Mixed Condensation Research Articles

Entropy Analysis of Mixed Convective Condensation by Evaluating Fan Velocity With a New Approach

Present paper conducts an extensive numerical study on entropy analysis of mixed convective condensation inside a vertical parallel plate channel. A new approach is proposed to separate pump velocity component/Reynolds number from inlet mixed convection velocity. Influence of inlet governing parameters on condensation heat and mass transfer at different inlet pressure, velocity, channel length, and width are widely studied. The central focus of this paper is to study entropy generation under mixed convective condensation. Variation of local as well as overall entropy generation and second law efficiency for different geometric and environmental conditions are presented. For effective condenser design, present study provides two important correlations of overall volumetric entropy generation due to thermal transport and overall volumetric entropy generation due to mass transport.

Composite operator and condensate in the SU(N) Yang-Mills theory with U(N−1) stability group

Recently, some reformulations of the Yang-Mills theory inspired by the Cho-Faddeev-Niemi decomposition have been developed in order to understand confinement from the viewpoint of the dual superconductivity. In this paper we focus on the reformulated $SU(N)$ Yang-Mills theory in the minimal option with $U(N-1)$ stability group. Despite existing numerical simulations on the lattice we perform the perturbative analysis to one-loop level as a first step towards the non-perturbative analytical treatment. First, we give the Feynman rules and calculate all renormalization factors to obtain the standard renormalization group functions to one-loop level in light of the renormalizability of this theory. Then we introduce a mixed gluon ghost composite operator of mass dimension two and show the BRST invariance and the multiplicative renormalizability. Armed with these results, we argue the existence of the mixed gluon-ghost condensate by means of the so-called local composite operator formalism, which leads to various interesting implications for confinement as shown in preceding works.

Heat transfer characteristics of mixed hydrocarbon refrigerant flow condensation in shell side of helically baffled shell-and-tube heat exchanger

For optimizing the helically baffled shell-and-tube heat exchanger (HBHX) used in the liquefied natural gas (LNG) process, the condensation heat transfer mechanism of the mixed hydrocarbon refrigerant flow condensation in shell side of HBHX should be known. In the present study, the ethane/propane mixture and the ethane/propane/butane mixture were used as the tested fluids for analyzing the heat transfer mechanism of mixed hydrocarbon refrigerants. The results show that, as the vapor quality increases, the heat transfer coefficient initially increases and then decreases, representing a maximum at vapor quality of 0.8 – 0.9; the two-phase condensation heat transfer coefficients of ethane/propane mixture and ethane/propane/butane mixture are smaller than that of pure propane by 29–72% and 71–44%, respectively. A heat transfer coefficient correlation for the mixed hydrocarbon refrigerant flow condensation in shell side of HBHX was developed within a deviation of ±25%.

Synthesis of metallocomplexes of water soluble bisquinolinylporhyrins as potential antimicrobial agents

At present, extensive research is being carried out on the phenomenon of resistance of microbes to antibiotics, including the newest of them. Among the most promising drug candidates for treatment such superbugs is derivatives of 5,15-disubstituted water-soluble porphyrins developed and patented by Destiny Pharma, UK. Here, we continued of our investigation of quinolinylporphyrins and report about synthesis of 5,15-di(n-propyl)-10,20-di(3-quinolinyl)porphyrine and its isomer - 5,10-di(n-propyl)-15,20-di(3-quinolinyl)porphyrine and their complexes with Fe and Mn. The porphyrins was obtained by mixed aldehydes condensation of mixture quinoline-3-carbaldehyde and n-butyraldehyde with pyrrole in propionic acid with small amount propionic anhydride. Above mentioned porphyrins was separated and purified by column chromatography on silica gel and their Fe and Mn complexes was synthesized in refluxing DMF by treatment respectively FeCl3 and Mn(CH3CO2)2. Water-soluble form of the metalloporphyrines was obtained by quaternization of nitrogen atom of quinolinyl substituents by methyl-paratoluenesulfonate for further investigation their antimicrobial properties.

