Average Angle Research Articles

Uniaxial Molecular Alignment in Thin Films Composed of Discrete NDI‐T2 Oligomers Investigated by Variable‐Angle Spectroscopic and Imaging Ellipsometry

The understanding of the optical characteristics and the influence of thermally induced crystallization is vital to evaluate newly synthesized organic semiconductors for their potential applications. Variable‐angle spectroscopic ellipsometry (VASE) is employed to determine the complex dielectric function of two recently developed discrete oligomers based on naphthalene diimide (NDI) and bithiophene (T2), applying an anisotropic optical model. It is shown that the as‐cast films are optically near‐isotropic, while the annealed films exhibit pronounced anisotropies with respect to the orientation of the π−π* transition. Differences between the two distinct molecules are observed and discussed. The degree of optical anisotropy is quantified using the average molecular orientation angle φ, associated with the orientation of the π−π* transition dipole, and the related orientation order parameter S. The molecules are shown to form crystallites of several microns in size upon annealing. Imaging ellipsometry is thus additionally employed to study their optical anisotropy on a microscopic scale, and the agreement with results from macroscopic measurements is evaluated.

Real-Time Forward Head Posture Detection and Correction System Utilizing an Inertial Measurement Unit Sensor

Forward head posture (FHP) has become a prevailing health issue in modern society as people spend more time on computers and smartphones. FHP is a posture where the head is forward and the anterior and posterior curvatures of the lower cervical and upper thoracic spines are both, respectively, exaggerated. FHP is often associated with neck pain, bad static balance, and hunched shoulders or back. To prevent this, consciously maintaining good posture is important. Therefore, in this study, we propose a system that gives users real-time, accurate information about their neck posture, and it also encourages them to maintain a good posture. This inexpensive system utilizes a single inertial measurement unit sensor and a Raspberry Pi system to detect the changes in state that can progress to an FHP. It retrieves data from the sensor attached to the user’s cervical spine to indicate their real-time posture. In a real-world office environment experiment with ten male participants, the system accurately detected the transition to the FHP state for more than 10 s, with a delay of less than 0.5 s, and it also provided personalized feedback to encourage them to maintain good posture. All ten participants recognized that their average craniovertebral angle had to be increased after receiving visual alerts regarding their poor postures in real time. The results indicate that the system has potential for widespread applications.

Foliar solution hydrophobicity influenced by plant species, product, and concentration

AbstractFoliar application of nutrients and pesticides is a popular practice for plant maintenance and weed control. Understanding how different products and adjuvants interact with the intended plant leaf surface will improve uptake and decrease losses. Various fertilizer, adjuvant, and pesticide solutions were tested to determine solution hydrophobicity on St. Augustinegrass, tall fescue, and white clover. A 1 µL droplet of each solution was placed on the adaxial leaf surface and imaged with a stereomicroscope to determine average solution contact angle. For all solutions groups, plant species had the most consistent effect, with white clover having the highest average contact angle followed by St. Augustinegrass and tall fescue, respectively. All product solutions significantly reduced the average contact angle compared to water. The urea solution resulted in the largest decrease for the fertilizer group at 7.6%. The largest decrease was found with the siloxane nonionic surfactant, which resulted in a decrease of 87.5% compared to water alone. Significant interactions were found between plant species and product solutions, indicating product solutions interact differently dependent upon the leaf surface characteristics. The results suggest that plant leaf surface, product solution and concentration, and their combination should be accounted for to increase wettability of a foliar application and improve product absorption.

