bluuebunny/crossref_metadata_2025 huggingface dataset:
Combining thermization and evaporative cooling toward milk freshness preservation at the smallholder farm level
Authors: Sempiira Edison J. , Mugisa Dana J. , Galiwango Joseph , Kisaalita William S.
Published: September 2020

Thermization and low‐cost evaporative cooling have been seamlessly combined (evakuuling process) to preserve milk freshness for next day market. For proper regulation, a more exact profile of thermized milk in the hands of smallholders is needed. The purpose of this paper was to establish the milk quality‐profile of “evakuuled” milk. Thermization was done using temperatures between 55 and 70°C. Evakuuled milk quality‐profile (total viable and psychotrophic microbial counts, fat, protein, and pH) was compared to chilled and fresh milk. A consumer sensory test was also performed to evaluate consumer preference. The results showed that the quality‐profile of milk thermized at 65°C, followed by evaporative cooling (evakuuled) was indistinguishable from chilled and fresh milk. A consumer preference test scored evakuuled, fresh and chilled milks on average equal in terms of taste, appearance, aroma, and general acceptability.

Practical applications

The finding of evakuuled milk having the same quality attributes as fresh or chilled milk and meeting consumer preference in terms of aroma, taste appearance and general acceptability has potential practical significance. These results provide evidence in support of inclusion of evakuuled milk in the East African raw milk standard.
An analysis of Dow 30 global core indicator disclosures and environmental, social, and governance‐related ratings
Authors: Calvin Christopher G. , Street Donna L.
Published: September 2020

We examine the extent to which US Dow 30 companies disclose the Global Core Indicators (GCIs), which are measures to assess companies’ contribution toward the United Nation’s 2030 Agenda for Sustainable Development. We find that the Dow 30 are generally compliant with disclosing GCIs that align with US capital market reporting expectations, high‐profile current events, and issues that are financially relevant. We also find the Dow 30 are more likely to disclose institutional and economic issues, rather than environmental and social issues, and note disclosure variation across industries in which the Dow 30 operate. Supplemental analyses indicate that GCI disclosure levels are generally higher when those GCIs are associated with financially relevant ESG issues, suggesting companies are more amenable to addressing sustainability when doing so aligns with their mandate to shareholders. Correlation analyses reveal that the GCI indices moderately or strongly correlate with two of three MSCI sustainability ratings, highlighting companies’ focus on financially relevant areas, and weakly correlate with companies’ CDP climate change ratings, highlighting the limited scope of the GCIs in capturing detailed environmentally focused sustainability efforts. We also show that the MSCI sustainability ratings of the Dow 30 have generally trended higher over time, with increases driven by companies in the manufacturing, financial, and retail industries. Our findings help fill a void in sustainability literature on US company reporting of the GCIs and may be informative to the United Nations Conference on Trade and Development as it reviews the GCIs in support of the 2030 Agenda.
The Arabidopsis R‐SNARE protein YKT61 is essential for gametophyte development
Authors: Ma Ting , Li En , Li Lu‐Shen , Li Sha , Zhang Yan
Published: September 2020

Gametophyte development is a pre‐requisite for plant reproduction and seed yield; therefore, studies of gametophyte development help us understand fundamental biological questions and have potential applications in agriculture. The biogenesis and dynamics of endomembrane compartments are critical for cell survival, and their regulatory mechanisms are just beginning to be revealed. Here, we report that the Arabidopsis thaliana SNARE (soluble N‐ethylmaleimide sensitive factor attachment protein receptor) protein YKT61 is essential for both male and female gametogenesis. By using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR‐associated protein 9 (Cas9)‐based genome editing, we demonstrated that male and female gametophytes carrying YKT61 loss‐of‐function alleles do not survive. Specifically, loss of YKT61 function resulted in the arrest of male gametophytic development at pollen mitosis I and the degeneration of female gametophytes. A three‐base‐pair deletion in YKT61 in the ykt61‐3 mutant resulted in a single‐amino acid deletion in the longin domain of YKT61; the resulting mutant protein does not interact with multiple SNAREs and showed substantially reduced membrane association, suggesting that the N‐terminal longin domain of YKT61 plays multiple roles in its function. This study demonstrates that Arabidopsis YKT61 is essential for male and female gametogenesis and sets an example for functional characterization of essential genes with the combination of Cas9‐mediated editing and expression from a Cas9‐resistant transgene.
The Limits of Limited Liability: Evidence from Industrial Pollution
Authors: AKEY PAT , APPEL IAN
Published: September 2020

We study how parent liability for subsidiaries' environmental cleanup costs affects industrial pollution and production. Our empirical setting exploits a Supreme Court decision that strengthened parent limited liability protection for some subsidiaries. Using a difference‐in‐differences framework, we find that stronger liability protection for parents leads to a 5% to 9% increase in toxic emissions by subsidiaries. Evidence suggests the increase in pollution is driven by lower investment in abatement technologies rather than increased production. Cross‐sectional tests suggest convexities associated with insolvency and executive compensation drive heterogeneous effects. Overall, our findings highlight the moral hazard problem associated with limited liability.
Cardiovascular safety of mirabegron add‐on therapy to tamsulosin for the treatment of overactive bladder in men with lower urinary tract symptoms: A post hoc analysis from the MATCH study
Authors: Katoh Takao , Kakizaki Hidehiro , Lee Kyu‐Sung , Ishida Kota , Katou Daisuke , Yamamoto Osamu , Jong Jar Jar , Sumarsono Budiwan , Uno Satoshi , Yamaguchi Osamu
Published: September 2020

Objectives

To investigate the cardiovascular safety of mirabegron add‐on treatment to tamsulosin in male patients with residual overactive bladder symptoms.

