grinding

研磨
  • 文章类型: Journal Article
    已知苯并咪唑化合物具有广谱的治疗潜力。通过一锅伸缩研磨方法设计并合成了苯并咪唑衍生物的小型库。这些分子作为提出的抗癌剂的能力是通过它们与两个重要的癌症途径蛋白靶标结合的潜力来评估的。人雌激素受体和细胞周期蛋白依赖性激酶,3ERT和5FGK分别。进一步的核酸结合和活性氧(ROS)清除能力在抗癌潜力评估的范围内,这些分子的能力也被评估了。Further,为了支持实验和计算结果,使用AI辅助工具来预测抗癌活性(PASS)以及识别假阳性(PAINS)。此外,通过遵循其药代动力学参数-ADME评估拟议化合物的可药用性。
    Benzimidazole compounds are known for their broad spectrum therapeutic potentials. A small library of benzimidazole derivatives were designed and synthesized via a one-pot telescopic grinding approach. The ability of these molecules as proposed anticancer agents were evaluated by their potential to bind to two important cancer pathway protein targets, human estrogen receptors and cyclin dependant kinases, 3ERT and 5FGK respectively. Further nucleic acid binding and reactive oxygen species (ROS) scavenging capacity being in the scope for anticancer potential evaluations, the ability of these molecules have been evaluated for the same. Further, to support the experimental and computational results, AI-assisted tools were employed to predict the anticancer activity (PASS) as well as to identify false positives (PAINS). Also, the druggability of the proposed compounds was evaluated by following their pharmacokinetic parameters - ADME.
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  • 文章类型: Journal Article
    目的是确定豆粕(SBM)和全麦颗粒大小的相互作用。大麦和麦麸(CER)对产肠毒素大肠杆菌F4攻击后断奶猪的生长性能(实验1)和断奶后立即的胃肠道(GIT)发育(实验2)。实验1由192头猪(24±3日龄;7.4±1.1kg断奶体重[BW])组成,选择用于大肠杆菌(E.大肠杆菌)F4敏感性。在断奶后第7天给予猪口服大肠杆菌接种物,以诱导肠道健康挑战。实验2由40头猪(24±3日龄;7.2±1.0kg断奶BW)组成,这些猪在断奶后第8天或第9天被杀死,以确定粒径对GIT发育和功能的影响。在2×2阶乘设计中使用了四种实验饮食:(1)粗CER和粗SBM,(2)粗CER和细SBM(CERcSBMf),(3)细CER和粗SBM,或(4)优良的CER和优良的SBM(CERFSBMF)。结果表明,SBM和CER粗糙度对生长性能没有交互作用,GIT开发和功能。与其他饮食相比,在大肠杆菌攻击后的2周内,CERFSBMf的腹泻发生率更高(p<0.05)。与CERF相比,饲喂CERC的猪在此期间的日增重和采食量更高(p<0.05)。与CERF相比,CERC的空胃重量倾向于增加8%(p=0.09)。与SBMc相比,SBMf的胃蛋白(p=0.05)和淀粉(p=0.04)消失更多。因此,在大肠杆菌攻击后的2周内,CERcSBMF产生了最佳的生长性能和最低的腹泻发生率。这可以通过胃功能的变化来解释,但不能通过GIT其他部分的变化来解释。
    The objectives were to determine the interactive effect of particle size of soyabean meal (SBM) and whole wheat, barley and wheat bran (CER) on growth performance of weanling pigs after an enterotoxigenic Escherichia coli F4 challenge (Experiment 1) and on gastrointestinal (GIT) development immediately after weaning (Experiment 2). Experiment 1 consisted of 192 pigs (24 ± 3 days of age; 7.4 ± 1.1 kg weaning bodyweight [BW]) selected for Escherichia coli (E. coli) F4 susceptibility. Pigs were given an oral E. coli inoculum at postweaning day 7, to induce an enteric health challenge. Experiment 2 consisted of 40 pigs (24 ± 3 days of age; 7.2 ± 1.0 kg weaning BW) that were killed on postweaning day 8 or 9, to determine the effects of particle size on GIT development and functionality. Four experimental diets were used in a 2 × 2 factorial design: (1) coarse CER and coarse SBM, (2) coarse CER and fine SBM (CERcSBMf), (3) fine CER and coarse SBM, or (4) fine CER and fine SBM (CERfSBMf). Results showed no interaction between SBM and CER coarseness on growth performance, GIT development and functionality. Diarrhoea incidence was higher (p < 0.05) for CERfSBMf during the 2 weeks following the E. coli challenge compared to the other diets. Daily gain and feed intake during this period were higher (p < 0.05) for pigs fed CERc compared to CERf. Empty stomach weight tended to be greater by 8% (p = 0.09) for CERc compared to CERf. Gastric protein (p = 0.05) and starch (p = 0.04) disappearances were greater for SBMf compared to SBMc. Thus, CERcSBMf resulted in the best growth performance and lowest diarrhoea incidence during the 2 weeks following the E. coli challenge, which may be explained by changes in stomach functionality but not by changes in other parts of the GIT.
