Mechanical Transmission Research Articles

Electric drive system for seed metering and its effects on the distribution and development of the corn crop

The present study aimed to evaluate the efficiency of the electric transmission drive of the seed metering mechanism of a precision seeder, in relation to the mechanical drive, in the distribution of corn seeds, and its effects on the development of the crop. The experiment was carried out using precision agriculture techniques - geostatistics - in a plot of 4.19 ha managed under no-tillage system. The area was divided into a grid with 35 points for each treatment (electrical transmission of the seed metering mechanism and mechanical transmission of the seed metering mechanism). To carry out the experiment, a precision seeder consisting of 7 lines was used, configured with 0.45m line spacing, being: 4 consecutive lines by electrical transmission and 3 consecutive lines driven by mechanical transmission. The electrical transmission of the seed dosing mechanism provided, in relation to mechanical transmission, a lower coefficient of variation of the linear distribution of seeds, a lower spacing index with failure, a higher normal spacing index, and a smaller difference in seeding density. As a consequence, the electrical transmission of the seed metering mechanism increased the productivity of the corn crop by 1.33% (87.96 kg ha-1) when compared to mechanical transmission.

On the design and power output response of hydraulic wind turbines

Standard horizontal axis wind turbines typically use gearboxes for large-scale applications and direct coupling for small-scale designs to connect the rotor to the generator. However, gearboxes pose challenges due to their weight, cost, and exposure to dynamic loads and vibrations within the nacelle. A promising alternative is replacing mechanical transmission with a hydrostatic counterpart, offering advantages such as reduced nacelle mass, generator placement at the tower base, and elimination of the gearbox. It can potentially lead to cost savings of up to 20% in the levelized cost of electricity for offshore wind turbines. This study compares regulated hydrostatic transmission with unregulated transmission and damping components under different wind conditions, including atmospheric boundary layer and low-level jet inputs. Dynamic simulations of a horizontal axis wind turbine incorporating a hydrostatic transmission are conducted to evaluate its response to wind fluctuations caused by prevailing wind velocity profiles, atmospheric boundary layer, and low-level jet velocity profiles. Addressing torque fluctuations and power impact on power quality and mechanical components is crucial in wind turbine operation. The proposed hydrostatic transmission includes primary and secondary proportional controllers for adaptability to varying wind speeds, along with integrated accumulators in the high and low-pressure lines. The main findings indicate that the regulated hydrostatic transmission achieves an efficiency range of 69%–75% across various wind velocity profiles, surpassing the unregulated counterpart. It reduces torque fluctuation amplitude by 35% and improves efficiency by nearly 20% compared to the basic transmission. Torque and power fluctuations are also reduced by 35% and 40%. These improvements are attributed to the damping capabilities of the hydrostatic transmission and the actions of the proportional controller. Implementing the regulated hydrostatic transmission offers several technical and economic advantages, including relocating the generator to ground level and achieving continuous hydraulic variable transmissions without the need for a gearbox. The methodology is applicable to a range of wind turbine sizes.

CREB3L2 Regulates Hemidesmosome Formation during Epithelial Sealing.

The long-term success rate of dental implants can be improved by establishing a favorable biological sealing with a high-quality epithelial attachment. The application of mesenchymal stem cells (MSCs) holds promise for facilitating the soft tissue integration around implants, but the molecular mechanism is still unclear and the general application of MSC sheet for soft tissue integration is also relatively unexplored. We found that gingival tissue-derived MSC (GMSC) sheet treatment significantly promoted the expression of hemidesmosome (HD)-related genes and proteins in gingival epithelial cells (GECs). The formation of HDs played a key role in strengthening peri-implant epithelium (PIE) sealing. Further, high-throughput transcriptome sequencing showed that GMSC sheet significantly upregulated the PI3K/AKT pathway, confirming that cell adhesion and HD expression in GECs were regulated by GMSC sheet. We observed that the expression of transcription factor CREB3L2 in GECs was downregulated. After treatment with PI3K pathway inhibitor LY294002, CREB3L2 messenger RNA and protein expression levels were upregulated. Further experiments showed that overexpression or knockdown of CREB3L2 could significantly inhibit or promote HD-related genes and proteins, respectively. We confirmed that CREB3L2 was a transcription factor downstream of the PI3K/AKT pathway and participated in the formation of HDs regulated by GMSC sheet. Finally, through the establishment of early implant placement model in rats, we clarified the molecular function of CREB3L2 in PIE sealing as a mechanical transmission molecule in GECs. The application of GMSC sheet-implant complex could enhance the formation of HDs at the implant-PIE interface and decrease the penetration distance of horseradish peroxidase between the implant and PIE. Meanwhile, GMSC sheet reduced the length of CREB3L2 protein expression on PIE. These findings elucidate the potential function and molecular mechanism of MSC sheet regulating the epithelial sealing around implants, providing new insights and ideas for the application of stem cell therapy in regenerative medicine.

