiral molecules lifts the degeneracy between cavity modes of different polarisations. Even a tiny imbalance is imprinted on the condensate polarisation in a 'winner takes it all' effect. When used as a sensor for enantiomeric excess, the predicted sensitivity exceeds that of contemporary methods based on circular dichroism. Our results introduce a new symmetry-breaking mechanism that is independent of the external pump, and demonstrate that the photon BEC can be used for practical purposes.

Networking and Dynamic Switches in Biological Condensates

Cellular liquid-liquid phase separation (LLPS) plays a key role in the dynamics and function of RNA-protein condensates like stress granules. In this issue ofCell, Yang et al., Guillén-Boixet et al., and Sanders et al. use a combination of experiment and modeling to provide an exciting mechanistic insight into the relationship between stress granules and LLPS, for example, in the context of protein disorder, switchable interactions, graph theory, and multiple interacting dense phases.

A Bayesian Analysis for Circular Galaxies Using a Bose—Einstein Condensate as a Dark Matter Halo

In this paper we present an extension of a Bayesian study for a Bose–Einstein Condensate type halo surrounding a Schwarzschild–type black hole. The predictions obtained via the Thomas–Fermi approximation are tested using observations from SPARC galaxy rotation curves sampler with 10 circular galaxies and whose inclination (angle) is less that 80 deg. The statistical analysis is confronted with the Navarro–Frenk–White density profile model where we found that at the centre of galaxies is require a supermassive black hole with a constrain of log10 M/M ⊙ = 12.00 ± 0.73 to allow a BEC configuration at this stage. Also, we show that the proposed scenario can fit the galaxy rotation curves on average rate .

Investigation of instability on loop heat pipe with flat evaporator

Loop heat pipes (LHPs) are heat transfer devices whose operating principle are based on the evaporation and condensation of a working fluid, using the capillary pumping forces to ensure the fluid circulation. A series of tests have been carried out with a loop heat pipe (LHP) with flat evaporator and a fin-and-tube type condenser. At some low heat loads, temperature oscillations were observed throughout the loop. Detailed study was conducted on the characteristics of temperature oscillation of the flat LHP at various heat loads. It is expected that the compensation chamber is the most critical component of the LHP; its hydrodynamic state dictates the extent and the characteristics of the temperature oscillations. The heat leakage from the evaporator to the compensation chamber, the heat loss to ambient and the subcooled liquid temperature dictate the vapor condition inside the compensation chamber, and the rate of vapor growth or dissipation dictated the nature of the temperature oscillation. The effects of different working fluid to the temperature oscillations were studied in detail.

Distinct Features of Stress Granule Proteins Predict Localization in Membraneless Organelles

Recently generated proteomic data provides unprecedented insight into stress granule composition and stands as fruitful ground for further analysis. Stress granules are stress-induced biological assemblies that are of keen interest due to being linked to both long-term cell viability and a variety of protein aggregation-based diseases. Herein, we compile recently published stress granule composition data, formed specifically through heat and oxidative stress, for both mammalian (Homo sapiens) and yeast (Saccharomyces cerevisiae) cells. Interrogation of the data reveals that stress granule proteins are enriched in features that favor protein liquid-liquid phase separation, being highly disordered, soluble, and abundant while maintaining a high level of protein-protein interactions under basal conditions. Furthermore, these “stress granuleomes” are shown to be enriched for multidomained, RNA-binding proteins with increased potential for post-translational modifications. Findings are consistent with the notion that stress granule formation is driven by protein liquid-liquid phase separation. Furthermore, stress granule proteins appear poised near solubility limits while possessing the ability to dynamically alter their phase behavior in response to external threat. Interestingly, several features, such as protein disorder, are more prominent among stress granule proteins that share homologs between yeast and mammalian systems also found within stress-induced foci. We culminate results from our stress granule analysis into novel predictors for granule incorporation and validate the mammalian predictor's performance against multiple types of membraneless condensates and by colocalization microscopy.

