Synthesis of multi-input multi-degree-of-freedom fixed shaft gear transmission configuration for vehicles

The rapid development of dual-clutch transmission (DCT) and hybrid and purely electric vehicles stimulate the researches on multi-input fixed shaft gear transmission mechanisms. The multiple degree-of-freedom (DOF) transmission mechanism can achieve a wider range of speed ratio adjustment and more modes under certain space and weight constraints, which is an ideal choice for multi gear transmission. In this paper, a synthesis method of fixed shaft gear transmission configuration is proposed. Based on the established graph theory model, kinematic characteristics of the fixed shaft gear transmission configuration are studied and the shift sequence is determined. Using these characteristics, a derivation method from the basic configuration to the comprehensive gears and shafts configuration is proposed. Multiple parameters such as the synchronizer arrangement and speed ratios are optimized. Finally, the proposed method is vigorously verified by a seven-speed DCT with four DOFs. This method is comprehensive and systematic in designing fixed shaft gear transmission configurations, which can be applied to DCT, transmissions for parallel hybrid electric vehicles, and to some novel multi-input transmissions.

A general framework for straightforward model construction of multi-component thermodynamic equilibrium systems

Mathematical modelling of molecular systems helps elucidating complex phenomena in (bio)chemistry. However, equilibrium conditions in systems consisting of more than two components can typically not be analytically determined without assumptions and resulting (semi-)numerical models are not trivial to derive by the non-expert. Here we present a framework for equilibrium models that utilizes a general derivation method capable of generating custom models for complex molecular systems, based on the simple, reversible reactions describing these systems. Several molecular systems are revisited via the framework and demonstrate the simplicity, the generality and validity of the approach. The ease of use of the framework and the ability to both analyze systems and gain additional insights in the underlying parameters strongly aids the analysis and understanding of molecular equilibrium systems. This conceptual framework severely reduces the time and expertise requirements which currently impede the broad integration of these highly valuable models into chemical research.

Overlooked current estimation biases arising from the Lagrangian Argo trajectory derivation method

An Argo simulation system is used to provide synthetic Lagrangian trajectories based on the Estimating the Circulation and Climate of the Ocean model, Phase II (ECCO2). In combination with ambient Eulerian velocity at the reference layer (1000 m) from the model, quantitative metrics of the Lagrangian trajectory-derived velocities are computed. The result indicates that the biases induced by the derivation algorithm are strongly linked with ocean dynamics. In low latitudes, Ekman currents and vertically sheared geostrophic currents influence both the magnitude and the direction of the derivation velocity vectors. The maximal shear-induced biases exist near the equator with the amplitudes reaching up to about 1.2 cm s-1. The angles of the shear biases are pronounced in the low latitude oceans, ranging from -8° to 8°. Specifically, the study shows an overlooked bias from the float drifting motions that mainly occurs in the western boundary current and Antarctic circumpolar current (ACC) regions. In these regions, a recently reported horizontal acceleration measured via Lagrangian floats is significantly associated with the strong eddy-jet interactions. The acceleration could induce an overestimation of Eulerian current velocity magnitudes. For the common Argo floats with a 9-day float parking period, the derivation speed biases induced by velocity acceleration would be as large as 3 cm s-1, approximately 12% of the ambient velocity. It might have implications to map the mean mid-depth ocean currents from Argo trajectories, as well as understand the dynamics of eddy-jet interactions in the ocean.