Research on gearbox fault detection model based on ridge regression and decision tree

Gearbox is widely used in mechanical equipment and plays an important role in mechanical transmission. Therefore, it is necessary to detect and diagnose the fault of the gearbox in time. This paper needs to establish a fault detection model of the gearbox to detect whether the gearbox is in a fault state. Because the result can only be yes or no, the ridge regression model is first established. However, because the difference between the original sample data is not obvious, the accuracy of the obtained ridge regression model is low. Therefore, this study extracts the features of the data of the four parts, and defines five indicators: effective value, pulse index, skewness index, margin index and kurtosis index. The decision tree model is established with 70 % of the sample data. Firstly, the depth of the largest tree is set to 5. Secondly, the importance of the feature is determined according to the size of the Gini value, and the fault detection decision tree model is constructed. Finally, the model is tested with 30 % of the test data, and the accuracy is 91.17 %. The precision rate is 88.9 %, and the recall rate is 94.12 %. It is considered that the model is more reliable.

Intraday price discovery and volatility transmission between the dual-listed stock index futures and spot markets – new evidence from India

PurposeThis study empirically explores the intraday price discovery mechanism and volatility transmission effect between the dual-listed Indian Nifty index futures traded simultaneously on the onshore Indian exchange, National Stock Exchange (NSE) and offshore Singapore Exchange (SGX) and its spot market by using high-frequency data.Design/methodology/approachThis study applies the vector error correction model to analyze the lead-lag relationship in price discovery among three markets. The contributions of individual markets in assimilating new information into prices are measured using various measures, Hasbrouck's (1995) information share, Lien and Shrestha's (2009) modified information share and Gonzalo and Granger's (1995) component share. Additionally, the Granger causality test is conducted to determine the causal relationship. Lastly, the BEKK-GARCH specification is employed to analyze the volatility transmission.FindingsThis study provides robust evidence that Nifty futures lead the spot in price discovery. The offshore SGX Nifty futures consistently ranked first in contributing to price discovery, followed by onshore NSE Nifty futures and finally by the spot. Empirical results also show unidirectional causality and volatility transmission from Nifty futures to spot, as well as bidirectional causal relationship and volatility spillovers between NSE and SGX Nifty futures. These novel findings provide fresh insights into the informational efficiency of the dual-listed Indian Nifty futures, which is distinct from previous literature.Practical implicationsThese findings can potentially help market participants, policymakers, stock exchanges and regulators.Originality/valueUnlike previous studies in this area, this is the first study that empirically examines the intraday price discovery mechanism and volatility spillover between the dual-listed futures markets and its spot market using 5-min overlapping price data and trivariate econometric models.

Fuel consumption of a wheel loader with power reflux hydraulic transmission system

The world is facing a limited supply of fossil fuel resources and stringent environmental constraints. Therefore, it is very important to develop advanced technologies to improve vehicle fuel economy, especially for construction vehicles, which have large engine displacements and poor emission characteristics. The majority of these vehicles use hydraulic mechanical transmission in the power train in order to improve maneuverability. However, a key issue on the hydraulic mechanical transmission is the low-efficiency torque converter. Focusing on this issue, we proposed the power reflux hydraulic transmission system (PRHTS), which is a new continuously variable transmission system. The PRHTS can improve the overall transmission efficiency of the power train by splitting the engine power into mechanical and hydraulic power. Therefore, the PRHTS is a valid solution to reduce the fuel consumption and subsequently decrease emissions from construction vehicles. In order to quantitatively study the effect of using the PRHTS on improving the fuel economy for construction vehicles, a wheel loader coupled with the PRHTS is modeled, and numerical simulation is conducted under the wheel loader driving condition. The simulation results show that the total fuel consumption of the wheel loader coupled with PRHTS is reduced by 3.39 % compared with that of the original wheel loader.