Fierz-complete NJL model study. III. Emergence from quark-gluon dynamics

Our understanding of the dynamics and the phase structure of dense strong-interaction matter is to a large extent still built on the analysis of low-energy models, such as those of the Nambu-Jona-Lasinio-type. In this work, we analyze the emergence of the latter class of models at intermediate and low energy scales from fundamental quark-gluon interactions. To this end, we study the renormalization group flow of a Fierz-complete set of four-quark interactions and monitor their strength at finite temperature and quark chemical potential. At small quark chemical potential, we find that the scalar-pseudoscalar interaction channel is dynamically rendered most dominant by the gauge degrees of freedom, indicating the formation of a chiral condensate. Moreover, the inclusion of quark-gluon interactions leaves a significant imprint on the dynamics as measured by the curvature of the finite-temperature phase boundary which we find to be in accordance with lattice QCD results. At large quark chemical potential, we then observe that the dominance pattern of the four-quark couplings is changed by the underlying quark-gluon dynamics, without any fine-tuning of the four-quark couplings. In this regime, the scalar-pseudoscalar interaction channel becomes subleading and the dominance pattern suggests the formation of a chirally symmetric diquark condensate. In particular, our study confirms the importance of explicit $U_{\mathrm{A}}(1)$ breaking for the formation of this type of condensate at high densities.

Impact of salty water medium and condenser on the performance of single acting solar still incorporated with parabolic trough collector

The impact of salty water medium and condenser type on the performance of single slope solar still is experimentally performed. Two solar still types are examined; conventional solar still with glass condenser (CSS) and solar still with plated finned heat sink condenser (MSS). The study is investigated for three saline water mediums in the still basin; pure saline water, sand saturated with saline water and steel wire meshes submerged inside the saline water. These stills are investigated in case of still only or still incorporated with parabolic trough collector (PTC) in hot and cold climate conditions of upper Egypt. Findings show that utilizing wire mesh, sand and heat sink condenser (HSC) raises the still freshwater yield and efficiency. The maximum freshwater yield rising in summer is 67%, 7.3% and 6% due to using PTC, HSC, and sand, respectively compared to CSS. The efficiency of all still systems in summer is found greater than winter. Moreover, utilizing HSC raises the still efficiency by 11.6% in summer and 8% in winter compared to CSS. MSS achieves the greatest efficiency of 41.95% in summer and 31.96% in winter while MSS+sand+PTC accomplishes the minimum freshwater cost with a decrease of 25.2% compared to CSS.

Physical Principles Underlying the Complex Biology of Intracellular Phase Transitions.

Many biomolecular condensates appear to form via spontaneous or driven processes that have the hallmarks of intracellular phase transitions. This suggests that a common underlying physical framework might govern the formation of functionally and compositionally unrelated biomolecular condensates. In this review, we summarize recent work that leverages a stickers-and-spacers framework adapted from the field of associative polymers for understanding how multivalent protein and RNA molecules drive phase transitions that give rise to biomolecular condensates. We discuss how the valence of stickers impacts the driving forces for condensate formation and elaborate on how stickers can be distinguished from spacers in different contexts. We touch on the impact of sticker- and spacer-mediated interactions on the rheological properties of condensates and show how the model can be mapped to known drivers of different types of biomolecular condensates.

Syntheses of Novel Tetrasubstituted Thiophenes from Benzene-1,2-Diamines, Ethyl Bromopyruvate, Malononitrile, and Aryl Isothiocyanates

Synthesis of highly functionalized tetrasubstituted thiophenes has been reported involving 3-(bromomethyl)quinoxalin-2(1H)-ones as activated halomethylene compounds precursors. Thus sequential base mediated condensation of readily available malononitrile with aryl isothiocyanates followed by S–alkylation of the resulting enethiolate salts with 3-(bromomethyl)quinoxalin-2(1H)-one compounds and concurrent intramolecular enamine type condensation of S–alkylated compounds affords substituted thiophenes in excellent yields.

RedH and PigC Catalyze the Biosynthesis of Hybrubins via Phosphorylation of 4'-Methoxy-2,2'-Bipyrrole-5'-Carbaldehyde.