An Analytic Transform Kernel Derivation Method for Video Codecs

In the standardization of versatile video coding (VVC), discrete cosine transform (DCT)-2, discrete sine transform (DST)-7, and DCT-8 are regarded as the primary transform kernels. However, DST-4 and DCT-4 can also be considered as the transform kernels instead of using DST-7 and DCT-8 owing to their effectiveness in smaller resolution test sequences. To implement these different block size transform kernels, a considerable amount of memory has to be allocated. Moreover, memory consumption to store different block size transform kernels is regarded as a major issue in video coding standardization. To address this problem, a common sparse unified matrix concept is introduced in this study, where any block size transform kernel matrix can be obtained after some mathematical operations. The proposed common sparse unified matrix saves approximately 80% of the static memory by storing only a few transform kernel elements for DCT-2, DST-7, and DCT-8. Full-required transform kernels are derived using the stored transform kernels and generated unit-element matrices and a permutation matrix. The static memory required is only for 1648 elements instead of 8180 elements, each with 8-bit precision. The defined common sparse unified matrix is composed of two parts: a unified DST-3 matrix and a grouped DST-7 matrix. The unified DST-3 matrix is used to derive different points of DCT-2 transform kernels, and the grouped DST-7 matrix is used to derive different points of DST-7 and DCT-8 transform kernels. The new technique of grouping concept is introduced, which shows the relationship between different rows of DST-7 transform kernels with various block sizes. The proposed grouping concept supports the fast algorithm of DST-7 by implementing the proposed method of the “one group one feature” principle. The simulation was conducted using the VTM-3.0 reference software under common test conditions. The simulation result of the all intra (AI) configuration is Y = 0.00%, U = −0.02%, V = 0.00% with an encoding time of 100%, and a decoding time of 100%. Similarly, the simulation results of random access (RA) configuration are Y = −0.01%, U = 0.09%, V = 0.06%, and the encoding and decoding times are 101% and 100%, respectively. The simulation result of the low delay B (LDB) configuration is Y = 0.01%, U = 0.08%, and V = −0.27%, for encoding and decoding times of 101% and 100%, respectively.

Theoretical Derivation of Mean Cutting-Point Space of Grinding Wheel

In a surface grinding process, a successive cutting-point space of grinding wheel affects the maximum abrasive grain depth of cut, which is a major factor affecting grinding characteristics such as the grinding forces and temperature. These characteristics degrade the productivity and machining accuracy. Therefore, we have to clearly define the successive cutting-point space. There are, however, few reports on the derivation method of the theoretical formula since abrasive grains inside the wheel are randomly distributed. This study aimed to theoretically derive the mean cutting-point space and to clarify the successive cutting-point space. We proposed a new derivation method for the mean cutting-point space, which was measured by mapping the diamond wheel surface using an EPMA. The theoretically derived mean cutting-point space was then compared with the measurement results.

Deriving a Fire Occurrence Scenario Using Fire-Statistical Causation

According to the statistics obtained by the Ministry of Land, Infrastructure and Transport in 2019, approximately 40% of the buildings in the nation are buildings aged 30 or more years after completion. The Framework Act on Firefighting Services does not apply to old buildings, and they fall into a blind spot of the fire safety performance system. A large fire in a multi-dense facility causes heavy social casualties. This study therefore aimed to establish the type of fire occurrence and fire source scenario of a building for securing fire safety performance. The current fire scenario derivation method, which was identified as a causation factor among other detailed statistical factors, was analyzed to allow for differentiation from the proposed method. The base data were analyzed to establish fire response and prevention and for developing a performance-based fire-fighting design scenario by deriving a fire occurrence scenario.

Introducing a Pure Weight-Based Concept for Automatic Test Case Generators

For decades, automatic test case generators for context-free grammars usually have adopted a derivation method designed to obtain the minimum set of shortest sentences.<div>Within this paper, a <i>pure weight-based</i> approach is described: such approach uniquely uses <i>weights </i>to select a rule while expanding a nonterminal symbol; we will assess how it is always possible to identify <i>balanced </i>weights which ensure the convergence of the process and we will see how the generated sentences are usually more complex than the shortest ones, so having more chances to exercise the underlying system more extensively.</div>

Study of the constrictor properties of the neobladder under the influence of new chemical compounds in vivo experiment

