CURVAZ—a program to calculate magnitude and direction of maximum structural curvature and fracture-flow index

This study highlights the thermal characterization of ABS-Graphene blended three dimensional (3D) printed functional prototypes by fused deposition modeling (FDM) process. These functional prototypes have some applications as electro-chemical energy storage devices (EESD). Initially, the suitability of ABS-Graphene composite material for FDM applications has been examined by melt flow index (MFI) test. After establishing MFI, the feedstock filament for FDM has been prepared by an extrusion process. The fabricated filament has been used for printing 3D functional prototypes for printing of in-house EESD. The differential scanning calorimeter (DSC) analysis was conducted to understand the effect on glass transition temperature with the inclusion of Graphene (Gr) particles. It has been observed that the reinforced Gr particles act as a thermal reservoir (sink) and enhances its thermal/electrical conductivity. Also, FT-IR spectra realized the structural changes with the inclusion of Gr in ABS matrix. The results are supported by scanning electron microscopy (SEM) based micrographs for understanding the morphological changes.

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Geophysical Monitoring of Gaseous and Supercritical CO2 Fracture Flow Through a Brine-Saturated Shale Caprock

SSRN Electronic Journal ◽

10.2139/ssrn.3365752 ◽

2019 ◽

Author(s):

Mohammad Nooraiepour ◽

Magnus Soldal ◽

Joonsang Park ◽

Nazmul Haque Mondal ◽

Helge Hellevang ◽

...

Keyword(s):

Supercritical Co2 ◽

Fracture Flow ◽

Geophysical Monitoring ◽

Flow Through

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Quantification of shear viscosity and wall slip velocity of highly concentrated suspensions with non-Newtonian matrices in pressure driven flows

Rheologica Acta ◽

10.1007/s00397-021-01281-5 ◽

2021 ◽

Author(s):

Patrick Wilms ◽

Jan Wieringa ◽

Theo Blijdenstein ◽

Kees van Malssen ◽

Reinhard Kohlus

Keyword(s):

Shear Stress ◽

Liquid Phase ◽

Shear Rate ◽

Shear Viscosity ◽

Slip Velocity ◽

Volume Fraction ◽

Solid Volume Fraction ◽

Wall Slip ◽

Flow Index ◽

Concentrated Suspensions

AbstractThe rheological characterization of concentrated suspensions is complicated by the heterogeneous nature of their flow. In this contribution, the shear viscosity and wall slip velocity are quantified for highly concentrated suspensions (solid volume fractions of 0.55–0.60, D4,3 ~ 5 µm). The shear viscosity was determined using a high-pressure capillary rheometer equipped with a 3D-printed die that has a grooved surface of the internal flow channel. The wall slip velocity was then calculated from the difference between the apparent shear rates through a rough and smooth die, at identical wall shear stress. The influence of liquid phase rheology on the wall slip velocity was investigated by using different thickeners, resulting in different degrees of shear rate dependency, i.e. the flow indices varied between 0.20 and 1.00. The wall slip velocity scaled with the flow index of the liquid phase at a solid volume fraction of 0.60 and showed increasingly large deviations with decreasing solid volume fraction. It is hypothesized that these deviations are related to shear-induced migration of solids and macromolecules due to the large shear stress and shear rate gradients.

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Visualization of three-dimensional microcirculation of rodents’ retina and choroid for studies of critical illness using optical coherence tomography angiography

Scientific Reports ◽

10.1038/s41598-021-93631-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jang Ryul Park ◽

ByungKun Lee ◽

Min Ji Lee ◽

Kyuseok Kim ◽

Wang-Yuhl Oh

Keyword(s):

Blood Flow ◽

Optical Coherence Tomography ◽

Severe Sepsis ◽

Critical Illness ◽

Hemorrhagic Shock ◽

Optical Coherence Tomography Angiography ◽

Flow Index ◽

Optical Coherence ◽

Sepsis Model ◽

Lactate Levels

AbstractWe developed a method to measure the relative blood flow speed using optical coherence tomography angiography (OCTA) in retina and choroid, and investigated the feasibility of this method for assessing microcirculatory function in rat models of sepsis and hemorrhagic shock. Two sepsis models, 6-h severe sepsis without treatment and 30-h moderate sepsis maintaining mean arterial pressure, and volume controlled hemorrhagic shock and fluid resuscitation model were used to see the change of microcirculation. The blood flow index (BFI), which was calculated from the OCTA images to represent the average relative blood flow, was decreasing during the 6-h severe sepsis model. Its change is in parallel with the mean arterial blood pressure (MAP) and blood lactate levels. In the 30-h moderate sepsis model, the BFI was decreased while maintaining MAP, and lactate was increased. In the hemorrhagic shock model, the change of BFI is in line with MAP and lactate levels. In all models, BFI change is more sensitive in choroid than in retina. This study presents the OCTA-based retinal and choroidal microcirculatory blood flow monitoring method and shows its utility for assessment of critical illness.