Hybrubins are "unnatural" alkaloids with the same 4'-methoxy-2,2'-bipyrrole-5'-methine moiety found in prodiginines and a different ring derived from tetramic acids. Here, we demonstrated that RedH, a homologue of prodigiosin synthetase PigC, was responsible for the biosynthesis of hybrubins A and B in Streptomyces lividansIn vitro reactions indicated that RedH and PigC catalyzed the intermolecular condensation between 4'-methoxy-2,2'-bipyrrole-5'-carbaldehyde (MBC) and (Z)-5-ethylidenetetramic acid (ETA) to produce hybrubin B. Moreover, we demonstrated that RedH and PigC activated MBC via phosphorylation of the aldehyde group to form an intermediate Pi-MBC and that the subsequent condensation between Pi-MBC and (Z)-5-ethylidenetetramic acid occurs in a nonenzymatic way.IMPORTANCE Hybrubins are an emerging class of prodiginines possessing a new C ring derived from 5'-substituted tetramic acids and the methylene bridge connecting the C ring at a different position. We have supposed that condensation between 4'-methoxy-2,2'-bipyrrole-5'-carbaldehyde (MBC) and 5-ethylidenetetramic acid (ETA) yields the hybrid natural products hybrubins, which was proposed to be catalyzed by the undecylprodigiosin synthetase RedH. However, it is doubted whether RedH is able to catalyze another type of condensation between MBC and tetramic acids. In this study, we have demonstrated that the MBC-ETA condensation proceeds through RedH/PigC-catalyzed enzymatic activation of MBC via phosphorylation and a nonenzymatic condensation of Pi-MBC with ETA. Since MBC analogues have been shown to be accepted by PigC, more hybrubin analogues might be produced by using combinations of MBC analogues and other tetramic acids in future studies.

Comparison of Digital and Conventional Impression Methods by Preclinical Students: Efficiency and Future Expectations.

ABSTRACTAims and Objectives:The purpose of this study is to compare digital and conventional impression methods by preclinical students in terms of time and ease and to evaluate their preferences and future expectations.Materials and Methods:Twenty volunteered, 2nd year preclinical students (11 females and 9 males) participated in this study. Students took digital and conventional impressions of the left lower first molar which was made full ceramic crown preparation and opposite full arch from a typodont model (Frasaco, Frasaco GmbH, Tettnang, Germany). They used intraoral scanner (CEREC Omnicam, Sirona Dental GmbH, Bensheim, Germany) for digital impression and also used additional type (Express XT Penta H, 3M ESPE, Seefeld, Germany) and condensation type (Zetaplus, Zhermack SpA, Badia Polesine, Italy) silicones for conventional impression. Their taking impression time was measured. Before taking impression and after taking impression, two kinds of questionnaires were conducted to students about their preference, ease of impression methods, and their future expectations. Statistical analysis was performed by IBM SPSS 23 and Excel 2010 version. Differences between conventional and digital impression in terms of time were analyzed by student’s-t paired test and effect of gender was analyzed by students’s-t independent test.Results:There were statistically significant differences between digital and conventional impression methods in terms of taking impression and total impression time (P < 0.001). But there wasn’t any statistically significant difference between two methods in terms of preparation time. About 85% of students preferred the digital impression method and also 85% of students found that the digital impression method was easy. 95% of students expected to find intraoral scanner in the clinic where working first time.Conclusions:As a result of this study, it has been seen that the students preferred the digital impression method to the conventional impression method and found that the digital impression method was easier.

Tropylium cation-fused aromatic [26]dicarbaporphyrinoids with NIR absorptions: Synthesis, spectroscopic and theoretical characterization

An easy and efficient synthetic methodology for two hitherto unknown tropylium-cation-fused Hückel aromatic [26] dicarbaporphyrinoids has been developed by acid-catalyzed Lindsey type condensation of bithiophene/biselenophene diol with azulene using BF3 · Et2O followed by oxidation with chloranil and/or DDQ. Both the macrocycles have been achieved in moderately good yields. Their structures, aromaticity and optical properties have been elucidated by NMR, UV-vis-NIR spectroscopic analyses and in-depth theoretical calculations. Both the macrocycles exhibited strongly diatropic characteristics with the UV-vis spectra closely resembling the spectra for true porphyrins. Detailed structural analyses using 1H–1H COSY, ROESY and DFT level theoretical investigations indicated fully conjugated [26][Formula: see text] main conjugation pathway being benefitted by the tropylium character of the seven membered rings.

Theoretical Analysis of a Shell and Tubes Condenser with R134a Working Refrigerant and Water-Based Oxide of Aluminum Nanofluid (Al&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;)

The article analyzes a shell and tube type condenser’s thermal performance using concepts of efficiency and effectiveness. Freon 134a is used as a coolant flowing through the shell. Water or water-based aluminum oxide nanoparticles are at relatively low saturation pressure in the tube. The condenser consists of 36 tubes divided into three central regions for analysis: superheated steam, saturated steam, and subcooled liquid. The three regions contain four tubes with three steps each, that is, 12 tubes. Region I, superheated steam, includes three horizontal baffles. Profiles of temperature, efficiency, and effectiveness are presented graphically for the three regions, with fixed refrigerant flow equal to 0.20 kg/s and fluid flow rate in the tube ranging from 0.05 kg/s to 0.40 kg/s. The experimental result for vapor pressure equal to 1.2 MPa and water flow equal to 0.41 kg/s was used as one of the references for the model’s physical compatibility.