The orthotopic ileocystoplasty is the most preferred urine derivation method for patients after removal of the bladder. The best quality of life, self-esteem, cosmetic appearance of one’s own body, and the possibility of physiological urination characterize the artificial bladder as the “gold standard” of urine derivation. There are a greater number of postoperative complications associated with the functionality of the neobladder, considering the complexity of orthotopic derivation of urine. The autocaturation is required in some patients day or night urinary incontinence, and in the other group, periodic urinary retention. Urinary retention is more common in women up to 43 % compared with 20 % in men, who need intermittent catheterization. The aim of investigation was to evaluate the possibility of pharmacological correction of contractile activity of mini-pigs neobladder in vivo, under the influence of new chemical compounds and the anticholinesterase drug nivalin. Materials and methods Experimental studies were performed on 21 female mini-pigs, with an average age of 6 to 14 months. The duration of the experiment was 12 months. Performing of enterocystometry in experimental animals is possible only under anesthesia and, accordingly, only part of the urodynamic parameters can be obtained. Results. The obtained results of in vivo experimental studies demonstrated the constrictor activity of the studied new chemical compounds. Compound I in comparison with the control group statistically significantly increased basal tone by 62.09 %, the amplitude of contractions by 37.34 %, and the duration of contractions by 35.71 %. The new chemical compound II, in comparison with the control group, showed less pronounced results of constrictor activity, so the basal tone statistically significantly increased by 38.86 %, and the amplitude of contractions by 15.0 %. Conclusion. Thus, under the influence of new chemical compounds in the conditions of an experimental artificial bladder, constrictor properties are proved, which require further research and study. In turn, cholinomimetic nivalin has prospects for use in urology, in particular in patients with hypoactive forms of artificial and neurogenic bladder.

A climatological benchmark for operational radar rainfall bias reduction

The presence of significant biases in real-time radar quantitative precipitation estimations (QPEs) limits its use in hydrometeorological forecasting systems. Here, we introduce CARROTS (Climatology-based Adjustments for Radar Rainfall in an OperaTional Setting), a set of fixed bias reduction factors, which vary per grid cell and day of the year. The factors are based on a historical set of 10 years of 5 min radar and reference rainfall data for the Netherlands. CARROTS is both operationally available and independent of real-time rain gauge availability and can thereby provide an alternative to current QPE adjustment practice. In addition, it can be used as benchmark for QPE algorithm development. We tested this method on the resulting rainfall estimates and discharge simulations for 12 Dutch catchments and polders. We validated the results against the operational mean field bias (MFB)-adjusted rainfall estimates and a reference dataset. This reference consists of the radar QPE, that combines an hourly MFB adjustment and a daily spatial adjustment using observations from 32 automatic and 319 manual rain gauges. Only the automatic gauges of this network are available in real time for the MFB adjustment. The resulting climatological correction factors show clear spatial and temporal patterns. Factors are higher away from the radars and higher from December through March than in other seasons, which is likely a result of sampling above the melting layer during the winter months. The MFB-adjusted QPE outperforms the CARROTS-corrected QPE when the country-average rainfall estimates are compared to the reference. However, annual rainfall sums from CARROTS are comparable to the reference and outperform the MFB-adjusted rainfall estimates for catchments away from the radars, where the MFB-adjusted QPE generally underestimates the rainfall amounts. This difference is absent for catchments closer to the radars. QPE underestimations are amplified when used in the hydrological model simulations. Discharge simulations using the QPE from CARROTS outperform those with the MFB-adjusted product for all but one basin. Moreover, the proposed factor derivation method is robust. It is hardly sensitive to leaving individual years out of the historical set and to the moving window length, given window sizes of more than a week.

Calculation of Mohr-Coulomb Parameters for Rocks of Doha, Qatar

Among practitioners, designers and researchers, modern-day geotechnical software packages still predominantly use Mohr-Coulomb (MC) input modelling parameters, despite the immense computing power of today’s software and hardware components. The same particularly applies to this field of work in the state of Qatar. The goal of this technical note is to demonstrate the most appropriate derivation method for Mohr-Coulomb parameters, by proving that this must ensue by first obtaining or estimating proper Hoek-Brown parameters, followed by appropriate method for conversion. Only such an approach can remove uncertainty and high variability of results in geotechnical estimations and design inputs.