This study investigated the individual variability in oral tactile sensitivity considering touch, by means of Von Frey Hair monofilaments (VFH) and spatial resolution, using the grating orientation ...test (GOT). The relationships of the two measures with 6‐n‐propylthiouracil (PROP) responsiveness and fungiform papillae density and size were investigated. One hundred and forty‐four subjects (48.6% women, aged 18–30) participated in the study. VFH and GOT thresholds were assessed by three‐down/one‐up staircase method. Responsiveness to 3.2 mM PROP was assessed on the general Labeled Magnitude Scale. Fungiform papillae density (FPD) and size were determined from automated counting. VFH thresholds appeared unsuitable to reveal individual variation in responsiveness to point‐pressure on the tongue. The frequency of GOT thresholds approximated a normal distribution and covered the whole range of variation, thus indicating an ability to measure individual variation in oral tactile sensitivity. No significant linear correlations were found between any of the oral tactile sensitivity measures and PROP responsiveness, FPD total and size class. VFH and GOT thresholds were not significantly associated. Agglomerative hierarchical clustering was used to classify participants for their PROP responsiveness, total FPD and GOT threshold. Three clusters were identified, C1 (n = 67), Cl2 (n = 42), and Cl3 (n = 35), differing for PROP responsiveness and FPD only. Results encourage future studies to explore association between GOT and both perception and preference for different food texture. Furthermore, deeper investigation of individual variability in sensitivity to different types of oral tactile stimuli would be helpful to capture differences in tactile sensitivity among the most sensitive individuals.
Submerged waterjets often yield low coal-breaking efficiency and have limited permeability. This study introduced a novel approach to enhance submerged waterjets by harnessing the annular fluid ...hydraulic energy of a borehole. A new waterjet modulator was developed using large eddy simulation (LES) combined with the response surface method (RSM). The reliability of the method was verified by submerged waterjet high-frequency pulsation pressure test experiments. The results indicated that the pulsation amplitude of the annular fluid enhanced self-excited oscillation pulsed waterjet (AFESOPW) was 330.05%, 45.17%, and 32.56% higher than those of the continuous waterjet, self-excited oscillation pulsed waterjet (SOPW), and pre-optimized waterjet, respectively. Additionally, the pulsating pressure peak increased by 42.84%, 19.60%, and 25.81%, respectively. Under the submerged condition, the outlet pulsating pressure peak of the AFESOPW was 1.32–1.58 times the inlet pressure. The self-priming annular fluid weakened the hinderance of the submerged environmental pressure and enhanced the waterjet pulsation effect.
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•A novel approach to enhance the submerged waterjet was proposed.•The mechanism of self-priming pressurization was revealed.•A new waterjet modulator optimization method was formed.•A new submerged waterjet pulsating pressure test system was developed.
During the manufacturing of composite pressure vessels, the fiber tension of the filament winding process has an important influence on the mechanical properties as well as on the gravimetric ...efficiency of the structure and is therefore investigated within this paper. Three series of samples were manufactured and tested: A) steel liners as reference, B) composite vessels with low fiber tension of 3 N, and C) vessels with high fiber tension of 80 N. The manufacturing process is discussed in this paper with special focus on the parameter of fiber tension and its related challenges. Burst tests with strain measurements and acoustic emission (AE) were conducted, and a statistical analysis of the results is presented. Additional numerical investigations on the structural behavior of the vessels and effect on the gravimetric efficiency are performed to support the experimental result. The investigations show that the increase in fiber tension induced compressive stress on the steel liner, leading to an increase in burst pressure and influence on AE. Furthermore, the fiber volume fraction (FVF) of the composite laminate increased due to increased fiber tension, resulting in higher mechanical properties and an improvement in gravimetric efficiency.