A novel subsurface damage model in diamond wire sawing of silicon wafers

The subsurface damages (SSDs) generated during fixed abrasive diamond wire sawing (DWS) of silicon wafers can reduce the fracture strength and increase the breakage probability of these wafers. It is crucial to accurately evaluate these SSDs. A theoretical model of SSD depth is developed for the fixed abrasive DWS of silicon wafers considering the size effects of material properties, micro-geometries of abrasive grits, and inclination/interaction effects of subsurface cracks. A series of silicon wafers are processed, and the silicon material properties, diamond wire parameters, and surface/subsurface morphologies of silicon wafers are measured. The model is experimentally validated and then used to study the effects of processing parameters on inclination/interaction effects, cutting behaviors, and SSDs. The results show that the model has a relative error of less than 5.0% after revealing that the inclination/interaction parameters, cutting behavior parameters, and SSD depth almost follow a normal distribution, with a maximum distribution probability ranging from 30% to 50%. The average inclination angle is approximately 30°, the average cutting depth is in the range of one to two hundred micrometers, the average load is a few millinewtons, and the SSD depth is in the range of a few micrometers. With an increasing density of abrasive grit, a decreasing feed rate, or an increasing wire speed, the interaction effect becomes more pronounced, while the inclination angle, cutting depth, load, active grit ratio, and SSD depth decrease. When the protrusion height increases, or the half sharpness angle or tip radius of abrasive grit decreases, there is an increase in the cutting depth, load, active grit ratio, or SSD depth. The inclination angle decreases as the protrusion height, half sharpness angle, or tip radius increases. This research helps to understand the cutting mechanism and evaluate the SSDs during the DWS of silicon wafers.

Design and stability performance optimization of a novel hybrid inspection robot walking device for smart grid applications

Inspecting in high-altitude windy environments requires maintaining a stable attitude to avoid significant oscillations, which is a crucial factor in advancing the use of hybrid power transmission line inspection robots (PTLIRs) in real-world scenarios for the electrical power and energy industry. We developed and optimized a novel walking device to improve the safety of hybrid PTLIRs operating in strong wind conditions. First, we investigate the operational conditions of transmission line inspection and design a walking device capable of transporting a flight device to be suspended under the line for inspection purposes. Second, a force equilibrium analysis is performed to explore the relationship between the key structural parameters of the walking device and the wind-induced deflection of the robot. A multiobjective optimization model is formulated to minimize the maximum deflection angle of the robot along three axes under wind loads. Finally, an optimization algorithm, using an improved non-dominated sorting particle swarm optimization (NSPSO) approach, is proposed to solve the model with good global search ability and fast convergence speed. A test platform is constructed to collect the wind deflection angle of a self-developed hybrid PTLIR under the transmission line. The test results demonstrate that the walking device can carry 30 kg to move along the transmission line. The average deflection angle of the robot around the Z axis is the highest under the influence of wind force level 7 (wind speed of 15.5 m/s) perpendicular to the windward surface of the robot. After optimization, the maximum deflection angle is limited to 10.38°, aligning within safety thresholds. The optimization algorithm effectively reduces the maximum deflection angles around the X, Z, and Y axes by 33.19 %, 39.21 %, and 13.23 %, with minimal average errors of 2.40 %, 3.87 %, and 2.13 %, respectively. The research in this paper can solve the bottleneck problem of robot practicality, which has important theoretical significance and practical application value for the safety, stability, and intelligent operation and maintenance management of power transmission lines.

Exploiting the land use to predict shallow landslide susceptibility: A probabilistic implementation of LAPSUS-LS

Due to the significant role of land use on the occurrence of rainfall-induced shallow landslides, this factor is commonly employed as a landslide susceptibility predictor. However, the land use classification is oftentimes very broad, neglecting the proven mechanical and hydrogeological role of the land management on slope stability. Given the necessity of including spatially distributed and management-specific inputs, the process-based landscape evolution model LAPSUS-LS was chosen and adapted to achieve a probabilistic approach which takes into account land management as an input by adopting management-specific values of root cohesion. The model was applied to four test sites in the Oltrepò Pavese (Italy), where different vineyard management techniques play a significant role in triggering landslides. The results for the four test areas had, cumulatively, an Area Under the Roc curve greater than 0.73, with false negative cells being < 1 % of the total for all simulations. In the model’s application, land use practices characterised by higher root cohesion proved to benefit slope stability, whereas tilled vineyards, shrublands and abandoned vineyards were more prone to the formation of shallow landslides. In addition, we found that the inclusion of management-specific input parameters produced more accurate outputs and that in catchments characterised by average slope angles lower than 15°, varying the vineyard management, did not appear to affect the landslide susceptibility. Due to the model’s high dependency on the land use and its ability to include land management, it can take into account the spatial variability of input values such as the root cohesion. Additionally, it can be applied i) to manage current conditions, ii) to explore future land use change, iii) to study less invasive yet beneficial land use management change scenarios and iv) provide farmers of at-risk areas insight on how to improve slope stability.

