bluuebunny/crossref_metadata_2025 huggingface dataset:
Seed bank offers potential for active restoration of mountain meadows
Authors: Ludewig Kristin , Hansen Wiebke , Klinger Yves P. , Eckstein R. Lutz , Otte Annette
Published: October 2020

The nitrogen‐fixing legume Lupinus polyphyllus invaded semi‐natural mountainous grasslands across Europe during the last decades. This invasion resulted in degraded habitats through changes in the structure and function of the mountain meadow vegetation. In our study, we analyzed (1) the effects of increasing cover of L. polyphyllus on the seed bank of mountain meadows, and (2) the potential of the seed bank of these stands for active restoration of mountain meadows in terms of species composition and number. We conducted a seed bank analysis on 84 plots with increasing cover of L. polyphyllus in three mountain‐meadow types of the Rhön Biosphere Reserve, Germany. Seedlings from 119 species germinated from the seed bank samples, including 17 Red List species but only a few seedlings of L. polyphyllus. The species composition of the seed bank matched distinct patterns of the three meadow types, but differed from the species composition of the current aboveground vegetation in a nonmetric multidimensional scaling ordination. While the influence of L. polyphyllus on the current vegetation was visible, no effects on the seed bank were apparent. L. polyphyllus had no influence on total seed density, seed density of typical mountain‐meadow species, or species numbers in the seed bank. Only the seeds of the Red List species were significantly related to the cover of L. polyphyllus. We conclude that the seed bank offers potential for active restoration of species‐rich mountain meadows, but species absent from the seed bank have to be added by other measures.
Clinical utility of ventilatory and gas exchange evaluation during low‐intensity exercise for risk stratification and prognostication in pulmonary arterial hypertension
Authors: Sayegh Ana Luiza C. , Silva Bruno Moreira , Ferreira Eloara V.M. , Ramos Roberta P. , Fisher James P. , Nery Luiz E. , Ota‐Arakaki Jaquelina S. , Oliveira Rudolf K.F.
Published: October 2020

Background and objective

Peak oxygen consumption (pVO2), determined from CPET, provides a valuable indication of PAH severity and patient prognosis. However, CPET is often contraindicated in severe PAH and frequently terminated prior to achievement of a sufficient exercise effort. We sought to determine whether in PAH low‐intensity [i.e. freewheeling exercise (FW)] exercise reveals abnormal VE/VCO2 and PETCO2 responses that are associated with pVO2 and serve as indices of PAH risk stratification and mortality.

Methods

Retrospective analysis of CPET from 97 PAH patients and 20 age‐matched controls was undertaken. FW VE/VCO2 and PETCO2 were correlated with pVO2% age‐predicted. Prognostication analysis was conducted using pVO2 > 65% age‐predicted, as known to represent a low mortality risk. Primary outcome was mortality from any cause.

Results

FW PETCO2 was correlated with pVO2 (P < 0.0001; r = 0.52), while FW VE/VCO2 was not (P = 0.13; r = −0.16). ROC curve analyses showed that FW PETCO2 (AUC = 0.659), but not FW VE/VCO2 (AUC = 0.587), provided predictive information identifying pVO2 > 65% age‐predicted (best cut‐off value of 28 mm Hg). By Cox analysis, FW PETCO2 < 28 mm Hg remained a predictor of mortality after adjusting for age and PAH aetiology (HR: 2.360, 95% CI: 1.144–4.866, P = 0.020).

Conclusion

Low PETCO2 during FW is associated with reduced pVO2 in PAH and provides predictive information for PAH risk stratification and prognostication.
Child health impact of the Nepalese civil war
Authors: Ko Hansoo
Published: October 2020

This study provides the first evidence that the Nepalese civil war (1996–2006) negatively affected the health of children by exploiting spatial and temporal variation in exposure to war‐related conflicts. Samples (14,447 children aged 5 years or younger) are extracted from the 1996, 2001, 2006 Demographic and Health Surveys. The results from mother fixed effects regression show that exposure has modest but significantly negative impacts on height of children under age 5 on the intensive margin. Conditional on average months of exposure to war violence of the study sample, the height of children decreases by 0.08 standard deviation. In particular, this negative health impact is statistically significant and similar across the whole height distribution.
How Serious is the Neglect of Intra‐Household Inequality in Multidimensional Poverty and Inequality Analyses? Evidence from India
Authors: Klasen Stephan , Lahoti Rahul
Published: October 2020

Monetary poverty measures as well as most existing multidimensional poverty indices (MPI) assume equal distribution within the household and thus are likely to yield a biased assessment of individual poverty, and poverty by age or gender. We show that the direction of the bias of such household‐based assessments in measuring poverty or inequality among individuals depends on how these measures use individual data to determine the poverty status of households. We use data from the 2012 Indian Human Development Survey and compare a standard household‐based MPI to an individual‐level MPI. The poverty rate among women is 14 percent points higher than that of men in our individual MPI measure but almost the same when using the household‐based measure. 22 percent of males and 27 percent of females are misclassified as poor or non‐poor using the household‐based measure. We also show that intra‐household inequality is 30 percent of total inequality.
Sedimentology and isotope geochemistry of transitional evaporitic environments within arid continental settings: From erg to saline lakes
Authors: Pettigrew Ross P. , Priddy Charlotte , Clarke Stuart M. , Warke Matthew R. , Stüeken Eva E. , Claire Mark W.
Published: October 2020

