Wall Length Research Articles

A semicircular wall for harvesting wind energy from vortex-induced vibration and galloping

Harvesting energy from ambient air is crucial for sustaining the operation of low-power electronic devices under autonomous conditions. In this study, a specially designed semicircular wall with a thin splitter plate was proposed, behind which the wake exhibited evolution from vortex-induced vibration (VIV) to galloping. Benefiting from this peculiar flow pattern, a piezoelectric energy harvester placed in the cylinder wake can perform well under variable wind speed conditions. The effects of aspect ratio (α) and nondimensional afterbody length (l*) of the semicircular wall on the energy harvester's performance were experimentally examined. The results showed that the aspect ratio was highly correlated with the modes of flow-induced vibrations. When 2/3 ≤ α ≤ 4/3 and l* = 1/2, the harvester experienced VIV, transition from VIV to galloping, and galloping with a continuously increasing wind speed. Frequency analysis further revealed that the resonance force and lift instability caused by vortex shedding of the semicircular wall might arise almost simultaneously, with the latter serving as the driving factor in the evolution from VIV to galloping. It is also found that the harvester operated efficiently at wind speeds of 1.0–12.0 m/s, and an appropriate nondimensional afterbody length was required to achieve high-level power outputs. These findings provide beneficial suggestions for developing the coupled VIV-galloping energy harvesters.

Role of slip in the stability of viscoelastic liquid flow through a channel

For a horizontal channel flow of a weakly viscoelastic liquid that follows the constitutive model of Walters’ liquid B′′, a linear stability analysis is performed when the channel walls are slippery. In this case, the viscoelastic channel flow is driven by the streamwise pressure gradient. We explore the primary instability for a symmetric slip flow with the same slip length of the channel walls, an asymmetric slip flow with different slip lengths of the channel walls, and an analogy to the Poiseuille–Couette flow of a viscoelastic liquid with a slip effect on the lower wall but no slip effect on the upper wall. We observe that the viscoelastic parameter shows a destabilizing impact, but the slip length shows a stabilizing impact on the most unstable shear mode in all three flow configurations. Moreover, the Poiseuille and Poiseuille–Couette flows for the viscoelastic liquid are linearly more unstable to infinitesimal disturbances than those of the Newtonian liquid. As a result, wall velocity needs to be higher than in the Newtonian liquid to stabilize the viscoelastic Poiseuille–Couette flow. Using the asymptotic analysis, we have determined the critical value of the slip length, or equivalently, the critical value of the lower wall velocity, above which the asymmetric slip flow and the Poiseuille–Couette flow of the viscoelastic liquid are permanently stable to infinitesimal disturbances.

Associations between Orbital Morphology and Exophthalmos Changes after Endoscopic Orbital Decompression to Treat Thyroid-related Orbitopathy

Purpose: To investigate orbital morphology parameters associated with exophthalmos changes in patients undergoing endoscopic orbital decompression to treat thyroid-related orbitopathy.Methods: In total, 33 eyes of 18 patients with thyroid-related orbitopathy who underwent endoscopic orbital decompression were included in this retrospective study. Data were collected before and 6 months after surgery. We performed Hertel exophthalmometry and derived orbital morphology parameters from two-dimensional facial computed tomography records. Parameters associated with exophthalmos reduction on univariate linear regression analysis were subjected to multivariate linear regression analyses.Results: Univariate linear regression showed that the preoperative length of the medial orbital wall (β = 0.179, <i>p</i> = 0.032) and the postoperative distance from the cone apex to the medial wall defect (β = -0.139, <i>p</i> = 0.006) were associated with exophthalmos reduction after endoscopic orbital decompression surgery. Multivariate linear regression of these two parameters showed that the distance from the apex to the medial wall defect was associated with exophthalmos reduction (β = -0.118, <i>p</i> = 0.019).Conclusions: The postoperative distance from the cone apex to the medial wall defect was associated with exophthalmos reduction. In patients with thyroid-related orbitopathy, this association should be considered when planning endoscopic orbital decompression.

