Simplified Samples Research Articles

Geometric Complexity Control in Topology Optimization of 3D-Printed Fiber Composites for Performance Enhancement.

This paper investigates the impact of varying the part geometric complexity and 3D printing process setup on the resulting structural load bearing capacity of fiber composites. Three levels of geometric complexity are developed through 2.5D topology optimization, 3D topology optimization, and 3D topology optimization with directional material removal. The 3D topology optimization is performed with the SIMP method and accelerated by high-performance computing. The directional material removal is realized by incorporating the advection-diffusion partial differential equation-based filter to prevent interior void or undercut in certain directions. A set of 3D printing and mechanical performance tests are performed. It is interestingly found that, the printing direction affects significantly on the result performance and if subject to the uni direction, the load-bearing capacity increases from the 2.5D samples to the 3D samples with the increased complexity, but the load-bearing capacity further increases for the 3D simplified samples due to directional material removal. Hence, it is concluded that a restricted structural complexity is suitable for topology optimization of 3D-printed fiber composites, since large area cross-sections give more degrees of design freedom to the fiber path layout and also makes the inter-layer bond of the filaments firmer.

INFLUENCE OF EDGE REINFORCING RING ROTATION ON LOAD CARRYING CAPACITY OF CONICAL SHELLS LOADED BY EXTERNAL PRESSURE

The aim of the article is to present a part of the problem of calculating the load carrying capacity of conical shells, which by their dimensions and selected boundary conditions do not comes under within the scope the standards. The investigated conical shells have a semi vertex angle in the range of 75 ° - 85 ° and are provided with a reinforcing ring at the lower edge. When the conical shells are loaded by external pressure, not only does the edge ring move in the radial direction, but also its rotation (the moment has the direction of the tangent to the edge of the cone). This paper addresses the question of how this rotation affects the overall load capacity of a conical shell. Due to the fact that the investigated shell structures cannot be solved using standard methods and procedures, this problem is solved by means of numerical analyzes and experiments. Based on the results of numerical analyzes of the load carrying capacity of conical shells with different boundary conditions, the suitability of using simplified numerical models and samples for performing experiments was verified.

A methodology for mechanical stress and wafer warpage minimization during 3D NAND fabrication

The introduction of the 3D NAND architecture brought new integration challenges, including the impact of fabrication-induced mechanical stress. If not controlled, the mechanical stress can result in high wafer warpage, incompatible with wafer handling and lithography steps. This work presents a study of the impact of annealing on the warpage and residual stress of blanket SiO2/Si3N4 stacks relevant to 3D NAND fabrication. It is shown that annealing promotes H outgassing from the Si3N4 layers and minimizes their residual stress. The optimal temperature is calculated by combining the warpage measurements with finite element modelling. That allows to calibrate the model on simplified samples and then expand it for stacks with a higher number of layers, which can be beneficial for the future 3D NAND generations. Index terms3D NAND, fabrication, mechanical stress.

Harnessing manufacturing elements to select local process parameters for metal additive manufacturing: A case study on a superconducting solenoid coil

In additive manufacturing (AM), low geometrical tolerances, high-quality material properties, and low surface roughness are challenges. To increase the process capabilities, a promising concept is to tailor process parameters for the fabrication of a part. Instead of selecting identical process parameters to the geometry of the whole part, different sets of process parameters are assigned to different regions named manufacturing elements (MEs). The ME approach offers three main advantages: significant reduction of required sacrificial support structures based on the reduced build angles and less post-processing efforts; reduced AM processing time due to less sacrificial support structures and a higher laser speed; and local adjustment of the material and surface properties. Previous studies have examined the ME approach and applied it to simplified test samples. This study shows an end-to-end implementation of the ME approach for the fabrication of a real-world industrial part and highlights the associated opportunities and challenges for the implementation. The application is demonstrated for a complex-shaped industrial part that can only be manufactured using the ME approach. The industrial part is a winding former of a superconducting solenoid coil. The implementation consists of three major steps: (1) the development of a process parameter model for laser-based powder bed fusion ( L -PBF) and stainless steel 316 L; (2) segmentation of the part into MEs; and (3) use of the enhanced design freedom for surface texturing. The ME approach facilitated support-free fabrication of the part with build angles of as low as 25°. The enhanced design freedom enabled surface texturing, which allowed the maximum shear strength to be improved by 63% compared to that of a nontextured surface. The results are discussed, and possible enhancements and research directions are outlined, such as the automated assignment of process parameter sets. The results are applicable to reduce the costs of a superconducting solenoid coil for the treatment of cancer with proton beams. This can enable a larger number of patients to have access to this cancer treatment. In addition, the results are further applicable to increase the performance of the future circular collider at CERN.