Methods

This was a post hoc analysis of MATCH, the first double‐blind, placebo‐controlled study comparing mirabegron and placebo as add‐on therapy to tamsulosin for treatment of overactive bladder in men with lower urinary tract symptoms. The analysis focused on treatment‐emergent adverse events relating to the cardiovascular system or blood pressure, and changes in vital signs during 12 weeks of follow‐up.

Results

Cardiovascular‐related treatment‐emergent adverse events were reported by 6/566 patients, although only one serious treatment‐emergent adverse event was related to treatment (unstable angina in the tamsulosin + placebo group). Hypertension (two patients) and increased blood pressure (one patient) were reported in the tamsulosin + placebo group, but there were no blood pressure‐related treatment‐emergent adverse events among tamsulosin + mirabegron patients. There were no clinically meaningful changes from baseline in blood pressure, and changes in pulse rate were small (+1.2 bpm in the tamsulosin + mirabegron group). Increased pulse rate was more frequent with tamsulosin + mirabegron than with tamsulosin + placebo in older patients, although within the normal range.

Conclusions

Cardiovascular‐related adverse events were uncommon in both treatment groups. Mirabegron is a well‐tolerated add‐on therapy to tamsulosin in Japanese and Korean males with residual overactive bladder symptoms.
Trait‐based diversity of deep‐sea benthic megafauna communities near the Deepwater Horizon oil spill site
Authors: Nunnally Clifton C. , Benfield Mark C. , McClain Craig R.
Published: September 2020

Deep‐sea ecosystems are fragile yet diverse habitats that are sensitive to disturbance. In the northern Gulf of Mexico deepwater extraction of hydrocarbons led to the accidental release of four million barrels of oil from the Macondo wellhead in 2010. The release of oil combined with the addition of dispersant at depth and the resulting delivery of oiled “marine snow” led to dramatic disruptions of diversity and ecosystem services within the near field deep‐sea benthic communities. Analysis of the biological trait diversity of the surrounding megabenthos reveals notable loss of traits that may explain the stunted recovery of communities within 2 km of the wellhead. The present megafauna show complete loss of some traits relating to tier, motility, and feeding mechanisms. Functional evenness was higher than in surveyed unaffected sites, highlighting some loss of trait space, reflecting increasing abundances of scavengers and the loss of sessile invertebrates. Loss of biological traits that aid in ecosystem resilience has impeded recovery of benthic communities severely impacted by the Deepwater Horizon oil spill.
On the way to specificity ‐ Microbiome reflects sponge genetic cluster primarily in highly structured populations
Authors: Díez‐Vives Cristina , Taboada Sergi , Leiva Carlos , Busch Kathrin , Hentschel Ute , Riesgo Ana
Published: September 2020

Most animals, including sponges (Porifera), have species‐specific microbiomes. Which genetic or environmental factors play major roles structuring the microbial community at the intraspecific level in sponges is, however, largely unknown. In this study, we tested whether geographic location or genetic structure of conspecific sponges influences their microbial assembly. For that, we used three sponge species with different rates of gene flow, and collected samples along their entire distribution range (two from the Mediterranean and one from the Southern Ocean) yielding a total of 393 samples. These three sponge species have been previously analysed by microsatellites or single nucleotide polymorphisms, and here we investigate their microbiomes by amplicon sequencing of the microbial 16S rRNA gene. The sponge Petrosia ficiformis, with highly isolated populations (low gene flow), showed a stronger influence of the host genetic distance on the microbial composition than the spatial distance. Host‐specificity was therefore detected at the genotypic level, with individuals belonging to the same host genetic cluster harbouring more similar microbiomes than distant ones. On the contrary, the microbiome of Ircinia fasciculata and Dendrilla antarctica ‐ both with weak population structure (high gene flow) ‐ seemed influenced by location rather than by host genetic distance. Our results suggest that in sponge species with high population structure, the host genetic cluster influence the microbial community more than the geographic location.
‘The Fearful Silence of Three Women (Mark 16:8)’
Authors: O'Collins Gerald
Published: September 2020

This article aims at reinstating an older interpretation (offered e.g. by R. H. Lightfoot) of the astonishment, fear, and silent flight with which three women responded to the message they heard from the angel in Jesus's open and empty tomb. It was an appropriate reaction to the astonishing revelation of the resurrection. The article argues that this reaction is not to be reckoned as an unexpected failure on the part of the women. Throughout Mark's Gospel they proved exemplary in their following of Jesus, right through to being present at his crucifixion. Mary Magdalene and her two companions remained temporarily silent until they could deliver the angel's message to the appropriate audience, the male disciples.
Clinical Outcome of Remnant‐Preserving and I.D.E.A.L. Femoral Tunnel Technique for Anterior Cruciate Ligament Reconstruction
Authors: Su Chao , Kuang Shi‐da , Liu Wei‐jie , Li Yu‐sheng , Xiong Yi‐lin , Zhao Xin , Gao Shu‐guang
Published: September 2020

Objective

To assess the clinical results of the remnant‐preserving and I.D.E.A.L. femoral tunnel technique in the arthroscopic treatment of anterior cruciate ligament (ACL) injuries.