Merging Triptycene, BODIPY and Porphyrin Chemistry: Synthesis and Properties of Mono‐ and Trisubstituted Triptycene Dye Arrays

A series of functionalized triptycene scaffolds has been synthesized using 2‐formyltriptycene and 5‐(2‐triptycenyl)dipyrromethane. Using these two key precursors, mixed condensations with different aromatic aldehydes and aryl‐dipyrromethanes gave access to all members of triptycenyl meso‐substituted porphyrins (AB3‐, A2B2‐, A3B‐, and A4) and allowed their photophysical and electrochemical characterization. Additionally, the first crystal structure of tetratriptycenylporphyrin is reported. 2‐Formyltriptycene was also used for the preparation of two different mono‐BODIPY‐triptycene compounds, while 2,6,14‐triiodotriptycene was used in Suzuki and Sonogashira cross‐coupling reactions to obtain threefold BODIPY‐substituted triptycene–dye conjugates. The mono‐ and tri‐BODIPY‐substituted triptycene scaffolds exhibit good absorption in the visible to NIR region indicating the potential use of the triptycene scaffold as the core of multi‐dye light‐harvesting systems.

Development of an efficient viral aerosol collector for higher sampling flow rate.

Viral aerosol infection through cough generates large amounts of viral aerosol and can result in many adverse health effects such as influenza flu and severe acute respiratory syndrome (SARS). To characterize the coughed viral aerosol, the sampler needs to sample at higher flow rate and possess high physical collection efficiency as well as high viral preservation. However, most current inertia-based high flow bioaerosol samplers are not suited for viral aerosol sampling since the viability will be lost doing the sampling process. Current condensation growth methods only have good physical collection efficiency and viral preservation at low flow rate (< 10 LPM). In this study, we developed a viral aerosol sampling system using a cooler and steam-jet aerosol collector (SJAC) for bioaerosol collection for the first time. The system is based on mixing condensation growth method and has high viral preservation at a higher flow rate (12.5 LPM). We control the inlet aerosol flow temperature and the SJAC mixing reservoir temperature to improve the physical collection efficiency and viability preservation of the viral aerosol. Results indicate that the physical collection efficiency is 70–99% for aerosol 30–100 nm when the aerosol flow and mixing reservoir temperature was 19 and 50 °C, respectively. In addition, the system was 7 and 22 times more efficient for viability preservation of MS2 bacteriophage than the commonly used All Glass Impinger 30 (AGI-30) and BioSampler®, respectively. Finally, the system can be applied to sample at a lower concentration (105 PFU/m3), and results shows the system was 4.7 times more efficient for viability preservation than using AGI-30 alone. The developed viral collection system will improve our understanding of the characteristics of coughed aerosol and can be used for future evaluation of respiratory protective equipment and environmental sampling.

Asymmetrically substituted tetra(meso-aryl)porphyrins bearing peripheral 2,6-diisobornylphenol and 2,6-di-tert-butylphenol moieties

Asymmetrically substituted tetra(meso-aryl)porphyrins bearing peripheral diisobornyl- phenol and di-tert-butylphenol moieties were synthesized by a mixed aldehyde condensation.