Comparing repeated end range movements and Kinesio taping effects on head and neck movement pattern and discomfort in smartphone users

IntroductionUsing smartphones has increased exponentially, especially after the COVID-19 pandemic. However, there is a relationship between neck flexion angle during working with a smartphone and neck musculoskeletal disorders. Therefore, this study compares the effect of Kinesio taping and Repeated End Range Movements (RERM) on head and neck flexion angles changes during texting and discomfort after texting with a smartphone. MethodTwenty-four smartphone users participated in this cross-over study. All of 24 subjects were experimented with the control, RERM and taping conditions. They filled Numeric Rating Scale questionnaire before and after 30 min of texting. In addition, their head and neck flexion angles were measured during the task by photogrammetry. ResultsIn the RERM group, individuals felt significantly less discomfort than the control group after the task (P = 0.032). Although the slope of average head and neck flexion angles linear regression lines of all the three groups was positive before the break time, it became negative in the taping and control groups after the break time. In addition, the linear regression of average head and neck flexion angles of the RERM group was significantly different (P < 0.001). ConclusionRERM can effectively maintain normal head and neck movement pattern during and reduce neck discomfort after texting on smartphone.

The impact of spheno-occipital synchondrosis exposure via extended endoscopic endonasal surgery on midface growth in pediatric patients.

Pediatric extended endonasal procedures pose significant surgical challenges. Lesions from the suprasellar region to the lower clivus necessitate extensive exposure. This study examined whether drilling the spheno-occipital synchondrosis (SOS) to remove the posterior clinoid process and dorsum sellae (DS) for greater exposure affects pediatric midfacial growth. From 2014 to 2020, the authors performed endoscopic endonasal surgery (EES) in 14 patients aged 12 years or younger. The lesions consisted of 11 cases of craniopharyngioma, 1 pituitary neuroendocrine tumor, 1 Rathke's cleft cyst, and 1 Langerhans cell histiocytosis. In 8 of the 14 cases, an extended EES procedure was used by exposing the SOS to remove the posterior clinoid process and DS. Measurement of the central face was based on head MRI before and after surgery. Measuring points were the sellae-nasion (SN) plane, the foremost points of the anterior maxilla (point A), and the maximum concavity point of the mandibular symphysis (point B). The authors measured and evaluated the SNA angle (angle created by the SN plane and the NA [a line connecting point A and the nasion] plane), SNB angle (angle created by the SN plane and the NB [a line connecting point B and the nasion] plane), and the ANB angle (angle created by the NA plane and the NB plane). In addition, a comparison was made with 6 pediatric cases in which transcranial surgery was performed for craniopharyngiomas. In the extended EES group, the average preoperative age was 7 years, and the average postoperative age was 12 years. Mean preoperative angles in this group were 84° (SNA), 80.9° (SNB), and 3.1° (ANB); mean postoperative angles were 83.5° (SNA), 83.9° (SNB), and -0.4° (ANB). In the standard EES group, the average preoperative age was 9 years, and the average postoperative age was 14.5 years. Average preoperative angles in the standard EES group were 83° (SNA), 80.3° (SNB), and 2.7° (ANB); average postoperative angles were 82.7° (SNA), 81° (SNB), and 1.6° (ANB). In the transcranial surgery group, the average preoperative age was 4.5 years, and the average postoperative age was 9.8 years. Mean preoperative angles were 83.8° (SNA), 80.3° (SNB), and 3° (ANB); mean postoperative angles were 83.8° (SNA), 82.6° (SNB), and 1.2° (ANB). The only significant difference between groups was the postoperative ANB angle, which was negative in the extended EES group compared to the standard EES group, indicating the maxilla was positioned posteriorly compared to the mandible. The measurement values of the EES groups and the transcranial surgery group exhibited minimal differences, except for a significant decrease in the postoperative ANB angle in the extended EES group compared with the standard EES group. These results show that extended EES may impact midface growth. Further research is required to understand the long-term impact of SOS exposure.

