bluuebunny/crossref_metadata_2025 huggingface dataset:
Identifying Molecular Roadblocks for Transcription Factor-Induced Cellular Reprogramming In Vivo by Using C. elegans as a Model Organism
Authors: Özcan Ismail , Tursun Baris
Published: August 2023

Generating specialized cell types via cellular transcription factor (TF)-mediated reprogramming has gained high interest in regenerative medicine due to its therapeutic potential to repair tissues and organs damaged by diseases or trauma. Organ dysfunction or improper tissue functioning might be restored by producing functional cells via direct reprogramming, also known as transdifferentiation. Regeneration by converting the identity of available cells in vivo to the desired cell fate could be a strategy for future cell replacement therapies. However, the generation of specific cell types via reprogramming is often restricted due to cell fate-safeguarding mechanisms that limit or even block the reprogramming of the starting cell type. Nevertheless, efficient reprogramming to generate homogeneous cell populations with the required cell type’s proper molecular and functional identity is critical. Incomplete reprogramming will lack therapeutic potential and can be detrimental as partially reprogrammed cells may acquire undesired properties and develop into tumors. Identifying and evaluating molecular barriers will improve reprogramming efficiency to reliably establish the target cell identity. In this review, we summarize how using the nematode C. elegans as an in vivo model organism identified molecular barriers of TF-mediated reprogramming. Notably, many identified molecular factors have a high degree of conservation and were subsequently shown to block TF-induced reprogramming of mammalian cells.
Analysis of Individual V˙O2max Responses during a Cardiopulmonary Exercise Test and the Verification Phase in Physically Active Women
Authors: Succi Pasquale J. , Benitez Brian , Kwak Minyoung , Bergstrom Haley C.
Published: August 2023

This study aimed to investigate the test–retest reliability, mean, and individual responses in the measurement of maximal oxygen consumption (V˙O2max) during a cardiopulmonary exercise test (CPET) and the verification phase during cycle ergometry in women. Nine women (22 ± 2 yrs, 166.0 ± 4.5 cm, 58.6 ± 7.7 kg) completed a CPET, passively rested for 5 min, and then completed a verification phase at 90% of peak power output to determine the highest V˙O2 from the CPET (V˙O2CPET) and verification phase (V˙O2verification) on 2 separate days. Analyses included a two-way repeated measures ANOVA, intraclass correlation coefficients (ICC2,1), standard errors of the measurement (SEM), minimal differences (MD), and coefficients of variation (CoV). There was no test (test 1 versus test 2) × method (CPET vs. verification phase) interaction (p = 0.896) and no main effect for method (p = 0.459). However, test 1 (39.2 mL·kg−1·min−1) was significantly higher than test 2 (38.3 mL·kg−1·min−1) (p = 0.043). The V˙O2CPET (ICC = 0.984; CoV = 1.98%; SEM = 0.77 mL·kg−1·min−1; MD = 2.14 mL·kg−1·min−1) and V˙O2verification (ICC = 0.964; CoV = 3.30%; SEM = 1.27 mL·kg−1·min−1; MD = 3.52 mL·kg−1·min−1) demonstrated “excellent” reliability. Two subjects demonstrated a test 1 V˙O2CPET that exceeded the test 2 V˙O2CPET, and one subject demonstrated a test 1 V˙O2verification that exceeded the test 2 V˙O2verification by more than the respective CPET and verification phase MD. One subject demonstrated a V˙O2CPET that exceeded the V˙O2verification, and one subject demonstrated a V˙O2verification that exceeded the V˙O2CPET by more than the MD. These results demonstrate the importance of examining the individual responses in the measurement of the V˙O2max and suggest that the MD may be a useful threshold to quantify real individual changes in V˙O2.
Data-Weighted Multivariate Generalized Gaussian Mixture Model: Application to Point Cloud Robust Registration
Authors: Ge Bingwei , Najar Fatma , Bouguila Nizar
Published: August 2023

In this paper, a weighted multivariate generalized Gaussian mixture model combined with stochastic optimization is proposed for point cloud registration. The mixture model parameters of the target scene and the scene to be registered are updated iteratively by the fixed point method under the framework of the EM algorithm, and the number of components is determined based on the minimum message length criterion (MML). The KL divergence between these two mixture models is utilized as the loss function for stochastic optimization to find the optimal parameters of the transformation model. The self-built point clouds are used to evaluate the performance of the proposed algorithm on rigid registration. Experiments demonstrate that the algorithm dramatically reduces the impact of noise and outliers and effectively extracts the key features of the data-intensive regions.
Automatic 3D Postoperative Evaluation of Complex Orthopaedic Interventions
Authors: Ackermann Joëlle , Hoch Armando , Snedeker Jess Gerrit , Zingg Patrick Oliver , Esfandiari Hooman , Fürnstahl Philipp
Published: August 2023