Pavement crack detection and classification based on fusion feature of LBP and PCA with SVM

ABSTRACT A new crack detection approach based on local binary patterns (LBP) with support vector machine (SVM) was proposed in this paper. The propsed algorithm can extract the LBP feature from each frame of the video taken from the road. Then, the dimension of the LBP feature spaces can be reduced by Principal Component Analysis(PCA). The simplified samples are trained to be decided the type of crack using Support Vector Machine(SVM). In order to reflect the directional imformation in detail, the LBP processed image is devided into nine sub-blocks. In this paper, driving tests were performed 10 times and 12,000 image data were applied to the proposed algorithm. The average accuracy of the proposed algorithm with sub-blocks is 91.91%, which is about 6.6% higher than the algorithm without sub-blocks. The LBP-PCA with SVM applying sub-blocks reflects the directional information of the crack so that it has high accuracy of 89.41% and 88.24%, especially in transverse and longitudinal cracks. In the performance analysis of different crack classifiers, the F-Measure, which considered balance between the precision and the recall, of alligator cracks classifier was the highest at 0.7601 and hence crack detection performance is higher than others.

Effects of adjunctive light-activated disinfection and probiotics on clinical and microbiological parameters in periodontal treatment: a randomized, controlled, clinical pilot study

ObjectivesThe aim of this pilot study was to evaluate the clinical and microbiological outcomes of light-activated disinfection (LAD) alone or combined with probiotics as an adjunct to non-surgical periodontal treatment.Materials and methodsIn this single-blinded, randomized, controlled clinical pilot study, 48 patients (28 females and 20 males) with untreated periodontitis (stages II and III, grade B) were included. Using a parallel-group design, patients were randomly assigned into 3 groups to receive subgingival debridement (SD) alone (group 1, n = 16), SD with LAD (group 2, n = 16), or SD with LAD plus probiotic treatment (group 3, n = 16). Probing pocket depth (PPD), clinical attachment level (CAL), bleeding on probing (BOP), gingiva-index simplified (GIs), plaque-control record (PCR), and subgingival microbiological samples were analyzed at baseline, 3 months, and 6 months of follow-up.ResultsAll treatment modalities demonstrated clinical improvements in PPD and CAL at 6 months compared to baseline but without a statistical significant difference between the groups. The combination of SD + LAD + probiotic treatment (group 3) demonstrated significantly greater reductions in BOP, GIs, and red complex bacteria P. gingivalis and T. forsythia compared with other groups at 6 months (p < 0.05).ConclusionsA single application of LAD as an adjunct to SD provided no additional clinical and microbiological benefits compared to SD alone. The combination of SD + LAD + probiotic treatment in group 3 led to further improvements of the inflammatory parameters.Clinical relevanceThe additional use of probiotics in periodontal treatment can be a useful approach to support inflammation and infection control of periodontal tissues. Further studies are necessary to determine the extent of added benefit for this treatment approach.

Clinical pharmacokinetics and drug exposure-toxicity correlation study of docetaxel based chemotherapy in Chinese head and neck cancer patients.