Influence of tidal asymmetry on local scour near the offshore platform

An in-situ mooring measurement was conducted using a profiling sound of navigation and ranging (SONAR) system to reveal the influence of tidal asymmetry on the local scour near an artificial offshore platform, Southwest Offshore Windfarm Complex, Korea. During the mooring period, the flood tide was significantly dominated by positive tidal duration asymmetry and skewness. The lengths of scour hole were 9.8m and 5.1m along the flood and ebb directions, respectively. Flood-dominated currents intensified the horseshoe vortex, resulting in an approximately 10% deeper scour hole on the flood face than the ebb face. The periodic occurrence of bidirectional currents generated vortices that facilitated the mixing and redistribution of seabed sediments, forming a gentle slope within the scour hole. The average slope angles ranged from 14° to 16° on the flood face and 6° to 8° on the ebb face. Despite the strong influence of local scour, variations in scour depth (Ds) consistently remained around −2.15m, suggesting the exposure of the underlying consolidated sediment layer. During the intermediate period from spring to neap tide, the Ds on the lower slope of scour hole increased by 0.12m, while it decreased by 0.11m from neap to spring tide, suggesting that the net Ds gradually approached zero over the tidal cycle. These findings underscore the importance of understanding tidal impacts on the local scour morphology to enhance the stability and design of offshore wind turbine foundations.

Acoustic emission monitoring of a large-scale 50-year-old prestressed concrete bridge girder during an eccentric three-point bending test

Deterioration of reinforced and prestressed concrete structures is one of the main challenges in structural engineering. As the majority of our infrastructure is built around 1960-1980, most structures have reached or will soon reach their design lifetime, giving rise to more structural problems and costs in the coming decades. It is therefore important to develop efficient assessment schemes allowing to assure the safety and reliability of these existing structures and to estimate their residual lifetime. Within the framework of the Bridge|50 research project, a 50-year-old prestressed concrete bridge showing signs of corrosion damage was decommissioned. The bridge girders were recovered and have been subjected to large-scale load tests with varying loading patterns. This paper presents the results acquired during acoustic emission (AE) monitoring of one of the I-shaped girders during a monotonic three-point bending test with an eccentric point load. The results show that the failure mode and location could be detected based on AE activity and zonal AE localization. The onset of concrete cracking was observed by a decrease in peak frequency of the AE signals. Average frequency (AF) and rise angle (RA) value analysis was used to characterize the crack mode, which shifted from tensile to shear mode during bending.

Debridement and Bone Graft Fusion via the Lateral Extracavitary Approach Combined with Lateral and Posterior Screw-rod Fixation in the Treatment of Thoracic Spinal Tuberculosis: A Retrospective Study of 38 Cases