In clinical practice, image-based postoperative evaluation is still performed without state-of-the-art computer methods, as these are not sufficiently automated. In this study we propose a fully automatic 3D postoperative outcome quantification method for the relevant steps of orthopaedic interventions on the example of Periacetabular Osteotomy of Ganz (PAO). A typical orthopaedic intervention involves cutting bone, anatomy manipulation and repositioning as well as implant placement. Our method includes a segmentation based deep learning approach for detection and quantification of the cuts. Furthermore, anatomy repositioning was quantified through a multi-step registration method, which entailed a coarse alignment of the pre- and postoperative CT images followed by a fine fragment alignment of the repositioned anatomy. Implant (i.e., screw) position was identified by 3D Hough transform for line detection combined with fast voxel traversal based on ray tracing. The feasibility of our approach was investigated on 27 interventions and compared against manually performed 3D outcome evaluations. The results show that our method can accurately assess the quality and accuracy of the surgery. Our evaluation of the fragment repositioning showed a cumulative error for the coarse and fine alignment of 2.1 mm. Our evaluation of screw placement accuracy resulted in a distance error of 1.32 mm for screw head location and an angular deviation of 1.1° for screw axis. As a next step we will explore generalisation capabilities by applying the method to different interventions.
Measurement of Near-Surface Current Shear Using a Lagrangian Platform and Its Implication on Microplastic Dispersion
Authors: Lee Jun-Ho , Choi Jun Myoung
Published: August 2023

Air–sea interactions within the ocean’s near-surface layer play a pivotal role in climate regulation and are essential for understanding the dispersion of marine pollutants such as microplastics and oil slicks. Despite its significance, high-resolution data exploring the physical dynamics near the air–sea interface are noticeably sparse. To address this, we introduced a novel Lagrangian observational platform, outfitted with an upward-facing high-resolution ADCP, designed to measure current shear within the top 2 m of the surface water. Through two short field experiments, we identified enhanced currents and shear in the near-surface layer, and observed a negative vertical momentum flux aligned with the wind direction and a positive one orthogonal to it. The measurement suggest that Stokes drift contributes to 10% of horizontal mass transport and 20% of shear in the top surface layer, with the direct and local wind-driven current being the predominant influence. To accurately model the physical behavior of buoyant microplastics, this observation underscores the necessity of parameterizations that account for both the Stokes drift and the direct, local wind-driven current, a factor that is often overlooked in many models.
Model-Parameter-Free Prescribed Time Trajectory Tracking Control for Under-Actuated Unmanned Surface Vehicles with Saturation Constraints and External Disturbances
Authors: Ren Yi , Zhang Lei , Ying Yanqing , Li Shuyuan , Tang Yueqi
Published: August 2023

This paper mainly addresses the model-parameter-free prescribed time trajectory tracking control issue for under-actuated unmanned surface vehicles (USVs) that are susceptible to model uncertainties, time-varying disturbances, and saturation constraints. Firstly, a state extension based on coordinate transformation was designed to address the lack of control in the sway channel. Secondly, nonlinear behavior stemming from saturation constraints is not always differentiable. Regarding this, a smooth dead-zone-based model was conducted to fit the behavior, leaving a relatively simple actuator model. Then, an improved prescribed time–prescribed performance function (PTPPF) and error transformation method were utilized to propose a model-parameter-free control algorithm that guarantees user-defined constrained boundaries while ensuring all tracking errors converge within small domains before a preassigned settling time. The theoretical analysis was conducted by the initial value theorem, Lyapunov’s second method, and proof by contradiction, followed by comparative simulation results that verified the effectiveness of the proposed control scheme.
Genotyping Analysis of Cryptococcus deuterogattii and Correlation with Virulence Factors and Antifungal Susceptibility by the Clinical and Laboratory Standards Institute and the European Committee on Antifungal Susceptibility Testing Methods
Authors: Andrade-Silva Leonardo Euripedes , Vilas-Boas Anderson , Ferreira-Paim Kennio , Andrade-Silva Juliana , Santos Daniel de Assis , Ferreira Thatiana Bragine , Borges Aercio Sebastião , Mora Delio Jose , Melhem Marcia de Souza Carvalho , Silva-Vergara Mario Léon
Published: August 2023

Data about the relationship between their molecular types, virulence factors, clinical presentation, antifungal susceptibility profile, and outcome are still limited for Cryptococcus deuterogattii. This study aimed to evaluate the molecular and phenotypic characteristics of 24 C. deuterogattii isolates from the southeast region of Brazil. The molecular characterization was performed by multilocus sequence typing (MLST). The antifungal susceptibility profile was obtained according to CLSI-M27-A3 and EUCAST-EDef 7.1 methods. The virulence factors were evaluated using classic techniques. The isolates were divided into four populations. The molecular analysis suggests recombinant events in most of the groups evaluated. Resistance and susceptibility dose-dependent to fluconazole were evidenced in four isolates (16%) by EUCAST and in four isolates (16%) by CLSI methods. The agreement at ±two dilutions for both methods was 100% for itraconazole, ketoconazole, and voriconazole, 96% for amphotericin B, and 92% for fluconazole. Significant differences in virulence factor expression and antifungal susceptibility to itraconazole and amphotericin B were found. The mixed infection could be suggested by the presence of variable sequence types, differences in virulence factor production, and decreased antifungal susceptibility in two isolates from the same patient. The data presented herein corroborate previous reports about the molecular diversity of C. deuterogattii around the world.
The Enigmatic World of Fungal Melanin: A Comprehensive Review
Authors: Suthar Malika , Dufossé Laurent , Singh Sanjay K.
Published: August 2023