BackgroundArea under time-concentration curve (AUC) of docetaxel is related with its toxicity and efficacy. The aim of this study is to investigate the target range of docetaxel AUC in Chinese head and neck cancer (HNC) patients.MethodsEligible HNC patients were enrolled and received at least 2 cycles of docetaxel-based chemotherapy. A simplified pharmacokinetic (PK) strategy (2 monitored samples) was developed to simulate docetaxel AUC using the nonlinear mixed-effect modelling program. Preliminary target range of AUC was pre-set as 2.5–3.7 µg·hr/mL according to pooled analysis from 8 previous studies. Fisher exact test was used to analyze the relationship between AUC with neutropenia and efficacy, and to verify the target range.ResultsThirty-nine eligible patients were enrolled. Grade 3-4 and grade 4 neutropenia rate in 1st cycle was 64% and 36%, respectively. AUC simulation by simplified PK strategy was acceptable compared to full sampling method from the analysis of archived 300 patients’ data, with −5.67% of mean prediction error (MPE). Median AUC of all patients was 2.58 µg·hr/mL (range from 1.28 to 9.39). A significant correlation (P=0.007) was detected between AUC and body surface area (BSA)-dosage, but BSA contributed only 18.3% of AUC inter-individual variability. Docetaxel AUC was significantly related with the severity (grade 3–4) of neutropenia (correlation of coefficient was 0.452, P=0.004). Fourteen patients (36%) were within the target AUC range. Patients with AUC above the target experienced more severe neutropenia (grade 3–4 rate 100% vs. 56%, P=0.036; grade 4 rate 86% vs. 25%, P=0.005). No significant difference of response rate was found between patients within the target or not.ConclusionsA simplified samples PK strategy was developed for docetaxel AUC simulation. The target range of docetaxel AUC in Chinese HNC patients was suggested at 2.5–3.7 µg·hr/mL for reduced toxicity without compromising efficacy of docetaxel treatment.

The use of thin-layer chromatography in the assessment of the quality of lutein-containing dietary supplements

Bivariant multiple development thin-layer chromatography technique (BMD–TLC) along with high-performance liquid chromatography–diode array detection–electrospray ionization–mass spectrometry (HPLC–DAD–ESI–MS) analysis was used in determination of lutein or lutein mixed with zeaxanthin in eight dietary supplements. The developed two-step TLC separation procedure combined purification, compaction of samples and separation of the analyzed compounds what significantly shortened and simplified samples preparation. Qualitative analysis was based on co-chromatography with reference substances and HPLC–DAD–ESI–MS analysis. It was revealed that three of eight dietary supplements did not contain lutein. In turn, quantitative analysis with the use of developed TLC conditions along with densitometry showed that the amount of lutein or its mixture with zeaxanthin in the others differed from that claimed by producers.

Characterisation of rain erosion at ex-service turbofan blade leading edges

Rain erosion of turbofan blades creates problems in the aeronautics community, since the changes of profiles on leading edges affect aerodynamic performance that subsequently leads to significant efficiency drop for the aircraft engine. Water-hammer pressure induced by droplet impingements is primarily responsible for the damaged induced during the initial compression stage. As the surface roughened, the damage mechanism is then governed by lateral flow jetting assisted with hydraulic penetration. Studies on WDE are restricted to laboratory testing with simplified conditions and samples. Hence, this will be the first study to demonstrate real-life WDE damage on real turbofan blades during their ‘complicated’ in-service conditions.A set of Ti-6Al-4V ex-service turbofan blades are sectioned to examine their in-service degradation. Different parts of the blade, with impact velocities ranging from 144 m s−1 to 396 m s−1, were selected to study the effect of impact velocity on rain erosion damage. Erosion morphology and the damage mechanisms are characterised with Alicona profilometer and SEM. The results reveal that rain erosion occurs exclusively at the leading edges. Increase of rain erosion severity with increasing impact velocity is identified. The normalised volume loss is proportional to Vn, where V is the impact velocity, ranging from 286 m s−1 to 348 m s−1, and the exponent (n) is estimated to be around 8 for Ti-6Al-4V ex-service turbofan blade, which agrees with the literature from laboratory tests. The damage features during early incubation period cannot be detected due to the roughening of the leading edges. However, intergranular fracture is detected at the tip of the leading edge with less severe damage. In the steady state, material removal appears to be due to coalescence of microcracks to form erosion craters. The cracks continue to propagate from the side wall and bottom of the erosion craters, attributable to the joint effect of lateral outflow jetting and hydraulic penetration induced by repetitive droplet impingements. Thus, the present research is an invaluable opportunity to validate the results obtained from laboratory tests by comparing with the real-life WDE, which then helps to further elucidate the damage mechanisms behind WDE.