ObjectivesThoracic spinal tuberculosis (TB) is still common, and surgical treatment can rapidly relieve pain, correct deformity, reduce bone loss and prevent further damage to neurological function. We have practiced an efficient and safe surgical method. MethodsFrom January 2013 to April 2021, 38 patients with thoracic spinal TB were included in our study. Debridement and bone grafting were performed via the lateral extracavitary approach, combined with two different fixation methods. Data from these cases were analyzed retrospectively. ResultsFor all cases, the C-reactive protein (CRP) level and erythrocyte sedimentation rate (ESR) of all the patients decreased to normal levels at the last follow-up. The average visual analog scale (VAS) score was 7.5±1.6 preoperatively and 0.6±0.8 at the last follow-up, showing a significant reduction. The average angle of kyphosis correction was 6.3±4.7°, and the loss of correction was 1.4±1.6°. Neurological function was significantly improved in all cases according to the American Spinal Injury Association (ASIA) classification. Solid fusion was observed in all cases at the last follow-up. ConclusionsDebridement and bone graft fusion via the lateral extracavitary approach combined with two fixation methods can be very effective in the treatment of thoracic spinal TB.

Computer modeling and validation testing for glenoid component rotation and optimal glenoid screw angles for reverse shoulder arthroplasty in an Asian population.

Good initial fixation of glenoid component for reverse total shoulder arthroplasty (RTSA) relies on component placement and screw purchase in the scapula bone. This is especially difficult in an Asian population with small glenoid geometry. Optimal glenoid component roll angle and screw angulation to achieve the longest screws for best fixation has not been defined in the current literature. Computer 3D modelling of 133 scapulas with RTSA performed were analyzed to determine patient specific optimal glenoid roll angle (GRA) for the longest bi-cortical screws attainable. The cranial-caudal angle (CCA), anterior-posterior angle (APA) and lengths for the superior and inferior screws were measured. Validation testing using calculated average (CA) angles and rounded average (RA) angles to the nearest 5 degree were recomputed for each case to determine the bi-cortical screw lengths achievable. The CA and RA screw lengths were compared against patient specific modelling using paired-sample t-tests. Average GRA was - 1.6°, almost perpendicular to the long axis of the glenoid and achieves an average bi-cortical screw length of 51.3mm and 45.5mm for the superior and inferior screws respectively. The CCA and APA were 9.1° cranial and 6.5° posterior for the superior screw and screw angulation of 11.2° caudal and 0.7° anterior for the inferior screw. Validation testing shows statistically shorter screw lengths in the CA and RA models compared to patient specific modelling (p < 0.01). Validation testing with average angles for GRA, CCA and APA demonstrates strong patient heterogeneity and anatomical variation. Despite this, screw lengths attainable in the RA group were > 38mm with good safety profile. Surgeons may consider the additional use of navigation-assisted, or 3D printed patient specific instrumentation to optimize baseplate and screw configuration for RTSA.

Evaluating the efficacy of uniformly designed square mesh resin 3D printed scaffolds in directing the orientation of electrospun PCL nanofibers

Replicating the architecture of extracellular matrices (ECM) is crucial in tissue engineering to support tissues’ natural structure and functionality. The ECM’s structure plays a significant role in directing cell alignment. Electrospinning is an effective technique for fabricating nanofibrous substrates that mimic the architecture of extracellular matrices (ECM). This study aims to evaluate the efficacy of resin 3D-printed scaffolds made from a low-conductivity material (i.e., a resin composed of methacrylated oligomers, monomers, and photoinitiators) in directing the alignment of electrospun polycaprolactone (PCL) nanofibers. Six 3D-printed scaffolds were fabricated using stereolithography (SLA) technology and strategically positioned on an aluminum foil collector plate during electrospinning. The structured geometry of the scaffolds, rather than the local electric field distribution, is hypothesized to guide nanofiber alignment. Images acquired through the scanning electron microscopy (SEM) were used to analyze and statistically quantify the nanofibrous scaffolds to evaluate the alignment of nanofibers over the scaffolds compared to a set of randomly deposited control nanofiber samples in the absence of the 3D printed scaffolds. SEM images also showed significant alignment of nanofibers within the pores of scaffolds, using histograms as a means for indicating the distribution of orientation angles. Statistical analysis revealed that this distribution deviates from normality due to the deviations in the tails and the existence of relatively smaller peaks at angles relative to 0°, particularly within a range of ± 50° and ± 40°. It is further found that the average peak orientation angle relative to 0° had a maximum probability of 0.014. Furthermore, the statistical analysis confirmed the distribution and significant differences in orientation between test samples with 3D-printed scaffolds and control samples. These findings demonstrate the effectiveness of resin 3D-printed scaffolds, particularly their geometric filtering effect, leading to controlled nanofiber alignment, which is proposed to be beneficial for enhancing cell adhesion, proliferation, and cell migration in tissue engineering applications.

