Polyvinyl Chloride Tubes Research Articles

A model for predicting flexural capacity of PVC‐CFRP tube confined reinforced concrete beams

AbstractThis paper presents an experimental study on 18 specimens, including 15 polyvinyl chloride (PVC)‐carbon fiber‐reinforced polymer (CFRP) tube confined reinforced concrete beams with longitudinal CFRP sheets (PCT‐RCBs‐LCS) and 3 PVC‐CFRP tube confined reinforced concrete beams (PCT‐RCBs). The effects of five studied parameters, such as longitudinal reinforcement rate (), concrete strength grade (), width () and number () of longitudinal CFRP sheet, and specimen dimensions (), on the failure mode and flexural capacity are investigated. The PCT‐RCBs‐LCS with lower and fail by the breakage of the PVC tube and the fracture of longitudinal CFRP sheets. Conversely, the cracking of PVC tube dominates the damage of the PCT‐RCBs‐LCS with higher and , while the longitudinal CFRP sheets are not broken. The introduction of longitudinal CFRP sheets can significantly improve the flexural capacity. The ultimate flexural capacity of the PCT‐RCBs‐LCS increases as the , , , or increases. In addition. considering the influence of RC beam section shape, a model for predicting the ultimate flexural capacity of the PCT‐RCBs‐LCS is proposed based on the limit equilibrium theory and cross‐sectional strain relationship. The predicted results of the proposed model agree well with test data.

Crushing behavior of GFRP composite-reinforced PVC tubes: Experimental testing and numerical simulation

This paper introduces glass fiber reinforced polymer (GFRP)-reinforced Polyvinyl Chloride (PVC) tubes, both corrugated and non-corrugated, designed as energy absorber devices. The PVC tubes were externally and internally reinforced with GFRP composite oriented at ±45∘ and subjected to quasi-static axial compression tests. Results indicated that all reinforced tubes exhibited significantly higher load-bearing capacity, energy absorption capability, and crushing force efficiency compared to standard PVC tubes. Among the tested specimens, externally reinforced corrugated tubes demonstrated the highest specific energy absorption (SEA), surpassing other configurations by 17.5 kJ/kg when considering both pre- and post-crushing stages combined. However, these corrugated specimens showed instability during crushing, reflected in poor instantaneous crush force efficiency (iCFE) and the lowest iCFE among the composite tubes, with an average decrease of 43.59%.The corrugation notably increased the initial peak load, enhancing energy absorption in the pre-crushing stage without compromising the stability of crush force efficiency (CFE). Additionally, the combination of external and internal reinforcement significantly improved CFE and iCFE. Consequently, the PVC tubes combining corrugation with both external and internal reinforcement emerged as the best-performing configuration among all tested tubes.Furthermore, a 3D Finite Element (FE) model was developed using ABAQUS FE code with user-defined subroutines to simulate the crushing process. The constitutive models and numerical procedures employed are detailed. The FE model’s predictions showed a satisfactory correlation with experimental results, providing valuable insights into the crushing mechanics and offering a predictive tool for future design optimizations.

Determination of dialkyl phthalate esters in indoor air of PVC industry: Risk assessment for human health using Monte-Carlo simulations

Dialkyl phthalate esters are incorporated to enhance the pliability and prevent brittleness in polyvinyl chloride (PVC) tubing. Exposure to these compounds occurs throughout human lifetimes via ingestion, inhalation, and direct skin contact. A study was conducted to evaluate concentrations of four specific phthalates—dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), and di(2-ethylhexyl) phthalate (DEHP)—in the indoor air of both industrial and administrative sectors within the PVC manufacturing facilities. Air sampling was conducted in the spring season at two polyethylene factories in Zahedan Industrial Park (Sistan and Baluchestan Province, Iran). The outcomes demonstrated that mean concentrations of these substances in industrial along with administrative departments 485.7 μg/m3 and 49.83 μg/m3for DMP, 807.38 μg/m3 and 30.17 μg/m3 for DEP, 849.62 μg/m3 and 37.50 μg/m3 for DBP along with 1268.08 μg/m3 and 45.50 μg/m3 for DEHP respectively. The probabilistic lifetime cancer risk (LTCR) of DEHP in the indoor air of Zahedan PVC factories for men and women was determined using the Monte Carlo simulation technique. The computed mean LTCRs of DEHP for men and women in the indoor air of industrial and administrative departments in Zahedan PVC were 1.3 × 10−3, 1.2 × 10−3and 4.7 × 10−5,4.2 × 10−5respectively. Data showed that DEHP was a potential risk to human health.