Arid continental basins typically contain a spectrum of coeval environments that coexist and interact from proximal to distal. Within the distal portion, aeolian ergs often border playa, or perennial, desert lakes, fed by fluvial incursions or elevated groundwaters. Evaporites are common features in these dryland, siliciclastic dominant settings. However, sedimentary controls upon evaporite deposition are not widely understood, especially within transitional zones between coeval clastic environments that are dominantly controlled by larger scale allocyclic processes, such as climate. The sulphur (δ34S) and oxygen (δ18O, Δ17O) isotope systematics of evaporites can reveal cryptic aspects of sedimentary cycling and sulphate sources in dryland settings. However, due to the lack of sedimentological understanding of evaporitic systems, isotopic data can be easily misinterpreted. This work presents detailed sedimentological and petrographic observations, coupled with δ34S, δ18O and Δ17O data, for the early Permian Cedar Mesa Sandstone Formation (western USA). Depositional models for mixed evaporitic/clastic sedimentation, which occurs either in erg‐marginal or lacustrine‐marginal settings, are presented to detail the sedimentary interactions present in terms of climate variations that control them. Sedimentological and petrographical analysis of the evaporites within the Cedar Mesa Sandstone Formation reveal a continental depositional environment and two end member depositional models have been developed: erg‐margin and lake‐margin. The δ34S values of gypsum deposits within the Cedar Mesa Sandstone Formation are consistent with late Carboniferous to early Permian marine settings. However, a marine interpretation is inconsistent with sedimentological and petrographic evidence. Consequently, δ34S, δ18O and Δ17O values are probably recycled and do not reflect ocean‐atmosphere values at the time of evaporite precipitation. They are most likely derived from the weathering of older marine evaporites in the hinterland. Thus, the results demonstrate the need for a combination of both sedimentological and geochemical analysis of evaporitic systems to better understand their depositional setting and conditions.
Extending a Hand in Perilous Times: Beneficial Immigration Policy in the Fifty States, 2005–2012
Authors: Sanchez Lisa M. , Williams Isabel
Published: October 2020

Objective

The passage of Arizona SB 1070 in 2010 focused national attention on punitive, state‐level immigration legislation. Largely ignored is the increasing number of beneficial, state‐level policies passed duringthe sameperiod. We seek to understand whether beneficial immigration policy making amounts to reversing the factors underlying punitive immigration policy making, as is implied by current literature.

Methods

We utilize data from the National Conference of State Legislatures from 2005 to 2012 to uncover the puzzling enactment of beneficial state immigration laws during a period of high anti‐immigrant sentiment and budgetary declines in the 50 states.

Results

Beneficial immigration policy making is not a reversal of the process that underlines punitive immigration policy making and is particularly responsive to the need generated by immigrant population size, regardless of the documentation status of the beneficiary.

Conclusion

The passage of beneficial immigration policies requires further analysis, as it is not as simple as reversing the process that produces punitive immigration policies.
Developmental acclimation of the thylakoid proteome to light intensity in Arabidopsis
Authors: Flannery Sarah E. , Hepworth Christopher , Wood William H. J. , Pastorelli Federica , Hunter Christopher N. , Dickman Mark J. , Jackson Philip J. , Johnson Matthew P.
Published: October 2020

Photosynthetic acclimation, the ability to adjust the composition of the thylakoid membrane to optimise the efficiency of electron transfer to the prevailing light conditions, is crucial to plant fitness in the field. While much is known about photosynthetic acclimation in Arabidopsis, to date there has been no study that combines both quantitative label‐free proteomics and photosynthetic analysis by gas exchange, chlorophyll fluorescence and P700 absorption spectroscopy. Using these methods we investigated how the levels of 402 thylakoid proteins, including many regulatory proteins not previously quantified, varied upon long‐term (weeks) acclimation of Arabidopsis to low (LL), moderate (ML) and high (HL) growth light intensity and correlated these with key photosynthetic parameters. We show that changes in the relative abundance of cytb6f, ATP synthase, FNR2, TIC62 and PGR6 positively correlate with changes in estimated PSII electron transfer rate and CO2 assimilation. Improved photosynthetic capacity in HL grown plants is paralleled by increased cyclic electron transport, which positively correlated with NDH, PGRL1, FNR1, FNR2 and TIC62, although not PGR5 abundance. The photoprotective acclimation strategy was also contrasting, with LL plants favouring slowly reversible non‐photochemical quenching (qI), which positively correlated with LCNP, while HL plants favoured rapidly reversible quenching (qE), which positively correlated with PSBS. The long‐term adjustment of thylakoid membrane grana diameter positively correlated with LHCII levels, while grana stacking negatively correlated with CURT1 and RIQ protein abundance. The data provide insights into how Arabidopsis tunes photosynthetic electron transfer and its regulation during developmental acclimation to light intensity.
CIA2 and CIA2‐LIKE are required for optimal photosynthesis and stress responses in Arabidopsis thaliana
Authors: Gawroński Piotr , Burdiak Paweł , Scharff Lars B. , Mielecki Jakub , Górecka Magdalena , Zaborowska Magdalena , Leister Dario , Waszczak Cezary , Karpiński Stanisław
Published: October 2020