INVESTIGATION OF WETTABILITY, ANTIBACTERIAL ACTIVITY, THERMAL INSULATION, AND MECHANICAL CHARACTERISTICS OF ELASTOMER BLEND ADHESIVES WITH HIGH-DENSITY FIBERBOARD WOOD AND ALUMINUM

Attention has recently been given to finding alternative and sustainable raw material sources for wood and metal adhesives, such as polyvinyl alcohol (PVA), corn starch (CS), arabic gum (AG), and dextrins (D). Modifying polymer dispersion using unique substances, such as modifying reactive elastomer liquid (EL) using PVA, CS, AG, or D results in sufficiently moisture-resistant adhesive joins. In the present study, the physical characteristics of EL/blended with the natural polymers PVA, CS, AG, and D, based on high-density fiberboard (HDF) wood and aluminum (Al) adhesives and coatings, were investigated and compared to those of pure EL. The EL was blended with PVA, CS, AG, or D at a ratio of 60/40 (w/w) to form EL/blends. The chemical structures, surface and interface morphology, adhesion strengths (including shear strength and pull-off strength), surface roughness, wettings, color intensity, and thermal insulation of the prepared EL and EL/blends were investigated. A scanning electron microscopy (SEM) investigation confirmed filler dispersion and adhesion between the blends, and coated HDF wood, or Al. The developed EL/AG blend had a pull-off strength of 144±5 and 102±3 MPa and a shear strength of 771±11, and 52±3 N with HDF wood and Al substrate, respectively. The EL/PVA blend had a maximum surface roughness value 4.57 µm, and its average water contact angle (WCA) was 85.6°. A plasma jet was used to treat the surface roughness and hence the wettability of the pure EL and the EL/blends, for example, plasma treatment decreased the roughness of the EL/AG blend from 4.36 to 3.28 μm. WCA, and hence wettability, was also significantly influenced by plasma treatment, for example, plasma treatment decreased the WCA of the pure EL from 71.7±0.4° to 30.7±0.7°. The lightness value of the EL/blends was less than that of the pure EL, indicating that (the color adhesives have darkened). Similarly, the yellowness-blueness and redness-greenness values of the EL/blends were greater than those of the pure EL,( rendering the blended adhesives more reddish and bluish). The EL/AG blend was found to have a minimum thermal conductivity (of 0.27 W/m.K), indicating maximum insulation.

Investigation on in-situ tensile behaviors of 6061 aluminum alloy fabricated by wire additive friction stir deposition

Rod based additive friction stir deposition (R-AFSD) offers unique advantages for the integrated manufacturing of aluminum alloy near-net-shape large parts. However, the deposition process often faces issues like thick ends of raw material rods and difficulties in continuous feeding. In this study, wire based additive friction stir deposition (W-AFSD) was used for the solid state deposition of 3 mm diameter 6061 aluminum alloy wire. The microstructure evolution and mechanical properties of the deposit along the build direction were systematically characterized, clarifying the recrystallization mechanism and isotropy of the mechanical properties. In-situ scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) were used to study the deformation behavior of the deposit during in situ tensile testing, revealing a cooperative deformation mechanism involving grain rotation and intragranular slip. Results show that during in-situ tensile testing, the average rotation angle of five selected grains is 6.90°. Additionally, deposits with numerous grain boundaries due to recrystallization can hinder dislocation movement and pin the slip system within the grains during tensile testing. Due to the synergy of these mechanisms, the yield strengths of the longitudinal and transverse samples of the deposit are 183 MPa and 190 MPa, respectively, much higher than previously reported values. This article introduces a new solid state additive manufacturing method, offering new insights for efficient, high-strength continuous additive manufacturing of aluminum alloys and their deformation mechanisms.