A novel polystyrene with non-symmetrical zinc phthalocyanines as terminal group

A new non-symmetrical zinc(II) phthalocyanine (ZnPc) with an alkynyl functional group was prepared by an efficient mixed statistical condensation of 4-((4-ethynylbenzyl)oxy)phthalonitrile (1) and 4-(4-tert-butylphenoxy)phthalonitrile (2). The isolated unsymmetrical phthalocyanine molecule with additional three 4-tert-butylbenzyloxy groups to maintain solubility was used in the Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition, better known as the “click chemistry”, as one of the precursors. The second component of the click reaction was polystyrene (PS) which was obtained by atom transfer radical polymerization (ATRP) and then its bromo end group was converted to azide by treatment with sodium azide. FT-IR, 1H-NMR, 13C-NMR, MALDI TOF MS, UV–Vis, GPC, and elemental analysis techniques were used to characterize the precursors and targeted ZnPc-functionalized polystyrene. Molecular weight of obtained polymer was examined by gel permeation chromatography (GPC), thermal properties were also evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It is observed that thermal stability of PS-ZnPc has been improved owing to high thermal stability of phthalocyanine group. Surface properties of PS-ZnPc thin films investigated by contact angle measurements indicate that it has more hydrophobic character when compared with PS-Br film.

Open charm-bottom axial-vector tetraquarks and their properties

The charged axial-vector J^{P}=1^{+} tetraquarks Z_{q}=[cq][bar{b} bar{q} ] and Z_{s}=[cs][bar{b} bar{s}] with the open charm-bottom contents are studied in the diquark–antidiquark model. The masses and meson–current couplings of these states are calculated by employing a QCD two-point sum rule approach, where the quark, gluon and mixed condensates up to eight dimensions are taken into account. These parameters of the tetraquark states Z_{q} and Z_{s} are used to analyze the vertices Z_q B_c rho and Z_s B_c phi to determine the strong g_{Z_qB_c rho } and g_{Z_sB_c phi } couplings. For these purposes, the QCD light-cone sum rule method and its soft-meson approximation are utilized. The couplings g_{Z_qB_c rho } and g_{Z_sB_c phi }, extracted from this analysis, are applied for evaluating the strong Z_q rightarrow B_c rho and Z_s rightarrow B_c phi decays’ widths, which are essential results of the present investigation. Our predictions for the masses of the Z_{q} and Z_{s} states are confronted with similar results available in the literature.

Statistical analysis as a tool for assisting geochemical interpretation of the Upper Triassic Yanchang Formation, Ordos Basin, Central China

The Yanchang Formation in the Ordos Basin is the most important petroleum play not only for conventional oil and gas accumulations, but also for newly emerging shale oil and tight gas resources. The molecular characterization of the basinwide source rocks predicts three groups of generative petroleum types: Paraffinic High Wax Oil, mixed base (Paraffinic-Naphthenic-Aromatic) Low Wax Oil, and Gas and Condensate. Supplementary to previous work, 68 samples including the crude oils, source bitumens and reservoir extracts from the Yanchang petroleum play are analyzed. The distribution of two terpane classes (eight tricyclic terpanes and eight pentacyclic terpanes) are determined with subsequent simultaneous RQ-mode factor analysis for a composite data set of these samples alongside 216 published crude oils worldwide with known facies descriptions. Thermal maturity has been evaluated as a consistent distribution at first using a combined method of a maturity-related biomarker [Ts / (Ts+Tm)] and aromatic parameters (Methyldibenzothiophene Ratios) to alleviate the maturity differences effect when discussing geochemical characterization. The R-mode factor analysis consists of the first two factors that are describing 45 present of the cumulative total variance in the data set, and presents a sample grouping pattern in Q-mode factor analysis which is determined by different contributions of terpane associations, i.e., the tricyclic C21 coupled with pentacyclic C26, C27, C28 and C30, in the same factor space. Three terpane associations, the C26 and C28 terpanes, the C21 and C30 terpanes and the C27 pentacyclic terpenes, are respectively responsible for discriminating crude oil, reservoir extracts and source bitumens in RQ-mode factor analysis. Molecular compositions further address more detailed interrelationships among three sample groups that crude oils and reservoir extracts are sharing close genetic relationships both in depositional environment typing and C27-C28-C29 sterane distribution. Samples from source rocks vary much significantly. A mixing process which occurs after oils has been expelled from host source rocks into carrier units during accumulation. In addition, the migration-contamination of C29 sterols when oils are cross through the Chang 7–2 unit along migration pathways might also explain this lack of correlation between source rocks and oil-reservoir system.