Chloroplast‐to‐nucleus retrograde signaling is essential for cell function, acclimation to fluctuating environmental conditions, plant growth and development. The vast majority of chloroplast proteins are nuclear‐encoded, and must be imported into the organelle after synthesis in the cytoplasm. This import is essential for the development of fully functional chloroplasts. On the other hand, functional chloroplasts act as sensors of environmental changes and can trigger acclimatory responses that influence nuclear gene expression. Signaling via mobile transcription factors (TFs) has been recently recognized as a way of communication between organelles and the nucleus. In this study, we performed a targeted reverse genetic screen to identify dual‐localized TFs involved in chloroplast retrograde signaling during stress responses. We found that CHLOROPLAST IMPORT APPARATUS 2 (CIA2) has a functional plastid transit peptide, and can be located both in chloroplasts and the nucleus. Further, we found that CIA2, along with its homolog CIA2‐like (CIL) are involved in the regulation of Arabidopsis responses to UV‐AB, high light and heat shock. Finally, our results suggest that both CIA2 and CIL are crucial for chloroplast translation. Our results contribute to a deeper understanding of signaling events in the chloroplast‐nucleus cross‐talk.
Dal‐induced red blood cell incompatibilities in a Doberman Pinscher with von Willebrand factor deficiency and ehrlichiosis
Authors: Conti‐Patara Andreza , Ngwenyama Thandeka R. , Martin Linda G. , Wardrop K. Jane
Published: October 2020

Objective

To describe a complex case involving the management of a dog with von Willebrand disease (vWD), active ehrlichiosis infection, nonregenerative anemia, and blood type incompatibility related to theDalantigen.

Case Summary

A 13‐week‐oldintact male Doberman Pinscher weighing 7.2 kg was presented to the emergency service for a previous hemorrhaging event and progressive nonregenerative anemia. The dog had received a fresh whole blood transfusion 8 days prior to presentation due to severe anemia. Upon presentation, the puppy was tachycardic, and his mucous membranes were pale. A CBC revealed a nonregenerative anemia with a PCV of 0.11 L/L (11%). von Willebrand factor deficiency was suspected and later confirmed. The dog's blood type was dog erythrocyte antigen (DEA) 1 positive, but cross‐matching to 4 RBC units, both DEA 1 positive and negative, failed to yield any compatible units. Antibody against a possibleDalRBC antigen was suspected, and 11 blood donors (Dalmatians and Dobermans) were cross‐matched to find 2 compatible donors. After an uneventful fresh whole blood transfusion, a bone marrow biopsy revealed a hypocellular bone marrow and erythroid hypoplasia. A SNAP4DxPlus test and subsequent polymerase chain reaction (PCR) testing were positive forEhrlichia ewingiiandE. canis. Treatment with doxycycline was started, and the PCV was 0.17 L/L (17%) at discharge. At the 1‐week follow‐up, the PCV was 0.24 L/L (24%), and the puppy was doing well.

New or Unique Information Provided

This is a unique case of a dog presenting with several challenging disorders, including vWD resulting in hemorrhage, ehrlichiosis potentially contributing to a nonregenerative anemia, and a blood type incompatibility due to theDalantigen. Doberman Pinschers have a high prevalence of vWD‐ andDal‐negative phenotype, which emphasizes the value of cross‐matching and the recognition of antigen prevalence in specific breeds.
The effect of time on packed cell volume following packed red blood cell transfusion in anemic dogs
Authors: Morris Jennifer L. , Bloch Christopher P. , Brabson Tamera L.
Published: October 2020

Objective

To compare the PCV at several timepoints following packed red blood cell (pRBC) administration to anemic dogs and to assess if underlying cause of anemia or regenerative status significantly affects these measurements.

Design

Prospective, observational study from November 2016 to October 2017.

Setting

A small animal emergency and specialty hospital.

Animals

Forty‐six anemic client‐owned dogs that received a total of 50 pRBC transfusions for management of anemia.

Interventions

Blood was collected, and a PCV was obtained prior to pRBC transfusion (T0), immediately after (T1), 30 minutes after (T2), 1 hour after (T3), 2 hours after (T4), and 4 hours after (T5) the transfusion. Underlying causes of anemia were classified as hemorrhage, hemolysis, and ineffective erythropoiesis. Dogs were also categorized in regard to regenerative status of anemia and the presence or absence of expected continued blood loss or destruction.

Measurements and Main Results

The mean PCV atT0 was 0.15 L/L (15%). After administration of a pRBC transfusion, the mean PCV atT1 was 0.28 L/L (28%). For all other timepoints (T2,T3,T4, andT5), the mean PCV was 0.27 L/L (27%). The PCV did not change significantly over time post‐transfusion (P = 0.184), and no pairwise combinations of times differed significantly (pairedt‐tests;P > 0.05 for all). When dogs were categorized via regeneration status and continued blood loss or hemolysis, results were consistent.

