Application of shortened heat treatment cycles on A356 automotive brake calipers with respective globular and dendritic microstructures

Since the automotive industry has many possible applications for semi-solid metal (SSM)-high-pressure die casting (HPDC) parts, the newly developed heat treatment cycles, as well as the traditional heat treatment cycles, were applied to A356 brake calipers cast using a LK DCC630 HPDC machine.Vickers hardness measurements at a cross section of the brake calipers were performed, indicating that similar values can be obtained when using the significantly shorter heat treatment cycles.Finally, the typical tensile properties that can be obtained for SSM-HPDC A356 brake calipers are compared with those manufactured by gravity die casting.Results indicate that the differences in microstructures (globular or dendritic) do not have a noteworthy effect on the heat treatment response.This implies that the short heat treatment cycles originally developed for globular SSM-HPDC A356 castings can be successfully applied to dendritic liquid A356 castings too.

Development of the 3D-Designed Lathe Fixture of a Float Brake Caliper

According to the technique requests of the brake caliper in the process of production, a special fixture of float brake caliper has been developed based on 3 D design in this paper. The development process and verified data from 3D modeling and kinematics simulation for this special fixture show that this 3D-designed process can conveniently forecast the assembly interference of the fixture and accurately add the mass of lead brick before the prototype is made. In this way the flutter caused by the unbalanced lathe fixture can be eliminated and the precision of run-out tolerance in cylinder hole compared with machine tool spindle can be improved, thus the processing quality of the cylinder hole in a brake caliper can be greatly guaranteed.

Volumetric measurement techniques for assessment of cutaneous neurofibromas:A review

Cutaneous neurofibroma(cNF)is a prevalent clinical manifestation of neurofibromatosis type 1,significantly affecting the well-being and quality of life of the affected individuals.The adoption of reliable and reproducible volumetric measurement techniques is essential for precisely evaluating tumor burden and plays a critical role in the development of effective treatments for cNF.This study focuses on widely used volumetric measurement techniques,including vernier calipers,ultrasound,computed tomography,magnetic resonance imaging,and three-dimensional scanning imaging.It outlines the merits and drawbacks of each technique in assessing the cNF load,providing an overview of their current applications and ongoing research advancements in this domain.

In-situ stress inversion in Liard Basin, Canada, from caliper logs

This paper proposes an integrated method of analytical calculation,artificial intelligence,and probabilistic analysis to cost-effectively determine geomechanical properties and in-situ stresses from borehole deformation via caliper logs.It's also demonstrated in this paper that the actual borehole size can not be simply taken as the bit size by default,and adjusted borehole size has to be used to find the reasonable borehole deformation.In the proposed method,an artificial neural network(ANN)is applied to map the relationship among in-situ stress,adjusted borehole size,geomechanical properties,and borehole displacements.The genetic algorithm(GA)searches for the set of unknown stresses and geomechanical properties that match the objective borehole deformation function.Probabilistic analysis is conducted after ANN-GA modeling to estimate the most possible ranges of the parameters.The hybrid method has been demonstrated by a field case study to estimate the adjusted borehole size,Young's modulus,and the two horizontal in-situ stresses using borehole deformation information reported from four-arm caliper logs of a vertical borehole in Liard Basin in Canada.

Associations between Sow Body Lesions with Body Condition and Subsequent Reproductive Performance

The objective was to determine the association between foot, leg, vulva and shoulder lesions with body condition and reproduction in group housed sows. Whiteline sows (n = 887) were measured before farrowing and at weaning at a commercial farm in eastern North Carolina. Foot and leg abnormalities included cracked hooves, toe length differences, overgrown hooves and locomotion. Vulva lesions were scored no lesion or lesion present. Shoulder lesions were scored no lesion, abrasion or open wound. Sow body condition measures included the Knauer sow caliper (CS), body weight (WT), visual body condition score (BCS), backfat (BF) and longissimus muscle area (LMA). Sow production traits included number born alive, litter birth weight, number weaned, litter weaning weight, piglet survival (number weaned ÷ (total number born + net transfer)), wean-to-conception interval and average daily lactation feed intake. Data were analyzed in SAS using PROC GLM for continuous traits and PROC GLIMMIX for categorical traits. Vulva lesions were recorded on 17.6% of sows at farrowing and 0% at weaning. No shoulder lesions, abrasions and open wounds were recorded on 100%, 0% and 0%, respectively, of sows at farrowing and 73%, 21% and 6%, respectively, at weaning. Foot and leg abnormalities were not associated with body condition or reproduction. Vulva lesions at farrowing were associated with lower CS, WT, BCS and BF at farrowing, and reduced piglet survival (4.3%). Lower CS at farrowing was associated with increased shoulder abrasions and open wounds at weaning. Backfat and BCS at farrowing had curvilinear associations with shoulder lesions at weaning, a BF of 39 mm and a BCS of 4.2 minimizing lesions. Results suggest vulva and shoulder lesions were associated with thinner sows at farrowing and vulva lesions at farrowing were associated with lower piglet survival.