Microchip Isotachophoresis: Analysis of Pharmaceuticals.

Microchip isotachophoresis (μITP) is a miniaturized version of conventional isotachophoresis (ITP) characterized by low sample and buffer consumption and reduced waste production. μITP with universal conductivity detection is suitable for quantitative analysis of relatively simplified samples that contain analyte(s) at relatively high concentration, e.g., pharmaceutical preparations. Here we describe in detail a principle of μITP in terms of reaching highly precise results. A practical use of μITP is shown on the analyses of various pharmaceutical preparations for content of major constituents including active pharmaceutical ingredients as well as pharmaceutical counterions. The pharmaceuticals are treated only minimally prior to the ITP run on a microchip with coupled channels and sample injection channel with 0.9μL volume. Developed method is suitable for rapid (analysis time up to 10min), precise (less than 1% RSD of analyte zone length), and accurate (recovery of 98-101%) determination of major pharmaceutical ingredients using a method of internal standard for data evaluation.

The Effect of a Vertical Electric Field on the Surface Flashover Characteristics of a Bushing Model

High-voltage bushings play a crucial role in energy conveyance. Their specialized electric structure makes the bushing more vulnerable to surface discharge. However, the influence of a vertical electric field on the surface flashover of bushing structures remains unclear. To investigate this mechanism, four simplified bushing samples were built and the influence of pollution, leakage length, and the electric field component vertical to the dielectric surface on flashover properties of the bushing samples were tested. It was found that the surface pollution level was the decisive factor that influenced flashover voltage. When the leakage length and form factor were the same, the pollution flashover of the bushing structure was lower than that of the post structure. It was also found that increasing the leakage length was not very effective in improving the flashover voltage of bushings when the equivalent salt deposit density (ESDD) was high. No obvious correlation was found between pollution flashover voltage and electric field stress. Furthermore, the uneven wetting flashover performance of the bushings was tested. Under this condition, the flashover voltage decreased with an increase of the electric field component vertical to the dielectric surface. In addition, the electric field distribution of the samples was calculated and the results were in accordance with the experimental results.

The validation of simplified EEG derived from the bispectral index monitor in post-cardiac arrest patients

AimsWe aimed to validate retrospectively the accuracy of simplified electroencephalography (EEG) monitoring derived from the bispectral index (BIS) monitor in post-cardiac arrest (CA) patients. MethodsSuccessfully resuscitated CA patients were transferred to the Catherization Lab followed by percutaneous coronary intervention when indicated. On arrival at the coronary care unit, bilateral BIS monitoring was started and continued up to 72 h. Raw simplified EEG tracings were extracted from the BIS monitor at a time point coinciding with the registration of standard EEG monitoring. BIS EEG tracings were reviewed by two neurophysiologists, who were asked to indicate the presence of following patterns: diffuse slowing rhythm, burst suppression pattern, cerebral inactivity, periodic epileptiform discharges and status epilepticus (SE). Additionally, these simplified BIS EEG tracings were analysed by two inexperienced investigators, who were asked to indicate the presence of SE only. ResultsThirty-two simplified BIS EEG samples were analysed. Compared to standard EEG, neurophysiologists interpreted all simplified EEG samples with a sensitivity of 86%, a specificity of 100% and an interobserver variability of 0.843. Furthermore, SE was identified with a sensitivity of 80% and a specificity of 94% by two unexperienced physicians. ConclusionUsing a simple classification system, raw simplified EEG derived from a BIS monitoring device is comparable to standard EEG monitoring. Moreover, investigators without EEG experience were capable to identify SE in post-CA patients. Future studies will be warranted to confirm our results and to determine the added value of using simplified BIS EEG in terms of prognostic and therapeutic implications.