Application of metal rubber for semi-active vibration control of mechanical transmission systems

This study proposes a novel semi-active vibration control technique for mechanical transmission systems. The backbone of current research technology is the adaptive stiffness and damping properties of metal rubber (MR) which plays the role of tuning to the vibrational system eigenmodes. The adaptive properties of MR material were proved by a previous study, but the present research investigates the effect of this feature on the structural response and designs an MR-based semi-active vibration controller for industrial application. For this purpose, the semi-active control strategy is created based on an optimal tuning using experimental harmonic test results. The control strategy is applied in practice using a linear actuator controlled by a double pole double throw (DPDT) relay, and National Instruments hardware and software for reading data and writing the control task. The isolator attachment position is defined through the analysis of eigenmode shapes that are predetermined by numerical simulation. A maximum isolation rate of 55.17% is measured near the vibration isolator position. It is observed that the isolation position has a prominent effect on structure vibration behavior where the elastic wave has been reduced in amplitude by passing the isolator position. The effectiveness of the MR-based semi-active control approach is eminent and its application for vibration isolation of commercial mechanical transmission systems could be studied in the future.

Biomechanical Evaluation of an Adaptive-Motion Pedicle Screw Fixation System: Experimental and Numerical Analysis.

Rigid fixation is mostly used in thoracolumbar spine surgery, which restricts the thoracolumbar spine segments moving and is not conducive to postoperative rehabilitation. We developed an adaptive-motion pedicle screw and established a finite element model of the T12-L3 segments of the thoracolumbar spine in osteoporosis patients based on the CT image data. A variety of internal fixation finite element models were established for mechanical simulation analysis and comparison. The simulation results showed that compared with the conventional internal fixation system, the mobility of the new adaptive-motion internal fixation system was improved by about 13.8% and 7.7% under the classic conditions such as lateral bending and flexion. in vitro experiments were conducted simultaneously with fresh porcine thoracolumbar spine vertebrae, and the axial rotation condition was taken as an example to analyze the mobility. The in vitro results showed that the mobility of the adaptive-motion internal fixation system had better mobility characteristics under axial rotation conditions, which was consistent with the finite element analysis. The adaptive-motion pedicle screws can preserve a certain degree of vertebral mobility, and avoid excessive vertebral restriction. It also increases the stress value of the intervertebral disk, which is closer to the normal mechanical transmission of the human body, avoiding stress masking and slowing down the degeneration of the intervertebral disk. The adaptive-motion pedicle screws can reduce the peak stress of the implant and avoid surgical failure due to implant fracture.

Mechanical transmission of dengue virus by Aedes aegypti may influence disease transmission dynamics during outbreaks.

Dengue virus outbreaks are increasing in number and severity worldwide. Viral transmission is assumed to require a minimum time period of viral replication within the mosquito midgut. It is unknown if alternative transmission periods not requiring replication are possible. We used a mouse model of dengue virus transmission to investigate the potential of mechanical transmission of dengue virus. We investigated minimal viral titres necessary for development of symptoms in bitten mice and used resulting parameters to inform a new model of dengue virus transmission within a susceptible population. Naïve mice bitten by mosquitoes immediately after they took partial blood meals from dengue infected mice showed symptoms of dengue virus, followed by mortality. Incorporation of mechanical transmission into mathematical models of dengue virus transmission suggest that this supplemental transmission route could result in larger outbreaks which peak sooner. The potential of dengue transmission routes independent of midgut viral replication has implications for vector control strategies that target mosquito lifespan and suggest the possibility of similar mechanical transmission routes in other disease-carrying mosquitoes. This study was funded by grants from the National Health Research Institutes, Taiwan (04D2-MMMOST02), the Human Frontier Science Program (RGP0033/2021), the National Institutes of Health (1R01AI143698-01A1, R01AI151004 and DP2AI152071) and the Ministry of Science and Technology, Taiwan (MOST104-2321-B-400-016).

The Role of Virgin Coconut Oil in Corn Starch/NCC-Based Nanocomposite Film Matrix: Physical, Mechanical, and Water Vapor Transmission Characteristics.