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  • 文章类型: Journal Article
    这项研究检查了酸水解的影响,节奏氧化,和物理上的机械研磨,热,α-几丁质纳米晶和纳米纤维的结构性质。制造方法可能会影响直径,功能组,和所得纳米颗粒的晶体图案。对DLS结果的分析揭示酸性纳米晶体的尺寸更小并且显示出改善的分散性。XRD图表明化学和机械处理没有改变α-壳多糖的结晶排列。FT-IR光谱分析显示化学和机械方法不影响纳米颗粒的官能团。DSC结果表明,纳米粒子在400℃以下具有良好的热稳定性,并且发现纳米纤维由于其更长的长度而具有更好的耐热性。在FE-SEM图像中,观察到纳米颗粒为长度超过100nm的纤维垫。还发现纳米颗粒的直径小于100nm。
    This study examined the impact of acid hydrolysis, tempo oxidation, and mechanical grinding on the physical, thermal, and structural properties of α-chitin nanocrystals and nanofibers. The manufacturing methods could influence the diameter, functional groups, and crystal patterns of the resulting nanoparticles. Analysis of the DLS results revealed that the size of acidic nanocrystals were smaller and showed improved dispersibility. The XRD patterns indicated that the chemical and mechanical treatments did not alter the crystalline arrangement of the α-chitin. FT-IR spectra analysis revealed that the chemical and mechanical methods did not affect the functional groups of the nanoparticles. DSC results showed that the nanoparticles had good thermal stability up to 400 °C, and it was found that the nanofibers had better thermal resistance due to their longer length. In the FE-SEM images, the nanoparticles were observed as fiber mats with a length of more than 100 nm. It was also found that the diameter of the nanoparticles was less than 100 nm.
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  • 文章类型: Journal Article
    SiC陶瓷通常是硬且脆的材料。由于单晶金刚石磨粒的自锐能力差,在研磨过程中会发生严重的表面/亚表面损伤。然而,最近的研究结果表明,多孔金刚石颗粒可以实现高效率和低损伤加工。然而,多孔金刚石磨粒在磨削SiC陶瓷材料时的去除机理研究仍处于瓶颈阶段。建立了研磨SiC陶瓷时多孔金刚石磨粒的离散元仿真模型,以优化研磨参数(例如,砂轮速度,未变形的切屑厚度)和孔参数(例如,多孔金刚石砂砾的切削刃密度)。从微观角度探讨了上述参数对SiC陶瓷去除和损伤的影响,与单晶金刚石颗粒相比。结果表明,多孔金刚石磨粒对SiC陶瓷的损伤较小,比单晶金刚石磨粒具有更好的磨削性能。此外,最佳切削刃密度和未变形切屑厚度应控制在1-3和1-2um,分别,砂轮转速应大于80m/s。研究成果为以SiC陶瓷为代表的硬脆材料的高效低损伤磨削奠定了科学基础,具有理论意义和实用价值。
    SiC ceramics are typically hard and brittle materials. Serious surface/subsurface damage occurs during the grinding process due to the poor self-sharpening ability of monocrystalline diamond grits. Nevertheless, recent findings have demonstrated that porous diamond grits can achieve high-efficiency and low-damage machining. However, research on the removal mechanism of porous diamond grit while grinding SiC ceramic materials is still in the bottleneck stage. A discrete element simulation model of the porous diamond grit while grinding SiC ceramics was established to optimize the grinding parameters (e.g., grinding wheel speed, undeformed chip thickness) and pore parameters (e.g., cutting edge density) of the porous diamond grit. The influence of these above parameters on the removal and damage of SiC ceramics was explored from a microscopic perspective, comparing with monocrystalline diamond grit. The results show that porous diamond grits cause less damage to SiC ceramics and have better grinding performance than monocrystalline diamond grits. In addition, the optimal cutting edge density and undeformed chip thickness should be controlled at 1-3 and 1-2 um, respectively, and the grinding wheel speed should be greater than 80 m/s. The research results lay a scientific foundation for the efficient and low-damage grinding of hard and brittle materials represented by SiC ceramics, exhibiting theoretical significance and practical value.