Associations between Sow Body Condition with Subsequent Reproductive Performance

The objective was to quantify relationships between sow body condition and subsequent reproduction. Multiparous sows were measured at breeding (n = 1571) and farrowing (n = 887) on a commercial farm in eastern North Carolina. Sow body condition measures included: sow body condition caliper (CS), weight (BW), backfat, longissimus muscle area (LMA) and visual body condition score (BCS). Sow production traits were: number born alive (NBA), litter birth weight (LBW), number weaned (NW), piglet survival (PS), litter weaning weight (LWW), wean-to-conception interval (WCI), farrowing rate and lactation average daily feed intake. Data were analyzed in SAS using PROC GLM for continuous traits and PROC GLIMMIX for categorical traits. Breeding CS had a curvilinear relationship (P 0.05) with NBA, LBW, NW, PS and WCI, with a CS of 15 being optimal for NBA, NW and PS and 14 ideal for LBW and WCI. Breeding LMA had a curvilinear relationship (P 0.05) with PS, with 51.5 cm2 maximizing survival. Breeding BCS had a curvilinear relationship (P 0.05) with NBA, LBW, NW, PS and WCI, with 3.2 being optimal for NBA, NW and WCI and 3.0 ideal for LBW and PS. Farrowing CS had a curvilinear relationship (P 0.05) with NW and PS, with 15 being optimal. Farrowing BCS had a curvilinear relationship (P 0.05) with NW and PS, with 3.6 being ideal. Farrowing BW had a curvilinear relationship (P 0.05) with LWW and PS, with a BW of 220 and 210 kg, respectively, being optimal. Farrowing LMA had a curvilinear relationship (P 0.05) with WCI, with 51.6 cm2 being ideal. Results provide sow body condition targets to maximize reproductive throughput. The present study suggests feeding sows to a target sow body condition caliper score of 14 to 15 (representing a back angle of 130˚ to 132.5˚) to maximize sow productivity.

Kinematically Aligned Total Knee Arthroplasty for Valgus Osteoarthritis of More than 10°―Is It Still a “Challenging Surgery”?

Mechanically aligned total knee arthroplasty (TKA) for valgus knee is considered a “challenging surgery.” Recently, the kinematic alignment (KA) method has gained attention. This study aimed to present objective clinical data, such as intraoperative balance assessment and radiographic evaluation of postoperative lower extremity alignment after TKA using the KA method for valgus deformity. Twenty-one TKA knees (mean age, 74 years;2 males, 19 females) with KA for severe valgus deformity (hip-knee-ankle-angle ≥ 10°) performed at our department in the past 3 years were included in this study. Intraoperative gap and balance measurements and postoperative radiographic evaluation were performed. A total arc of range of motion was achieved up to 98% of preoperative values at 3 weeks postoperatively. Intraoperative gap and balance were stable throughout the entire range of motion. In addition, there were no statistically significant differences in either balance or gap values at each flexion angle. KA TKA is a “simple surgery” rather than a “challenging surgery” because additional soft tissue procedures are not required, operative time is short, intraoperative and postoperative balance is very stable, and a good alignment is achieved. This procedure may relieve surgeons of the stress of TKA for valgus deformities.

学习分析技术规范比较研究

随着大数据技术对教育的影响日趋深入,基于大数据的学习分析逐渐被应用于教育领域,对教育教学产生深刻影响。然而,目前各类学习系统或平台在数据采集、分析、处理、展示方面都有其专有形式,通用化程度低,不利于学习分析技术的推广应用。为应对这一问题,适时开展学习分析技术规范的国际比较研究,充分掌握现有规范的特点和不足,进而制定我国的自有标准,显得十分迫切和必要。本文从学习分析的概念界定入手,介绍与学习分析相关的分析模型、分析方法和分析工具,重点分析ADL、IMS和ISO/IEC三大标准组织制定的学习分析技术规范,并从学习数据记录存储流程、学习活动模型以及传输机制等方面剖析学习分析技术规范的内涵,然后从数据模型、服务接口与安全传输机制、标准间的映射关系、应用系统范畴四方面对当前国际主流的Caliper Analytics和xAPI两个学习分析技术规范进行比较,解析两者间的不同点和内在联系。文章最后从促进教育变革、助力学习者全面发展、基本数据与技术规范统一、制度保障等角度阐述学习分析技术对教育信息化教学的重要影响以及促进学习分析应用要关注的问题,以期对我国学习分析技术规范的制定提供参考。