Cavitation dynamics of the semi-sealed cylindrical shell during high-speed water entry

This paper experimentally investigates the vertical high-speed water entry of a semi-sealed cylindrical shell, which has one end sealed and one end opened. The unsteady water-entry cavitating flow characteristics of the shell are analyzed, and the evolution of cavities and jet impacts with different structures is studied. The results show that a nested multi-cavity is generated due to the self-jet phenomenon during water entry. The jet causes the diameter of the secondary cavity to be much larger than that of the primary cavity, and the morphology of the secondary cavity is more atomized. Due to the irregular motion of the jet, the primary cavity undergoes neck-shrinking phenomenon and is compressed, and the neck-shrinking position moves up as the secondary cavity grows. After secondary impact, a small jet appears at the bottom of the shell, which ejects out from the shell and increases the size of the bottom cavity, leading to the formation of quaternary cavity. Moreover, as the inner wall length increases, the time of the primary jet is advanced, while the depth of secondary cavity shortens. With the increase in the thickness, cavity shape becomes more similar to traditional supercavity, and the maximum diameter of the primary cavity increases.

Cardiac exposure in left-sided breast cancer patients undergoing deep inspiratory breath hold radiation therapy.

Left-sided breast cancer (BC) patients undergoing post-operative radiation therapy (PRT) may have higher risk of late cardiovascular toxicity, which may be reduced by hearth-sparing RT techniques. This study evaluated dosimetric parameters of the deep inspiration breath hold (DIBH) compared to free breathing (FB) RT. We analysed factors impacting on doses to the heart and cardiac substructures and sought anatomic factors allowing patient selection for DIBH. The study group included 67 left-sided BC patients who underwent RT after breast-conserving surgery or mastectomy. Patients treated with DIBH were trained to hold their breath. Computed tomography (CT) scans were performed in both FB and DIBH patients. Plans were generated using 3-dimensional (3D) conformal RT. The dosimetric variables were obtained from dose-volume histograms, and the anatomical variables were derived from the CT scans. The variables in the two groups were compared by t-test, the U test, and the chi-squared test. Correlation analysis was performed using Pearson's correlation coefficient. Receiver operating characteristic curves were used to analyze the efficacy of the predictors. Compared to the FB, DIBH allowed for a mean dose reduction to the heart, left anterior descending coronary artery (LAD), left ventricle (LV), and right ventricle (RV) by 30.0%, 38.7%, 39.3%, and 34.7%, respectively. DIBH markedly increased the heart height (HH), heart chest wall distance (HCWD), the mean distance between the ipsilateral lung and breast (DBIB), and decreased the heart-chest wall length (HCWL) (P<0.05). The different value of HH, DBIB, HCWL, and HCWD between DIBH and FB were 1.31, 1.95, -0.67, and 0.22 cm, respectively (all P<0.05). ΔHH was an independent predictor of the mean dose to the heart, LAD, LV, and RV, with the area under the curve values of 0.818, 0.725, 0.821, and 0.820, respectively. DIBH significantly reduced the dose to the entire heart and its substructures in left-sided BC patients undergoing post-operative RT. ΔHH predicts the mean dose to the heart and its substructures. These results may inform patient selection for DIBH.