Characterization of extracted alpha cellulose from Manihot esculenta (cassava) peels as formulation aid for paracetamol tablet

Background: Alpha-cellulose as a pharmaceutical excipient can be employed as a binding agent in tablet formulation. Cassava peels husk are waste agricultural material and is being investigated for its α-cellulose for use in oral solid pharmaceutical formulation. Purpose: The objective of this study is to extract α-cellulose from cassava peels agro-industrial waste using a standard method, subject the extracted cassava peels cellulose and determine its phytochemical and physicochemical properties of formulated granules of paracetamol. Methods: Alpha-cellulose from cassava peel was extracted using alkali method. The fresh peels were prepared, milled into slurry and de-watered to obtain a coarse wet material, dried, milled and sieved to obtain very fine powdered particles. Phytochemical analysis and characterization of extracted α-cellulose powder were determined. Differential scanning calorimetry (DSC), scanning electron micrographs (SEM), and x-ray diffractogram (XRD) analysis of extracted cassava peel cellulose were done. Paracetamol granules was prepared by wet granulation using varying concentrations of the binders. Results: DSC and XRD results revealed a semi-crystalline material with amorphous and crystalline regions. while the SEM showed a lumpy structure and reticular shape. Pre-compression evaluations of the formulated batches of paracetamol granules showed that cassava peels cellulose (CPC) have similar flow properties with those of microcrystalline cellulose BP (MCC) and acacia BP (ACA) powders respectively. The granules have free flow properties with average angles of repose (CPC ≤ 27.60 MCC &lt; 26.90 and ACA ≤ 25.60), compressibility index (CPC ≤ 25, MCC ≤ 23 and ACA ≤ 21.7%), Hausner’s ratio (CPC ≤ 1.32, MCC ≤ 1.31, and ACA ≤ 1.27) respectively. Conclusion: The extracted cassava peel α-cellulose was found ideal as pharmaceutical excipient binder in oral solid dosage forms.

Numerical Analysis and Design of New Exhaust Section Downstream of Constant Volume Combustor

Abstract Pressure gain combustors (PGC) exploit either their isochoric or detonative combustion increasing the theoretical thermal efficiency of a gas turbine cycle. On this basis, a constant-volume combustor (CVC) is developed operating with rotary valves while the chamber is fed with mixture of air and liquid iso-octane. This work describes the numerical design of a new exhaust section after the CVC. First, the design parametrization of the transition duct and the resulting design of experiments (DOE) of 81 samples are introduced. Every case is numerically tested and the election of the best sample is based on the pressure losses and the oscillations characterization. In the last part, the LS89-VKI vane is added at the aft part of the best transition duct and the ensemble exhaust system is analyzed with the help of transient CFD analysis. Every component is evaluated in terms of pressure losses and oscillations, while the operation of the vane is investigated in details. The results of the stator's performance are discussed and compared with steady experimental data. During a CVC period, the cycle average outlet flow angle remains close to the outlet metal angle denoting promising results for the future numerical analysis of the subsequent rotor.