Antithrombotic and Antimicrobial Potential of S-Nitroso-1-Adamantanethiol-Impregnated Extracorporeal Circuit.

This study presents the utilization of a novel, highly lipophilic nitric oxide (NO) donor molecule, S-nitroso-1-adamantanethiol (SNAT), for developing an NO-emitting polymer surface aimed at preventing thrombus formation and bacterial infection in extracorporeal circuits (ECCs). S-nitroso-1-adamantanethiol, a tertiary nitrosothiol-bearing adamantane species, was synthesized, characterized, and used to impregnate polyvinyl chloride (PVC) tubing for subsequent in vivo evaluation. The impregnation process with SNAT preserved the original mechanical strength of the PVC. In vitro assessments revealed sustained NO release from the SNAT-impregnated PVC tubing (iSNAT), surpassing or matching endothelial NO release levels for up to 42 days. The initial NO release remained stable even after 1 year of storage at -20°C. The compatibility of iSNAT with various sterilization techniques (OPA Plus, hydrogen peroxide, EtO) was tested. Acute in vivo experiments in a rabbit model demonstrated significantly reduced thrombus formation in iSNAT ECCs compared with controls, indicating the feasibility of iSNAT to mitigate coagulation system activation and potentially eliminate the need for systemic anticoagulation. Moreover, iSNAT showed substantial inhibition of microbial biofilm formation, highlighting its dual functionality. These findings underscore the promising utility of iSNAT for long-term ECC applications, offering a multifaceted approach to enhancing biocompatibility and minimizing complications.

Multi-objective optimization through desirability function analysis on the crashworthiness performance of thermoplastic/thermoset hybrid structures

This paper aims to optimize the crashworthiness capability of glass-reinforced epoxy composites (GFRE) over wrapped polyvinyl chloride (PVC) circular tubes with cutouts. The intended tubes were prepared by a wet wrapping method; then subjected to quasi-static axial compression. To compute crashworthiness indications, three design parameters, each at three levels, were used. The design parameters are the hole diameter (d), the hole's number (n), and the hole position (L). A few runs were accompanied by the L9 orthogonal array based on the Taguchi technique. With the lowest initial peak crash force (Fip) and the largest absorbed energy (U), the optimal parameters were found. Furthermore, the main effect, signal-to-noise ratio (S/N), as well as the analysis of variance (ANOVA), have been studied using the commercial software program MINITAB 18. Furthermore, to optimize the process parameters in terms of the crashworthiness indicators, desirability function analysis (DFA) was applied. Lastly, tests for confirmation were performed to verify the predicted values in light of the experimental results and compare them with the intact tubes. Regarding the single optimization, the optimum Fip tube is smaller than the intact PVC tube and intact hybrid tube, at 24.01 and 72.85 %, respectively. Nonetheless, the optimal U was 21.43 % lower than the intact hybrid tube and 152.75 % greater than the intact PVC tube. While, for Fip and U, the multi-objective optimization specimen achieves 5.13 and 70.02 % greater than the intact PVC tube. But it was 62.44 % and 47.14 % less than what the intact hybrid tube had accomplished.

