Cost optimization of two-stage helical gearboxes with second stage double gear-sets

In practice, the cost of a gearbox plays a very important role in the trade. Therefore, reducing the cost of gearboxes is an important task not only when manufacturing the gearboxes but also when designing them. In order to reduce the cost of a gearbox, there are many solutions in which determining the optimal partial gear ratios of a gearbox is an effective measure. This is because it not only the size, the mass but also the cost of a gearbox depends greatly on the partial gear ratios. This work presents a method for calculating the cost function of two-stage helical gearboxes with second-stage double gear-sets based on the mass of the components that construct the gearbox. The cost objective function is minimized to achieve the optimal transmission ratios. Furthermore, screening experiments are carried out with nine important input parameters that have significant effects on the optimum transmission ratio of the second stage. These parameters are the total gearbox ratio, the coefficient of wheel face width of the first stage, coefficient of wheel face width of the second stage, the allowable contact stress of the first stage, the allowable contact stress of the second stage, the output torque, the cost of gearbox housing, the cost of gears, and the shaft cost. The experimental results of were analysed by using the Analysis of Variance (ANOVA) method with the help of Minitab 19 software. The results demonstrate that the effective weight of the input parameters and their interactions on the output response was investigated. Also, a regression model for computing the optimal transmission ratio of the second stage was proposed. This brings significance not only in the design process but also in manufacturing since the gearbox cost can decreas

Design and fabrication of the trapezoidal electrostatic comb-drive actuator

This paper reports the design, fabrication and characterization process of the trapezoidal Electrostatic Comb-drive Actuator (ECA) with the slope angle α=20. Together with the trapezoidal ones, the rectangular ECA with identical dimension was also designed and fabricated for comparison purpose. In order to reduce calculating deviation, the fringing effect was also taken into consider while carrying out theoretical analysis. The obtained results pointed out the fact, that the trapezoidal ECA excels the rectangular ones with the same numbers of teeth in electrostatic force and displacement generation, while requires relatively low driving voltage. But it is also observed that with higher driving voltage (larger than 50V), the trapezoidal ECA starts to lose its stability (the lateral pull-in phenomenon occurs)

Integration of an RSA-2048-bit public key cryptography solution in the development of secure voice recognition processing applications

The authors initially employs the fast Fourier transform (FFT) approach to transforming voice inputs into digital signals before integrating a speech recognition solution (which includes two models: the hidden Markov model (HMM) and the artificial neural network (ANN)). To achieve standard-tone identification of voice signals and digitally store speech, the authors then incorporated a 2048-bit Rivest-Shamir-Adleman (RSA) encryption method to encrypt and decrypt digital speech. The authors’ building team constructed the program using a 256-bit advanced encryption standard - Galois counter mode (AES-GCM) encryption method to assure the application’s effectiveness. The authors successfully created a voice recognition application according to the HMM of ANN. The collected findings suggest that the authors’ secure speech recognition program (named soft voice - RSA) has improved in terms of safety, keeping speech material secret, and speed. It takes roughly 0.2 s to generate a 2048-bit RSA key pair that exceeds the National Institute of Standards and Technology (NIST) standard, 700-1070 ms to process speech, 1-4 ms to encrypt 2048-bit RSA, 6-8 ms to decrypt 2048-bit RSA

VẬT LIỆU TIO2/THAN HOẠT TÍNH TỪ TRO TRẤU VÀ KHẢ NĂNG HẤP PHỤ XANH METHYLENE

In the present work, TiO2/activated-carbon composite (TiO2/RHAC) was synthesized with an assembly method. Activated carbon was fabircated from rice husks. The water-soluble titanium complex was synthesized from anatase via the peroxide complex. The mixture of activated carbon and water-soluble TiO2 was calcined at 600 °C. The obtained samples were characterized by using XRD, SEM, EDX, and UV-Vis-DR. The results show that the obtained composites exhibit excellent adsorption toward methylene blue (MB). The equilibrium data fit the Langmuir isotherm model well. The maximum monolayer capacity calculated from the Langmuir model is 144.7 mg·g–1. The TiO2/RHAC could be self-cleaned after use by photocatalytic degradation. The adsorption capacity insignificantly decreases after three recycles of adsorption, and TiO2/RHAC is a promising adsorbent for removing dyes from the aqueous environment.Trong nghiên cứu này, TiO2/than hoạt tính từ tro trấu (TiO2/RHAC) đã được tổng hợp bằng phương pháp trộn lẫn than hoạt tính và phức titanium. Than hoạt tính được tổng hợp từ tro trấu và phức titanium hòa tan trong nước tổng hợp từ anatase bằng cách tạo phức peroxide. Hỗn hợp được nung trong môi trường thiếu oxy ở 600 °C. Vật liệu tổng hợp được phân tích bằng nhiễu xạ tia X, kính hiển vi điện tử quét và đẳng nhiệt hấp phụ/giải hấp phụ ni tơ. TiO2/RHAC có khả năng hấp phụ cao đối với xanh methylene. Số liệu đẳng nhiệt cân bằng tuân theo mô hình Langmuir và dung lượng hấp phụ cực đại tính theo mô hình này là 144,7 mg·g–1. Chất bị hấp phụ có thể được loại bỏ bằng cách chiếu sáng bằng đèn chiếu nhờ khả năng xúc tác quang hóa của nó. Sau ba lần tái sinh, dung lượng hấp phụ thay đổi không đáng kể. TiO2/RHAC có tiềm năng làm chất hấp phụ xử lý phẩm màu nói chung