Crashworthiness analysis and uncertainty optimization of novel multi-wall tube

Multi-wall tube has excellent crashworthiness therefore is widely used in energy absorption. The crashworthiness of multi-wall tube is not only related to shape but also materials. However, the specific value of some material parameters cannot be determined, instead, only interval can be confirmed. In this work, a novel multi-wall tube (NMT) that is composed of octagon and nested quadrilateral was designed and an interval uncertainty optimization method was proposed to improve the crashworthiness. Firstly, the crashworthiness of the NMT, octagonal multi-wall tube (OMT) and square double-wall tube (SDT) under axial load was compared and analyzed by experimental and numerical simulation. It indicated that NMT has obvious energy absorption advantages and good progressive deformation mode. Moreover, the energy absorption of NMT structure is more sensitive to wall thickness than wall spacing ratio and inner wall length. Then, based on the theory of simplified super folding element (SSFE), the theoretical model of NMT was proposed. The theoretical analysis is consistent with the simulation results. Finally, according to the interval number theory, the uncertain interval optimization problem was transformed into deterministic optimization and reliability analysis. Non-dominated sorting genetic algorithm II (NSGA-II) was used to seek superior crashworthiness of NMT. When considering interval uncertainty in optimization, the reliability of crashworthiness of the NMT can be further improved. The research results provide a good guidance and theoretical support for crashworthiness optimization design.

Influence of different structural parameters of 3D woven honeycomb composites on three-point bending behavior

In this study, various honeycomb preforms with different cell geometries were woven by changing the cell size, opening angle, free wall length, bonded wall length, and the number of layers keeping cell shape constant and composite thickness constant. The shape of the cells was altered by altering the pick numbers. E-glass tows of 600 Tex were used to produce fabric samples. All the constituent walls have the same construction and are woven with 2D plain fabric. Composite samples were created from honeycomb fabric and epoxy resin (matrix) using the VARIM (vacuum-assisted resin infusion method) technology. Three-point bending test was carried out for different cell geometries of 3D woven honeycomb composites. It was found that specific bending load is higher for a honeycomb structure with an opening angle of 60°, smaller cell sizes, small wall length, and for more layers keeping thickness and cell shape constant. Face wrinkling causes specimen failure in the following ways: localized buckling of the compressed face, debonding of the face sheet, and Mode 1 cell wall collapse in the region between the fixed support and load application.

Comparison of speech understanding taking into account the exact electrode position (SRA/MRA/CA)

Cochlear implantation has been a routine hearing rehabilitation procedure for years. Nevertheless, not all parameters that influence speech understanding after implantation are known. We test the hypothesis whether there is a connection between speech understanding and the position of different electrode types in relation to the modiolus in the cochlea with identical speech processors. For this purpose, in this retrospective study, we compare the hearing results with different electrode types ("Straight Research Array" [SRA], "Modiolar Research Array" [MRA] and "Contour Advance" [CA]) from the manufacturer Cochlear in matched pair groups.After creating three groups using "matched pairs" (n=52 patients per group), the cochlear parameters (length of the outer wall, angle of insertion, insertion depth, cochlear coverage and total length of the electrode in the cochlea, wrapping factor) were measured in the routinely performed manner pre- and post-operative high-resolution CT or DVT. The Freiburg monosyllabic understanding was used as a target variable one year after implantation.In the Freiburg monosyllabic test one year postoperatively, patients with MRA had a monosyllabic understanding of 51.2%, patients with SRA 49.5% and patients with CA 58.0%. It could be shown that with increasing cochlear coverage with MRA and CA, the speech understanding of the patients decreases and with SRA it increases. In addition, it could be shown that the monosyllabic understanding increases with increasing "wrapping factor".The results show that the position of the electrode to the modiolus is not the only factor explaining differences in outcome after cochlear implantation.

Low-velocity impact behavior of 3D woven structural honeycomb composite

This paper describes the in-plane impact behavior of 3D woven honeycomb sandwich composites comprising glass fiber reinforced epoxy composite. In this study, 3D woven honeycomb structures with similar cell shapes were developed with different cell geometry by varying the cell size, free wall length, bonded wall length, opening angle, and the number of honeycomb layers keeping the overall thickness of the composite constant. The variation of cell geometry was carried out by changing the number of picks in the honeycomb walls. Composite samples were made using VARIM (vacuum-assisted resin infusion method) process. The behavior of the force-displacement curve and the energy-time relationship under impact loading of 100 J were analyzed. The total energy absorption was determined for different cell geometry and the number of layers of the honeycomb composites. The results showed that structural changes in honeycomb composite significantly affect the specific energy absorption. The specific energy absorption increases with a large cell size, less opening angle, higher wall length, and a greater number of layers.