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Optimization studies of low-density polyethylene process: effect of different interval numbers

Chemical Product and Process Modeling ◽

10.1515/cppm-2019-0125 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Ashraf Azmi ◽

Suhairi Abdul Sata ◽

Fakhrony Sholahudin Rohman ◽

Norashid Aziz

Keyword(s):

Dynamic Optimization ◽

Monomer Conversion ◽

Polymerization Process ◽

Low Density Polyethylene ◽

Quadratic Program ◽

Flow Index ◽

Low Density ◽

Orthogonal Collocation ◽

Interval Numbers ◽

Optimization Study

AbstractThe highly exothermic nature of the low-density polyethylene (LDPE) polymerization process and the heating-cooling prerequisite in tubular reactor can lead to various problems particularly safety and economic. These issues complicate the monomer conversion maximization approaches. Consequently, the dynamic optimization study to obtain maximum conversion of the LDPE is carried out. A mathematical model has been developed and validated using industrial data. In the dynamic optimization study, maximum monomer conversion (XM) is considered as the objective function, whereas the constraint and bound consists of maximum reaction temperature and product melt flow index (MFI). The orthogonal collocation (OC) on finite elements is used to convert the original optimization problems into Nonlinear Programming (NLP) problems, which are then solved using sequential quadratic program (SQP) methods. The result shows that five interval numbers produce better optimization result compared to one and two intervals.

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Shenfu injection improves cerebral microcirculation and reduces brain injury in a porcine model of hemorrhagic shock; SFI reduces brain injury after hemorrhagic shock

Clinical Hemorheology and Microcirculation ◽

10.3233/ch-211100 ◽

2021 ◽

pp. 1-11

Author(s):

Junyuan Wu ◽

Zhiwei Li ◽

Wei Yuan ◽

Qiang Zhang ◽

Yong Liang ◽

...

Keyword(s):

Brain Injury ◽

Hemorrhagic Shock ◽

Interleukin 6 ◽

Aquaporin 4 ◽

Flow Index ◽

Sham Operation ◽

Volume Resuscitation ◽

Cerebral Microcirculation ◽

Shenfu Injection ◽

Tnf Α

BACKGROUND: Shenfu injection (SFI) is a traditional Chinese herbal medicine which has been clinically used for treatment of septic shock and cardiac shock. The aim of this study was to clarify effects of SFI on cerebral microcirculation and brain injury after hemorrhagic shock (HS). METHODS: Twenty-one domestic male Beijing Landrace pigs were randomly divided into three groups: SFI group (SFI, n = 8), saline group (SA, n = 8) or sham operation group (SO, n = 5). In the SFI group, animals were induced to HS by rapid bleeding to a mean arterial pressure of 40 mmHg within 10 minutes and maintained at 40±3 mmHg for 60 minutes. Volume resuscitation (shed blood and crystalloid) and SFI were given after 1 hour of HS. In the SA group, animals received the same dose of saline instead of SFI. In the SO group, the same surgical procedure was performed but without inducing HS and volume resuscitation. The cerebral microvascular flow index (MFI), nitric oxide synthase (NOS) expression, aquaporin-4 expression, interleukin-6, tumor necrosis factor-α (TNF-α) and ultrastructural of microvascular endothelia were measured. RESULTS: Compared with the SA group, SFI significantly improved cerebral MFI after HS. SFI up regulated cerebral endothelial NOS expression, but down regulated interleukin-6, TNF-α, inducible NOS and aquaporin-4 expression compared with the SA group. The cerebral microvascular endothelial injury and interstitial edema in the SFI group were lighter than those in the SA group. CONCLUSIONS: Combined application of SFI with volume resuscitation after HS can improve cerebral microcirculation and reduce brain injury.

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Effects of remote ischemic conditioning on microcirculatory alterations in patients with sepsis: a single-arm clinical trial

Annals of Intensive Care ◽

10.1186/s13613-021-00848-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Inga Kiudulaite ◽

Egle Belousoviene ◽

Astra Vitkauskiene ◽

Andrius Pranskunas

Keyword(s):