Synthetic dyes are generally not safe for human health or the environment, leading to the continuous search and growing demand for natural pigments that are considered safer, biodegrade more easily, and are environmentally beneficial. Among micro-organisms, fungi represent an emerging source of pigments due to their many benefits; therefore, they are readily viable on an industrial scale. Among all the bioactive pigments produced by fungi, melanin is an enigmatic, multifunctional pigment that has been studied for more than 150 years. This dark pigment, which is produced via the oxidative polymerization of phenolic compounds, has been investigated for its potential to protect life from all kingdoms, including fungi, from biotic and abiotic stresses. Over time, the research on fungal melanin has attracted a significant amount of scientific interest due to melanin’s distinct biological activities and multifarious functionality, which is well-documented in the literature and could possibly be utilized. This review surveys the literature and summarizes the current discourse, presenting an up-to-date account of the research performed on fungal melanin that encompasses its types, the factors influencing its bioactivity, the optimization of fermentation conditions to enhance its sustainable production, its biosynthetic pathways, and its extraction, as well as biochemical characterization techniques and the potential uses of melanin in a wide range of applications in various industries. A massive scope of work remains to circumvent the obstacles to obtaining melanin from fungi and exploring its future prospects in a diverse range of applications.
Association of Broad-Spectrum Antibiotic Therapy and Vitamin E Supplementation with Vitamin K Deficiency-Induced Coagulopathy: A Case Report and Narrative Review of the Literature
Authors: Matthaiou Andreas M. , Tomos Ioannis , Chaniotaki Sofia , Liakopoulos Dimitrios , Sakellaropoulou Katerina , Koukidou Sofia , Gheorghe Loredana-Mariana , Eskioglou Stefanos , Paspalli Angeliki , Hillas Georgios , Dimakou Katerina
Published: August 2023

Vitamin K is a lipid-soluble vitamin that is normally maintained within appropriate levels by means of dietary intake and bacterial production in the intestinal microflora. It holds a central role in coagulation homeostasis, and thus its depletion leads to hypocoagulation and haemorrhagic diathesis. The association of antibiotic therapy and vitamin E supplementation with vitamin K deficiency was previously described in animal experiments, clinical studies, and case reports. Broad-spectrum antibiotic therapy potentially leads to intestinal microflora dysbiosis and restriction of vitamin K-producing bacterial populations, resulting in decreased vitamin K levels, whereas antibiotics of the cephalosporin class with 1-N-methyl-5-thiotetrazole (NMTT) or 2-methyl-1,3,4-thiadiazole (MTD) side groups inhibit vitamin K function. Vitamin E supplementation interferes with both the bioavailability and function of vitamin K, yet its mechanisms are not fully understood. We present the case of a 45-year-old male patient, with a history of epilepsy and schizophrenia, catatonically incapacitated and immobilised, who was hospitalised in our centre for the investigation and management of aspiration pneumonia. He demonstrated a progressively worsening prolongation of international normalised ratio (INR), which was attributed to both broad-spectrum antibiotic therapy and vitamin E supplementation and was reversed upon administration of vitamin K. We highlight the need for close monitoring of coagulation parameters in patients receiving broad-spectrum antibiotic therapy, especially those with underlying malnutritive or malabsorptive conditions, and we further recommend the avoidance of NMTT- or MTD-containing antibiotics or vitamin E supplementation, unless absolutely necessary, in those patients.
Comparison of Sampling and Grid Methods for Regional Soil Erosion Assessment
Authors: Gu Zhijia , Cao Shaomin , Li Ao , Yi Qiang , Li Shuang , Li Panying
Published: August 2023

To control soil erosion, the intensity, area, and distribution of regional soil erosion must be determined to accurately plan and implement corresponding soil conservation measures. Therefore, regional soil erosion assessment has received extensive attention worldwide. At present, a sampling survey approach and full-coverage grid-based calculation are mainly applied in regional soil erosion assessment. The quantitative evaluation of the entire region depends on the quality of the data source. Furthermore, owing to the greatness of the evaluation object, the difficulty of data acquisition, the high cost, and poor usability, the present approach is bound to be at the expense of data accuracy, spatial resolution, time resolution, etc. The sampling survey approach can obtain high-precision data of soil erosion factors. Therefore, it can accurately quantify soil erosion in a field investigation unit. However, the sampling method, sampling density, and extrapolation methods have a significant impact on regional soil erosion assessments. This study considers the case of Baiquan County in the rolling hills of Northeast China as an example. Regional soil erosion evaluation using sampling survey and grid computing were compared. The impact of the data source accuracy on the soil erosion assessment was also quantitatively evaluated. The results of grid method showed a phenomenon of large rates of soil erosion and the ratio of the soil erosion area (the share of areas above the mild level), which were overestimated by 20% and 6%, respectively. A digital elevation model (DEM) with a resolution of 30 m can be used for soil erosion evaluation in plain areas, but that with the same resolution in hilly areas has insufficient calculation accuracy and provides large errors. The grid method can be adopted when land use and soil conservation measures are accurate. Otherwise, the sampling method is recommended. Interpolation of the ratio of the soil erosion area in the survey unit based on land use can better evaluate regional soil erosion.
Indexing Deficiency: Connecting Language Learning and Teaching to Evaluations of US Spanish
Authors: Licata Gabriella
Published: August 2023