Exploring MBH–P scaling relations in spiral galaxies: a comparative analysis of inner and outer arm structures

ABSTRACT We study the galactic spiral arm pitch angle dependence with wavelength as predicted by the density wave theory. A sample of 10 barred and unbarred spiral galaxies with two distinct, well-defined arms is used for the measurements. The data sample consists of galaxies with inner arms and galaxies with both inner and outer arms. We use six wavebands, namely 3.6 $\mu$m, 8.0 $\mu$m, B band, H $\alpha$, H i, and CO for the image analysis. The pitch angles are visually measured with the python-ol script and more precise measurements are obtained using spirality. We find a 1:1 correlation between pitch angle measurements in the 3.6 and 8.0 $\mu$m bands. We predict supermassive black hole (SMBH) masses for 3.6 $\mu$m waveband pitch angles using a standard scaling relation. We find that the black hole mass of a galaxy with both inner and outer arms is determined by the average pitch angle of the inner arms. Using only galaxies with inner arms, we find an SMBH mass–pitch angle relation of $\log (M_{\rm BH}/\mathrm{M}_\odot)=(7.11 \pm 0.33)+(0.003 \pm 0.017){\textit P}$. Using only galaxies with both inner and outer arms, we find an SMBH mass–pitch angle relation of $\log (M_{\rm BH}/\mathrm{M}_\odot)=(7.56 \pm 0.28)-(0.038 \pm 0.013){\textit P}$.

Collagen fiber arrangement in the normal bladder lamina propria and their potential impact on the pathological substaging of bladder cancer stage T1.

The lamina propria (LP) of the urinary bladder lies between the urothelial mucosa and the muscularis propria. This complex stratum is composed of extracellular matrix, several cell types, and collagen types I and III fibers. LP invasion by urothelial carcinoma (progression from stage Ta to T1) is a determinant of bladder cancer advancement. We attempted to characterize collagen fiber arrangement in the LP. This could enrich our understanding of this important layer and potentially provide clues for sub-staging of the T1 bladder cancer. A total of 24 Masson trichrome-stained images of normal bladder, including 12,530 collagen fibers were quantitatively analyzed using the Dragonfly software. The LP was divided according to fiber orientation into superficial LP (SLP, 15% of the thickness) and the deep LP (DLP, 85% of the thickness). Collagen fiber geometry analysis demonstrated that the SLP fibers are more parallel to the urothelium with an average angle of 260±230 compared to 400±260 in the DLP (p=3.4X10-144), more packed (average distance to the closest fiber of 0.61±0.67 compared to 0.66±0.77, p=0.0001), and their aspect ratio is considerably longer (average of 1.93±0.12 compared to 0.20±0.11, p=2.84x10-8). No difference was found in fiber perimeter or Feret diameter. Thus, we conclude that bladder collagen fibers are arranged in two distinct layers: a dense-ordered SLP and a loose disorder DLP. This indicates that the physical barrier to cancer cell invasion probably lies in the SLP, immediately underneath the urothelium. Once this barrier is breached, the looser and disorganized DLP poses no remarkable obstacle. Thus, we believe that histology-based subdivisions of stage T1 are expected to fail in providing clinically meaningful prognostic information.

Three-Dimensional Analysis of the First Metacarpal Axes in Healthy Individuals and Early-Stage Thumb Carpometacarpal Osteoarthritis Patients-Potential Implication on First Metacarpal Corrective Osteotomy.

Background: Numerous anatomical features of the first carpometacarpal (CMC I) joint have been investigated as potential predispositions for CMC I osteoarthritis (OA). Even though load transmission through the CMC I joint-and, therefore, the development of osteoarthritis-is believed to be influenced by the geometry of the first metacarpal (MC I) bone, there is no common definition of the MC I axes. Methods: CT scans of twenty healthy volunteers and pre- and postoperative CT scans of six patients with CMC I OA undergoing Wilson osteotomy were analyzed. We proposed a calculation method based on anatomical landmarks for the proximal joint surface axis (PA) angle and the definition of an anatomical (AA) and a mechanical (MA) longitudinal axis. We hypothesized that for an MC I extension osteotomy to be effective, the AA and MA need to be aligned surgically. Results: To align AA and MA, an average correction angle of 22.60° (SD 2.53°) at 1 cm and 26.73° (SD 2.55°) at 1.5 cm distal to the CMC I joint line is required. Conclusions: The hereby proposed method for patient-specific calculation of the correction can be used to improve the surgical technique.