Corn starch-based nanocomposite films usually have low moisture barrier properties. Adding virgin coconut oil (VCO) as a hydrophobic component can improve the nanocomposite film's characteristics, especially the film's permeability and elongation properties. This study aimed to determine the role of VCO with various concentrations (0, 3, 5 wt%) on the physical, mechanical, and water vapor transmission characteristics of corn starch/NCC-based nanocomposite films. Adding 3% VCO to the film showed the lowest WVTR value by 4.721 g/m2.h. At the same time, the value of tensile strength was 4.243 MPa, elongation 69.28%, modulus of elasticity 0.062 MPa, thickness 0.219 mm, lightness 98.77, and water solubility 40.51%. However, adding 5 wt% VCO to the film increased the film's elongation properties by 83.87%. The SEM test showed that adding VCO formed a finer structure with pores in several areas. The FTIR films showed that adding VCO caused a slightly higher absorption peak shift at the O-H groups and new absorption peaks at wave numbers 1741 cm-1 and 1742 cm-1. The results of this study may provide opportunities for the development of nanocomposite films as biodegradable packaging in the future.

Design and Control Strategies for Mechanical Hydraulic Transmission Systems

With the development of social and economic development, all walks of life are progressing rapidly, and mechanical hydraulic transmission technology has been widely used. Mechanical hydraulic transmission technology is a widely used, high efficiency, energy-saving and environmentally friendly transmission technology, mainly using liquid as the medium, relying on the pressure of the liquid to transmit power. Due to the strong mobility of the liquid, the pressure and flow of the liquid can be changed at will, therefore, it is widely used in mechanical hydraulic transmission systems. This paper takes the design of mechanical hydraulic transmission system as content, combined with the analysis of contemporary problems in the design and control of mechanical hydraulic transmission system, and explores the common problems and solutions in the design process of mechanical hydraulic transmission system. This paper discusses the design and control methods of mechanical hydraulic transmission system control strategy, and hopes to provide some reference for colleagues.

Characterization of damping in 3D metal printed gear body using parameter optimization

With the rapid development of the global economy and the widespread use of high-speed machinery, vibration and noise pollution is becoming increasingly serious. The increased energy costs, environmental pollution, and carbon emissions have prioritized sustainable development for industry. As an important link of mechanical transmission, the gear transmission vibration and noise adversely affect the physical and mental health of operators and interfere with the normal use of machinery. This paper proposes a new metal 3D printing-made vibration-damping lightweight gear model. The solid gear web is replaced with a lightening hole structure that is expected to ensure rigidity and torsional compliance while controlling the damping effects of the gear web structure. Gears were manufactured from an additive manufacturing material using a metal 3D printing technique. This work advanced an experimental analysis of the dissipation properties of metal printed gear exploiting vibration tests. A gear frequency-sweeping excitation test bench was designed and developed to simulate in-plane excitation to produce a circumferential torsional mode of the specimen. Circumference damping estimates are guided by executing vibration exciter excitation on the setup. The half-power bandwidth and modal fitting methods were arranged and compared, relying on the measured frequency response function (FRF) single-degree-of-freedom (SDOF) approximation.

Optimization of key gear parameters to reduce weight

Problem. The problems of designing, and especially improving, mechanical gears are of key importance in modern mechanical engineering and automotive transport. Gear transmissions are quite widespread relative to other mechanical transmissions because they have a number of crucial advantages. Gear transmissions are widely used in a variety of drives for vehicle components and assemblies, with modern development trends aimed at reducing their weight and size. As the size of the transmission decreases, the dimensions of other parts and assemblies also decrease, and, accordingly, their cost. Therefore, research related to the study of the interdependence of the main parameters of gears for the purpose of their further optimization does not lose its relevance. Goal. The main purpose of this work is to study the dependence of the mass and dimensions of the gears under study on their main parameters. Knowing the influence of various characteristics on the mass, it is possible to provide recommendations for the design of gears to achieve their optimal (smallest) dimensions, which leads to a number of significant advantages. Methodology. First of all, a rather detailed analysis of the scientific literature is performed in order to identify the main statements regarding the influence of certain parameters on the mass and dimensions of the designed gear. The very dependencies of the gear mass on its various characteristics are found by applying a numerical method that is entirely based on the known design dependencies for the design calculation of gears. Also, to compare the results obtained analytically, the method of calculating the mass and dimensions by creating 3D models of gears in the "Autodesk Inventor" environment is used in the work. Results. Based on the results obtained, it can be noted that, ceteris paribus, including gear load, the weight is almost independent of the module and the relative width ratio. At the same time, in some cases, a particular standard value can significantly affect the weight of the gear, i.e., by selecting specific values, it is possible to reduce the weight of the gear by about 15-25%. Originality. Useful results were obtained using a relatively affordable method. The research was conducted both analytically and with the use of modern computer-aided design systems. Practical value. The proposed recommendations for the rational choice of some characteristics of gears will reduce the weight and dimensions of the mechanical drive.