The examination of language attitudes towards US Spanish variables unearths indexical meanings rooted in deficit perspectives, particularly in educational contexts. Standard language ideologies undergird pedagogical practice and learning experiences in second language (L2) and heritage language (HL) Spanish classes. The present study utilizes dual research paradigms of social cognition (matched guise technique (MGT); implicit association test (IAT)) to determine if varying experiences with (Spanish) standard language ideologies in academic settings condition bias towards standardized Spanish (SS) and US Spanish (USS) repertoires. L2 and HL students as well as teachers of Spanish (n = 81) have more positive associations of SS in both the MGT and IAT, demonstrating that standard language ideologies influence perceptions of language acquisition and academic language learning. No correlations between the bias measures were reported yet attitudes did not differ, suggesting that attitudes are stable and reflected in both early learnings of social information and lived experiences throughout formative education. These results contribute to a growing body of research that examines how monoglossic ideologies reinforce and reproduce the stigma associated with features of US Spanish(es).
An Airflow Analysis of Spanish and English Anticipatory Vowel Nasalization among Heritage Bilinguals
Authors: Beristain Ander
Published: August 2023

Gestural timing overlap between a vowel and subsequent nasal consonant results in the vowel being articulatorily nasalized. Research has shown that such degree of coarticulation varies cross-linguistically (e.g., English exhibits a greater gestural timing overlap than Spanish). This phenomenon has mainly been investigated in monolingual samples, and with only a small number of studies focusing on second and heritage language gestural timing patterns of nasality; the role of bilingualism in this respect is thus an open question, which is the focus of the current study. Sixteen second-generation US-born heritage bilinguals participated in this experiment. Their degree of bilingualism was assessed via the Bilingual Language Profile. They completed two separate read-aloud tasks: one in Spanish (heritage language) and one in English (second language). Simultaneous oral and nasal airflow were collected via pressure transducers from words that included phonetically oral and nasalized vowels. Results indicate that heritage bilinguals increment the degree of vocalic nasalization from Spanish to English. Nevertheless, their degree of bilingualism did not yield statistical significance in phonetic performance. The current study is the first one implementing aerodynamic methods with a heritage bilingual population and presents data for the possibility to possess two segment-to-segment timing strategies in heritage grammars.
Mediated Bricolage and the Sociolinguistic Co-Construction of No Sabo Kids
Authors: Callesano Salvatore
Published: August 2023

Sociolinguistic styles and the resultant ascribed identities are understood as the product of simultaneous variables, leading to the notion of bricolage, or the co-occurrence of variables and their collective indexical meanings. Relatively little attention has been paid to these processes as they manifest on social media platforms. The goal of the current paper is to understand which linguistic and thematic features co-occur in the online production of the no sabo kid style and identity, which manifests as a form of linguistic discrimination towards U.S. Latinx youth. “Hashtag communities” were used to locate posts about no sabo kids on TikTok (N = 95), and videos were automatically and manually coded for salient linguistic and discursive resources in the online no sabo kid community. The results show the co-occurrence of code-switching and phonological and lexical variation, alongside discursive themes, namely ‘proficiency’, ‘ethnicity’, and ‘performative lexical gaps’. I argue that the no sabo kid hashtag community is a mediated manifestation of ideologies surrounding U.S. Latinx bilinguals, where a supposed lack of proficiency in Spanish and grammatical blending of Spanish and English index inauthentic ethnicity. Mediated instantiations of sociolinguistic styles shed light on how linguistic features become enregistered through multimodality and semiotic bricolage.
Topiramate (Topamax): Evolving Role in Weight Reduction Management: A Narrative Review
Authors: Wajid Irza , Vega Alexis , Thornhill Katherine , Jenkins Jack , Merriman Chandler , Chandler Debbie , Shekoohi Sahar , Cornett Elyse M. , Kaye Alan D.
Published: August 2023

Obesity has emerged as a widespread disease with epidemic proportions, necessitating effective management to enhance the overall health outcomes of patients. Medical intervention for weight loss becomes necessary when diet and exercise prove ineffective, and topiramate emerges as a potential treatment option for this global problem. Currently approved as an anti-epileptic and migraine prophylaxis medication, topiramate is frequently utilized as adjunctive therapy for patients with mood and eating disorders, as well as for alcohol use disorders. Its multifaceted mechanisms of action contribute to reducing neuronal excitation and enhancing neuronal inhibition. Given its variety of mechanisms, topiramate shows several off-label outcomes, including weight loss, for patients prescribed this medication. Although the specific mechanism of action concerning weight loss remains uncertain, various hypotheses have been reported. Notably, topiramate may contribute to weight loss by reducing calorie intake, decreasing fat gain, and lowering triglyceride and cholesterol levels. Additionally, its impact on reward pathways associated with food could play a role. Multiple clinical studies have supported the use of topiramate as a weight-loss medication. Notably, the medication demonstrates effectiveness in reducing body weight across different dosages and sustaining weight loss over time, outperforming alternative weight loss methods. Moreover, it was generally well-tolerated in clinical studies, with few side effects observed. In conclusion, topiramate offers promising potential as a weight loss solution and can be a valuable addition to the range of treatment options for combating obesity.
The Role of Bifidobacterium in COVID-19: A Systematic Review
Authors: Taufer Clarissa Reginato , Rampelotto Pabulo Henrique
Published: August 2023