Experimental investigation of oscillating heat pipe efficiency for a novel condenser by using Fe3O4 nanofluid

This paper presents a novel study on the performance of closed-loop oscillating heat pipe (CLOHP) using iron oxide (Fe3O4) as the working fluid for three types of condensers. The tested CLOHP consists of six turns made of copper tubes, 4.5 mm outer diameter and 3 mm inner diameter with heating power input in a range of 0–200 W. The experimental results showed that the thermal performance of the CLOHPs has been improved when the corrugated horizontal condenser was used compare to straight and corrugated vertical condensers. Based on 800 sets of available experimental data, the results show that the CLOHPs with corrugated horizontal condenser had better thermal performance when charged with Fe3O4/water at 2% mass concentration.

Rotating Binary Bose-Einstein Condensates and Vortex Clusters in Quantum Droplets.

Quantum droplets may form out of a gaseous Bose-Einstein condensate, stabilized by quantum fluctuations beyond mean field. Determining the ground state of a rotating binary condensate, we show that multiple singly quantized vortices may form in these droplets at moderate angular momenta in two dimensions. Droplets carrying these precursors of an Abrikosov lattice remain self-bound for certain timescales after switching off an initial harmonic confinement. Intriguingly, we find evidence of a metastable persistent current in these new types of binary condensates. We discuss how this finding can be used to experimentally generate vortex-carrying quantum droplets.

MODELING OF THE PROCESSES OF INTERACTION OF FIBER MASS WITH BOILER GRID AND ISOLATION OF HERBULAR IMPURITIES FROM IT

In the republic, the volumes of harvesting of hard-to-clean breeding varieties «S-6524», «Sulton», «An-Bayaut-2», «Namangan-77», «Omad» and others have increased annually. In 2018, their share amounted to 80% of the total harvest. With each year, the volume of harvesting raw cotton of machine harvest is increasing. The weediness of raw cotton at machine gathering is 10-15% more than manual. The peel with fiber, broken seeds and nodules are formed in the process of ginning and, therefore, they can only be removed when ginning raw cotton. In order to improve the quality of the fiber, in the mid-80s, two individual grates were installed in the gin itself for cleaning the fiber. But due to the flaws in the mounting structure of the individual grates on the side walls of the gin, it is impossible to establish the required gaps between the saw teeth and the edges of the grates, which reduces the release of hives and trash, as well as increased waste fiber. In developed cotton-growing countries such as the USA, China, India, etc., fiber cleaning sections are not used in the construction of gins. They have fiber cleaned on fiberglass aerodynamic and condenser type. In this case, the fiber is subjected to enhanced cleaning according to the principle of scratching, which increases the fiber content of the waste, thereby reducing the amount of fiber produced by grades. Improving the quality of fiber, reducing waste losses and competitiveness in the global market is an urgent task. To achieve these goals, a modernized saw gin with a grate of a new design for fiber cleaning has been created. A theoretical study was made on the change in the mass of a piece of fibrous material that occurs in the process of shock interaction with the fire grate.

Laboratory investigation of Accuracy of Impression Materials for Border Molding.

Border molding of the edge of the individual impression tray is an important stage of prosthetic treatment of edentulous jaws, which often depends on the final result of the treatment. Classical thermoplastic impression materials for border molding have positive qualities that make them preferable by clinicians for their hardness, unlimited manipulation time and high impression sharpness. Modern silicone impression materials for border molding have long manipulating time and appropriate viscosity to allow dentists to perform functional tests. To determine the accuracy of different impression materials for border molding of individual impression trays. Four impression materials for border molding were laboratory tested: Kerr impression compound green sticks and thermoplastic GC Iso functional sticks, additive type silicone Detaseal function and condensation type silicone sta-seal f. A modified individual impression tray designed by authors was used, allowing for laboratory load and stability. Ten impressions were taken and their formed edges were measured at 10 points three times - immediately after hardening/elasification, and 24 hours and 48 hours after hardening/elasification. The results were analysed using ANOVA repetition analysis, where a statistically insignificant difference in the accuracy of three of the impression materials for border molding was established, except the C-type of silicone. Good manipulative qualities and measured accuracy in laboratory tests define these materials as very good for border molding procedures.