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  • 文章类型: Journal Article
    薄壁轴承因其结构轻巧的优点而得到广泛应用,高硬度,和强大的承载能力。然而,薄壁轴承在加工过程中往往容易变形,会严重影响轴承的性能。此外,轴承的加工变形和质量难以平衡。为了解决上述问题,本文研究了加工参数对加工变形的影响,表面质量,薄壁轴承在粗加工阶段的加工效率。研究了粗磨中变形抑制与高质量之间的动态平衡,得到了薄壁轴承外圈磨削的最优参数。通过仿真和实验分析揭示了薄壁轴承磨削变形的机理。结果表明,当工件速度为55r/min时,加工变形与质量达到平衡,砂轮转速为2000r/min,进料速率为0.1mm/min。变形随工件速度和砂轮速度的增加而增加。同时,表面粗糙度随着工件速度的增加而增加,但是车轮速度的增加会改善表面粗糙度。随着工件速度的增加,表面形貌显示出更明显的材料储备,通过增加砂轮速度来改善。随着工件旋转速度的增加,每单位时间内过程中涉及的磨粒数量减少,工件的表面去除效果较差,而砂轮旋转速度的增加具有相反的效果。薄壁轴承的磨削变形主要是由加工热和应力引起的。随着转速的增加,在研磨区的热通量增加。更多的热通量流入工件表面,导致轴承套环内表面上的热应力增加,导致更大的变形。磨削区域的温度可以在加工过程中降低,实现变形的减少。研究内容有助于在加工过程中实现高质量和低变形之间的平衡。
    Thin-walled bearings are widely used owing to the advantages of their light structure, high hardness, and strong load-carrying capacity. However, thin-walled bearings are often prone to deformation during the machining process, which can seriously affect the performance of the bearings. In addition, the machining deformation and quality of bearings are difficult to balance. To address the above issues, this paper investigates the effects of the machining parameters on the machining deformation, surface quality, and machining efficiency of a thin-walled bearing during the roughing stage. The dynamic balance between deformation inhibition and high quality in rough grinding was studied, and the optimal parameters for thin-walled bearing outer ring grinding were obtained. The deformation mechanism of thin-walled bearings caused by grinding was revealed through simulation and experimental analysis. The results show that the machining deformation and quality reach a balance when the workpiece speed is 55 r/min, the grinding wheel rotational speed is 2000 r/min, and the feed rate is 0.1 mm/min. Deformation increases with the increase in workpiece speed and grinding wheel speed. At the same time, the surface roughness increases with the increase in the workpiece speed, but the increase in the wheel speed will improve the surface roughness. As the workpiece speed increases, the surface topography shows a more pronounced stockpile of material, which is ameliorated by an increase in grinding wheel speed. As the rotational speed of the workpiece increases, the number of abrasive grains involved in the process per unit of time decreases, and the surface removal of the workpiece is less effective, while the increase in the rotational speed of the grinding wheel has the opposite effect. The grinding deformation of thin-walled bearings is mainly induced by machining heat and stress. As the rotational speed increases, the heat flux in the grinding zone increases. More heat flux flows into the surface of the workpiece, causing an increase in thermal stresses on the inner surface of the bearing collar, leading to greater deformation. The temperature in the grinding area can be reduced during machining, realizing a reduction in deformation. The research content contributes to the balance between high quality and low distortion in machining processes.
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  • 文章类型: Journal Article
    砂轮通常通过粉末冶金工艺制造,即,通过成型和烧结。由于这需要生产特殊的模具,并且烧结通常在连续炉中进行,这个过程是耗时和成本密集的。因此,只有中大批量才值得。粉末冶金工艺路线的另一个影响因素是烧结过程中的高热负荷。由于其高的热敏感性,如金刚石或立方氮化硼等超硬材料很难以这种方式加工。在这项研究中,提出了一种新颖创新的方法,其中超磨料砂轮是通过热喷涂制造的。为此,扁平样品以及砂轮体通过低压(LP)冷气体喷涂与商用Cu-Al2O3冷气体喷涂粉末和镍涂层金刚石的混合物进行涂层。根据其组成对金相检查涂层。实现了12%的充分嵌入的超级磨料含量。喷涂过程后,对砂轮进行调节和测试,以用于硬质合金的磨削应用,并评估砂轮和硬质合金的形貌。达到了与其他精加工工艺相当的研磨表面的表面质量。这种新颖的工艺路线在粘合剂和硬质材料的组合中提供了极大的灵活性,以及具有成本效益的单部分和小批量生产。
    Grinding wheels are usually manufactured by powder metallurgical processes, i.e., by molding and sintering. Since this requires the production of special molds and the sintering is typically carried out in a continuous furnace, this process is time-consuming and cost-intensive. Therefore, it is only worthwhile for medium and large batches. Another influencing factor of the powder metallurgical process route is the high thermal load during the sintering process. Due to their high thermal sensitivity, superabrasives such as diamond or cubic boron nitride are very difficult to process in this way. In this study, a novel and innovative approach is presented, in which superabrasive grinding wheels are manufactured by thermal spraying. For this purpose, flat samples as well as grinding wheel bodies were coated by low-pressure (LP) cold gas spraying with a blend of a commercial Cu-Al2O3 cold gas spraying powder and nickel-coated diamonds. The coatings were examined metallographically in terms of their composition. A well-embedded superabrasive content of 12 % was achieved. After the spraying process, the grinding wheels were conditioned and tested for the grinding application of cemented carbides and the topographies of both the grinding wheel and the cemented carbide were evaluated. Surface qualities of the ground surface that are comparable to those of other finishing processes were reached. This novel process route offers great flexibility in the combination of binder and hard material as well as a cost-effective single-part and small-batch production.