Methods

This was a retrospective single‐center, single‐surgeon study reviewing data from November 2016 to March 2019. Based on our inclusion/exclusion criteria, a total of 31 patients (18 males, 13 females; mean age, 23.6 years) who underwent arthroscopic ACL reconstruction with the remnant preservation and I.D.E.A.L. femoral tunnel technique were recruited and had a minimum follow‐up of 12 months. Clinical data and status of knee stability were recorded. The International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner activity scale were collected both preoperatively and at a minimum of 1‐year follow‐up.

Results

Statistically significant differences were detected between the preoperative and postoperative values for Lachman test and pivot‐shift test (P < 0.01). The mean postoperative Lysholm score was 89.6 ± 9.4, whereas the mean preoperative Lysholm score was 47.3 ± 12.8 (P < 0.01). The mean Tegner activity score was significantly higher at postoperative evaluation than at preoperative evaluation (6.5 ± 2.1 vs 2.6 ± 1.8; P < 0.01). The mean IKDC score was significantly improved from 49.5 ± 10.6 preoperatively to 88.2 ± 10.7 postoperatively (P < 0.01). No case of infection was reported. No radiograph showed any joint space narrowing or degenerative change at the last postsurgical follow‐up.

Conclusion

The anatomical remnant‐preserving and I.D.E.A.L. femoral tunnel technique achieves a satisfactory clinical outcome and provides an effective option for the treatment of ACL injuries.
Recognizing pulses of extinction from clusters of last occurrences
Authors: Zimmt Joshua B. , Holland Steven M. , Finnegan Seth , Marshall Charles R.
Published: September 2020

The distribution of last occurrences of fossil taxa in a stratigraphic column are used to infer the pattern, timing and tempo of extinction from the fossil record. Clusters of last occurrences are commonly interpreted as an abrupt pulse of extinction. However, stratigraphic architecture alone can produce clusters of last occurrences that can be misinterpreted as an extinction pulse. These clusters will typically occur in strata that immediately underlie facies changes and sequence‐stratigraphic surfaces. It has been proposed that a basin‐wide analysis of the fossil record within a sequence‐stratigraphic framework can be used to distinguish between clusters of last occurrences caused solely by extinction pulses from those generated by sequence‐stratigraphic architecture. A basin‐wide approach makes it possible to observe lateral facies shifts in response to sea‐level change, mitigating the effects of stratigraphic architecture. Using computer simulations of plausible Late Ordovician mass‐extinction scenarios tuned to an inferred Late Ordovician sea‐level curve, we show that stratigraphically‐generated clusters of last occurrences are observed even in basin‐wide analyses of the simulated fossil records due to the basin‐wide loss of preferred facies for many taxa. Nonetheless, we demonstrate that by coarsening the stratigraphic resolution to the systems‐tract level and identifying facies preferences of simulated taxa, we can filter out taxa whose last occurrences coincide with the basin‐wide loss of their preferred facies. This enables consistent identification of the underlying extinction pattern for a wide variety of extinction scenarios. Applying this approach to empirical field data can help to constrain underlying extinction patterns from the fossil record.
HUME'S GENERAL POINT OF VIEW: A TWO‐STAGE APPROACH
Authors: Ben‐Moshe Nir
Published: September 2020

I offer a novel two‐stage reconstruction of Hume's general‐point‐of‐view account, modeled in part on his qualified‐judges account in ‘Of the Standard of Taste’. In particular, I argue that the general point of view needs to be jointly constructed by spectators who have sympathized with (at least some of) the agents in (at least some of) the actor's circles of influence. The upshot of the account is twofold. First, Hume's later thought developed in such a way that it can rectify the problems inherent in his Treatise account of the general point of view. Second, the proposed account provides the grounds for an adequate and well‐motivated modest ideal observer theory of the standard of virtue.
Reinventing Cloth Masks in the Face of Pandemics
Authors: Salter Stephen
Published: September 2020