СОКОПРОДУКТИВНОСТЬ КЛЕНА ВЫСОКОГОРНОГО

In the North Caucasus are presented data on the intensity of sap production and sap productivity of the Trautvetter maple. Experimental tapping was carried out in an old-growth maple forest in the forest fund of North Ossetia-Alania, the Koban tract. Maple tapping was carried out by laying drill channels with a diameter of 10 mm and a depth of no more than 30 mm. From 1 to 4 channels were laid on one trunk. A polyvinyl chloride tube with an outer diameter of 10 mm was used as a sap line. Plastic containers with a volume of 5 and 10 liters served as juice collectors. The volume of secreted juice was determined with an accuracy of 10 ml. It has been established that the intensity and duration of juice secretion depends on the weather conditions at the beginning of the growing season. The sap productivity of the Trautfetter maple also depends on the size of the tree and its condition. A direct and strong dependence of the intensity of juice secretion on the diameter of the trunk has been proven - the larger the diameter, the more juice. At the same time, there are cases when the intensity of sap production by trees with a small trunk diameter is higher than that of trees with a trunk diameter of about 1 m. It is noted that the presence of heart rot and hollowness of the trunk affects both the intensity of sap production and sap productivity. An interesting feature was revealed in individual Trautfetter maple trees: when 2-4 sapling canals are laid on one trunk, sap flow from one, or less often from two canals at once, quickly stops. The period of rapid decrease in juice secretion takes from 30 minutes to several hours. A characteristic phenomenon for alpine maple is the growth of trees in nests, when from 2 to 10-12 trunks develop from a single root system. It is indicated that the intensity of sap production does not depend on the number of trees in the “nest”, and the overall sap productivity of the “nest” is higher than that of individual trees.

Experimental and numerical studies on the seismic performance of fully cast‐in‐situ concrete exterior walls

AbstractTo investigate differences in the seismic performance of the main structure between a window sill wall and a coupling beam under two different flexible connections, two coupled shear wall specimens with concrete window sill walls and one counterpart specimen without infill walls (S‐1) were designed for quasistatic tests. The test results indicated the following: In specimen S‐2, fully disconnected by polyvinyl chloride (PVC) tubes, the coupling beam and window sill wall formed a double coupling beam working mode. The failure mode of the main structure of specimens S‐1 and S‐2 was the beam‐hinge mechanism. In specimen S‐3, which was partially disconnected by extruded polystyrene board strips, the coupling beam and the window sill wall worked together as an integral beam and underwent shear failure, revealing significant differences in failure mode compared to S‐1. In addition, the relative deformation between the first‐floor window wall and the main structure of specimen S‐2 could occur, and the interaction between the two was relatively small compared with that of specimen S‐3. Similarly, compared with those of specimen S‐1, the peak loads of specimens S‐2 and S‐3 were approximately 52.37% and 79.99% greater, respectively. The ductility coefficient of S‐2 was equivalent to that of S‐1, while the displacement ductility coefficient of S‐3 decreased by approximately 41.95% compared to that of S‐1. The connection between the main structure and the concrete infill wall with PVC effectively reduced the interaction between the two components and reduced the damage. Finally, MSC. Marc software was used to establish a solid model and simplified model of the equivalent compression bars of all the specimens, and the results were compared with the test results.

Evidence of the Existence of Site-Specific Female Contact Pheromones Involved in the Sexual Interaction Behavior of the Pacific Whiteleg Shrimp Penaeus vannamei.