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, mainly causes respiratory and intestinal symptoms and changes in the microbiota of patients. We performed a systematic search in major databases using “Bifidobacterium” and “COVID-19” or “SARS-CoV-2” as key terms to assess the relationship of the genus to COVID-19. After the selection steps, 25 articles were analyzed. Of these, eighteen were observational, and seven were interventional articles that evaluated the use of Bifidobacterium alone or in mix as probiotics for additional treatment of patients with COVID-19. All stages and severities were contemplated, including post-COVID-19 patients. Overall, Bifidobacterium was associated with both protective effects and reduced abundance in relation to the disease. The genus has been found to be abundant in some cases and linked to disease severity. The studies evaluating the use of Bifidobacterium as probiotics have demonstrated the potential of this genus in reducing symptoms, improving pulmonary function, reducing inflammatory markers, alleviating gastrointestinal symptoms, and even contributing to better control of mortality. In summary, Bifidobacterium may offer protection against COVID-19 through its ability to modulate the immune response, reduce inflammation, compete with pathogenic microbes, and maintain gut barrier function. The findings provide valuable insights into the relationship between the disease and the genus Bifidobacterium, highlighting the potential of microbiota modulation in the treatment of COVID-19.
The Impact of Number of Medications on Falls in Aging Persons with Human Immunodeficiency Virus
Authors: Thai Leanne , Hill Lucas , Balcombe Shannon , Karim Afsana , Young Karris Maile
Published: August 2023

We aimed to evaluate the impact of polypharmacy on the risk of having a fall in older persons with HIV (PWH). PWH at least 50 years of age who were seen at our institution from September 2012 to August 2017 were included. Unique participants were selected for either a case or control cohort depending on the presence of a documented fall during the study time period. Demographics, HIV-related measures, VACS score, number of medications, as well as the impact of taking benzodiazepines and opioids were compared between the two cohorts. Fall was documented for 637 patients compared to 1534 without a fall during the same time period. Multivariable logistic regression revealed that the total number of medications, having a higher VACS score, taking an opioid, being female sex assigned at birth, and having a lower nadir CD4 count were significantly associated with higher odds of having a fall. In this cohort of older PWH, taking a higher number of non-ARV medications significantly increased the odds of having a fall. In addition, taking an opioid resulted in the highest odds of having a fall. These results suggest the importance of deprescribing and addressing opioid use in reducing the risk of having a fall in older PWH.
Selenium-Containing Organic Fertilizer Application Affects Yield, Quality, and Distribution of Selenium in Wheat
Authors: Chen Peng , Shaghaleh Hiba , Hamoud Yousef Alhaj , Wang Jing , Pei Wenxia , Yuan Xianfu , Liu Jianjian , Qiao Cece , Xia Wenhui , Wang Jianfei
Published: August 2023

This study was designed to investigate the effect on wheat yield of applying organic fertilizers (OF) with five different selenium (Se) concentrations. The mineral nutrients, cadmium (Cd) content, and the distribution of Se in wheat plants were also measured. The results showed that wheat yields reached a maximum of 9979.78 kg ha−1 in Mengcheng (MC) County and 8868.97 kg ha−1 in Dingyuan (DY) County, Anhui Province, China when the application amount of selenium-containing organic fertilizer (SOF) was up to 600 kg ha−1. Among the six mineral nutrients measured, only the calcium (Ca) content of the grains significantly increased with an increase in the application amount of SOF in the two regions under study. Cd content showed antagonistic effects with the Se content of wheat grains, and when the SOF was applied at 1200 kg ha−1, the Cd content of the grains was significantly reduced by 30.1% in MC and 67.3% in DY, compared with under the Se0 treatment. After application of SOF, the Se content of different parts of the wheat plant ranked root > grain > spike-stalk > glume > leaf > stem. In summary, SOF application at a suitable concentration could increase wheat yields and significantly promote the Ca content of the grains. Meanwhile, the addition of Se effectively inhibited the level of toxic Cd in the wheat grains.
Key Parameters and Experimental Study of High-Speed Rotating Meshing Gear Injection Lubrication Based on Moving Particle Semi-Implicit Method
Authors: Zou Tiangang , Yan Qingdong , Sui Tuo , Zhao Zhenguo , Li Junye , An Yuanyuan
Published: August 2023

With the rapid development of China’s manufacturing industry, products are changing toward better energy efficiency and precision. Reducing transmission energy waste, enhancing transmission lubrication, and increasing transmission efficiency have all become critical concerns. The moving particle semi-implicit particle approach is utilized in this study to create a high-speed rotating meshing gear lubrication model and conduct a simulation analysis of transmission gears by studying the influence law of sensitive parameter injection diameter on lubrication. The oil distribution state on the gear surface, the gear tooth surface heat dissipation effect, and the degree of gear operating stability are all calculated by computing the gear surface fluid coverage and convective heat transfer coefficient. According to the numerical simulation results, increasing the liquid injection diameter can greatly enhance fluid coverage and convective heat transfer coefficient on the gear surface, hence improving lubrication. However, when the injection diameter reaches a critical value, the contact area between the liquid and the gear is maximized, and additional increases in the injection diameter will not improve the lubricating effect. Experiments have revealed that the liquid injection diameter is the most critical factor influencing gears. The gear torque dramatically increases as the liquid injection diameter increases. According to a rigorous analysis, the gear lubrication effect is optimal when the liquid injection diameter is 2.0 mm. This provides a theoretical foundation for transmission system lubrication design.
Influence of Nitrile Butadiene Rubber (NBR) Shore Hardness and Polytetrafluoroethylene (PTFE) Elastic Modulus on the Sealing Characteristics of Step Rod Seals
Authors: Wang Bingqing , Li Xiaoxuan , Peng Xudong , Li Yuntang , Li Xiang , Chen Yuan , Jin Jie
Published: August 2023