Because asymptomatic carriers of COVID‐19 produce respiratory droplets that can remain suspended in air for several hours, social distancing may not be a reliable physical barrier to transmission. During the COVID‐19 pandemic, however, some governments were reluctant to mandate public mask use out of concern this would worsen shortages of respirators for healthcare workers. Cloth masks with a filtering effectiveness of 70–90% can be made from widely available materials, and are a better option than respirators for the public. Countries could rapidly implement Effective Fiber Mask Programs (EFMPs) to use local resources to mass produce effective and affordable cloth masks, and to engage the public in their correct use. EFMPs could be a cost‐effective measure to ease isolation while limiting new infections during pandemics. EFMPs could also protect healthcare workers by increasing the supply of respirators for their use, reducing their risk of acquiring the illness from their communities, and by reducing the number of patients they must treat.
Ribavirin and cellular ribavirin‐triphosphate concentrations in blood and bronchoalveolar lavage fluid in two lung transplant patients with respiratory syncytial virus
Authors: Mueller Scott W. , Kiser Tyree H. , Morrisette Taylor , Zamora Martin R. , Lyu Dennis M. , Kiser Jennifer J.
Published: September 2020

Respiratory syncytial virus (RSV) is responsible for significant morbidity and mortality in the lung transplant population. Oral and aerosolized ribavirin may improve outcomes in lung transplant patients with RSV; however, data relating ribavirin concentrations in plasma and intracellular ribavirin triphosphate (iRTP) concentrations in blood and bronchoalveolar lavage (BAL) fluid cells with efficacy and safety are lacking. We describe ribavirin and iRTP concentrations within various compartments in two adult lung transplant recipients with RSV who were sampled throughout successful treatment courses with oral and inhaled ribavirin. In patient 1, iRTP BAL concentrations decreased by 45% over 3 days after changing inhaled ribavirin to oral (6.32 to 3.43 pmol/106 cells). In patient 2, iRTP BAL concentrations were 103 pmol/106 cells after 5 days of oral followed by 5 days of inhaled ribavirin. Further study is needed to describe ribavirin pharmacokinetics in the respiratory compartment to inform clinical use of ribavirin for respiratory viruses.
Examination of the relationship between iron status and cognitive function among healthy young women with and without a recent history of blood donation
Authors: France Janis L. , Hod Eldad A. , Caccappolo Elise A. , Suhr Julie A. , France Christopher R. , Kessler Debra A. , Shaz Beth H.
Published: September 2020

Background

With growing awareness of the prevalence of nonanemic iron deficiency among blood donors, there is a need to explore the extent of potential negative consequences. This study examined the relationship between various measures of iron status, blood donation history, and neuropsychological and psychosocial functioning in healthy young women.

Study Design and Methods

Using a cross‐sectional design, 160 female undergraduates completed neuropsychology tests and measures of sleep, fatigue, quality of life, and depression before providing a blood sample. Correlational analyses examined the relationship between iron status (ferritin, iron, hemoglobin, and zinc protoporphyrin) and cognitive and psychosocial functioning. Performance on these measures was also examined as a function of recent blood donation history (zero, one, more than one donation in the past year).

Results

Iron status (low ferritin, iron, or hemoglobin or high zinc protoporphyrin) was not associated with poorer performance on the cognitive tasks. Further, participants who reported donating once in the previous year performed better, rather than worse, than those with no recent donation history on several measures of executive function, even when controlling for ferritin levels. Although there was some evidence of greater fatigue among those who had donated more than once in the past year, this effect was not accounted for by ferritin levels.

Conclusion

The present findings are consistent with prior evidence that nonanemic iron deficiency is not associated with cognitive impairment or psychosocial dysfunction in healthy young females. Because these results are based on cross‐sectional evidence, further study using longitudinal research is needed to confirm these findings.
Retrospective evaluation of acute kidney injury in dogs with pit viper envenomation (2008–2017): 56 cases
Authors: Martinez Jennifer , Londoño Leonel A. , Schaer Michael
Published: September 2020

Objectives

To describe the clinicopathological characteristics of dogs that develop acute kidney injury (AKI) secondary to pit viper envenomation, and to describe the association between development of AKI and clinical course and outcome.

Design

Retrospective study.

Setting

University teaching hospital.

Animals

Client‐owned dogs treated with at least 1 vial of antivenom following pit viper envenomation and that had at least 2 plasma creatinine concentrations measured during the course of hospitalization.

Interventions

None.

Measurements and Main Results

Sixty‐three dogs met the inclusion criteria. One was excluded due chronic kidney disease, and 6 were excluded due to nonsteroidal anti‐inflammatory drug administration. Of the 56 dogs included in the study, 16 developed AKI (29%). Dogs with AKI received a significantly higher dose of antivenom, 8.7 ± 6.8 total vials versus dogs in the non‐AKI group that received 4.2 ± 2.6 vials (P = 0.006). Dogs in the AKI group were significantly more tachycardic (P = 0.028), hypotensive (P = 0.002), had a higher shock index (P = 0.012), and were more likely to receive transfusions with packed red blood cells (P = 0.042) than dogs in the non‐AKI group. No significant association was identified between the development of AKI and length of hospitalization. The only factors that were significantly associated with degree of severity of AKI included the receipt of blood transfusion (P = 0.006) and number of vials of antivenom administered (P = 0.03). The development of AKI was significantly associated with outcome (P < 0.001), with 5 of 16 (31%) dogs in the AKI group surviving to discharge, 7 of 16 (44%) dying, and 4 of 16 (25%) being euthanized versus 39 of 40 (98%) surviving to discharge in the non‐AKI group and 1 of 40 (2%) dying in hospital.