Precise determination of N‐acetylcysteine in pharmaceuticals by microchip electrophoresis

A novel microchip electrophoresis method for the rapid and high-precision determination of N-acetylcysteine, a pharmaceutically active ingredient, in mucolytics has been developed. Isotachophoresis separations were carried out at pH 6.0 on a microchip with conductivity detection. The methods of external calibration and internal standard were used to evaluate the results. The internal standard method effectively eliminated variations in various working parameters, mainly run-to-run fluctuations of an injected volume. The repeatability and accuracy of N-acetylcysteine determination in all mucolytic preparations tested (Solmucol 90 and 200, and ACC Long 600) were more than satisfactory with the relative standard deviation and relative error values <0.7 and <1.9%, respectively. A recovery range of 99-101% of N-acetylcysteine in the analyzed pharmaceuticals predetermines the proposed method for accurate analysis as well. This work, in general, indicates analytical possibilities of microchip isotachophoresis for the quantitative analysis of simplified samples such as pharmaceuticals that contain the analyte(s) at relatively high concentrations.

Al2O3/Al Cermets by Plasma Spraying: Optical Response of Experimental and Numerically Represented Materials

Optical properties of plasma-sprayed coatings and numerically represented samples were studied at wavelengths ranging from visible to mid-infrared. The paper focuses on Al2O3 and Al2O3/Al cermet coatings with different metal concentrations. Microstructure and composition of the samples were characterized in order to explain their optical response that is highly dependent on volume and/or surface scattering as a function of the wavelength range. 2D scanning electron microscopy and 3D x-ray microtomography images were exploited to get statistical data in order to numerically represent simplified samples from the complex microstructure of plasma-sprayed coatings. A Monte Carlo ray-tracing model, based on geometrical optical laws, was then applied to reproduce experimental trends of the acquired optical spectra. Good agreement with the experimental data was obtained.

Ground tests with active neutron instrumentation for the planetary science missions

We present results of experimental work performed with a spare flight model of the DAN/MSL instrument in a newly built ground test facility at the Joint Institute for Nuclear Research. This instrument was selected for the tests as a flight prototype of an active neutron spectrometer applicable for future landed missions to various solid solar system bodies. In our experiment we have fabricated simplified samples of planetary material and tested the capability of neutron activation methods to detect thin layers of water/water ice lying on top of planetary dry regolith or buried within a dry regolith at different depths.

Abstract 202: The Use of Bispectral Index EEG Monitoring as a Screening Tool for the Reliable Detection of Epileptic Activity in Post--Cardiac Arrest Patients

Background: Assessment of prognosis in post[[Unable to Display Character: &amp;#8211;]]cardiac arrest (CA) patients became very challenging since the introduction of therapeutic hypothermia (TH). Continuous EEG monitoring has been proposed to improve prognostication; however, its use is limited due to difficulties in readily interpretation. This emerges the need for a simple EEG montage. The bispectral index (BIS) monitor is a simplified EEG system, mainly calculating an index ranging from 0 (isoelectric EEG) to 100 (full consciousness) to provide information on hypnotic depth of anesthesia. The aim of the study was to validate the accuracy of simplified EEG monitoring in a CA - setting. Methods: BIS monitoring (BIS VISTA TM ) was applied to collect frontotemporal data in TH-treated CA patients. A standard 19 [[Unable to Display Character: &amp;#8211;]] channel EEG was performed after return to normothermia. Afterwards, small EEG frames coincident with the time of full EEG registration were extracted from the BIS monitor. We asked 2 neurologists to indicate the presence of status epilepticus (SE), cerebral inactivity (CI), burst suppression (BS) or a diffuse slowing pattern (DS). In addition, these samples were analyzed by 2 inexperienced physicians, who were asked to indicate the presence of SE. Results: Thirty simplified EEG samples were analyzed. According to standard EEG, 11 patients showed a DS pattern, 3 had CI, 6 showed BS and 10 had an SE. Neurologists interpreted all samples with a high accuracy (sensitivity: 82% and specificity: 92%). Only 1 SE was missed by one neurologist. Interobserver reliability was high (kappa=0.843). High correlations were found for the comparison of full and simplified EEG for both neurologists (r=0.809). Further, the 2 inexperienced physicians identified SE with a sensitivity of 85% and specificity of 98%. Conclusion: Simplified EEG monitoring, using BIS, resulted in high accuracy of a simple classification system in post [[Unable to Display Character: &amp;#8211;]] CA patients. Not only neurologists, but also treating physicians were capable to identify SE, which may play an important role in the early detection of SE. We suggest using BIS as a screening tool in post [[Unable to Display Character: &amp;#8211;]] CA patients to save valuable time in the detection of SE, without replacing the need of full EEG monitoring for confirmation.