Although the presence of female contact sex pheromones in P. vannamei has been hypothesized, to date its existence has not been proven. To gather more evidence of their existence, cuticular liposoluble extracts were obtained from the following samples of adult females to be used as the experimental treatments: (1) ventral exoskeleton of immature female (VI), (2) dorsolateral exoskeleton of immature female (DI), (3) ventral exoskeleton of mature female (VM), and (4) dorsolateral exoskeleton of mature female (DM). Polyvinyl chloride tubes (artificial females; AF) were coated with each extract and the behavior displayed by sexually mature males in contact with the AF was recorded and classified as follows: 0 = no response; 1 = contact; 2 = pushing; and 3 = prolonged contact (≥10 s). To test the hypothesis that the extracts collected from the ventral portion of the abdomen exoskeleton have a higher effect on the behavior of males than the extracts collected from the dorsolateral portion of the abdomen exoskeleton, the experiment was divided into two bioassays: Bioassay I (VI vs. DI) and Bioassay II (VM vs. DM). In each bioassay, all experimental treatments were significantly different (p > 0.05) from the CTL group (AF coated with hexane). Notably, the pushing behavior was significantly higher (p < 0.05) in the VI treatment compared to the CTL and DI treatment. These results provide evidence of the existence of contact female sex pheromones with sexual recognition function located primarily in the ventral portion of the abdomen exoskeleton of P. vannamei.

A randomized comparison of three intubation techniques/tube materials for nasotracheal intubation.

We sought to compare three intubation methods using different intubation techniques/tube materials for tube advancement from the nasal cavity into the oral cavity during nasotracheal intubation. We conducted a randomized clinical trial with adult patients scheduled to undergo elective surgery requiring nasotracheal intubation for general anesthesia. Participants were randomly allocated to a polyvinyl chloride (PVC) tube group (group P), PVC tube attached to a rubber catheter group (group PR), or velvet-soft PVC tube group (group V). Tracheal intubation was then performed based on group allocation. The primary outcome was the first-attempt success rate of tube advancement into the oral cavity; secondary outcomes included the time required for tube advancement into the oral cavity, total intubation time, and the incidence of epistaxis. A total of 149 patients were included in the study. The first-attempt success rate in group V (90%) was significantly higher than that in group P (58%) (odds ratio, 6.5; 95% confidence interval [CI], 2.2 to 19.2), but similar to that in group PR (100%). The mean (standard deviation) time required for tube advancement into the oral cavity was significantly shorter in group V (16 [13] sec) than in group PR [40 (10) sec; 95% CI of mean difference, 17 to 30] and group P (26 [16] sec; 95% CI of mean difference, 3 to 16). Total intubation time was longest in group PR. Epistaxis occurred the least in group V. Among the three intubation techniques/tube materials for nasotracheal intubation, the velvet-soft PVC tube provided the highest first-attempt success rate, most expeditious advancement into the oral cavity, and lowest incidence of epistaxis. ClinicalTrials.gov (NCT04695444); first submitted 30 December 2020.

Optimizing the crashworthy behaviors of hybrid composite structures through Taguchi approach

AbstractThis paper calculates the crashworthiness capability of glass‐reinforced epoxy composites over wrapped polyvinyl chloride (PVC) circular tubes with a triggering mechanism in the form of cutouts. The intended tubes were prepared by a wet wrapping method; after which they were subjected to quasi‐static axial compression. To compute crashworthiness indications, three design parameters, each at three levels, were used. The design parameters are the hole diameter (d), the hole's number (n), and the hole position (L). The Taguchi technique has been employed in the design of experiments (DOE) tactic to obtain the best crashworthiness parameters. With the maximum specific energy absorbed (SEA) and crashing force efficiency (CFE), the optimal parameters were found. Furthermore, the main effect, signal‐to‐noise ratio (S/N), as well as the analysis of variance (ANOVA), have been studied using the commercial software programme MINITAB 18. A few experiments were accompanied by the L9 orthogonal array. According to the results, “N” has the largest impact on the value of SEA with a contribution percent of 29.27%. While “d” has the main influence on the value of CFE with a contribution percent of 67.29%. Lastly, tests for confirmation were performed. to verify the predicted values in light of the experimental results. The optimized SEA developed tube is 74.72%, which is higher than the intact PVC tube and 12.29% lower than the intact hybrid tube. However, the optimum CFE was also 48 and 29.82% higher than the intact PVC tube and the intact hybrid tube, respectively.Highlights The number of holes has the highest impact on SEA value by 29%. The ideal specimen enhances SEA by 75% compared to the intact PVC tube. Hole diameter has the most influence on CFE value by 67%. The best specimen improves the CFE by 48% related to the intact PVC tube.