Conclusion

Development of AKI in dogs following pit viper envenomation carries an increased risk of mortality that is associated with severity of shock at presentation and increased doses of antivenom administration.
Phylogeny and species reassessment of Hyalopterus (Aphididae, Aphidinae)
Authors: Liu Tongyi , Chen Jing , Jiang Liyun , Qiao Gexia
Published: September 2020

The broadly distributed genus Hyalopterus currently comprises three formally recognized species that are highly similar morphologically and hence difficult to be identified with certainty. This group has undergone multiple revisions in the past century, but none of these has assessed species from Asia, which has hampered our understanding of the species diversity within this genus. Based on a comprehensive data set from morphological data and host‐associated data, and by coalescent‐based delimitation approaches, the Hyalopterus species boundaries, distribution and diversity were clarified here to further reveal the composition of the species. Two single‐locus (ML‐GMYC and mPTP) and two multilocus (BPP and STACEY) delimitation methods were conducted based on extensive sampling. Then, the phylogenetic relationships and morphological divergence were assessed. Our data strongly supported that the number of recognized species in Hyalopterus had likely been underestimated. The phylogenetic analyses recovered four major clades, which corresponded to distinct host‐plant preferences. Also, the morphological analyses showed significant differentiation for only one of the newly recognized candidate species uncovered by the delimitation approaches, suggesting the existence of at least two independent evolutionary lineages within Hyalopterus arundiniformis, which showed different patterns of host association. Moreover, based on our data, the taxonomic misidentification of H. arundiniformis in China was corrected here. This study lays the groundwork for the thorough taxonomic revision of Hyalopterus and for future evolutionary studies and underlines the importance of an integrated framework for species determination.
Numerical Investigation on the Aerodynamic Performance of a Low-Pressure Steam Turbine Exhaust Hood Using Design of Experiment Analysis
Authors: Diurno Tommaso , Fondelli Tommaso , Nettis Leonardo , Maceli Nicola , Arcangeli Lorenzo , Andreini Antonio , Facchini Bruno
Published: September 2020

Nowadays, the rising interest in using renewable energy for thermal power generation has led to radical changes in steam turbine design practice and operability. Modern steam turbines are required to operate with greater flexibility due to rapid load changes, fast start-up, and frequent shutdowns. This has given rise to great challenges to the exhaust hood system design, which has a great influence on the overall turbine performance converting the kinetic energy leaving the last stage of low-pressure turbine into static pressure. The radial hoods are characterized by a complex aerodynamic behavior since the flow turns by 90 deg in a very short distance and this generates a highly rotational flow structure within the diffuser and exhaust hood outer casing, moreover, the adverse pressure gradient can promote the flow separation drastically reducing the hood recovery performance. For these reasons, it is fundamental to design the exhaust system in order to ensure a good pressure recovery under all the machine operating conditions. This paper presents a design of experiment (DOE) analysis on a low-pressure steam turbine exhaust hood through computational fluid dynamics (CFD) simulations. A parametric model of an axial-radial exhaust hood was developed, and a sensitivity of exhaust hood performance as a function of key geometrical parameters was carried out, with the aim of optimizing the pressure recovery coefficient and minimizing the overall dimensions of the exhaust casing. Since hood performance strongly depends on a proper coupling with the turbine rear stage, such a stage was modeled using the so-called mixing-plane approach to couple both stator–rotor and rotor-diffuser interfaces. A detailed analysis of the flow field in the exhaust hood in the different configurations was performed, detecting the swirling structures responsible for the energy dissipation in each simulation, as well as correlating the flow field with the pressure recovery coefficient.
A Method to Use Kriging With Large Sets of Control Points to Morph Finite Element Models of the Human Body
Authors: Janák Tomáš , Lafon Yoann , Petit Philippe , Beillas Philippe
Published: September 2020

As developing finite element (FE) human body models for automotive impact is a time-consuming process, morphing using interpolation methods such as kriging has often been used to rapidly generate models of different shapes and sizes. Kriging can be computationally expensive when many control points (CPs) are used, i.e., for very detailed target geometry (e.g., shape of bones and skin). It can also lead to element quality issues (up to inverted elements) preventing the use of the morphed models for finite element simulation. This paper presents a workflow combining iterative subsampling and spatial subdivision methodology that effectively reduces the computational costs and allows for the generation of usable models through kriging with hundreds of thousands of control points. As subdivision introduces discontinuities in the interpolation function that can cause distortion of elements on the boundaries of individual subdivision areas, algorithms for smoothing the interpolation over those boundaries are proposed and compared. Those techniques and their combinations were tested and evaluated in a scenario of mass change on the detailed 50th percentile male model of the global human body models consortium (GHBMC): the model, which has body mass index (BMI) 25.34, was morphed toward a statistical surface model of a person with body mass index 20, 22.7 and 35. 234 777 control points were used to successfully morph the model in less than 15 min on an office PC. Open source implementation is provided.
An Effective Thermal Conductivity Model for Architected Phase Change Material Enhancer
Authors: Hubert Romain , Bou-Matar Olivier , Foncin Jerome , Coquet Philippe , Tan Dunlin , Li Hongling , Teo Edwin , Merlet Thomas , Pernod Philippe
Published: September 2020