Conclusions

There was no significant change in PCV from the value obtained immediately after pRBC transfusion up to 4 hours post‐transfusion in dogs with several different causes of anemia. These results suggest that obtaining a PCV immediately after administering a pRBC transfusion to an anemic dog may be just as reliable as obtaining a measurement 2 hours after the transfusion. This remains true for dogs with expected continued red blood cell loss or destruction.
Impact of diurnal variation, sex, tear collection method, and disease state on tear protein levels in dogs
Authors: Page Lauren , Allbaugh Rachel A. , Mochel Jonathan P. , Peraza Jacqueline , Bertram Morgan , Sebbag Lionel
Published: October 2020

Objective

To investigate the effects of various biological factors on total protein concentration (TPC) and serum albumin levels in canine tears.

Animals studied

10 healthy beagles (5 female, 5 male) were used.

Procedures

Experiments were conducted on separate days, collecting tears with either capillary tubes or Schirmer strips, as follows: (i) Tear collection at 3 hours intervals (from 6 am to 12 am); and (ii) Tear collection before and 20 minutes following topical histamine application (1, 10, 375 mg/mL) to induce mild, moderate, and severe conjunctivitis, respectively. TPC and serum albumin were measured with infrared spectroscopy and ELISA, respectively.

Results

Tear film TPC and serum albumin ranged from 9.7‐26.1 mg/mL and 6.4‐1662.6 µg/mL, respectively. Protein levels did not differ significantly among time points (P ≥ .080). Median coefficient of variation (CV%) was lower with Schirmer strips compared to capillary tubes for both TPC (12% vs 15%, P = .020) and serum albumin (57% vs 78%, P = .232). TPC (P < .001), but not serum albumin was greater in male vs. female dogs. Serum albumin, but not TPC (P ≥ .099), increased significantly with each grade of conjunctivitis severity (P < .001), with no differences between collection devices (P ≥ .322); median increase was 106%, 1389%, and 2871% in eyes with mild, moderate, and severe conjunctivitis, respectively.

Conclusions

There is no apparent diurnal variation in canine tear protein levels. Blood‐tear barrier breakdown with conjunctivitis allows serum albumin to leak into the tear film at high concentrations. Schirmer strips compare well with capillary tubes for bioanalytical purposes in healthy and diseased eyes, and this collection method may offer improved reproducibility for protein quantification.
Performance Evaluation of the Data Clustering Techniques and Cluster Validity Indices for Efficient Toolpath Development for Incremental Sheet Forming
Authors: Nagargoje Aniket , Kankar Pavan K. , Jain Prashant K. , Tandon Puneet
Published: October 2020

The goal of current research is to compare the data clustering techniques and cluster validity indices for geometrical feature extraction using point cloud. Here, the point clouds are generated by slicing of the computer-aided design (CAD) surface, and the data on each slice is used as inputs to the clustering algorithms. The clustering techniques are used to detect the multiple closed contours on the planer datasets. In this paper, the four most popular clustering techniques, i.e., partition-based (K-means), density-based (DBSCAN), single linkage hierarchical clustering, a variant of hierarchical clustering, and graph-based (spectral) clustering technique are compared using four different datasets. The single linkage hierarchical clustering is preferred over the other variants as it detects the arbitrarily shaped clusters efficiently and effectively. The comparison is based on the ability of successful detection of the closed contours on the planer dataset, the time required, and the input needed for the algorithm. From the investigations, it is found that DBSCAN is the most suitable technique for the feature-based toolpaths (FBTs) development. Besides, for the quality assessment of the clustering solutions and to pinpoint the superlative validity indices, techniques like Calinski-Harabasz, Ball-Hall, Davies-Bouldin, Dunn, Det Ratio, Silhouette, Trace WiB, and Log Det Ratio are compared. The solutions of the clustering techniques are used to compare the validity indices. On the basis of comparative analysis, it is concluded that the Ball-Hall, Dunn, Det Ratio, and Log Det Ratio indices are the best validity criterions for the arbitrary shaped closed contours. The overall outcomes of this research will help in building the algorithms for the feature-based toolpath development strategies for the various manufacturing processes using data science and machine learning techniques.
Contact Kinematics Between Three-Dimensional Rigid Bodies With General Surface Parameterization
Authors: Xiao MuBang , Ding Ye
Published: October 2020

This paper provides an improvement of classic Montana's contact kinematics equations considering non-orthogonal object parameterizations. In Montana's model, the reference frame used to define the relative motion between two rigid bodies in three-dimensional space is chosen as the Gauss frame, assuming there is an orthogonal coordinate system on the object surface. To achieve global orthogonal parameterizations on arbitrarily shaped object surfaces, we define the relative motion based on the reference frame field, which is the orthogonalization of the surface natural basis at every contact point. The first- and second-order contact kinematics, including the velocity and acceleration analysis of the relative rolling, sliding, and spinning motion, are reformulated based on the reference frame field and the screw theory. We use two simulation examples to illustrate the proposed method. The examples are based on simple non-orthogonal surface parameterizations, instead of seeking for global orthogonal parameterizations on the surfaces.
A Novel Origami-Inspired Delta Mechanism With Flat Parallelogram Joints
Authors: Kalafat Merve Acer , Sevinç Hasan , Samankan Shahrad , Altınkaynak Atakan , Temel Zeynep
Published: October 2020