Comparison of Multimodality Image-Based Volumes in Preclinical Tumor Models Using <i>In-Air</i>Micro-CT Image Volume as Reference Tumor Volume

Purpose: Changes in tumor volume are used for therapy response monitoring in preclinical studies. Unlike prior studies, this article introduces in-air micro-computed tomography (micro-CT) image volume as reference tumor volume in rodent tumor models. Tumor volumes determined using imaging modalities such as magnetic resonance imaging (MRI), micro-CT and ultrasound (US), and with an external caliper are compared with the reference tumor volume. Materials and Methods: In vivo MR, US and micro-CT imaging was performed 4, 6, 9, 11 and 13 days after tumor cell inoculation into nude rats. On the day of the imaging study, in vivo caliper measurements were also made. After in vivo imaging, tumors were excised followed by in-air micro-CT imaging and ex vivo caliper measurements of excised tumors. The in-air micro-CT image volume of excised tumors was determined as reference tumor volume. Then tumor volumes were calculated using formula V = (π/6) × a × b × c, where a, b and c are maximum diameters in three perpendicular dimensions determined by the three image modalities and caliper, and compared with reference tumor volume by linear regression analysis as well as Bland-Altman plots. Results: The correlation coefficients (R2) of the regression lines for in vivo tumor volumes measured by the three imaging modalities were 0.9939, 0.9669 and 0.9806 for MRI, US and micro-CT respectively. For caliper measurements, the coefficients were 0.9274 and 0.9819 for caliperin vivo and caliperex vivo respectively. In Bland-Altman plots, the average of tumor volume difference from reference tumor volume (bias) was significant for caliper and micro-CT, but not for MRI and US. Conclusion: Using the in-air micro-CT image volume as reference tumor volume, tumor volume measured by MRI was the most accurate among the three imaging modalities. In vivo caliper volume measurements showed unreliability while ex vivo caliper measurements reduced errors.

Determine Stability Wellbore Utilizing by Artificial Intelligence Systems and Estimation of Elastic Coefficients of Reservoir Rock

Rock elastic properties such as Young’s modulus, Poisson?s ratio, plays an important role in various stages upstream of such as borehole stability, hydraulic fracturing in laboratory scale for observing mechanical properties of the reservoir rock usually using conventional cores sample that obtained from underground in reservoir condition. This method is the most common and most reliable way to get the reservoir rock properties, but it has some weaknesses. Currently, neural network techniques have replaced usual laboratory methods because they can do a similar operation faster and more accurately. To obtain the elastic coefficient, we should have compressional wave velocity (VP), shear wave (Vs) and density bulk due to high cost of (Vs) measurement and low real ability of estimation through the (Vp) and porosity. Therefore in this study, neural networks were used as a suitable method for estimating shear wave, and then elastic coefficients of reservoir rock using different relationships were predicted. Neural network used in this study was not like a black box because we used the results of multiple regression that could easily modify prediction of (Vs) through appropriate combination of data. The same information that were intended for multiple regression were used as input in neural networks, and shear wave velocity was obtained using (Vp) and well logging data in carbonate rocks. The results showed that methods applied in this carbonate reservoir was successful, so that shear wave velocity was predicted with about 92% and 95% correlation coefficient in multiple regression and neural network method, respectively.

Fully automatic identification and discrimination of sperm’s parts in microscopic images of stained human semen smear

In the last years, digital image processing and analysis are used for computer assisted evaluation of semen quality with therapeutic goals or to estimate its fertility by means of spermatozoid motility and morphology. Sperm morphology is assessed routinely as part of standard laboratory analysis in the diagnosis of human male infertility. Nowadays assessments of sperm morphology are mostly done based on subjective criteria. In order to avoid subjectivity, numerous studies that incorporate image analysis techniques in the assessment of sperm morphology have been proposed. The primary step of all these methods is segmentation of sperm’s parts. In this paper, we have proposed a new method for segmentation of sperm’s Acrosome, Nucleus, Mid-piece and identification of sperm’s tail through some points which are placed on the sperm’s tail, accurately. These estimated points could be used to verify the morphological characteristics of sperm’s tail such as length, shape and etc. At first, sperm’s Acrosome, Nucleus and Mid-piece are segmented through a method based on a Bayesian classifier which utilizes the entropy based expectation–maximization (EM) algorithm and Markov random field (MRF) model to obtain and upgrade the class conditional probability density function (CCPDF) and the apriori probability of each class. Then, a pixel at the end of sperm’s Mid-piece, is selected as an initial point. To find other pixels which are placed on the sperm’s tail, structural similarity index (SSIM) is used in an iterative scheme. In order to stop the algorithm automatically at the end of sperm’s tail, local entropy is estimated and used as a feature to determine if a point is located on the sperm’s tail or not. To compare the performance of the proposed approach with those of previous approaches including manual segmentation, the Accuracy, Sensitivity and Specificity were calculated.

