Compared with conventional surface grinding (CSG) process, surface machining of carbon fiber-reinforced plastic (CFRP) composites using rotary ultrasonic machining (RUM) with vertical ultrasonic ...vibration generates smaller cutting forces because of improved machining performance and more damages to the machined CFRP surface due to the intermittent knocking induced by vertical ultrasonic vibration. It is reported that surface quality can be improved when the ultrasonic vibration is parallel to the feeding direction. In addition, elliptical ultrasonic vibration can be formed by the combination of horizontal and vertical ultrasonic vibrations. However, the effects of elliptical ultrasonic vibration in RUM surface machining of CFRPs are still unknown. This paper will study the influences of elliptical ultrasonic vibration on the machining performance and machined surface quality in RUM surface machining of CFRPs. The comparisons of output variables (including cutting forces, surface roughness, and machined surface topography) between RUM surface machining with elliptical ultrasonic vibration and the CSG process as well as RUM surface machining with vertical ultrasonic vibration will be conducted under different levels of input variables (including depth of cut, feedrate, and tool rotation speed). The abrasive-grain trajectory and the tool-workpiece contacting modes in these three machining processes are analyzed. It is found that RUM surface machining with elliptical ultrasonic vibration produced smallest feeding-direction cutting force, smallest vertical-direction cutting force, best morphology of machined surface, and smallest surface roughness among these three kinds of machining processes.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Wearable surface electromyography (sEMG) signal-acquisition devices have considerable potential for medical applications. Signals obtained from sEMG armbands can be used to identify a person's ...intentions using machine learning. However, the performance and recognition capabilities of commercially available sEMG armbands are generally limited. This paper presents the design of a wireless high-performance sEMG armband (hereinafter referred to as the α Armband), which has 16 channels and a 16-bit analog-to-digital converter and can reach 2000 samples per second per channel (adjustable) with a bandwidth of 0.1-20 kHz (adjustable). The α Armband can configure parameters and interact with sEMG data through low-power Bluetooth. We collected sEMG data from the forearms of 30 subjects using the α Armband and extracted three different image samples from the time-frequency domain for training and testing convolutional neural networks. The average recognition accuracy for 10 hand gestures was as high as 98.6%, indicating that the α Armband is highly practical and robust, with excellent development potential.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The proportion of natural sand replaced by steel slag sand affects the volumetric stability of steel slag mortar and steel slag concrete. However, the steel slag substitution rate detection method is ...inefficient and lacks representative sampling. Therefore, a deep learning-based steel slag sand substitution rate detection method is proposed. The technique adds a squeeze and excitation (SE) attention mechanism to the ConvNeXt model to improve the model's efficiency in extracting the color features of steel slag sand mix. Meanwhile, the model's accuracy is further enhanced by using the migration learning method. The experimental results show that SE can effectively help ConvNeXt acquire images' color features. The model's accuracy in predicting the replacement rate of steel slag sand is 87.99%, which is better than the original ConvNeXt network and other standard convolutional neural networks. After using the migration learning training method, the model predicts the steel slag sand substitution rate with 92.64% accuracy, improving accuracy by 4.65%. The SE attention mechanism and the migration learning training method can help the model acquire the critical features of the image better and effectively improve the model's accuracy. The method proposed in this paper can identify the steel slag sand substitution rate quickly and accurately and can be used for the detection of the steel slag sand substitution rate.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Inconel 718 has been widely used in aerospace, nuclear, and marine industries due to excellent high-temperature mechanical properties and corrosion resistance. In recent years, laser-directed energy ...deposition (DED) becomes a competitive method in the fabrication of Inconel 718 coatings. Compared with other surface coating processes, laser DED has the advantage of extremely fine-grained structures, strong metallurgical bonding, and high density. However, the hardness and wear resistance of Inconel 718 coatings still need to be improved. To further improve these properties, ceramic reinforced Inconel 718 coatings have been investigated. Compared with ex situ ceramic reinforcements, the in situ synthesized reinforcements have the advantage of refined ceramic particle size, uniform distribution, and low thermal stress. B
4
C was a preferable additive material to fabricate in situ synthesized multi-component ceramic reinforced Inconel 718 coatings. The addition of B
4
C could form a large number of borides and carbides as ceramic reinforcements. In addition, the in situ reactions between Inconel 718 and B
4
C could release heat during the fabrication, thereby promoting the melting of material powders. However, there are currently no investigations on the in situ synthesis mechanisms, microstructure, and mechanical properties of laser DED fabricated B
4
C-Inconel 718 coatings. In this study, the effects of B
4
C on the properties of Inconel 718 coatings were investigated. Results show that Ni
3
B, NbB, and Cr
3
C
2
phases were formed. With the addition of B
4
C, the size of Laves phase was refined and the porosity was decreased. The hardness and wear resistance of B
4
C reinforced coatings were improved by about 34% and 28%, respectively.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•Rotary ultrasonic surface micro-machining of brittle materials.•Theoretical investigation on the material removal rate and cutting force.•Significantly improved surface quality assisted by ...ultrasonic vibration.