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  • 文章类型: Journal Article
    本文介绍了磨削工艺优化的选定方面,考虑到这一过程的特有概率特征。指出了研磨过程的特征,这些特征会影响优化过程中用于定义目标和限制的数量的显着分散。注意了使用研究结果不确定的原因,信息提取程序的缺陷以及在优化程序中使用模拟和回归模型的数据量有限。分析了在磨削工艺优化程序中确定磨具耐久性的问题。规定了定义刀具寿命的方法,考虑到受控过程参数值的分散性。在描述研磨效率和成本的关系中考虑了干扰的影响。确定了考虑过程的概率性质的优化的好处。
    The paper describes selected aspects of the optimization of grinding processes, taking into account the characteristic probabilistic features of this process. Characteristic features of the grinding process that influence the significant dispersion of the quantities used in the optimization process to define goals and limitations are indicated. Attention was paid to the reasons for uncertainty in the use of research results, imperfections in information extraction procedures and the limited amount of data in the use of simulation and regression models in optimization procedures. The issue of determining the durability of abrasive tools in grinding process optimization procedures was analyzed. Methodologies for defining tool life are specified, taking into account the dispersion of the values of controlled process parameters. The effects of interference were taken into account in the relationships describing grinding efficiency and costs. The benefits of optimization taking into account the probabilistic nature of the process were determined.
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  • 文章类型: Journal Article
    由于航空航天等高附加值行业的需求不断增长,电子移动性或生物医学结合研磨技术是实现极端要求的关键。在研磨过程中,能量作为热量迅速消散,在地面部分产生热场,其特征是高温和非常陡峭的梯度。地面部分的后果被广泛地称为磨削烧伤。因此,磨削过程中工件温度的测量已成为一个关键问题。许多技术已用于磨削中的温度测量,其中,所谓的可磨热电偶显示出巨大的潜力,并已成功用于蠕变进给研磨操作,其中表速度低,因此,温度梯度不是很陡。然而,在具有更快的工作台速度的常规研磨操作中,正如大多数工业运营一样,热电偶响应的延迟导致最大测量值的较大误差。在本文中,研究了对可研磨热电偶响应的精确校准的必要性,作为信号积分校正热惯性的优先步骤。结果表明,如果直接使用来自热电偶的原始信号,最大温度相对于理论模型的偏差超过200K。即使对于高达40m/min的进给速度和低于20K的进给速度,误差也可以降低到93K。主要结论是,按照提议的程序,最高磨削温度可以有效地测量使用可磨热电偶即使在高值的表速度。
    Due to the continuously growing demands from high-added-value sectors such as aerospace, e-mobility or biomedical bound-abrasive technologies are the key to achieving extreme requirements. During grinding, energy is rapidly dissipated as heat, generating thermal fields on the ground part which are characterized by high temperatures and very steep gradients. The consequences on the ground part are broadly known as grinding burn. Therefore, the measurement of workpiece temperature during grinding has become a critical issue. Many techniques have been used for temperature measurement in grinding, amongst which, the so-called grindable thermocouples exhibit great potential and have been successfully used in creep-feed grinding operations, in which table speed is low, and therefore, temperature gradients are not very steep. However, in conventional grinding operations with faster table speeds, as most industrial operations are, the delay in the response of the thermocouple results in large errors in the maximum measured value. In this paper, the need for accurate calibration of the response of grindable thermocouples is studied as a prior step for signal integration to correct thermal inertia. The results show that, if the raw signal is directly used from the thermocouples, the deviation in the maximum temperature with respect to the theoretical model is over 200 K. After integration using the calibration constants obtained for the ground junction, the error can be reduced to 93 K even for feed speeds as high as 40 m/min and below 20 K for lower feed speeds. The main conclusion is that, following the proposed procedure, maximum grinding temperatures can be effectively measured using grindable thermocouples even at high values of table speed.