Phase Change Materials (PCM) have been widely used for thermal energy storage due to their high latent heat of fusion. However, PCMs suffer from their very low thermal conductivity which limits heat spreading around the heat source. Without proper thermal conductivity enhancement, melting would mainly occur at the interface between the heated surface and the PCM, and would slowly spread in the bulk of the PCM, greatly reducing its performance. Metallic foams are usually used as thermal conductivity enhancer, yet recent progress in additive manufacturing have allowed architected structures to be used and optimized. We present here an analytical investigation of the effective thermal conductivity of porous architected structures and emphasize is made on the effect of thermal constriction at the interface with a heat spreader in contact with the heat source.
Effect of Cell Design on the Thermal Performance of Direct Contact Membrane Distillation System Utilizing a Nanocomposite Membrane
Authors: Elmarghany Mohamed R. , El-Shazly A. H. , Radwan Ali , Abo-Zahhad Essam M. , Nady Norhan , Sabry Mohamed N. , Shouman Mahmoud A. , Salem Mohamed S.
Published: September 2020

In the present work, the performance of different cell designs used for the membrane distillation (MD) process was investigated. Three distinctive cell designs were proposed and compared. A numerical simulation using ANSYS Fluent 19 was used to study the performance of the cells. The effects of changing inlet Reynolds number on pressure drop, salt concentration and velocity contours with in the different cell deigns were investigated. Results show that the pressure drop is minimum across the first design, and the salt concentration decreases as Reynolds number increases. At Reynolds number = 125, the results show an enhanced velocity distribution compared to Reynolds number = 250 and 50. One of the proposed cell designs was then fabricated to study the effect of fluid flow on the performance in a direct contact membrane distillation system. Energy parameters were calculated to evaluate the performance of the cell. An evacuated tube solar collector was used to provide the system with hot water. System thermal efficiency, gained output ratio, and specific energy consumption analysis were performed for the system. The increase in the feed flow rate almost doubled the system thermal efficiency and the gained output ratio was increased from 0.31 to 0.60, while the specific energy consumption decreased from 2064 to 1037 kWh/m3.
Validation of an Enhanced Dispersion Algorithm for Use With the Statistical Phonon Transport Model
Authors: Medlar Michael P. , Hensel Edward C.
Published: September 2020

Computer simulations of quasi-particle based phonon transport in semiconductor materials rely upon numerical dispersion relations to identify and quantify the discrete energy and momentum states allowable subject to quantum constraints. The accuracy of such computer simulations is ultimately dependent upon the fidelity of the underlying dispersion relations. Dispersion relations have previously been computed using empirical fits of experimental data in high symmetry directions, lattice dynamics, and Density Function Theory (DFT) or Density Functional Perturbation Theory (DFPT) approaches. The current work presents high fidelity dispersion relations describing full anisotropy for all six phonon polarizations with an adjustable computational grid. The current approach builds upon the previously published Statistical Phonon Transport Model (SPTM), which employed a first nearest neighbor lattice dynamics approach for the dispersion calculation. This paper extends the lattice dynamics approach with the use of both first and second nearest neighbors interactions that are quantified using published interatomic force constants calculated from DFT. The First Brillouin Zone (FBZ) is segmented into eight octants of high symmetry, and discretized in wave vector space with a 14 by 14 by 14 grid. This results in 65,586 states of unique wave vector and frequency combinations. Dispersion calculations are performed at each of the six faces of the wave vector space volume elements in addition to the centroid, resulting in 460,992 solutions of the characteristic equations. For the given grid, on the order of 108 computations are required to compute the dispersion relations. The dispersion relations thus obtained are compared to experimental reports available for high symmetry axes. Full anisotropic results are presented for all six phonon polarizations across the range of allowable wave vector magnitude and frequency as a comprehensive model of allowable momentum and energy states. Results indicate excellent agreement to experiment in high symmetry directions for all six polarizations and illustrate an improvement as compared to the previous SPTM implementation. Dispersion relations based on the lattice dynamic model with first and second nearest neighbor atomic interactions relying upon DFT calculated inter-atomic force constants provides an accurate high fidelity energy and momentum model for use in phonon transport simulations.
Heat Transfer Augmentation and Flow Visualization With Delta Winglets in a Tube: A Numerical Approach
Authors: Islam Md. , Guangda Liang , Alam Md. Mahbub
Published: September 2020