Effects of different joint wall lengths on in-plane compression properties of 3D braided jute/epoxy composite honeycombs

To comply with the trend in the development of engineering materials towards lightweight, high strength, eco-friendly, sustainable, and multi-functional, a three-dimensional braided integrated composite honeycomb is designed. The effects of geometrical parameters particularly joint wall lengths on the in-plane mechanical behavior of the honeycombs were investigated. The results show that the in-plane mechanical properties are related to the number of cell walls, and the angle between the cell wall and the loading direction. Increasing the number of cell rows to double and triple at similar areal density lead to an improvement of the maximum load up to 2.5, and 3.8 times, respectively. Similarly, the total absorbed strain energy increased up to 2.6 and 5.9 times, respectively. The displacement at the maximum load is increased by 1.6 and 2.7 times as a result of increasing the cell row number. The total absorbed strain energy increased to 1.7 and 1.3 times, respectively. The failure angle of the 3D braided composite honeycomb is about 4°–7°. This investigation presents the geometrical factors of a 3D braided composite honeycomb can be further designed and optimized, but it also provides a reference for the development and design of a new composite honeycomb.

Effect of geometrical dimensions on flame spread rate over U‐shaped polyurethane facade and theoretical analysis

AbstractPolyurethane is widely used in building facades as a good energy‐saving and environment‐friendly organic material, and the U‐shaped structure is a common facade form as it could improve indoor lighting and ventilation. Through numerical simulation and theoretical analysis, this study found the flame spread rate of polyurethane foam over a U‐shaped facade was affected by the structural dimensions due to three main factors: lateral air entrainment restriction, bottom air entrainment restriction, and flame fusion between the back wall flame and side wall flame. The average flame spread rate was negative linearly correlated with the back wall width and positive exponentially correlated with the side wall length. This was due to that the side walls caused lateral air entrainment restriction, reduced the heat loss, enhanced the thermal feedback, generated an upward induced airflow close to the back wall, elongated the flame, and also caused the flame fusion between side walls and the back wall, thus accelerated the flame spread process compared to the flat structures.

Buoyancy-driven heat transfer performance, vorticity and fluid flow analysis of hybrid nanofluid within a U-shaped lid with heated corrugated wall

The thermal performance of alumina-copper/water hybrid nanofluid in buoyancy-driven heat transfer of a U-shaped cavity with a heated wavy wall is investigated in detail throughout this manuscript. A three-node triangular finite element method is used to solve the system by considering the Galerkin weighted residual algorithm. A Newton–Raphson algorithm with a damping coefficient is used as the convergence criterion. Numerical and experimental comparisons of previously published results are compared with the present calculations to ensure confidence in the present modeling. The physical representation of the modeling is presented through the streamlines, isotherms, and vorticity distribution. To quantify the overall heat transfer performance, the average and local Nusselt numbers are used for various combinations of parameters. It is found that the higher the cold rib dimension, the undulations, and the amplitudes of the heated corrugated walls produce a higher heat transfer rate. The inclusion of a hybrid nanofluid may inhibit the heat transfer rate when the length of the hot wall exceeds the length of the cold wall. As low as 4% and up to 16% thermal performance increase of utilizing hybrid nanofluid is observed compared to pure water in a wavy U-shaped enclosure.