Background: The inflammatory process represents a specific response of the organism’s immune system. More often, it is related to the rising pain in the affected area. Independently of its origin, ...pain represents a complex and multidimensional acute or chronic subjective unpleasant perception. Currently, medical doctors prescribe various analgesics for pain treatment, but unfortunately, many of them have adverse effects or are not strong enough to suppress the pain. Thus, the search for new pain-relieving medical drugs continues. Methods: New tetrapeptide analogs of FELL with a generaanalgesic-Glu-X3-X4-Z, where X = Nle, Ile, or Val and Z = NH2 or COOH, containing different hydrophobic amino acids at positions 3 and 4, were synthesized by means of standard solid-phase peptide synthesis using the Fmoc/OtBu strategy in order to study the influence of structure and hydrophobicity on the analgesic activity. The purity of all compounds was monitored by HPLC, and their structures were proven by ESI-MS. Logp values (partition coefficient in octanol/water) for FELL analogs were calculated. Analgesic activity was examined by the Paw-pressure test (Randall-Selitto test). Results: The obtained results reveal that Leu is the best choice as a hydrophobic amino acid in the FELL structure. Conclusions: The best analgesic activity is found in the parent compound FELL and its C-terminal amide analog.
International dysphagia diet standardisation initiative (IDDSI) is the most recent guideline for categorising texture modified food for people with dysphagia. Level 6 of the IDDSI guideline is known ...as soft & bite-sized, and the fork pressure test is the recommended test for this level. However, the result of this test is affected by the choice of fork and testing conditions. Therefore, the objective of this study was to mimic the standard IDDSI fork pressure test using a texture analyser with instrumentally controlled testing conditions. The data and observations made from the fork pressure test obtained using the texture analyser, correlated well (r = 0.948) with the those obtained from the standard IDDSI fork pressure test. The main effects for all testing conditions (food, crosshead speed, crosshead rest time, and sample position) had a significant effect (P < 0.05) on all three force-time curve parameters of the texture analyser except for crosshead rest time for the negative area (P = 0.116) and positive distance (P = 0.127), and crosshead speed for a positive distance of the curve (P = 0.069). The use of a texture analyser, with the protocol we developed, mimics the standard IDDSI test and it can be a more reliable alternative for industrial use and research purposes, to test foods designed for dysphagia sufferers.
•IDDSI fork pressure test mimicked using texture analyser with controlled conditions.•Instrumental fork pressure test correlated with the standard IDDSI test.•Positive area of the force-time curve explained differences of testing conditions.•This method is a reliable alternative to test foods designed for dysphagia sufferers.
The stringent safety regulations of type IV composite overwrapped pressure vessels (COPVs) for commercial vehicles mandate a certification process involving pressurization up to 1050 bar, with the ...critical requirement of withstanding burst pressures of 1570 bar. Analyzing proof test data is crucial to enhance and ensure tank safety regarding burst pressure. In this study, we developed various machine learning classifiers for structure health monitoring and damage prediction of COPVs. The classifiers were trained using a substantial amount of acoustic emission data collected during burst and pressure cycling tests. The test results were employed as label inputs during the training process. Statistical features were extracted per time unit and trained using Naive Bayes, Logistic Regression, Decision Tree, XGBoost, and TabNet models. Upon training the data collected from the burst pressure test, TabNet, Decision Tree, and XGBoost achieved classification accuracies above 0.94. Notably, TabNet demonstrated also the best performance for the pressure cycling test with an accuracy of 0.98. Furthermore, TabNet provided visualizations of feature sensitivity in relation to classification results. This study marks the first development of a machine learning classifier for predicting the damage state of COPV tanks in commercial applications pertaining to required safety tests.
•Development of ML classifier for burst pressure prediction of COPVs.•Training of the classifier using AE data collected during pressure tests.•Application and comparison of various ML models to develop the classifier.•TabNet provided visualizations of feature sensitivity in relation to results.
Wind tunnel tests have become one of the most effective ways to evaluate aerodynamics and aeroelasticity in bluff bodies. This paper has firstly overviewed the development of conventional wind tunnel ...test techniques, including high frequency base balance technique, static synchronous multi-pressure sensing system test technique and aeroelastic test, and summarized their advantages and shortcomings. Subsequently, two advanced test approaches, a forced vibration test technique and hybrid aeroelastic- force balance wind tunnel test technique have been comprehensively reviewed. Then the characteristics and calculation procedure of the conventional and advanced wind tunnel test techniques were discussed and summarized. The results indicated that the conventional wind tunnel test techniques ignored the effect of structural oscillation on the measured aerodynamics as the test model is rigid. A forced vibration test can include that effect. Unfortunately, a test model in a forced vibration test cannot respond like a structure in the real world; it only includes the effect of structural oscillation on the surrounding flow and cannot consider the feedback from the surrounding flow to the oscillation test model. A hybrid aeroelastic-pressure/force balance test technique that can observe unsteady aerodynamics of a test model during its aeroelastic oscillation completely takes the effect of structural oscillation into consideration and is, therefore, effective in evaluation of aerodynamics and aeroelasticity in bluff bodies. This paper has not only advanced our understanding for aerodynamics and aeroelasticity in bluff bodies, but also provided a new perspective for advanced wind tunnel test techniques that can be used for fundamental studies and engineering applications.