Micromorphology and thematic micro-mapping reveal differences in the soil structuring traits of three arbuscular mycorrhizal fungi

Arbuscular mycorrhizal (AM) fungi contribute to soil structure, but little is known about the effect of individual fungal species on soil aggregation. In this study, the influence of 3 AM fungi species on soil aggregation in a Vitric Andosol was determined using physical, micromorphological, and imaging analyses. We used a pipe of polyvinyl chloride (PVC) with a six-way connector, which was filled with soil plus AM fungal inoculum (Funneliformis mosseae, Rhizophagus intraradices, Gigaspora gigantea or non-inoculated -control-). Then lateral pipe connectors (experimental units) were covered with mesh systems (0.5, 0.25, and 0.034 mm), and PVC tubes filled with sterile soil were connected laterally using a clamp. The greenhouse experiment consisted of four treatments each with 32 experimental units. Four experimental units of each treatment were separated and collected at different times during the year: three were used to determine water-stable aggregates (disturbed soils), and one was preserved (undisturbed soil) to elaborate soil thin sections. Thematic micro-maps were constructed with image mosaics from a whole soil thin section, and micromorphological analyses were conducted using spatial operators. Our results showed that AM fungi affect soil aggregation forming micro-aggregates and macro-aggregates of different sizes. The most significant effects were observed with F. mosseae > R. intraradices >Gi. gigantea > control. Aggregation hierarchy was observed in micromorphological analysis, where F. mosseae and R. intraradices start binding organo-mineral particles and microaggregates to form macroaggregates, modifying soil structure from intergrain (apedal= without peds) to crumb aggregates (pedal= with peds). Gigaspora gigantea only promoted macroaggregation, by associating with pumice particles. The two AM fungi from Glomeraceae possess similar morphology compared to that isolate belonging to Gigasporaceae, which explain in part, their differential contribution traits on soil aggregation, as highlighted by using together physical and micromorphological analyses of soil thin sections based on high-resolution image mosaics.

Establishment of a Novel Miniature Double-Lumen Catheter Single-Cannulation Venovenous Extracorporeal Membrane Oxygenation Model in the Rat.

In recent years, venovenous extracorporeal membrane oxygenation (VV ECMO) has been used to support patients with severe lung disease. Active use of VV ECMO was also recommended for severe respiratory failure due to COVID-19. However, VV ECMO is also known to cause various complications due to extracorporeal circulation. Although we conducted ECMO research using rats, we have not been able to establish whether double-lumen single-cannulation VV ECMO models in rats have been described previously. The purpose of this study was to establish a simple, stable, and maintainable miniature double-lumen single-canulation VV ECMO model in rats. A double-lumen catheter used as a plain central venous catheter (SMAC plus Seldinger type; Covidien Japan Co., Tokyo, Japan) was passed through the right external jugular vein and advanced into the right atrium as a conduit for venous uptake. The VV ECMO system comprised a roller pump, miniature membrane oxygenator, and polyvinyl chloride tubing line. During VV ECMO, blood pressure and hemodilution rate were maintained at around 80 mmHg and 30%, respectively. Hemoglobin was kept at >9 g/dL, no serious hemolysis was observed, and VV ECMO was maintained without blood transfusion. Oxygenation and removal of carbon dioxide from the blood were confirmed and pH was adequately maintained. This miniature VV ECMO model appears very useful for studying the mechanisms of biological reactions during VV ECMO.