An Experimental Study on Measurement Methods of Bulk Density and Porosity of Rock Samples

Density and porosity are fundamental and important physical properties of rocks in various geological problems, and affect the other physical properties. Therefore, measurements of density and porosity of rock samples are important investigation items in both geo-science and geo-engineering areas. Several measurement techniques of the density and porosity are available and being applied currently. To ensure the data quality and to conduct its quality assessment, comparison of measurement results by different measurement techniques is necessary since the techniques are based on different principles and test procedures. In this study, we collected eight types of rock samples including a gabbro, a granite, four sandstones, a welded tuff and a mudstone as study materials, and also prepared several metal specimens for the experimental comparison. The porosities of the eight rocks covered a very wide range from 0.3% to 50% approximately. We employed three methods (caliper, buoyancy and helium-displacement pycnometer) to measure volumes of regularly-shaped specimens and to determine their bulk densities and porosities. As a result, the three techniques yielded almost same bulk densities and porosities for all the specimens. In addition, we also applied mercury intrusion porosimetry to measure density and porosity as well as to determine pore size distribution of the rock samples. Porosity values obtained by the porosimetry method were underestimated in the case of high-porosity (soft) rock samples and overestimated for the very low-porosity rock samples. Ability to determine pore size distribution, however, is a very important advantage of the porosimetry method.

Coronal Alignment of Three Different Types of Implants in Kinematically Aligned Total Knee Arthroplasty: A Comparative Study

Background: The number of total knee arthroplasty (TKA) surgeries performed each year is increasing worldwide and mechanical alignment (MA) is currently seen as the gold standard procedure. However, taking neutral alignment as the universal goal may be mistaken. In our hospital, we currently conduct kinematically aligned TKA (KA-TKA). Three different types of implants are used: the cruciate-retaining (CR) type, cruciate-sacrificing (CS) type, or bi-cruciate-retained (BCR) type. We aimed to compare the coronal alignment observed following KA-TKA and MA-TKA and in normal knees, as well as that achieved with different types of implants. Methods: The study comprised 206 knees of Japanese patients who underwent KA-TKA using varying implants in our Hospital between May 2019 and April 2020. Measurements of pre- and postoperative coronal alignment were determined from weight-bearing full-leg standing radiographs. The postoperative results were compared to measurements taken from patients who underwent MA-TKA (N = 96) and normal knees (N = 60). Results: No significant differences between the KA-TKA group and normal knees were found for the medial proximal tibial angle (MPTA) (–4.2° ± 2.6° vs –3.8° ± 2.5°) or joint line orientation angle (JLOA) (0.2° ± 1.9° vs 0.3° ± 1.4°). However, when MA-TKA was compared to KA-TKA and normal knees, there were significant differences in both the MPTA and JLOA (p < 0.01). Furthermore, for the different implant types, MPTA exhibited significantly greater varus alignment when a CS-type was used than with the other two. Conclusions: Here, we demonstrated that following KA-TKA, the articular surface of the tibia exhibited a similar varus alignment as that of normal knees, meaning that the technique reproduces the native knee. Furthermore, KA is patient-specific, and does not have the same failures as MA-TKA. Therefore, we anticipate a paradigm shift from mechanical to kinematic alignment, which may help reduce the dissatisfaction rate of TKA patients.

Characteristics analysis and parameters optimization for the grating eddy current displacement sensor

The grating eddy current displacement sensor (GECDS) for distance or position measurement used in watertight electronic calipers was described. The sensor relies on repetitive variation of inductance against displacement caused by the change of coupling areas between moving coils and static reflectors. The investigations focused on setting up and utilizing a computer model of the 3D eddy current fields and geometry to analyze causes of the production of measurement blind areas, and to investigate effects of the sensor parameters, such as axial gap between coils and reflectors, reflector length and reflector width on characteristics of the sensor. Simulation results indicated that the sensor has the smallest nonlinearity error of 0.15%, which agrees well with the experimental results.