The influence of NBR Shore hardness and PTFE elastic modulus on the sealing characteristics of step rod seals is analyzed in this paper based on the developed mixed elastohydrodynamic lubrication (EHL) model. The optimized selection studies of NBR Shore hardness and PTFE elastic modulus under different operating conditions are carried out based on the principle of minimizing net leakage and friction power loss. Results show that the Shore hardness of the NBR O-ring and, in particular, the elastic modulus of the PTFE ring has a significant effect on the sealing characteristics. Although the high values of these parameters result in high friction forces, they are beneficial for leakage control. To achieve both low leakage and low friction, it is recommended that high hardness and low modulus are selected for moderate-low pressure or high speed conditions, but low hardness and high modulus are selected for high pressure or low speed conditions.
Effect of Grain Orientation on Microstructure and Mechanical Properties of FeCoCrNi High-Entropy Alloy Produced via Laser Melting Deposition
Authors: Ge Fuyu , Liu Shuai , Zhang Xin , Shan Mengdie , Peng Cheng , Jia Fanghui , Han Jian , Cai Yangchuan
Published: August 2023

The long, straight grain boundary of the high-entropy alloy (HEA) produced via laser melting deposition (LMD) is prone to cracking due to unidirectional scanning (single wall). To enhance the competitive growth of columnar grains and improve the overall performance of the alloy, a vertical cross scanning method was employed to fabricate FeCoCrNi HEA (bulk). The influence of grain orientation on the microstructure and mechanical properties of FeCoCrNi-LMD was systematically investigated. Microhardness tests and tensile tests were conducted to assess the mechanical property differences between the single-wall and bulk samples. This study shows that using a single scanning strategy results in monolayer wall grains sized at 129.40 μm, with a max texture strength of 21.29. Employing orthogonal scanning yields 61.15 μm block-like grains with a max texture strength of 11.12. Dislocation densities are 1.084 × 1012 m−2 and 1.156 × 1012 m−2, with average Schmid factors of 0.471 and 0.416. In comparison to the FeCoCrNi-LMD single wall, the bulk material produced through cross-layer orthogonal scanning exhibited reduced residual stress, weakened anisotropy, and improved mechanical properties. These findings are expected to enhance the potential applications of FeCoCrNi-LMD in various industries.
Determination of the Basic Geotechnical Parameters of Blast-Furnace Slag from the Kremnica Region
Authors: Bulko Roman , Masarovičová Soňa , Gago Filip
Published: August 2023

A decisive aspect of site evaluation for construction is the presence of anthropogenic materials occurring in the geological environment. The geotechnical properties of blast-furnace slag were investigated as a potential substitute for aggregates in the construction industry. The basic geotechnical parameters of the slag were determined, which are critical for evaluating its stability, environmental impact, and usability in geotechnical construction. The research focused on monitoring the physical and mechanical properties of the two samples, and also included mineralogical analysis. The obtained results demonstrated that the slag belongs to the category of poorly graded gravel, G2/GP, and gravel with an admixture of fine-grained soil, G3/G-F. In addition, other important parameters, such as the water disintegration of the slag aggregate, the minimum and maximum bulk densities, the California bearing ratio (CBR), the oedometric modulus (Eoed), and shear tests (the angle of internal friction φ and cohesion c), were determined. The results from this paper provide important information for the proper management of blast-furnace slag so to minimize its environmental impact and achieve sustainability in the mining industry. At the same time, it enables a better understanding of the use of slag as a substitute for aggregates in geotechnical tasks. Despite its local importance in relation to the investigated case, the presented study has significant educational and scientific value for the construction sector, where it is necessary to evaluate anthropogenic activities and materials.
Influence of Oxygen Content in the Protective Gas on Pitting Corrosion Resistance of a 316L Stainless Steel Weld Joint
Authors: Maroufkhani Mohammad , Hakimian Soroosh , Khodabandeh Alireza , Radu Iulian , Hof Lucas A. , Jahazi Mohammad
Published: August 2023

Gas tungsten arc welding (GTAW) is commonly used for joining pipelines; however, it often leads to discoloration in the heat-affected zone (HAZ). In this study, 316L pipes were welded with different concentrations of oxygen present in the argon purge gas during welding. The objective of this study was to investigate the effect of oxygen concentration in the protective gas on the pitting corrosion resistance of welded pipes. The experimental results showed that the thickness of the oxide layer formed in the HAZ depends on the concentration of oxygen in the protective gas. Increasing the oxygen concentration in the protective gas resulted in an increase in pitting corrosion resistance until a critical value, beyond which the resistance decreased. The results showed that the thickness of the oxide layer formed in the HAZ depends on the concentration of oxygen in the protective gas. Increasing the oxygen concentration in the protective gas increased the pitting corrosion resistance until a critical value, beyond which the resistance decreased due to the formation of iron oxide. This study provides valuable insights for improving the corrosion resistance of welded pipes in the oil and gas industry.
Investigation of Deformation Behavior of Additively Manufactured AISI 316L Stainless Steel with In Situ Micro-Compression Testing
Authors: Teng Fei , Shiau Ching-Heng , Sun Cheng , O’Brien Robert C. , McMurtrey Michael D.
Published: August 2023