In this research, heat transfer and pressure penalty from a circular tube with delta winglets insert are numerically investigated through Computational Fluid Dynamics (CFD) methodology. Numerical analysis with and without vortex generators (VGs) insert in a tube are done for a turbulent air flow, Reynolds number ranging from 6000 to 33000, under constant heat flux condition on the circular tube model surface. In our current research, we employed the shear stress transport (SST) k-omega model. The Nusselt number and friction factor results show the influence of the VGs insert on thermal performance. Effects of different winglet attack angles and blockage ratios on thermal performance enhancement were examined. Thermal performance is enhanced 5.1–30.7% using winglets in a tube. It is observed that small blockage ratio, B = 0.1 performed better than its counterpart of 0.2 and 0.3 for all the Reynolds number and for the same attack angle. The attack angle β = 15° and 30° showed better thermal performance enhancement at lower Re while at higher Re, β = 15° showed better performance. The maximum enhancement obtained for β = 30° and B = 0.1. Winglet vortex generator could create swirling flow when attack angle is 0 or 15°. When attack angle is increased, both swirling flow and longitudinal vortices appeared. At attack angle of 45°, large longitudinal vortices was found.
Experimental Study of a Novel Hydro-Cyclone Apparatus (HCA) Using Flash Evaporation for Desalination and Water Remediation/Purification
Authors: Thyagarajan Ashok , Banerjee Debjyoti , Dhir Vijay
Published: September 2020

A novel apparatus that is capable of dynamic flash evaporation and phase separation using centrifugal flow (i.e., using a Hydro-Cyclone Apparatus/HCA) is explored in this study. The objective of this study is to demonstrate the segregation of phases using the novel apparatus that forms a stable air core at the center from a premixed air-water mixture. The stable air core is then retrieved using an air retrieval tube that is strategically placed in the test section for maximum retrieval of air. For the purpose of this study, a prototype of the apparatus was fabricated using rapid prototyping (3D Printing). Experiments were performed on the flow separator apparatus (HCA) by varying the ratio of the air and water flow rates. A high-speed digital image acquisition apparatus was used in this study for flow visualization in the HCA. Flow maps were generated based on the measurements for flow rates and pressure drops obtained from the experiments conducted in this study. This enabled the measurement of several parameters, which include: the dimensions and morphology of the stable air core, entrainment of the water from the air retrieval tube, etc. The data obtained from this study will be used in the design of experiments for the novel apparatus to demonstrate the feasibility of a compact dynamic flash evaporator and separator system that can be used for various water conservation applications, which include: desalination (e.g., seawater, brackish water, as well as total dissolved solids/ TDS from produced water in oil and gas industries), water remediation (e.g., suspended solids) and purification (e.g., urine purification apparatus/ UPA).
A Reduced Model for Efficient Simulation of Freezing of Water in Large Tanks
Authors: Ramesh Vishal , Terala Shashank , Mazumder Sandip , Matharu Gurpreet , Vaishnav Dhaval , Ali Syed
Published: September 2020

Water-urea mixtures are used in diesel vehicles for exhaust aftertreatment. The liquid mixture, stored in a tank, is susceptible to freezing in cold weather. Depending on weather conditions, the tank size and the liquid fill level, the freezing of the entire liquid may span over a day. Mitigation strategies require understanding of the freezing history. Traditional computational fluid dynamics and heat transfer (CFD/CHT) methodologies are impractical for modeling such freezing processes because of restrictions in the time-step size — typically milliseconds — posed by numerical stability and physical time-scale considerations. The primary constraint for using small time-step sizes is the fine-scale motion generated by natural convection in both the liquid and the gas (unoccupied space). A new model is proposed and demonstrated for efficient prediction of the propagation of the solidification front. In this model, heat transfer due to natural convection is modeled as a diffusive process analogous to how turbulent transport is modeled using an eddy diffusivity and a gradient diffusion model. The model enables use of large time-steps since the fine-scale motions due to natural convection are no longer resolved. The model was validated against experimental data, which were also collected as part of the study. Each experiment collected data at intervals of 6 seconds for a total duration of about 24 hours. Several different tank fill levels were considered, and good agreement with experimental data was noted, especially for shallow fill levels. Large-scale parallel three-dimensional calculations were conducted in a few days of computational time using the proposed model as opposed to a year (projected) of computational time using traditional CFD/CHT models and the same computational resources.
Suppressing the Supercooling Effect of Erythritol by Bubbling for Latent Heat Storage
Authors: Yang Sheng , Shao Xue-Feng , Fan Li-Wu
Published: September 2020

Erythritol, a phase change material (PCM) pertinent to the medium temperature range latent heat storage applications, has the advantages of large storage density, non-toxicity, and high chemical compatibility, but it also suffers from serious supercooling upon cool-down to release the stored heat. In this work, the bubbling method was attempted as an economic and easy way to suppress the supercooling effect of erythritol. At a flow rate of 300 mL/min, N2 bubbles of the size of about 4.4 mm in diameter were continuously introduced into molten erythritol under various subcooling temperatures of ΔTsub = 30, 40, 50, 60, and 95 °C. At the same flow rate, slightly larger bubbles of about 6 mm in diameter were also tested as a contrast case at a single subcooling temperature of ΔTsub = 30°C. The presence of the bubbles was clearly exhibited to successfully facilitate crystallization process of erythritol. It was shown that when ΔTsub = 40, 50, 60, and 95 °C, the introduction of N2 bubbles can reduce the nucleation temperatures Tn by 7.0, 8.2, 10.0 and 5.7°C, respectively, and shorten the crystallization time tc by 19.7%, 14.8%, 13.8%, and 6.4%, respectively. At the lowest subcooling of ΔTsub = 30 °C, erythritol cannot crystallize without the presence of bubbles. The size of the bubbles was found to have negligible effect as the complete crystallization time remains almost the same with the two bubble sizes.
Quasi-Photon Monte Carlo on Radiative Heat Transfer: An Importance Sampling Approach
Authors: Mishra Utkarsh A. , Bansal Ankit
Published: September 2020