Bidirectional seismic performance and design approach of RC infill wall with PVC tubes

In some regions, masonry infill walls are replaced by cast-in-situ reinforced concrete (RC) infill walls to effectively solve problems such as leakage, long construction periods, and high out-of-plane vulnerabilities. However, these high-stiffness RC infills impose excessively high constraints on the adjacent structural components, leading to disadvantageous seismic responses. Therefore, a flexible connection is required to isolate the infill walls and main structures. However, flexibly connected RC infill walls are not widely used in practical engineering because they are weakly supported by relevant standards and codes and have an insufficient calculation basis, especially for evaluating out-of-plane seismic properties. This study considers a type of RC infill wall with a common layout of polyvinyl chloride (PVC) tubes for coupled shear wall systems. The in-plane and out-of-plane seismic performances of the system are studied using quasi-static loading tests and finite element analysis, respectively. The system exhibits satisfactory seismic properties during the test because the PVC tubes provide effective flexible isolation. Out-of-plane pushover analysis and bidirectional loading are successively simulated with different parameters to study the out-of-plane reliability of the infill walls with and without openings. Finally, a seismic design approach for such infill walls, considering both in-plane and out-of-plane resistances, is proposed and validated using novel and concise design formulas. The accuracy of the design approach is verified using finite element calculations.

Environmental enrichment improves survival and growth of Portunus trituberculatus in recirculating aquaculture system by reducing energy expenditure and stress responses

Barren rearing environment of recirculating aquaculture system (RAS) is a stressful situation that may result in high mortality rate of the swimming crab Portunus trituberculatus, an important economic seawater crab species in China. Environmental enrichment can mitigate stress to animals held in captivity. However, the physiological responses as well as survival and growth phenotype of the swimming crabs in the enriched RAS are currently unknown. Here, we examined the changes in the survival and growth performance as well as metabolic and immune features after 28 day-environmental enrichment using sand and polyvinylchloride (PVC) tube in RAS. We observed that sand enrichment improved survival and growth performance accompanied by reduced stress to crabs. The reduced stress subsequently attenuated the glucolipid metabolism and enhanced the accumulation of glycogen and triglyceride. This in turn mitigated oxidative stress and knock-on positive effects on immunity and apoptosis of the swimming crabs. PVC tube induced the similar but less significant effects on the swimming crabs to/than sand. Overall, environmental enrichment using sand and PVC tube improved survival and growth performance of the swimming crabs by reducing stress of RAS, glucolipid metabolism, oxidative damage and apoptosis, as well as enhancing accumulation of energy substances and immunity. The application of environmental enrichment techniques in RAS is urgently required to improve the yield of the swimming crabs.

Interactive Effect of Residue Quality and Agroecologies Modulate Soil C‐ and N‐Cycling Enzyme Activities, Microbial Gene Abundance, and Metabolic Quotient

Understanding interactive effect of agroecology explained by rainfall, temperature, elevation, and biochemical composition of residues on soil microbial abundance and functions is crucial for unraveling soil ecological processes. This study aimed to investigate how agroecology and residue quality influence enzymatic activities, gene abundance, and metabolic quotient (qCO2). A field experiment was conducted using Leucaena leucocephala (LL) (high‐quality residue) and Acacia decurrens (AD) (low‐quality residue) in soils of highland and midland agroecologies. These residues differed in decomposability, characterized by a ratio of (lignin + polyphenol)/N of 5.0 for high‐quality residue versus 21.0 for low‐quality residue. Two experimental setups were employed: soil with litter mixture in polyvinyl chloride (PVC) tubes and residues buried in the surface soil using litterbags. Soil samples were collected after 30, 120, and 270 days of incubation and analyzed for biochemical properties, enzyme activities, and the abundance of nitrifying and total archaea and bacteria. Soil respiration was also measured at different intervals in the field. qCO2 was calculated using microbial biomass (MBC) and daily respiration (DCO2). Linear mixed model (P &lt; 0.05) revealed that combined factors of agroecologies and residue qualities affected enzymatic activities, microbial abundance, soil properties, and qCO2. Agroecological differences exerted a greater influence than residue qualities. Positive and negative significant correlations (P &lt; 0.05, r = 0.27 to 0.67) were found between different C and N pools as well as enzymatic activities. Positive correlations (P &lt; 0.05) were observed between the abundance of total bacteria, total archaea, and ammonia‐oxidizing bacteria versus leucine‐aminopeptidases. qCO2 was influenced more by β‐xylosidase, leucine‐aminopeptidases, and thermolysin‐like neutral metalloproteases (TLP) than by β‐D‐glucosidase and β‐D‐cellobiohydrolase. Leucine‐aminopeptidases and TLP were identified as rate‐limiting factors for protein and peptide decomposition, while β‐xylosidase controlled hemicellulose degradation. In summary, this study provides insights into the intricate relationships between agroecology, residue quality, enzymatic activities, and microbial communities, shedding light on key processes governing soil ecological functions.