Additive manufacturing techniques are being used more and more to perform the precise fabrication of engineering components with complex geometries. The heterogeneity of additively manufactured microstructures deteriorates the mechanical integrity of products. In this paper, we printed AISI 316L stainless steel using the additive manufacturing technique of laser metal deposition. Both single-phase and dual-phase substructures were formed in the grain interiors. Electron backscatter diffraction and energy-dispersive X-ray spectroscopy indicate that Si, Mo, S, Cr were enriched, while Fe was depleted along the substructure boundaries. In situ micro-compression testing was performed at room temperature along the [001] orientation. The dual-phase substructures exhibited lower yield strength and higher Young’s modulus compared with single-phase substructures. Our research provides a fundamental understanding of the relationship between the microstructure and mechanical properties of additively manufactured metallic materials. The results suggest that the uneven heat treatment in the printing process could have negative impacts on the mechanical properties due to elemental segregation.
Microstructure and Mechanical Properties of Ti/Al–SiC/Ti Clad Plates Prepared via the Powder-in-Tube Method
Authors: Hu Xianlei , Xie Qincheng , Yuan Yi , Zhi Ying , Liu Xianghua
Published: August 2023

SiC particle-reinforced Ti/Al/Ti clad plates were successfully fabricated by the powder-in-tube method. The surface micrography, element diffusion, peeling strength and tensile property of clad plates were studied after annealing and cold rolling. The experimental results show that 6 wt.% is optimal. The presence of SiC particles has been seen to significantly enhance the diffusion of Ti and Al elements. Additionally, it has been observed that the diffusion width of the intermetallic compound (IMC) increases as the size of SiC particles grows. However, it is worth noting that the average of Ti/Al–SiC/Ti clad plates initially increases and subsequently falls. The optimized diffusion thickness of the Ti/Al–SiC/Ti clad plate’s IMC layer determined via the powder-in-tube method is approximately 4.5 μm. The 1 μm SiC-reinforced Ti/Al/Ti clad plate can obtain the best mechanical properties after annealing at 500 °C and further hot rolling, and the peeling strength, ultimate tensile strength and elongation are 31.5 N/mm, 305 MPa and 26%, respectively. The efficacy of Ti/Al–SiC/Ti clad plates in delivering exceptional performance is substantiated by the analysis of peeling surfaces, peeling tests and tensile testing, which collectively demonstrate the presence of compact and homogenous intermetallic compounds.
An Experimental Investigation on the Foliation Strike-Angle Effect of Layered Hard Rock under Engineering Triaxial Stress Path
Authors: Wang Zhaofeng , Feng Guangliang , Liu Xufeng , Zhou Yangyi
Published: August 2023

Deep underground engineering encounters substantial layered hard rock formations, and the engineering triaxial stress path involves an increase in maximum principal stress, constant intermediate principal stress, and a decrease in minimum principal stress. However, previous research has focused on rock layer angles under conventional triaxial stress conditions, disregarding the influence of foliation strike angles in engineering triaxial stress scenarios. This study experimentally investigates the effects of foliation strike angles on layered hard rock under an engineering triaxial stress path. To account for the brittleness of layered hard rock, we propose a specific small sample-processing method tailored to the foliation strike angle. True triaxial loading tests are conducted on steep, thin slate samples with two different loading orientations, accompanied by acoustic emission monitoring. Results indicate that the strength under a traditional true triaxial compression condition is similar for specimens with 90° and 0° strike angles. Stress–strain curves show that larger deformations occur perpendicular to bedding planes, while surface fractures propagate exclusively along the bedding planes. Mechanical responses differ significantly between specimens subjected to the engineering triaxial stress path at 0° and 90° strike angles compared to conventional true triaxial loading tests, with a lower bearing capacity and differentiated intermediate and minimum principal strains in the 0° case. Conversely, the 90° case exhibits a higher bearing capacity, consistent deformation, and more acoustic emission events. Numerical simulations comparing plastic zone sizes during actual underground excavation support these conclusions. These findings highlight the effects of foliation strike angles, favoring the 90° strike-angle configuration for excavation activities and providing enhanced stability in the surrounding rock mass.
Research on In-Plane Deformation Performance of Rotating Honeycomb Structures
Authors: Zhang Yongzhong , Ma Yunhai , Guo Xue , Wang Qingyang
Published: August 2023