Dark Field ◽

Historical Control ◽

Flow Index ◽

Control Group ◽

Remote Ischemic Conditioning ◽

Ischemic Conditioning ◽

Sublingual Microcirculation ◽

Link Type ◽

Microcirculatory Flow ◽

Tertiary Teaching

Abstract Background Remote ischemic conditioning (RIC) is a promising technique that may protect organs and tissues from the effects of additional ischemic episodes. However, the therapeutic efficacy of RIC in humans with sepsis remains unknown. We hypothesized that RIC might improve sublingual microcirculation in patients with sepsis. Methods This prospective single-arm trial was performed in a mixed ICU at a tertiary teaching hospital. We included patients with sepsis or septic shock within 24 h of ICU admission. The RIC procedure comprised 3 cycles of brachial cuff inflation to 200 mmHg for 5 min followed by deflation to 0 mmHg for another 5 min. The procedure took 30 min. RIC was performed at the time of study inclusion and repeated after 12 and 24 h. Sublingual microcirculatory measurements were obtained before and after each RIC procedure using a Cytocam®-incident dark-field (IDF) device (Braedius Medical, Huizen, The Netherlands). The microcirculatory data were compared with a historical control. Data are reported as the medians along with the 25th and 75th percentiles. Results Twenty-six septic patients with a median age of 65 (57–81) years were enrolled in this study. The median Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores at admission were 20 (13–23) and 10 (9–12), respectively. All patients were receiving vasopressors. After the 1st RIC procedure, the microvascular flow index (MFI) and the proportion of perfused vessels (PPV) among small vessels were significantly higher than before the procedure, with pre- and post-treatment values of 2.17 (1.81–2.69) and 2.59 (2.21–2.83), respectively, for MFI (p = 0.003) and 87.9 (82.4–93.8) and 92.5 (87.9–96.1) %, respectively, for PPV (p = 0.026). This result was confirmed by comparison with a historical control group. We found no change in microcirculatory flow or density parameters during repeated RIC after 12 h and 24 h. Conclusion In patients with sepsis, the first remote ischemic conditioning procedure improved microcirculatory flow, whereas later procedures did not affect sublingual microcirculation. Trial registration NCT04644926, http://www.clinicaltrials.gov. Date of registration: 25 November 2020. Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04644926.

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Laboratory Study of the Ultraviolet Radiation Effect on an HDPE Geomembrane

Membranes ◽

10.3390/membranes11060390 ◽

2021 ◽

Vol 11 (6) ◽

pp. 390

Author(s):

Fernando Luiz Lavoie ◽

Marcelo Kobelnik ◽

Clever Aparecido Valentin ◽

Érica Fernanda da Silva Tirelli ◽

Maria de Lurdes Lopes ◽

...

Keyword(s):

Ultraviolet Radiation ◽

Morphological Changes ◽

Field Performance ◽

Melt Flow Index ◽

Flow Index ◽

Test Results ◽

Upward Trend ◽

Scanning Calorimetry ◽

Ultraviolet Exposure ◽

Brittle Behavior

High-density polyethylene (HDPE) geomembranes are polymeric geosynthetic materials usually applied as a liner in environmental facilities due to their good mechanical properties, good welding conditions, and excellent chemical resistance. A geomembrane’s field performance is affected by different conditions and exposures, including ultraviolet radiation, thermal and oxidative exposure, and chemical contact. This article presents an experimental study with a 1.0 mm-thick HDPE virgin geomembrane exposed by the Xenon arc weatherometer for 2160 h and the ultraviolet fluorescent weatherometer for 8760 h to understand the geomembrane’s behavior under ultraviolet exposure. The evaluation was performed using the melt flow index (MFI) test, oxidative-induction time (OIT) tests, tensile test, differential scanning calorimetry (DSC) analysis, and Fourier transform infrared spectroscopy (FTIR) analysis. The sample exposed in the Xenon arc equipment showed a tendency to increase the MFI values during the exposure time. This upward trend may indicate morphological changes in the polymer. The tensile behavior analysis showed a tendency of the sample to lose ductility, without showing brittle behavior. The samples’ OIT test results under both device exposures showed faster antioxidant depletion for the standard OIT test than the high-pressure OIT test. The DSC and FTIR analyses did not demonstrate the polymer’s changes.

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Enhancement of mechanical, thermal and water uptake performance of TPU/jute fiber green composites via chemical treatments on fiber surface

e-Polymers ◽

10.1515/epoly-2020-0015 ◽

2020 ◽

Vol 20 (1) ◽

pp. 133-143 ◽

Cited By ~ 6

Author(s):

Tuffaha Fathe Salem ◽

Seha Tirkes ◽

Alinda Oyku Akar ◽

Umit Tayfun

Keyword(s):

Water Absorption ◽

Water Uptake ◽

Mechanical Test ◽

Fiber Surface ◽

Melt Flow Index ◽

Jute Fiber ◽

Morphological Properties ◽

Flow Index ◽

Melt Flow ◽

Treatment Type

AbstractChopped jute fiber (JF) surfaces were modified using alkaline, silane and eco-grade epoxy resin. Surface characteristics of jute fibers were confirmed by FTIR and EDX analyses. JF filled polyurethane elastomer (TPU) composites were prepared via extrusion process. The effect of surface modifications of JF on mechanical, thermo-mechanical, melt-flow, water uptake and morphological properties of TPU-based eco-composites were investigated by tensile and hardness tests, dynamic mechanical analysis (DMA), melt flow index (MFI) test, water absorption measurements and scanning electron microscopy (SEM) techniques, respectively. Mechanical test results showed that silane and epoxy treated JF additions led to increase in tensile strength, modulus and hardness of TPU. Glass transition temperature (Tg) of TPU rose up to higher values after JF inclusions regardless of treatment type. Si-JF filled TPU exhibited the lowest water absorption among composites. Surface treated JFs displayed homogeneous dispersion into TPU and their surface were covered by TPU according to SEM micro-photographs.

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