Robust and self-lubricating polyvinyl alcohol tubes with a mucosa-like hierarchical architecture for endotracheal intubation.

Mechanical mismatch between interventional intubation tubes and human tissues often triggers inevitable friction and causes secondary injury to patients during interventional therapy. Herein, we propose a fabrication strategy of a self-lubricating polyvinyl alcohol (PVA) tube by industrial extrusion technology followed by simple infiltration with water. First, biocompatible glycerin was introduced to weaken the intrinsic hydrogen interaction of PVA by new molecular complexation, broadening the gap between the melting and decomposition temperatures and enabling the stable extrusion of the PVA tube. Subsequently, the as-prepared PVA tube was infiltrated with an aqueous solution to construct a strong hydrogen bonding network between PVA and water molecules, forming a soft hydration layer similar to the upper epithelium layer of mucosa. Benefiting from the solid and liquid properties of the hydration layer as well as the small proportion relative to the whole, the infiltrated PVA tube exhibited excellent hydration lubrication behavior and robust mechanical property. The friction coefficient, tensile strength and elongation at break were measured to be 0.05, 26.2 MPa and 654%, respectively, surpassing the values of 0.5, 16.4 MPa and 240% observed in a commercial polyvinyl chloride tube. In vitro, the PVA intubation tube demonstrated significant biocompatibility, and short-term exposure exhibited minimal impacts on the morphology and proliferation of L929 cells. Ultimately, the potential of the infiltrated PVA tube for interventional intubation was demonstrated successfully using an in vivo rabbit model, providing a new idea for the follow-up development of interventional intubation tubes.

ASSESSMENT OF SEDIMENTS AND GEOMORPHOLOGY OF FRESHWATER BODIES IN NORTHERN GUINEA SAVANNA ZONE, NIGERIA

Sediments from freshwater bodies of the Northern Guinea Savanna Zone of Nigeria act as reservoirs for mineral and chemical nutrients washed from different sources around the environment. This research aimed at assessing the chemical and macronutrients of the sediments from freshwater bodies and the geomorphology of the area. A global positioning system, Model N9 GARMIN eTrexLegend™, personal navigator® was used to determine the geomorphological features while a polyvinyl chloride tube of 1.0 m long, 25 mm in diameter and 2.0 mm thick was used for sediment collection from a depth of 0-15 cm. The result of the chemical properties of the sediment; pH, organic carbon, organic matter and total nitrogen were found to be higher in dry season whereas phosphorus was high in the rainy season and there was no variation in the macronutrient across the dry and rainy season. Sand had the highest percentage across both seasons for particle distribution. This study revealed that sediments are rich in macronutrients and can be employed for agricultural purposes.

Application of PVC pipes as an adjustable bilateral traction device in lower limb fractures