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  • 文章类型: Journal Article
    每年至少有2000亿只黑色士兵苍蝇(Hermetiaillucens)幼虫(BSFL)作为食物和饲料饲养,昆虫养殖业预计将迅速发展。尽管受到消费者的关注,生产者,和立法者,没有经验证据可以指导生产者对这些新颖的小型牲畜进行人道或即时屠宰。BSFL可以通过冷冻屠宰,沸腾,研磨,或其他方法;然而,标准操作程序(SOP)和设备设计可能会影响使用这些方法的瞬间死亡的可能性。我们测试了使用标准绞肉机屠宰的黑兵蝇幼虫的幼虫体大小和粒径板孔径如何影响瞬时死亡的可能性。幼虫的体型不会影响质量为106-175mg的幼虫瞬间死亡的可能性。然而,颗粒大小板孔径对瞬时死亡的可能性有显著影响,使用最大粒径板(12毫米孔直径)时,只有54%的幼虫立即死亡,而使用最小粒径板(2.55毫米)的比例为84%。然而,通过减少被困在机器中的幼虫的比例,可以实现更高的瞬时死亡百分比(高达99%)。最后,我们概述了具体建议,以支持生产者通过与类似设计的机器一起使用的特定SOP实现99%的瞬时死亡率。我们还为希望测试自己的研磨SOP的生产商制定了协议。
    At least 200 billion black soldier fly (Hermetia illucens) larvae (BSFL) are reared each year as food and feed, and the insect farming industry is projected to grow rapidly. Despite interest by consumers, producers, and legislators, no empirical evidence exists to guide producers in practicing humane - or instantaneous - slaughter for these novel mini-livestock. BSFL may be slaughtered via freezing, boiling, grinding, or other methods; however standard operating procedures (SOPs) and equipment design may affect the likelihood of instantaneous death using these methods. We tested how larval body size and particle size plate hole diameter affect the likelihood of instantaneous death for black soldier fly larvae that are slaughtered using a standard meat grinder. Larval body size did not affect the likelihood of instantaneous death for larvae that are 106-175 mg in mass. However, particle size plate hole diameter had a significant effect on the likelihood of instantaneous death, with only 54% of larvae experiencing an instant death when using the largest particle size plate (12-mm hole diameter) compared to 84% using the smallest particle size plate (2.55 mm). However, a higher percentage of instantaneous death (up to 99%) could be achieved by reducing the proportion of larvae that become stuck in the machine. We conclude by outlining specific recommendations to support producers in achieving a 99% instantaneous death rate through specific SOPs to be used with similarly designed machines. We also develop a protocol for producers that wish to test their own grinding SOPs.
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  • 文章类型: Journal Article
    描述一种新颖的手术技术,旨在接近位于地球赤道上方和后方的眼眶病变。
    我们描述了一种新颖的手术技术,该技术在四名患者中进行,以接近眶内肿瘤的上方和后方。此技术是通过上眼睑皮肤折痕完成的,然后研磨上眶缘以完全去除病变。
    在每种情况下都完成了病变的完全切除。所有患者均未出现术中并发症。在后续期间,1例患者出现额叶过敏和1例复视。
    在介绍的案例系列中,在我们的系列中,上眼睑皮肤折痕入路磨眶上缘被证明是一种安全有效的手术技术,可以去除位于眼眶上方和后方的病变。需要更多的研究来进一步评估这种方法的疗效和长期结果。
    UNASSIGNED: To describe a novel surgical technique aimed to approach those orbital lesions located superior and posterior to the equator of the globe.
    UNASSIGNED: We describe a novel surgical technique that was performed in four patients to approach intraorbital tumors superiorly and posteriorly located. This technique was completed through an upper eyelid skin crease followed by grinding the superior orbital rim to achieve complete removal of the lesions.
    UNASSIGNED: Complete removal of the lesion was accomplished in every case. No intraoperative complications were observed in any of the patients. During the follow-up period, one patient presented with frontal hypersensitivity and one with diplopia.
    UNASSIGNED: In the case series presented, the upper eyelid skin crease approach with grinding of the superior orbital rim proved to be a safe and effective surgical technique to remove lesions located superior and posterior within the orbit in our series. More studies are needed to further evaluate the efficacy and long-term results of this approach.
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