Many brittle materials, such as single-crystal materials, amorphous materials, and ceramics, are widely used in many industries such as the energy industry, aerospace industry, and biomedical industry. In recent years, there is an increasing demand for high-precision micro-machining of these brittle materials to produce precision functional parts. Traditional ultra-precision micro-machining can lead to workpiece cracking, low machined surface quality, and reduced tool life. To reduce and further solve these problems, a new micro-machining process is needed. As one of the nontraditional machining processes, rotary ultrasonic machining is an effective method to reduce the issues generated by traditional machining processes of brittle materials. Therefore, rotary ultrasonic micro-machining (RUμM) is investigated to conduct the surface micro-machining of brittle materials. Due to the small diameter cutting tool (<500 μm) and high accuracy requirements, the impact of input parameters in the rotary ultrasonic surface micro-machining (RUSμM) process on tool deformation and cutting quality is extremely different from that in rotary ultrasonic surface machining (RUSM) with relatively large diameter cutting tool (∼10 mm). Up till now, there is still no investigation on the effects of ultrasonic vibration (UV) and input variables (such as tool rotation speed and depth of cut) on cutting force and machined surface quality in RUSμM of brittle materials. To fill this knowledge gap, rotary ultrasonic surface micro-machining of the silicon wafer (one of the most versatile brittle materials) was conducted in this study. The effects of ultrasonic vibration, tool rotation speed, and depth of cut on tool trajectory, material removal rate (MRR), cutting force, cutting surface quality, and residual stress were investigated. Results show that the ultrasonic vibration could reduce the cutting force, improve the cutting surface quality, and suppress the residual compressive stress, especially under conditions with high tool rotation speed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Color directly affects fruit quality and consumer preference. In fig syconia, the female flower tissue is contained in a receptacle. Anthocyanin pigmentation of this tissue and the peel differs ...temporally and spatially. A transcriptome study was carried out to elucidate key genes and transcription factors regulating differences in fig coloring.
Anthocyanins in the female flower tissue were identified mainly as pelargonidin-3-glucoside and cyanidin-3-rutinoside; in the peel, the major anthocyanins were cyanidin 3-O-glucoside and cyanidin-3-rutinoside. Anthocyanin content was significantly higher in the female flower tissue vs. peel before fig ripening, whereas at ripening, the anthocyanin content in the peel was 5.39 times higher than that in the female flower tissue. Light-deprivation treatment strongly inhibited peel, but not female flower tissue, anthocyanin pigmentation. RNA-Seq revealed 522 differentially expressed genes (recruited with criteria log
≥ 2 and P < 0.05) at fig ripening, with 50 upregulated and 472 downregulated genes in the female flower tissue. Light deprivation upregulated 1180 and downregulated 856 genes in the peel, and upregulated 909 and downregulated 817 genes in the female flower tissue. KEGG enrichment revealed significantly changed expression in the phenylpropanoid-biosynthesis and flavonoid-biosynthesis pathways in the peel, but not in the female flower tissue, with significant repression of FcCHS, FcCHI, FcF3H, FcF3'H, FcDFR and FcUFGT transcripts. Light deprivation led to differential expression of 71 and 80 transcription factor genes in the peel and female flower tissue, respectively. Yeast one-hybrid screen revealed that FcHY5 and FcMYB114 bind the promoter regions of FcCHS and FcDFR, respectively in the flavonoid-biosynthesis pathway.