A Wearable, Bending-Insensitive Respiration Sensor Using Highly Oriented Carbon Nanotube Film

Recently, wearable electronics for health monitoring have been demonstrated with considerable benefits for early-stage disease detection. This article reports a flexible, bending-insensitive, bio-compatible and lightweight respiration sensor. The sensor consists of highly oriented carbon nanotube (HO-CNT) films embedded between electro-spun polyacrylonitrile (PAN) layers. By aligning carbon nanotubes between the PAN layers, the sensor exhibits a high sensitivity towards airflow (340 mV/(m/s)) and excellent flexibility and robustness. In addition, the HO-CNT sensor is insensitive to mechanical bending, making it suitable for wearable applications. We successfully demonstrated the attachment of the sensor to the human philtrum for real-time monitoring of the respiration quality. These results indicate the potential of HO-CNT flow sensor for ubiquitous personal health care applications

Evolution and transmission of antibiotic resistance is driven by Beijing lineage Mycobacterium tuberculosis in Vietnam

A previous investigation has elucidated the landscape of Mtb genomic diversity and transmission dynamics in Ho Chi Minh City, Vietnam. Here, we expand the scope of this survey by adding a substantial number of additional genomes (total sample size: 2,542) and phenotypic drug susceptibility data for the majority of isolates. We aim to explore the prevalence and evolutionary dynamics of drug resistance and our ability to predict drug resistance from sequencing data. Among isolates tested phenotypically against first-line drugs, we observed high rates of streptomycin [STR, 37.7% ( N = 573/1,520)] and isoniazid resistance [INH, 25.7% ( N = 459/1,786)] and lower rates of resistance to rifampicin [RIF, 4.9% ( N = 87/1,786)] and ethambutol [EMB, 4.2% ( N = 75/1,785)]. Relative to global benchmarks, resistance to STR and INH was predicted accurately when applying the TB-Profiler algorithm to whole genome sequencing data (sensitivities of 0.81 and 0.87, respectively), while resistance to RIF and EMB was predicted relatively poorly (sensitivities of 0.70 and 0.44, respectively). Exploring the evolution of drug resistance revealed the main phylogenetic lineages to display differing dynamics and tendencies to evolve resistance via mutations in certain genes. The Beijing sublineage L2.2.1 was found to acquire de novo resistance mutations more frequently than isolates from other lineages and to suffer no apparent fitness cost acting to impede the transmission of resistance. Mutations conferring resistance to INH and STR arose earlier, on average, than those conferring resistance to RIF and are now more widespread across the phylogeny. The high prevalence of “background” INH resistance, combined with high rates of RIF mono-resistance (20.7%, N = 18/87), suggests that rapid assays for INH resistance will be valuable in this setting. These tests will allow the detection of INH mono-resistance and will allow multi-drug-resistant isolates to be distinguished from isolates with RIF mono-resistance. IMPORTANCE Drug-resistant tuberculosis (TB) infection is a growing and potent concern, and combating it will be necessary to achieve the WHO’s goal of a 95% reduction in TB deaths by 2035. While prior studies have explored the evolution and spread of drug resistance, we still lack a clear understanding of the fitness costs (if any) imposed by resistance-conferring mutations and the role that Mtb genetic lineage plays in determining the likelihood of resistance evolution. This study offers insight into these questions by assessing the dynamics of resistance evolution in a high-burden Southeast Asian setting with a diverse lineage composition. It demonstrates that there are clear lineage-specific differences in the dynamics of resistance acquisition and transmission and shows that different lineages evolve resistance via characteristic mutational pathways

An algorithm for decoding product codes based on soft-decision decoding of dual codes of the component codes

Product codes have large minimum Hamming distance and their complexity might be compared with Turbo codes. Conventional algorithms for decoding product codes have low decoding performances and very high complexities. In order to ensure the applicability of product codes in practice, this article proposes a method for decoding product codes which provide good decoding performance and acceptable complexity. Simulation results of the proposed algorithm show that, a signal-to-noise ratio of about only 4,1 dB is required in order to produce a bit error ratio (BER) not to exceed10–6 with rate code at 0,7034