The radiative heat transfer phenomenon is a complex process with various events of absorption, emission, and scattering of photon rays. Moreover, the effect of a participating medium adds to the complexity. Existing analytical methods fail to achieve accurate results with all such phenomena. In such cases, brute force algorithms such as the Monte Carlo Ray Tracing (MCRT) or the Photon Monte Carlo (PMC) has gained a lot of importance. But such processes, even if they provide less error than analytical methods, are quite expensive in computation time. Moreover, there are various shortcomings with traditional PMC in effectively including the nature of the participating medium and high variance in results. In this study, a modified PMC is simulated for a one-dimensional medium-surface radiation exchange problem. The medium is taken to be CO (4+) band system, and the behaviour is modelled by Importance Sampling (IS) of the spectrum data for variance reduction. Furthermore, PMC with low-discrepancy sequences like Halton, Sobol, and Faure sequences, known as Quasi-Monte Carlo (QMC), was simulated. QMC proved to be more efficient in reducing variance and computation time. Effective IS included with QMC is observed to have a much smaller variance and is faster as compared to traditional PMC.
Retracted: “Flow Patterns of Liquid-Liquid Two-Phase Flow With Different Viscosities in Microchannels” [ASME 2020 Heat Transfer Summer Conference, Virtual, Online, July 13–15, 2020, Conference Sponsors: Heat Transfer Division, ISBN: 978-0-7918-8370-9, Copyright © 2020 by ASME. Paper No. HT2020-8995, pp. V001T12A012; 6 pages; doi: 10.1115/HT2020-8995]
Authors: ASME
Published: September 2020

This paper was removed from publication at the author’s request. October 2, 2020.

Copyright © 2020 by ASME
Retracted: “Temperature and Velocity Behaviour During Melting of a PCM in a Uniformly Heated Circular Cavity” [ASME 2020 Heat Transfer Summer Conference, Virtual, Online, July 13–15, 2020, Conference Sponsors: Heat Transfer Division, ISBN: 978-0-7918-8370-9, Copyright © 2020 by ASME. Paper No. HT2020-9016, V001T16A003; 7 pages; doi: 10.1115/HT2020-9016]
Authors: ASME
Published: September 2020

This paper was removed from publication at the author’s request. January 15, 2021.

Copyright © 2021 by ASME
Conditional Stability of Direct Contact Steam Condensation
Authors: Alden Zach , Maples Gunnar , Dressler Kristofer , Nellis Gregory , Berson Arganthaël
Published: September 2020

An investigation into the conditional stability of direct contact steam condensation is presented. Direct contact steam condensation systems heat process fluids more effectively than indirect contact heat exchangers because the total energy of the steam is introduced directly into the process fluid, bypassing any resistances associated with having to cross the heat exchanger boundary. In the present work, superheated steam is injected perpendicular to a flow of subcooled liquid water. Conditional stability of direct contact steam condensation stems from the type of fluctuations exhibited by the steam plume structure. Under certain flow conditions the steam plume condenses in the form of a stable conical jet with little to no acoustic noise or resultant pressure fluctuations. However, other conditions cause the steam plume to increase in oscillation intensity, eventually transitioning to an intermittent bubbling structure that results in high-amplitude acoustic noise and large pressure fluctuations in the flow of liquid water. A regime map is presented to establish the process criteria for the onset of instability of condensation. The transitional profile to instability is also presented as an analysis of plume oscillation frequencies and associated pressure oscillations propagating from these fluctuations. It is found that, as the mode of condensation goes unstable, steam plume oscillations increase in intensity and decrease in frequency until the structure collapses into bubbles that provoke strong pressure oscillations in the surrounding water.
A Computational Investigation of Dynamic Stabilization of Rayleigh-Bénard Convection Under System Acceleration
Authors: Topcuoglu Ilker , Kunz Robert F. , Smith Robert W.
Published: September 2020

The static and dynamic stability of Rayleigh-Bénard convection in a rectangular flow domain is computationally investigated. Sinusoidal vertical oscillations are applied to the system to provide dynamic flow stabilization. Stability maps are produced for a range of flow and heating conditions, and are compared to experimental measurements and linear stability analysis predictions from existing literature. Density variation is introduced through: 1) the Boussinesq approximation, 2) a linearly varying temperature dependent equation of state (EOS) and 3) the perfect gas EOS. Significant effects of choice of EOS on dynamic stability are observed. These weakly compressible flows are solved efficiently using an implicit numerical method that has been developed to solve the momentum, continuity, enthalpy and state equations simultaneously in fully coupled fashion. This block coupled system of equations is linearized with Newton’s method, and quadratic convergence is achieved. The details of these numerics are presented.