Stereoselective total synthesis of (−)-zeylenol, a key intermediate for the synthesis of (+)-pipoxide, (−)-uvarigranol G and (−)-tonkinenin A

Total synthesis of (−)-zeylenol, a key intermediate for the synthesis of (+)-pipoxide, (−)-uvarigranol G and (−)-tonkinenin A was achieved from commercially available starting material d-mannose. The key steps are mixed aldol condensation, Grignard reaction, ring closing metathesis and regioselective benzoylation.

Quantum and thermal phase transitions in a bosonic atom-molecule mixture in a two-dimensional optical lattice

We study the ground state and the thermal phase diagram of a two-species Bose-Hubbard model, with $U(1)\times \mathbb{Z}_2$ symmetry, describing atoms and molecules on a 2D optical lattice interacting via a Feshbach resonance. Using quantum Monte Carlo simulations and mean field theory, we show that the conversion between the two-species, coherently coupling the atomic and molecular states, has a crucial impact on the Mott-Superfluid transition and stabilizes an insulating phase with a gap controlled by the conversion term -- \textit{the Feshbach insulator} -- instead of a standard Mott insulating phase. Depending on the detuning between atoms and molecules, this model exhibits three phases: the Feshbach insulator, a molecular condensate coexisting with non condensed atoms and a mixed atomic-molecular condensate. Employing a finite-size scaling method, we observe 3D XY (3D Ising) transition when $U(1)$ ($ \mathbb{Z}_2$) is broken whereas the transition is first-order when both $U(1)$ and $ \mathbb{Z}_2$ symmetries are spontaneously broken. The finite temperature phase diagram is also discussed. The thermal disappearance of the molecular superfluid leads to a Berezinskii-Kosterlitz-Thouless transition with unusual universal jump in the superfluid density. The loss of the quasi-long-range coherence of the mixed atomic and molecular superfluid is more subtle since only atoms exhibit conventional Berezinskii-Kosterlitz-Thouless criticality. We also observe a classical first-order transition between the mixed superfluid and the normal Bose liquid at low temperature.

Calix[4]pyrroles with bulky substituents and their anion binding studies

Calix[4]pyrrole derivatives with bulky substituents at their meso-positions were synthesized via mixed condensation of pyrrole with cyclohexanone and acetophenone derivatives. Anion binding studies, carried out by isothermal titration calorimetry in 1,2-dichloroethane with Cl$^{-}$ and CH$_{3}$CO$_{2}^{-}$ anions in the form of their tetrabutylammonium salts, revealed that these new calix[4]pyrrole derivatives can bind the aforementioned anions as effectively as the unsubstituted ''parent'' system, octamethylcalix[4]pyrrole (1). Structural characterizations of new calix[4]pyrroles were carried out by using $^{1}$H and $^{13}$C NMR spectroscopy corroborated with mass spectrometry.

Comparative Micro–computed Tomographic Evaluation of the Sealing Quality of ProRoot MTA and MTA Angelus Apical Plugs Placed with Various Techniques

IntroductionThis study compared the effects of different mixing and placement techniques on sealing of ProRoot MTA (Dentsply Maillefer, Ballaigues, Switzerland) and MTA Angelus (Soluçoes Odontologicas, Londrina, Brazil) apical plugs using micro–computed tomographic (micro-CT) imaging. MethodsStandardized divergent open apex models were created using 120 extracted maxillary incisors and divided into 8 groups (n = 15). ProRoot MTA and MTA Angelus were mixed manually or mechanically and introduced to form apical plugs by hand condensation or indirect ultrasonic activation for 10 seconds. The samples were scanned using micro-CT imaging, and volumetric analysis of the voids between the dentin walls and the apical plugs and the porosity inside MTA was performed. ResultsIrrespective of the mixing and placement techniques used, the voids between the dentin walls and the apical plugs in the MTA Angelus groups were greater than those in the ProRoot MTA groups (P < .05). The mechanically mixed groups were significantly less porous than the manually mixed groups (P < .05). Combined mechanical mixing and indirect ultrasonic activation yielded a less porous structure for both types of MTA than combined manual mixing and hand condensation (P < .05). Marginal adaptation for ProRoot MTA, both mixed and placed manually, was greater than for MTA Angelus (P < .05), but no difference was found when indirect ultrasonic activation was performed (P > .05). ConclusionsProRoot MTA showed better marginal adaptation than MTA Angelus. Mechanically mixed products had better handling characteristics than the manually mixed product. Indirect ultrasonic activation did improve the adaptation of manually mixed MTA Angelus to the dentin walls.