In robotics, the origami-based design methodology uses straightforward fabrication and assembly processes to create small-scale parallel mechanisms. Delta mechanisms are among the well-known parallel mechanisms used mostly in pick-and-place operations due to their capability to reach high speeds and accelerations. In this work, we present a novel Delta mechanism based on origami-inspired designs and two-dimensional layer-by-layer fabrication methods, reducing the time and errors in manufacturing. We developed a new flat parallelogram providing translations in X–Y–Z directions, respecting the Delta mechanism’s conventional kinematic models. The fabrication and assembly processes include laser machining and lamination, eliminating manual-folding and bonding steps. The mechanism operates in a 20 × 20 × 20 mm3 workspace and a 17.5 cm diameter circular footprint when it is entirely flat. The kinematic performance of the mechanism is analyzed using a six degrees-of-freedom position sensor on the end effector. The experiments are conducted to follow circular trajectories with varying radii at different heights. Despite having no feedback control from the end effector, the mechanism follows the given trajectories with 1.5 mm root-mean-square (RMS) precision. We also present the effects of the elasticity of flexible materials at different regions of the mechanism on the performance of the Delta robot.
Cooling Mechanisms in a Rotating Brake Disc With a Wire-Woven-Bulk Diamond Cellular Core
Authors: Atkins Michael D. , Kienhöfer Frank W. , Kang Kiju , Lu Tian Jian , Kim Tongbeum
Published: October 2020

Thermofluidic behaviors governing the enhanced cooling performance of the wire-woven-bulk diamond (WBD) cored brake disc in comparison with the conventional pin-finned brake disc used on heavy vehicles were characterized experimentally. For each type of brake disc, detailed internal thermofluidic data of the two rotating brake discs were obtained using transient thermochromic liquid crystal (TLC) for end-wall heat transfer and particle image velocimetry (PIV) for the inflow field. The results demonstrate that the pin-finned brake disc exhibits a circumferentially periodic curved inline-like passage flow and large dead flow regions, with strong recirculation that reduces its thermal dissipation performance. The cooling advantage of the WBD core is primarily attributed to the combination of enlarged heat transfer surface area (both end-wall and core) and greater utilization of the larger surface due to favorable fluidic behavior developed from the WBD topology. The internal WBD core has approximately three times the surface density of the pin-finned disc which, in combination with the smaller and weaker recirculation zones, leads to more effective usage of the available core surface area for thermal dissipation. The aerodynamic anisotropy of the WBD core induced by its topological anisotropy causes a globally irregular thermofluidic distribution in the brake disc.
Influence of Plasticity and Friction on the Contact Mechanics of Auxetic Materials
Authors: Saxena Shreya , Fardan Ahmed , Ahmed Rehan
Published: October 2020

Contact interactions play an important role in the tribological behavior of engineering materials. This paper develops a finite element model to investigate the contact mechanics and stress distribution of auxetic materials, i.e., materials with negative Poisson’s ratio. The model results are compared with numerical and mathematical models for isotropic auxetic polymers. The indentation of auxetic materials is analyzed for the effects of friction, plasticity and allowing separation after contact with a spherical indenter using a commercial software, abaqus. The results are discussed in terms of stress profiles, force-indentation depth curves, plasticity, friction, internal energy, compressibility, sink-in, and the pile-up of material. It is concluded that for purely elastic contact, the indentation resistance increases for auxetic materials and the inclusion of friction shifts subsurface stresses closer to the surface. However, the introduction of plasticity negates the improvement of increased indentation resistance. The pile-up of material around the indent reduces for auxetic materials which makes them more suitable for rolling/sliding contacts. The internal strain energy decreases for purely elastic contact and increases for an elastic/plastic contact.
Design Considerations of a Subsea Shuttle Tanker System for Liquid Carbon Dioxide Transportation
Authors: Xing Yihan , Ong Muk Chen , Hemmingsen Tor , Ellingsen Kjell Einar , Reinås Lorents
Published: October 2020

Subsea pipelines and umbilicals are used for the transportation of fluids and electrical power between subsea installations and floating production units (FPUs). The installation and maintenance of these systems can be expensive. In a conventional subsea field development, the produced fluids can be transported from the well to a FPU where they can be offloaded to a tanker (surface ship). In the case of carbon dioxide (CO2) injection into the well, the direction of flow is reversed, i.e., CO2 flows from the tanker to the FPU, down the riser base and through the subsea pipelines to the well. This offloading process is weather-dependent and cannot be performed in severe weather conditions, i.e., strong winds and large waves. This paper presents a novel subsea shuttle tanker system proposed by Equinor ASA designed to be a possible alternative to subsea pipelines, umbilicals, and tanker ships. The subsea shuttle is intended to operate submerged under the sea surface to transport liquid CO2 from an existing offshore/land facility where CO2 is captured to a subsea well where the CO2 is injected into the reservoir. As the shuttle is subsea, it can operate under any type of weather conditions. Even though the subsea shuttle is proposed as a vehicle for liquid CO2 transport, it can also transport other types of cargo such as hydrocarbons, injection fluids, electrical power, or subsea tools. The paper will discuss the most important design considerations surrounding the subsea shuttle tanker.
Elasticity of Anisotropic Low-Density Lattice Materials
Authors: Molavitabrizi Danial , Mousavi S. Mahmoud
Published: October 2020