Introduction
With a rising number of bariatric procedures, the absolute number of postoperative complications is increasing, too. Postoperative bleeding, particularly along the staple line, is a ...recognized challenge. Numerous strategies including reinforcement of the staple line (SLR) have been proposed to improve bleeding rates, but no single technique has shown superiority over the others. In our bariatric center, we have implemented intraoperative blood pressure regulation alone, without SLR, to reduce hemorrhagic complications postoperatively.
Methods
This retrospective observational analysis compares the incidence of postoperative bleeding in two groups of consecutive patients (total
n
= 438 patients), one with and one without intraoperative blood pressure elevation to 150 mmHg systolic without the additional use of staple line reinforcement. This intervention was integrated into our standard bariatric surgical procedure, no randomization or matching was conducted. Significant postoperative bleeding was defined as drop of hemoglobin of more than 2.5 mg/dl in 48 h and one of the following symptoms: lactate ≥ 2 mmol/L, bloody drainage, quantity of drainage more than 200 ml and/or radiological signs.
Results
Defined postoperative bleeding occurred in 33 (7.5%) patients. We observed a decrease in bleeding rates from 10% to 5% (
n
= 22 vs.
n
= 11) after introducing intraoperative blood pressure increase (
p
= 0.034). The rate of revisional surgery for bleeding also decreased from 2.7% to 0.5% (
n
= 6 vs.
n
= 1). In multivariate analysis, the intervention with blood pressure elevation showed a significant decrease on bleeding rates (
p
= 0.038).
Conclusion
The use of increased intraoperative blood pressure alone, without staple line reinforcement, appears to be an effective and suitable method for reducing post-bariatric hemorrhagic complications.
Graphical Abstract
North Sulawesi has one large dam located in Pindol Village, Lolak District. The research objective was to determine the lithology of the bedrock of dam foundation, rock class, and subsurface ...permeability of the dam. The method used in this research is core logging analysis and water pressure test. The bedrock foundations of the dam consist of andesite units, shale units, sandstone units which are included in the Sedimentary Facies Tinombo Formation and Volcanic Tinombo Formation. The formations are included in the Eocene to Early Oligocene Eocene and deposited in the deep marine environment. The foundation rock class is predominantly CM class (rather soft and fairly weathered rock), the rock quality of design is poor-medium characterized by the presence of broken cores and easily crushed in some parts. Lolak Dam has 6 permeability zones, namely very high, high, medium, moderate, low, and very low permeability with an average lugeon value of 4.43 liters/minute. The standard of lugeon value for the dam foundation is Lu3, so it is necessary to repair the drill points on the pilot hole which has a lugeon value of 3 (low, moderate, medium, high, and very high permeability zones) to increase the capacity foundation rock.
The aim of this paper is the multiscale investigation of composite pressure vessel structures wound with varying fibre tension. The paper explores the potential of ”programming” the fibre tension ...force during the winding process of a high pressure hydrogen storage vessel. Two series of vessels were wound with two different tensions: Two series of vessels wound with forces of 3 N and 80 N respectively were experimentally investigated. Other technological factors, such as the type and weight of carbon fibre used, were kept constant throughout the study. Quasi-static burst tests were used to measure the elastic deformation of the vessel surface. Microscopic studies were also carried out to analyse the structure of the composite at different length scales. The fibre content, the geometric parameters of the voids and the distribution of the three main components of the composite – carbon fibre, technological defects and resin – were also determined. Representative RVE elementary cells were generated for both materials using statistical modelling. The composite was then homogenised and elasticity matrices were obtained for the fibre tensile forces in both materials.
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