Most natural materials have rotational and hierarchical properties, so they can show excellent mechanical properties such as shear resistance and impact resistance. In order to further improve the energy absorption characteristics of vibration absorbing structures, a new type of honeycomb structure with integral rotation and group rotation is designed and characterized. The effects of the geometrical parameters of rotation Angle on the impact deformation mode, stress response curve and energy absorption characteristics of the honeycomb structure are studied through numerical simulation and experimental design. The results show that the overall honeycomb performance of 15° is better than that of 0°, the specific energy absorption is the results show that the overall honeycomb performance of 15° is better than that of 0°, the specific energy absorption is increased by 6%, the bearing capacity is increased by 320 N, and the crushing force efficiency is increased by 2%. Compared with the whole cell and the group cell, the specific absorption energy increased by 35%, 73% and 71%. The results of this paper provide a new insight into the impact performance of monolithic and grouped rotating honeycomb structures, which is helpful for the results of this paper provide a new insight into the impact performance of monolithic and grouped rotating honeycomb structures, which is helpful for the optimization of crashworthiness structural design.
A Novel 1000 MPa Grade Ultrafine-Grained Dual-Phase Press Hardening Steel with Superior Oxidation Resistance and High Ductility
Authors: Yang Dapeng , Liang Jiawei , Zhou Junlong , Xu Xin , Hu Zhiping , Gu Xingli , Wang Guodong
Published: August 2023

1000 MPa grade low-carbon martensite press hardening steels (PHS) are widely used in energy-absorbing domains of automotive parts, such as the bottom of a B-pillar. To prevent oxide scale formation during hot forming, this PHS is often required to be protected by an additional Al–Si coating. In addition, although the low carbon martensitic microstructure grants it excellent bending toughness, the ductility tends to be limited. In this study, a novel 1000 MPa grade ultrafine-grained (UFG) martensite–ferrite (F–M) dual-phase (DP) PHS with superior oxidation resistance was designed using tailored additions of Cr, Mn, and Si, and refining the initial microstructure. Only 0.55 ± 0.18 μm thick oxide film is formed in the designed steel during austenitizing heating and stamping, which is significantly lower than the 24.6 ± 3.1 μm thick oxide film formed in conventional 1000 MPa grade low-carbon martensite PHS under the identical condition. The superior oxidation resistance of designed steel can be attributed to the rapid formation of the protective Si-rich, Cr-rich, and Mn-rich oxide layers during annealing. Moreover, due to the presence of ferrite and ultrafine microstructure, the designed steel also shows a significant improvement in ductility from 8.5% to 16.8% without sacrificing strength and bending toughness compared with conventional 1000 MPa grade low-carbon martensite PHS.
Thickness, Annealing, and Surface Roughness Effect on Magnetic and Significant Properties of Co40Fe40B10Dy10 Thin Films
Authors: Liu Wen-Jen , Chang Yung-Huang , Chiang Chia-Chin , Chen Yuan-Tsung , Wang Yu-Zhi , Wu Chueh-Lin , Lin Shih-Hung , Ou Sin-Liang
Published: August 2023

In this study, Co40Fe40B10Dy10 thin films were deposited using a direct current (DC) magnetron sputtering technique. The films were deposited on glass substrates with thicknesses of 10, 20, 30, 40, and 50 nm, and heat-treated in a vacuum annealing furnace at 100, 200, and 300 °C. Various instruments were used to examine and analyze the effects of roughness on the magnetic, adhesive, and mechanical properties. From the low frequency alternating current magnetic susceptibility (χac) results, the optimum resonance frequency is 50 Hz, and the maximum χac value tends to increase with the increase in the thicknesses and annealing temperatures. The maximum χac value is 0.18 at a film thickness of 50 nm and an annealing temperature of 300 °C. From the four-point probe, it is found that the resistivity and sheet resistance values decrease with the increase in film deposition thicknesses and higher annealing temperatures. From the magnetic force microscopy (MFM), the stripe-like magnetic domain distribution is more obvious with the increase in annealing temperature. According to the contact angle data, at the same annealing temperature, the contact angle decreases as the thickness increases due to changes in surface morphology. The maximal surface energy value at 300 °C is 34.71 mJ/mm2. The transmittance decreases with increasing film thickness, while the absorption intensity is inversely proportional to the transmittance, implying that the thickness effect suppresses the photon signal. Smoother roughness has less domain pinning, more carrier conductivity, and less light scattering, resulting in superior magnetic, electrical, adhesive, and optical performance.
Influence of the Grain Orientation of Wood upon Its Sound Absorption Properties
Authors: Guiman Maria Violeta , Stanciu Mariana Domnica , Roșca Ioan Călin , Georgescu Sergiu Valeriu , Năstac Silviu Marian , Câmpean Mihaela
Published: August 2023

The purpose of the study was to analyze the influence of the quality class and the orthotropy of wood upon the sound absorption coefficient, the reflection and the impedance ratio of two species widely used for stringed musical instruments, namely spruce (Picea abies L. Karst) and maple (Acer pseudoplatanus L.). An impedance tube for the frequency range 100–6400 Hz was used in these experimental determinations. Knowing the influence of porosity and tortuosity on the acoustic absorption, these properties were also determined, as well as the sound reduction coefficient and the maximum values of the acoustic absorption coefficients in relation to frequency. The main results highlighted the differences between the anatomical quality class of the wood within each species, but also concerning the sound direction relative to the three main sections of wood, as an orthotropic material. The article highlights the acoustic performance parameters related to the frequency of the wooden material and its relationship to density, porosity and quality class. The results represent useful information for musical instruments manufacturers and more.