Study on the equivalent plastic hinge length of superimposed RC shear walls with embedded bracings

The equivalent plastic hinge length of RC shear wall is often regarded as an important index to be studied in the framework of performance-based seismic design, for which a series of evaluation formulae have been widely proposed. However, existing equivalent plastic hinge length calculation formulae are proposed for cast-in-place RC shear walls, while that for superimposed RC shear walls with embedded bracings (SRCXSWs) still needs to be further studied. With an attempt to achieve this goal, a series of research including finite element analysis and theoretical derivation are conducted in this research. Based on the analysis of crack development and failure modes for SRCXSW, the relationship between the ultimate deformation and the equivalent plastic hinge length is established through the theoretical derivation, then 51 finite element models with 10 parameters are analyzed by OpenSEES to summarize the influence modes of different parameters on the equivalent plastic hinge length. Finally, the equivalent plastic hinge length calculation formulae for SRCXSWs are proposed and verified by the numerical and experimental results. The research results illustrate that there exists a function relation between the ultimate deformation and the equivalent plastic hinge length, and decreasing the ratio of deformation caused by shear effect to top deformation or increasing the compressive strain properties of concrete by parameter assignment will be more conducive to the formation and development of the plastic hinge zone of SRCXSWs. The existing formulae cannot effectively estimate the equivalent plastic hinge length of SRCXSWs, while the proposed formulae are suitable for predicting the equivalent plastic hinge length of SRCXSWs.

An Accurate and Individualized Preoperative Estimation Method for the Linear Insertion Depth of Cochlear Implant Electrode Arrays Based on Computed Tomography.

Cochlear implantation or auditory brainstem implantation is currently the only accepted method for improving severe or profound sensorineural hearing loss. The length of the electrodes implanted during cochlear implantation is closely related to the degree of hearing improvement of hearing after the surgery. We aimed to explore new methods to accurately estimate the electrode array (EA) linear insertion depth based on computed tomography (CT) images prior surgery, which could help surgeons select the appropriate EA length for each patient. Previous studies estimated the linear insertion depth by measuring the length of the lateral wall of the cochlea rather than the electrode's path in the cochlea duct. Here, we determined the actual position of the EA on the CT image after cochlear surgery in order to predict the path of the EA, and the length of the predicted EA path was measured by the contouring technique (CoT) to estimate the linear insertion depth of the EA. Because CoT can only measure the length of the estimated EA path on a two-dimensional plane, we further modified the measurement by weighting the height of the cochlea and the length of the EA tail (the length of the last stimulating electrode to the end, which cannot be displayed on the CT image), which we termed the modified CoT + height + tail (MCHT) measurement. Based on our established method, MCHT could reduce the error to the submillimeter range (0.67 ± 0.37 mm) when estimating the linear insertion depth of various kinds of EAs compared with the actual implant length. The correlation coefficient between the linear insertion depth as predicted by MCHT and the actual was 0.958. The linear insertion depth estimated by this method was more accurate than that estimated using the classical CoT technique ( R = 0.442) and using the modified Escudé's method ( R = 0.585). MCHT is a method based on CT images that can accurately predict the linear insertion depth of cochlear implants preoperatively. This is the first report that we are aware of a method for predicting linear insertion depth before cochlear implantation with only submillimeter errors and that is tailored to different types of EAs.

Numerical Investigation into GFRP Composite Pipes under Hydrostatic Internal Pressure.

Glass-fiber-reinforced plastic (GFRP) composite pipes are used extensively in high-performance applications, due to their high stiffness and strength, corrosion resistance, and thermal and chemical stability. In piping, composites showed high performance due to their long service life. In this study, glass-fiber-reinforced plastic composite pipes with [±40]3, [±45]3, [±50]3, [±55]3, [±60]3, [±65]3, and [±70]3 fiber angles and varied pipe wall thicknesses (3.78-5.1 mm) and lengths (110-660 mm) were subjected to constant hydrostatic internal pressure to obtain the pressure resistance capacity of the glass-fiber-reinforced plastic composite pipe, hoop and axial stress, longitudinal and transverse stress, total deformation, and failure modes. For model validation, the simulation of internal pressure on a composite pipe installed on the seabed was investigated and compared with previously published data. Damage analysis based on progressive damage in the finite element model was built based on Hashin damage for the composite. Shell elements were used for internal hydrostatic pressure, due to their convenience for pressure type and property predictions. The finite element results observed that the winding angles from [±40]3 to [±55]3 and pipe thickness play a vital role in improving the pressure capacity of the composite pipe. The average total deformation of all designed composite pipes was 0.37 mm. The highest pressure capacity was observed at [±55°]3 due to the diameter-to-thickness ratio effect.