Computational first-order homogenization theory is used for the elastic analysis of generally anisotropic lattice materials within classical continuum mechanics. The computational model is tailored for structural one-dimensional (1D) elements, which considerably reduces the computational cost comparing to previously developed models based on solid elements. The effective elastic behavior of lattice materials is derived consistently with several homogenization approaches including strain- and stress-based methods together with volume and surface averaging. Comparing the homogenization based on the Hill–Mandel Lemma and constitutive approach, a shear correction factor is also introduced. In contrast to prior studies that are usually limited to a specific class of lattice materials such as lattices with cubic symmetry or similarly situated joints, this computational tool is applicable for the analysis of any planar or spatial stretching- and bending-dominated lattices with arbitrary topology and anisotropy. Having derived the elasticity of the lattice, the homogenization is then complemented by the symmetry identification based on the monoclinic distance function. This step is essential for lattices with non-apparent symmetry. Using the computational model, nine different spatial anisotropic lattices are studied among which four are fully characterized for the first time, i.e., non-regular tetrahedron (with trigonal symmetry), rhombicuboctahedron type a (with cubic symmetry), rhombicuboctahedron type b (with transverse isotropy), and double-pyramid dodecahedron (with tetragonal symmetry).
Capacitive Performance of Reduced Graphene Oxide Modified Sodium Ion-Intercalated Manganese Oxide Composite Electrode
Authors: Xie Yibing
Published: October 2020

The reduced graphene oxide modified sodium ion-intercalated manganese oxide (RGO-NaxMnO2) is designed as a supercapacitor electrode material. The layered intercalation compound NaxMnO2 is prepared through a solid-state reaction process. RGO-NaxMnO2 is then formed by the chemical reduction of graphene oxide coated NaxMnO2 through a hydrothermal process. RGO-NaxMnO2 is supported on the substrate of nickel form (NF) and titanium nitride (TiN) to form RGO-NaxMnO2/NF and RGO-NaxMnO2/TiN composite electrodes. NaxMnO2 has a particle aggregate structure with the individual particle size of 1–2 µm. RGO-NaxMnO2 composite shows the densely packed arrangement of particles with the particle aggregate size of 8 µm. RGO modification can well improve the electrical conductivity of RGO-NaxMnO2. The current response is highly enhanced from 0.127 A g−1 for NaxMnO2/NF to 0.372 A g−1 for RGO-NaxMnO2/NF at 2 mV s−1. Furthermore, the TiN substrate with superior electrical conductivity and electrochemical anti-corrosion contributes to improving the electrochemical capacitance and cycle stability of RGO-NaxMnO2. RGO-NaxMnO2/TiN reveals higher specific capacitance (244.2 F g−1 at 2.0 A g−1) and higher cycling capacitance retention (99.7%) after 500 cycles at 2.0 A g−1 than RGO-NaxMnO2/NF (177.1 F g−1, 43.6%). So, RGO-NaxMnO2/TiN exhibits much higher capacitive performance than RGO-NaxMnO2/NF, which presents a potential application for electrochemical energy storage.
Temperature-Programmed Oxidation Experiments on Typical Bituminous Coal Under Inert Conditions
Authors: Zhang Yansong , Wang Houwang , Du Wenzhou , Niu Kuo , Wei Xiangrui
Published: October 2020

In this study, an experimental investigation was presented on the oxidation behaviors of bituminous coal for different inert gases (N2 and CO2) at different concentrations (oxygen concentration indexes 21%, 18.4%, 15.8%, and 13.1%) using a temperature-programmed experimental device. The purpose of this research was to examine the oxidation patterns of bituminous coal under different inert conditions. The results showed that: (1) the oxidative heating of the coal underwent two stages: an initial slow heating stage and a fast heating stage. The injection of both inert gases would result in a delay in the crossing point temperature (CPT) of the coal, but the injection of N2 resulted in greater delays in the CPT of the coal; (2) the injection of both N2 and CO2 inhibited the concentrations of CO and alkane/olefin gases produced from the oxidative heating of the coal, with CO2 displaying higher inhibition efficiencies than that of N2; (3) Under a non-inerting environment, the C2H4 and C2H6 generation temperatures were 110 °C and 100 °C. Under an inerting environment, when N2 was injected, the higher the N2 concentration, the higher the initial C2H4 and C2H6 generation temperatures; when CO2 was injected, the higher the CO2 concentration, the lower the initial C2H4 and C2H6 generation temperatures; and (4) under a non-inerting environment, the C3H8 generation temperature was 90 °C; and when an inert gas was injected, there was a hysteresis in the C3H8 generation temperature for all concentrations. The above research results can be used to predict the spontaneous combustion of residual coal in an inert environment and prevent fires.
A Simple Approach to Evaluate Near Field Thermal Radiation From Emitters With Layered Structures and Temperature Variations in One Direction
Authors: Wen Sy-Bor
Published: October 2020