The homogeneous and Lagrangian tracking approaches of the spray simulation in the containment

The spray system is an emergency containment cooling strategy to depressurize and remove heat in the steam or hydrogen generation scenarios. Different kinds of phenomena including gas-droplets mixing, water vaporization, and steam condensation, are coupled into the complicated flow. The thermal-hydraulic simulation code GASFLOW is widely used and verified in series of containment experiments. Also, a homogeneous spray model which treats the droplets as one species in the gas mixture is incorporated in this code. This paper developed the Lagrangian tracking way for the spray simulation which viewed the droplets as dispersed phase. And in this approach, the interactions for gas-droplets and wall-droplets were considered in all aspects of mass, momentum and energy. The priorities of Lagrangian tracking way over homogeneous way were showed by the TOSQAN 101 and 113 spray benchmarks tests. Detailed comparisons between the two models were concentrated on the condensation-evaporation procedure and gas mixing. All these revealed that the Lagrangian way could predict the phase transition and momentum exchange correctly.

Water-based single-flow mixing condensation particle counter

ABSTRACTA novel water-based condensation particle counter has been developed using a patented, single-flow mixing (SFM) condenser that permits a conventional thermal approach of using a hot saturator followed by a cold condenser to activate and grow particles for counting with an optical detector. A computational fluid dynamics (CFD) model of the internal flow, temperature, and vapor profiles was used to predict the effectiveness of the SFM condenser. Using the results from the CFD model, the counting efficiency was numerically calculated for pure water droplets, and the CPC cut-point (i.e., 50% counting efficiency) was predicted to be 8.3 nm. The experimental performance of the new CPC was measured with differential mobility analyzer-classified, monodisperse particles. The measured cut-points were 8.2 nm for Ag particles and 3.9 nm for NaCl particles. The reduction in the cut-point for NaCl is the result of a compound effect: water uptake by NaCl particles, which increases their size before entering into...

Synthesis, Characterization and Properties of Expanded Pyriporphyrins: A New Family of Alkylidenyl Porphyrin Homologues Bearing meso-Exocyclic Double Bonds.

We present the synthesis and characterization of a new family of expanded meso-alkylidenyl (2,6-pyri)porphyrinoids bearing multiple exocyclic double bonds at the meso-positions. The synthesis was accomplished by using mixed pyrrole condensation. Similar to meso-alkylidenyl porphyrinoids, this study revealed that pyriporphyrinoids do not possess a porphyrin-like, global-aromatic character. The synthesized 2,6-pyripentaphyrin 1 displays selective ratiometric sensing of pyrophosphate anion in organic solvent.

β-Keto-enol Tethered Pyridine and Thiophene: Synthesis, Crystal Structure Determination and Its Organic Immobilization on Silica for Efficient Solid-Liquid Extraction of Heavy Metals.