Antiviral Efficacy of Bacillus sp. against Groundnut bud necrosis orthotospovirus in Cowpea

Tomato spotted wilt, a disease caused by Groundnut bud necrosis virus (GBNV), is a major disease affecting tomatoes causing great yield loss to the farming community. In this study, the GBNV-TNAU 1 virus isolate was obtained from infected plants and maintained through mechanical transmission on cowpea cv. CO7, which induced chlorotic and necrotic local lesions by the fourth-day post-inoculation (dpi). The pathogenicity of GBNV on tomato cv. PKM1 was confirmed through sap transmission. In vitro screening of Bacillus sp. viz., B. amyloliquefaciens (Ka1), B. subtilis (Bbv 57), and B. subtilis (BST 8) demonstrated effective reduction of GBNV-induced lesions in cowpea. B. amyloliquefaciens (Ka1) and B. subtilis (BST8) displayed a maximum germination percentage of 100 %, while B. amyloliquefaciens (MM12) exhibited 83.33 %. Futhermore, maximum vigour index of 1743.8, 1699.6 & 1436.5 was noticed in B. amyloliquefaciens (Ka1), B. subtilis (BST8) & B. subtilis (Bbv 57) treated plants. These findings provide valuable insights on sustainable management strategies against the disease, benefiting farmers by enhancing tomato cultivation productivity and profitability.

Rolling Bearing Fault Diagnosis Based on Support Vector Machine Optimized by Improved Grey Wolf Algorithm.

This study targets the low accuracy and efficiency of the support vector machine (SVM) algorithm in rolling bearing fault diagnosis. An improved grey wolf optimizer (IGWO) algorithm was proposed based on deep learning and a swarm intelligence optimization algorithm to optimize the structural parameters of SVM and improve the rolling bearing fault diagnosis. A nonlinear contraction factor update strategy was also proposed. The variable coefficient changes with the shrinkage factor α. Thus, the search ability was balanced at different early and late stages by controlling the dynamic changes of the variable coefficient. In the early stages of optimization, its speed is low to avoid falling into local optimization. In the later stages of optimization, the speed is higher, and finding the optimal solution is easier, balancing the two different global and local optimization capabilities to complete efficient convergence. The dynamic weight update strategy was adopted to perform position updates based on adaptive dynamic weights. First, the dataset of Case Western Reserve University was used for simulation, and the results showed that the diagnosis accuracy of IGWO-SVM was 98.75%. Then, the IGWO-SVM model was trained and tested using data obtained from the full-life-cycle test platform of mechanical transmission bearings independently researched and developed by Nanjing Agricultural University. The fault diagnosis accuracy and convergence value of the adaptation curve were compared with those of PSO-SVM (particle swarm optimization) and GWO-SVM diagnosis models. Results showed that the IGWO-SVM model had the highest rolling bearing fault diagnosis accuracy and the best diagnosis convergence.