A simple analytical calculation scheme to determine near field radiation through decomposing an emission domain into lots of thin thermal current sheets is presented. Through finding the orthogonal modes of thermal current of each thin layer, the thin current sheets can be treated as radiation sources of electromagnetic waves with determined analytical solutions. The outgoing electromagnetic waves from each thin current sheets can be either in transverse electric (TE) or transverse magnetic (TM) modes depending on the orientations of the current in the thin current sheets with respect to the directions of amplitude modulations of the orthogonal modes. Electromagnetic waves arriving to a collection domain are related to the electromagnetic waves leaving from each thin current thermal sheet with transfer coefficients. Transfer coefficient for TE and TM waves can be determined analytically with transfer matrix method or scattering matrix methods. Compared with existing dyadic Green's function method, the new calculation scheme allows material and temperature variations along one direction of the emission domain based on determined analytical expressions of TE and TM waves leaving from each thin current sheets. The simple calculation scheme is especially useful in near field radiation of layered structures with different material such as hyperbolic material with negative refractive indices. With this new approach, we recovered analytical solutions of near field radiation between two semi-infinite domains with uniform temperature and derived closed form solution of near field radiation between two semi-infinite domains with temperature profiles with/without laminated structures.
Numerical Decomposition for the Reliability-Oriented Sensitivity With Dependent Variables Using Vine Copulas
Authors: Wang Pan , Li Haihe , Huang Xiaoyu , Zhang Zheng , Xiao Sinan
Published: October 2020

For the reliability-oriented sensitivity analysis with respect to the parameters of input variables, by introducing the copula function to describe the joint probability distribution with dependent input variables, the reliability-oriented sensitivity can be decomposed into independent sensitivity and dependent sensitivity, which can be used to measure the influence of distribution parameters separately. Since the parameters of multivariate copula function are difficult to be estimated and not flexible in high dimension, the bivariate copulas are preferred in practice. Then, the vine copula model is employed to transform the multivariate joint probability density function (PDF) into the product of multiple bivariate copulas and marginal PDF of all variables. Based on copula theory, the computation of reliability-oriented sensitivity with dependent variables can be transformed into the computation of a score function for each marginal PDF and the computation of a copula score function for each pair-copula PDF involved in the vine factorization. A general numerical approach is proposed to compute the separate sensitivity. Then, some numerical examples and engineering applications are employed to validate the rationality of the proposed method.
Reconciling Enumeration Contradictions: Complete List of Baranov Chains With Up to 15 Links With Mathematical Proof
Authors: Morlin Fernando Vinícius , Carboni Andrea Piga , Martins Daniel
Published: October 2020

The identification of Baranov chains is associated with the rigid subchain identification problem, which is a crucial step in several methods of structural synthesis of kinematic chains. In this article, a systematic approach for the detection of rigid subchains, based on matroid theory, is presented and proved. Based on this approach, a novel method for the enumeration of Baranov chains is proposed. A novel algorithm is applied to a database of nonisomorphic graphs of nonfractionated zero-mobility kinematic chains. By means of the proposed algorithm, the previous results for Baranov chains presented in the literature with up to 11 links are compared and validated. Furthermore, discrepancies in the number of Baranov chains with up to 13 links, presented in the literature, are pointed out, discussed, and the proven results are presented. Finally, the complete family of Baranov chains with up to 15 links is obtained. Examples of application of the proposed method are provided.
A Blockchain-Based G-Code Protection Approach for Cyber-Physical Security in Additive Manufacturing
Authors: Shi Zhangyue , Kan Chen , Tian Wenmeng , Liu Chenang
Published: October 2020

As an emerging technology, additive manufacturing (AM) is able to fabricate products with complex geometries using various materials. In particular, cyber-enabled AM systems have recently become widely applied in many real-world applications. It significantly improves the flexibility and productivity of AM but poses the system under high risks of cyber-physical attacks. For example, cyber-physical attack could maliciously tamper the product design and process parameters, which, in turn, leads to significant alteration of the desired properties in AM products. Therefore, there is an urgent need in incorporating advanced technologies to improve the cyber-physical security for the cyber-enabled AM systems. In this study, two common types of cyber-physical attacks regarding the G-code security were investigated, namely, unintended design modifications and intellectual property theft. To effectively secure the G-code against these two attacks, a new methodology is developed in this study, which consists of a novel blockchain-based data storage approach and an effective asymmetry encryption technique. The proposed method was also applied to a real-world AM case for ensuring the cyber-physical security of the face shield fabrication, which is critical during the COVID-19 pandemic. Based on the proposed methodology, malicious tampering can be accurately detected in time, and meanwhile, the risk of unauthorized access of the G-code file is greatly eliminated as well.
Effect of Aspect Ratio on Overall Thermal Performance of Forced Convective Heat Transfer Utilizing Turbulent Nanofluid Flow
Authors: Hinnawi H. , Al-abadi A. , Al-Huniti N. S.
Published: October 2020

This study is concerned with studying the performance of SiO2–water nanofluid flow through a three-dimensional straight mini-channel with different values of aspect ratio (AR) of (0.5, 1.0, and 1.6) and a fixed hydraulic diameter under a uniform heat flux. The governing equations are developed and solved numerically using the finite volume method for a single-phase flow with standard Kappa-Epsilon (ҡ–ɛ) turbulence model via a user-defined function (UDF) over the Reynolds number (Re) range of (10,000–35,000). Numerical results indicated that the average Nusselt number ratio increases as the Reynolds number and volume concentration of the nanoparticles increase for all values of the channel aspect ratio. The results indicated that the maximum enhancement of the heat transfer coefficient (benefit) achieved is 94.69% at AR = 0.5, along with the lowest increase of pressure drop (penalty) of 13.1%. The highest performance evaluation criterion (PEC) of 1.64 is found at AR = 0.5, Re = 35,000, and 5% concentration.
Numerical Investigation of Smoke Propagation in Road Tunnels Caused by a Burned Truck
Authors: Halawa Taher
Published: October 2020