The Application of Fuzzy Data Processing Technology in the Network Failure Mining

In order to solve the coordinate problem of high redundancy and lack of stability in traditional failure mining knowledge base, this paper presents a fuzzy failure mining algorithm to realize regular acquisition in inconsistent case and purification of learning samples by the comprehensive application of fuzzy data processing technology. With characters of simplified samples, strong adaptability, high failure tolerance and not easy to fall into local minimum point, the algorithm can effectively process the diagnosis and incompatible information in network failure mining. The experiments show that the system implemented by this method improves accuracy and speed of diagnosis and has a certain application value comparing to other similar methods.

Theoretical and experimental approach of friction in a multi-samples sand-slurry tribotester

The „sand-slurry” method is wellknown among the abrasive tribotesting procedures[1-5]. Based on the DIN50322 standard defining the different tribotesting categories the number VI.category suggests the application of simplified test samples and conditions under control. At theInstitute for Mechanical Engineering Technology a new sand-slurry tribotester was developed featuredby the multi-samples holders taking different speed and load condition into account within one testrush. The resulted friction loss of the tests can be calculated by torque measurements andapproaching calculation as well. The testrig and the method is used for testing different coated steelsamples.

Acoustic properties of air-saturated porous materials containing dead-end porosity

This study examines the acoustic properties of materials with complex micro-geometry containing partially open or dead-end (DE) porosity. One of these kinds of materials can be obtained from dissolving salt grains embedded in a solid metal matrix with the help of water. The solid matrix is obtained after the metal, in liquid form, has invaded the granular material formed by the salt particles at negative pressure and high temperature, and after cooling and solidification of the metal. Comparisons between theoretical and experimental results show that the classical Johnson-Champoux-Allard model does not quite accurately predict the acoustic behavior. These results suggest that the assumptions of the Biot theory may not all be fulfilled and that cavity resonators and dead ends can be present in the material. The first part of the study proposes a simple model to account for this geometry. Based upon this model, two acoustic transfer matrices are developed: one for non-symmetric and one for symmetric dead-end porous elements. It is thought that this model can be used to study the acoustic absorption and sound transmission properties of the type of material previously described. In the second part, a series of simplified samples are proposed and tested with a three-microphone impedance tube to validate the exposed model. Finally, the third part compares the predictions of the exposed model to the impedance tube results on a real aluminum foam sample containing dead-end pores. These first results are encouraging and show that this simple model also provides a good prediction for these materials with more complicated microstructure.

Phase Identification and Internal Stress Analysis of Steamside Oxides on Plant Exposed Superheater Tubes

During long-term, high-temperature exposure of superheater tubes in thermal power plants, various oxides are formed on the inner side (steamside) of the tubes, and oxide spallation is a serious problem for the power plant industry. Most often, oxidation in a steam atmosphere is investigated in laboratory experiments just mimicking the actual conditions in the power plant for simplified samples. On real plant-exposed superheater tubes, the steamside oxides are solely investigated microscopically. The feasibility of X-ray diffraction for the characterization of steamside oxidation on real plant-exposed superheater tubes was proven in the current work; the challenges for depth-resolved phase analysis and phase-specific residual stress analysis at the inner side of the tubes with concave surface curvature are discussed. Essential differences between the steamside oxides formed on two different steels typically applied for superheaters, ferritic-martensitic X20CrMoV12-1 and lean austenitic stainless steel TP347H, respectively, are revealed by X-ray diffraction.