Molecules bearing β-keto-enol functionality are potential candidates for coordination chemistry. Reported herein is the first synthesis and use of a novel designed ligand based on β-keto-enol group embedded with pyridine and thiophene moieties. The product was prepared in a one-step procedure by mixed Claisen condensation and was characterized by EA, m/z, FT-IR, (1H, 13C) NMR and single-crystal X-ray diffraction analysis. The new structure was grafted onto silica particles to afford a chelating matrix which was well-characterized by EA, FT-IR, solid-state 13C-NMR, BET, BJH, SEM and TGA. The newly prepared organic-inorganic material was used as an adsorbent for efficient solid-phase extraction (SPE) of Cu(II), Zn(II), Cd(II) and Pb(II) from aqueous solutions and showed a capture capacity of 104.12 mg·g−1, 98.90 mg·g−1, 72.02 mg·g−1, and 65.54 mg·g−1, respectively. The adsorption capacity was investigated, in a batch method, using time of contact, pH, initial concentration, kinetics (Langmuir and Freundlich models), and thermodynamic parameters (ΔG°, ΔH° and ΔS°) of the system effects.

Evaluación in vitro de la microfiltración de Enterococcus faecalis usando cinco técnicas de obturación / In Vitro Evaluation of Enterococcus faecalis Microleakage Using Five Obturation Techniques

&lt;p&gt;&lt;strong&gt;ABSTRACT. &lt;/strong&gt;&lt;em&gt;&lt;strong&gt;Background:&lt;/strong&gt;&lt;/em&gt; The root canal filling technique named Hybrid-Mixed Condensation, combines the advantages of cold lateral and warm vertical condensation. The ability of avoiding microbial microleakage has not been proven. &lt;em&gt;&lt;strong&gt;Purpose:&lt;/strong&gt;&lt;/em&gt; To evaluate the differences of microbial microleakage using &lt;em&gt;Enterococcus faecalis&lt;/em&gt;, in canals obturated with five different techniques: lateral, warm vertical, WaveOne® single cone, Guttacore®, and Hybrid-mixed condensation. &lt;em&gt;&lt;strong&gt;Methods:&lt;/strong&gt;&lt;/em&gt; 50 single-rooted human premolars extracted for orthodontic reasons were biomechanical prepared with primary file of WaveOne® system. Teeth were divided into 5 groups using different obturation techniques: single cone with WaveOne® Primary, lateral condensation using 2 % gutta-percha cones, Guttacore® 30, warm vertical condensation using down packing in a WaveOne® Primary cone and backfill with alpha gutapercha of Beefill®, and the hybrid mixed condensation modifying the lateral condensation with heat and a backfill using Beefill®. &lt;em&gt;Enterococcus faecalis&lt;/em&gt; was inoculated in the coronal third and apices were immersed in brain heart infusion broth with phenol red incubated at 37 °C for 12 weeks. Microfiltration was determined with color change and turbidity of the medium. Specimens were observed by scanning electron microscopy. &lt;em&gt;&lt;strong&gt;Results:&lt;/strong&gt;&lt;/em&gt; Only 11 teeth (22 %) were positive for leakage. 46 % with single cone, 30 % with Guttacore®, 20 % with lateral condensation, 10 % with warm vertical condensation and no microleakage was found for Hybrid-Mixed Technique over the period of 12 weeks of study. &lt;em&gt;&lt;strong&gt;Conclusion:&lt;/strong&gt;&lt;/em&gt; Hybrid Mixed Technique showed to be the most efficient technique to get three-dimensional seal and prevent microbial contamination of canals in the endodontic therapy.&lt;/p&gt;

The investigation on condensation performance of gas/steam mixtures with the fine coal particles in a vertical channel

Theoretical and experimental study is conducted to investigate the condensation heat transfer characteristics of mixed gas with fine coal particles in this paper. The visualization experiments of fine coal particles striking the film and mixed gas condensation heat transfer experiments in a vertical channel are carried out. Mixed gases contain different proportions of N2, steam and fine coal particles. The theoretical model of particles flicking condensate film is established. Results show that fine coal particles can penetrate the condensate film and flow inside the film when the particle diameter and the incidence velocity meet the conditions of penetrating judgment. The Nu number of heat transfer and the mass of the condensation decrease with the increase of the diameter and the concentration of the particles in the mixed gases.