A review of Open Channel Design for Mine Dewatering System Based on Environmental Observations

The purpose of mine dewatering system is to control runoff water that enters mine openings so that the mining process is not disturbed. The rainfall discharge (Q) is 0.0951 m³/second and the runoff discharge (Q) is 0.69 m³/second, making the total mining discharge entering the location 0.781 m³/second. The open channel design has dimensions of Channel wall slope (α) = 60°, Water depth (h) = 0.73 m, Channel depth (d) = 0.83 m, Channel base width (B) = 0.73 m, Surface width (b) = 1.57 m, Wet cross-sectional area of channel (A) = 0.92 m², and Channel wall length (a) = 0.97 m. The sedimentation pond has the following dimensions and compartments: Total length (l) = 104 m; width (b) = 8 m; depth (H) = 4 m; partition width = 4 m; partition depth = 4 m; partition length = 7 m. It consists of 3 compartments: conditioning compartment, separation between solids and mine water, and flow with an area of 277 m² per compartment. The sedimentation pond volume is 3094 m³ with a total area of 830 m². The results of the study obtained information that to control runoff water entering mine openings, a pond capacity as a settling site was needed of more than 3094 m³ with a maximum dredging time of settling pond particles that can be done once every 10 months.

Variations in structural support site failure patterns by prolapse size on stress 3D MRI.

Our objective was to develop a standardized measurement system to evaluate structural support site failures among women with anterior vaginal wall-predominant prolapse according to increasing prolapse size using stress three-dimensional (3D) magnetic resonance imaging (MRI). Ninety-one women with anterior vaginal wall-predominant prolapse and uterus in situ who had undergone research stress 3D MRI were included for analysis. The vaginal wall length and width, apex and paravaginal locations, urogenital hiatus diameter, and prolapse size were measured at maximal Valsalva on MRI. Subject measurements were compared to established measurements in 30 normal controls without prolapse using a standardized z-score measurement system. A z-score greater than 1.28, or the 90th percentile in controls, was considered abnormal. The frequency and severity of structural support site failure was analyzed based on tertiles of prolapse size. Substantial variability in support site failure pattern and severity was identified, even between women with the same stage and similar size prolapse. Overall, the most common failed support sites were straining hiatal diameter (91%) and paravaginal location (92%), followed by apical location (82%). Impairment severity z-score was highest for hiatal diameter (3.56) and lowest for vaginal width (1.40). An increase in impairment severity z-score was observed with increasing prolapse size among all support sites across all three prolapse size tertiles (p < 0.01 for all). We identified substantial variation in support site failure patterns among women with different degrees of anterior vaginal wall prolapse using a novel standardized framework that quantifies the number, severity, and location of structural support site failures.

Efficient Surrogate-Assisted Parameter Analysis for Coal-Supercritical Water Fluidized Bed Reactor with Adaptive Sampling

Supercritical water fluidized beds (SCWFBs) are promising and efficient reactors for the gasification of coal in supercritical water. The understanding and investigation of multi-phase flows as well as the gasification process usually rely on time-consuming experiments or numerical simulations, which prohibit fast and full exploration of the single and coupled effects of the operation and geometric parameters. To this end, this paper builds an efficient surrogate-assisted parameter analysis framework for the SCWFB reactor. Particularly, (1) it establishes a steady numerical simulation model of the SCWFB reactor for the subsequent analysis; and (2) it employs a Gaussian process surrogate modeling via efficient adaptive sampling to serve as an approximation for predicting the carbon conversion efficiency (CE) of the reactor. Based on this parameter analysis framework, this paper investigates the effects of five independent parameters (the mass flow rate of supercritical water, mass flow rate of the coal slurry, temperature of supercritical water, temperature of the outer wall and reactor length) and their interactions on the reaction performance in terms of the carbon conversion efficiency (CE). We found that the CE increases as a function of the temperature of supercritical water, the temperature of the outer wall and the reactor length; while it decreases as a function of the mass flow rate of supercritical water and the mass flow rate of the coal slurry. Additionally, the global sensitivity analysis demonstratesthat the influence of the temperature of the outer wall exerts a stronger effect than all the other factors on the CE, and the coupled interaction among parameters has a slight effect on the CE. This research provides useful guidance for scaled-up designs and optimization of the SCWFB reactor.