The efficiency of smoke extraction for longitudinal and transverse tunnel ventilation systems was studied in this paper by conducting numerical simulations using computational fluid dynamics (CFD). The smoke was assumed to result from a fire initiated from a truck inside the tunnel. The most dangerous issue regarding the fire inside tunnels is smoke as it leads to low visibility and choking and may lead to death. The most important result of this paper refers to that the longitudinal ventilation design does not provide efficient smoke extraction compared to the transverse ventilation design as the air jets push the smoke in the downstream direction and then the smoke spreads randomly after the flow loses its momentum gradually. There is a big drop in the visibility for the longitudinal ventilation design that appeared many times and at many locations downstream the fire location. On the other hand, the transverse ventilation design provided more efficient smoke extraction as the jet fan upstream the fire is turned off while the supply fan downstream the fire is reversed to work as an exhaust fan. As a conclusion based on the findings of this paper, it may be said that the transverse ventilation design provided more safe conditions, lower contaminants concentrations, and higher visibility values compared to the longitudinal ventilation design. This work tends to add more information to minimize the research gap related to having a detailed comparison between the two ventilation strategies for a special case where the fire size is relatively large in a long tunnel.
The Potential to Improve the Value of U.S. Geothermal Electricity Generation Through Flexible Operations
Authors: Millstein Dev , Dobson Patrick , Jeong Seongeun
Published: October 2020

Geothermal power plants have typically been operated as baseload plants. The recent expansion of wind and solar power generation creates a potential opportunity to increase the value of geothermal generation through flexible operations. In recent years, California’s wholesale electricity markets have exhibited frequent, short-term periods of negative pricing, indicating that additional flexibility would be valued in the market. Here, we examine local nodal hourly price records at all geothermal plants located in the western United States. We describe how the frequency and temporal characteristics of negative pricing episodes have changed over recent years. Based on these price series, we calculate the value of multiple strategies of flexible operations. Additionally, we use the estimates of future prices, developed through a capacity-expansion model and a dispatch model, to explore how the value of such flexible operations might change along with further penetration of variable renewable power sources. Based on the historical pricing records, we find that simple curtailment of operations during negative pricing episodes could increase the average energy value by 1–2 $/MWh and that allowing for increased production during limited high-priced hours, in addition to curtailment during negative priced hours, could potentially double the increase in value (up to 4 $/MWh). The forward-looking simulations indicate reduced values of flexibility from geothermal power despite higher penetrations of variable renewable energy. This result highlights the possibility that increasing flexibility options throughout the system may counteract the influence of increased variable renewable energy deployment.
Analysis of Energy Savings and CO2 Emission Reduction Contribution for Industrial Facilities in USA
Authors: Selim Osama M. , Abousabae Mohamed , Hasan Alaa , Amano Ryoichi S.
Published: October 2020

Energy audits can identify energy consumptions, energy costs of the facility and evolve to develop measures to maximize efficiency, optimize supply energy, and eliminate waste. This paper investigates the potential energy savings at 20 different industrial sectors with 152 assessments for various facilities in Wisconsin, USA. On average, eight energy recommendations were suggested and applied in each facility. This paper provides a detailed guideline for each industry in terms of eight different energy categories: heating, ventilation, and air conditioning (HVAC) systems, heat recovery systems, electrical demand management, and utility bills, motors, compressors, waste management, and productivity enhancement, lighting, besides building envelope. In total, the energy savings were as follows: 98 million kWh in the shape of electricity, 561 billion British thermal units (BTUs) gas savings, 44 million gallons water savings, and 2-million-pound solid waste savings. Based on these savings, a 100-thousand-ton reduction in carbon dioxide emissions was obtained.
Single-Step Shear-Based Deformation Processing of Electrical Conductor Wires
Authors: Issahaq Mohammed Naziru , Chandrasekar Srinivasan , Trumble Kevin P.
Published: October 2020

Commercial electrical conductor wires are currently produced from aluminum alloys by multi-step deformation processing involving rolling and drawing. These processes typically require 10 to 20 steps of deformation, since the plastic strain or reduction that can be imposed in a single step is limited by material workability and process mechanics. Here, we demonstrate a fundamentally different, single-step approach to produce flat wire aluminum products using machining-based deformation that also ensures adequate material workability in the formed product. Two process routes are proposed: (1) chip formation by free-machining (FM), with a post-machining, light drawing reduction (<20%) to achieve desired finish and (2) constrained chip formation by large strain extrusion machining (LSEM). Using commercially pure aluminum conductor alloys (Al 1100 and EC1350) as representative material systems, we demonstrate key features of the machining-based processing, including (a) single-step processing to achieve flat wire geometries, (b) surface finish (Ra = 0.2 to 1.0 μm) comparable to that of commercial wire products made by drawing/rolling, (c) deformation control independent of wire size, and (d) hardness increases of 50–150% over that of annealed wires, while retaining high electrical conductivity (>56% IACS). The wire microstructure, which can also be varied via the large-strain deformation parameters, is correlated with mechanical and electrical properties. Implications for commercial manufacture of flat wire products are discussed.