Phenylpropanoid- and flavonoid-biosynthesis pathways were differentially expressed spatially and temporally in the peel and female flower tissue of fig syconia; pathway expression in the peel was strongly regulated by light signal. Differentially expressed transcription factors were recruited as candidates to screen important expression regulators in the light-dependent and light-independent anthocyanin-synthesis pathway. Our study lays the groundwork for further elucidation of crucial players in fig pigmentation.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Lateral epicondylitis (LE) is a common musculoskeletal disorder for which an effective treatment strategy remains unknown. The goal of this study is to examine whether acupuncture is more effective ...than injection of glucocorticoid in adults with LE.Adults with LE received either acupuncture or injection of glucocorticoid were followed-up for 6 months. All patients assessed before treatment, 0, 3 months, and 6 months after the therapy. Outcome measures consisted of visual analog scores (VAS) and the Mayo elbow performance score (MEPS).The acupuncture group and the corticosteroid group did not differ on demographic or clinical characteristics (P < .05). VAS and MEPS score was not significantly different between 2 groups at 0 and 3 months. MEPS scores were significantly lower in the corticosteroid group at 6 months, compared with those in the acupuncture group (P < .05). However, the VAS score was not significantly different (P > .05). There were no complications related to the use of acupuncture or corticosteroid injection.We found that both methods were effective for external humeral epicondylitis. However, after 6 months of treatment, patients with chronic LE with acupuncture achieved pain relief and function improve significantly, exceeding the effect of corticosteroid injection.
Carbon-based nanomaterials mainly including carbon nanotubes (CNTs), graphene, and graphene oxide (GO) have superior properties of low density, outstanding strength, and high hardness. Compared with ...ceramic reinforcements, small amount of carbon-based nanomaterials can significantly improve the mechanical properties of metal matrix composites (MMCs) and ceramic matrix composites (CMCs). However, CNTs and graphite always aggregate or degrade during the fabrication with a high temperature, especially in MMCs. GO has the advantages of easier to be dispersed in other materials and better high-temperature stability. Laser-directed energy deposition (DED) has been used to fabricate GO-MMCs and GO-CMCs due to the unique capabilities of coating, remanufacturing, and producing functionally graded materials. Laser DED, as a fusion manufacturing process, could fully melt the material powders, which could refine the microstructure and increase the density and mechanical properties. However, GO could react with matrix materials at high temperatures. The survival, degradation, and reactions of GO in laser DED fabricated GO-MMCs and GO-CMCs are still unknown. There is also no investigation on the reinforcement mechanisms of GO in metal matrix materials and ceramic matrix materials in the laser DED process. In this study, GO-reinforced Ti (GO-Ti) and GO-reinforced zirconia toughened alumina (GO-ZTA) parts were fabricated by laser DED process. Raman spectrum, XRD analysis, and EDS analysis have been applied to investigate the forms of GO in both DED fabricated GO-MMCs and GO-CMCs. The reinforcement mechanisms of GO on microhardness and compressive properties of MMCs and CMCs have been analyzed.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract
Background and purpose
To explore the association of systemic inflammatory index (SIRI), systemic immune-inflammatory index (SII) and inflammatory prognosis index (IPI) with 90d outcomes in ...patients with acute ischemic stroke (AIS) after intravenous thrombolysis.
Methods
The patients who underwent intravenous thrombolysis were enrolled in the present study from September 2019 to December 2022. According to the relevant blood indexes obtained in 24 h after admission, the corresponding values of SIRI, SII and IPI were calculated. The correlation among SIRI, SII, IPI, and admission NIHSS scores was examined by Spearman correlation analysis. ROC curve analysis was conducted to determine the optimal cut-off value of SIRI, SII, IPI, and their corresponding sensitivity and specificity to evaluate their predictive value on admission for poor prognosis. To investigate whether high SIRI, SII, and IPI were independent predictors of poor outcomes within 90 days, variables with
P
-value < 0.05 during univariate analysis were included in multivariate analysis.
Results
Compared with the good outcome group, the poor outcome group had higher SIRI, IPI, and SII. Spearman correlation analysis showed that the SIRI, IPI, and SII levels significantly correlated with the admission NIHSS score (
r
= 0.338, 0.356, 0.427, respectively;
P
s
< 0.001). Univariate analysis and Multivariate logistic regression analysis revealed high SIRI, SII, and IPI values as independent risk factors for poor 90-day prognosis (OR = 1.09, 1.003 and 7.109, respectively).
Conclusions
High SIRI, IPI, and SII values are correlated with poor 90d outcomes in AIS patients undergoing intravenous thrombolysis.
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