ObjectiveTo introduce a new type of simple adjustable bilateral bidirectional polyvinyl chloride (PVC) tube traction device and discuss the value of using this device before surgery in patients with lower limb fractures.MethodsTo introduce the manufacturing process of an adjustable bilateral traction device made of PVC pipes. From August 2018 to November 2019, the data of 36 patients with lower limb fractures who were treated with this traction device were retrospectively analysed. The treatment outcomes were analysed, including length of both lower limbs, fracture reduction, lower limb mobility, visual analogue scale (VAS) score, incidence of complications, and patient satisfaction.ResultsAll patients were able to move the affected limb immediately after using the device. The patient's pain was significantly reduced, they were able to turn over freely during bed rest, and the length of the affected limb was restored to that of the healthy limb. Thirty-four (94.5%) patients were satisfied with the reduction of the fracture end, 2 (5.5%) patients with tibiofibular fractures showed angular displacement of the fractured end and satisfactory reduction after the position of the bone traction needle was adjusted; 7 (19.5%) patients developed deep vein thrombosis of the affected lower limb during traction; there was no decubitus or vascular nerve injury, and the overall complication rate was 25% (9/36). All the patients and their families were satisfied with the results of this treatment.ConclusionThe aim of this study is to introduce a new type of traction device. It is advantageous in that it is light weight, low cost, easy to assemble, promotes immediate movement of the affected limb after assembly, improves patient comfort and can be used with a titanium steel needle for MRI examination under traction. In the clinical setting, it has been shown to be suitable for the temporary treatment of patients with lower leg fractures prior to surgery, particularly patients who, for various reasons, require nonsurgical treatment in the short term.

Influence of the initial charge on the triboelectrification of millimeter size set of particles in an inclined tube

In this paper, the triboelectric charge buildup on a set of initially charged particles is investigated. During the study, 30 g of charged polypropylene particles of 2–3 mm size were repeatedly passed through a 1 m inclined copper or polyvinylchloride (PVC) tube. At the tube output, the charge is measured after each passage, allowing the cumulative charge evolution over time to be measured. The obtained curves are fitted to an exponential model to extract the time constant of the process. For each experience, particles are first charged at different levels and polarities relatively to the presumed saturation charge using both corona discharge and triboelectricity. The obtained results show that the initial charge value and polarity strongly affect the subsequent triboelectricity variations as well as the process speed. The triboelectric charge evolution is mainly related to the ratio between initial charge (Q0) and saturation charge value (Qs). Therefore, the particle's charge will increase if Q0 < Qs, decrease if Q0 > Qs, or be maintained at the same level when Q0 ≈ Qs. The particles can change polarity and be recharged with the opposite sign according to the tube and the initial charge level. This triboelectric charge behavior is explained based on the surface energy state in the electron transfer model. Furthermore, increasing the particles quantity from 5 g to 60 g reduces the saturation charge from 11 nC/g to 2.5 nC/g, which is approximately 77% less. Surface potential distribution measurements show an uneven distribution with less charge in large amounts compared to lower amounts.

In Vitro Thrombogenicity Testing of Biomaterials in a Dynamic Flow Loop: Effects of Length and Quantity of Test Samples.

The results of in vitro dynamic thrombogenicity testing of biomaterials and medical devices can be significantly impacted by test conditions. To develop and standardize a robust dynamic in vitro thrombogenicity tool, the key test parameters need to be appropriately evaluated and optimized. We used a flow loop test system previously developed in our laboratory to investigate the effects of sample length and the number of samples per test loop on the thrombogenicity results. Porcine blood heparinized to a donor-specific target concentration was recirculated at room temperature through polyvinyl chloride (PVC) tubing loops containing test materials for 1 h at 200 mL/min. Four test materials (polytetrafluoroethylene (PTFE), latex, PVC, and silicone) with various thrombotic potentials in two sample lengths (12 and 18 cm) were examined. For the 12-cm long materials, two different test configurations (one and two samples per loop) were compared. Thrombogenicity was assessed through percent thrombus surface coverage, thrombus weight, and platelet count reduction in the blood. The test system was able to effectively differentiate the thrombogenicity profile of the materials (latex > silicone > PVC ≥ PTFE) at all test configurations. Increasing test sample length by 50% did not significantly impact the test results as both 12 and 18 cm sample lengths were shown to equally differentiate thrombotic potentials between the materials. The addition of a second test sample to each loop did not increase the test sensitivity and may produce confounding results, and thus a single test sample per loop is recommended.