GoSAMTs are required for pectin methyl-esterification and mucilage release in seed coat epidermal cells.

GoSAMTs play a role in the methylation of polysaccharides synthesized by the Golgi. Pectin homogalacturonan (HG) methyl-esterification is essential for the proper function of this polysaccharide in cell walls. In order to better understand the role of GoSAMTs in HG biosynthesis, we analyzed mucilage methyl-esterification in gosamt mutants. To determine the function of GoSAMT1 and GoSAMT2 in HG methyl-esterification we utilized epidermal cells of seed coats, as these structures produce mucilage, which is a pectic matrix. We evaluated differences in seed surface morphology and quantified mucilage release. We measured methanol release, and used antibodies and confocal microscopy to analyze HG methyl-esterification in mucilage. We observed morphological differences on the seed surface and delayed, uneven mucilage release in gosamt1-1gosamt2-1 double mutants. We also found changes in the distal wall length indicating abnormal cell wall breakage in this double mutant. Using methanol release and immunolabeling, we confirmed that GoSAMT1 and GoSAMT2 are involved in HG methyl-esterification in mucilage. However, we did not find evidence of decreasing HG in the gosamt mutants. Confocal microscopy analyses detected different patterns in the adherent mucilage and a greater number of low-methyl-esterified domains near the seed coat surface, which correlates with a greater number of "egg-box" structures in this region. We also detected a shift in the partitioning between the Rhamnogalacturonan-I soluble and adherent layers of the double mutant, which correlated with increased amounts of arabinose and arabinogalactan-protein in the adherent mucilage. The results show that the HG synthesized in gosamt mutant plants is less methyl esterified, resulting in more egg-box structures, which stiffen the cell walls in epidermal cells and change the rheological properties of the seed surface. The increased amounts of arabinose and arabinogalactan-protein in adherent mucilage, also suggests that compensation mechanisms were triggered in the gosamt mutants.

Evaluation of Thin Wall Milling Ability Using Disc Cutters

In some cases, industrial practice requires the production of walls or parts with a thickness of less than one millimeter from a metal workpiece. Such parts or walls can be made by milling using disc cutters. This machining method can lead to the generation of residual stresses that determine the appearance of a form deviation characterized by bending the part or the thin wall. To evaluate the suitability of a metallic material for the manufacturing of thin walls by milling with disc cutters, different factors capable of exerting influence on the deviation generated by the residual deformation of the walls were taken into account. A test sample and an experimental research program were designed for the purpose of obtaining an empirical mathematical model. The empirical mathematical model highlights the magnitude of the influence exerted by different input factors on the disc cutter milling process regarding the size of the deviation from the form, and the correct position of the wall or thin part, in the case of a test sample workpiece made of an aluminum alloy. Input factors considered were cutting speed, feed rate, cutter thickness, wall or part thickness, thin wall length, and height. To rank the input factors whose increase leads to an increase in shape deviation, the values of the exponents attached to the factors in question in the empirical mathematical model of the power-type function were taken into account. It was found that the values of the exponents are in the order 0.782 > 0.319 > 0.169 for wall height, feed rate, and wall width, respectively. It was thus established that the strongest influence on the residual deformation of the thin wall is exerted by its height.