Mechanical, thermal, rheological, and morphological characterization of polyolefin/activated attapulgite nanocomposites

AbstractLinear low‐density polyethylene (LLDPE) and high‐density polyethylene (HDPE) are polyolefins widely used in the packaging sector. Seeking to improve the mechanical properties with good cost‐effectiveness, attapulgite (ATP) was chosen as a reinforcing filler for the polyolefins. ATP is a hydrated magnesium and aluminum clay mineral with a microfibrous morphology, and the purity of this filler depends on the deposit. ATP is associated with the presence of accessory minerals that need to be removed so as not to interfere with its final application. Thus, an ATP purification process was carried out through physical separation and chemical treatment with hydrogen peroxide (H2O2) and sulfuric acid (H2SO4). This purification process despite having a low yield and is very effective in reducing impurities and organic matter. This ATP was named ATPa. LLDPE/ATPa and HDPE/ATPa nanocomposites with the addition of 1, 3, and 5 wt% of ATPa were prepared by extrusion and hot pressing. The mechanical properties (Shore D hardness, tensile tests, and Izod impact strength), thermal properties (differential scanning calorimetry—DSC and thermogravimetric analysis—TGA), X‐ray diffraction, rheological, and transmission scanning microscopy (TEM) were determined for these nanocomposites. The mechanical properties of the nanocomposites increased with the addition of ATPa. HDPE/ATPa nanocomposites showed more promise than LLDPE/ATPa nanocomposites. The addition of 5 wt% ATPa increased the tensile strength by 14% for the HDPE matrix and 5% for the LLDPE matrix and increased the elastic modulus by 46% for HDPE and 26% for LLDPE.

Ensuring the operational-technological characteristics of the new design solution of the sucker-rod pumping unit

In Azerbaijan oil production is carried out both in the offshore and onshore. Offshore production is carried out on special platforms, while the onshore exploitation carried out directly by a mechanized method. Thus, the object of study is downhole pumps, which consist of a surface mechanical transmission and downhole equipment. For direct mechanization of ground equipment, a device called rocking machine is used, consisting of transmission and converting mechanisms. The main task of the rocking machine is to ensure the conversion of the rotational motion of the engine into the up and down stroke of the plunger of the pump. The downhole equipment includes rods column that lift liquid from the well, a cylinder and a plunger. However, the existing classic rocking machines have some advantages as well as some disadvantages. In order to overcome them, developed new design solution of the sucker-rod pumping unit, which consisting of a crank-rope-movable counterweight system has been designed. As a result of the research carried out in the article, a progressive expression was proposed for determining the strength condition of the rods column, which is one of the main working elements of the rocking machine. Then, in order to specify the wells in which the rocking machine can be applied, the statement regarding the determination of the value of the linear density of liquid column based on the strength condition of the rod column was put forward. These, in turn, can be determined in which oil wells with specific physical characteristics of the rocking machine with the given technical characteristics can be applied. All this can contribute to the prevention of accidents that may occur due to the breakage of the rods column of rocking machine. The formula proposed in this paper can be applied not only to the existing classic rocking machines, but also to other new design of rocking machines.

Mechanical, gamma rays and neutron radiation transmission properties for some ZnO–TeO2–P2O5-ZnX glasses

Oxyhalide glasses are utilized in the process of immobilizing nuclear waste and function as scintillating agents for the purpose of radiation detection. The objective of this study is to examine the enhanced mechanical and radiation attenuation characteristics of newly developed oxyhalide glasses by incorporating zinc-iodide. This study investigates the synthesis process, mechanical properties, and experimental gamma-neutron radiation transmission properties. A halogen-free base glass, consisting of an oxide mixture of P2O5, TeO2, and ZnO, was synthesized. Following that, the initial glass composition was further strengthened by the addition of zinc bromide (ZnBr2), zinc chloride (ZnCl2), zinc fluoride (ZnF2), and zinc iodide (ZnI2) in a successive manner. The experimental configuration entailed positioning circular glass samples between a 133Ba radioisotope and a Canberra High Purity Germanium (HPGe) detector. The determination of attenuation coefficients is achieved through the measurement of individual attenuation properties. Afterwards, theoretical approaches are utilized to determine the mechanical characteristics of halogenated glasses, including Young's modulus (Y), Bulk modulus (K), Shear modulus (G), Longitudinal modulus (L), and Poisson's modulus (v). The results of the study suggest that the implementation of the halogenation process on the P2O5–TeO2–ZnO base composition led to a significant enhancement in the examined properties. The incorporation of zinc-iodide in the halogenation process resulted in a significant improvement in the gamma absorption properties. The utilization of zinc in the halogenation process demonstrates multifunctional capabilities, which involve the potential to enhance various glass properties, including durability and gamma-ray absorption properties. It can be concluded that zinc-iodide demonstrates enhanced halogenation capabilities in comparison to zinc bromide, zinc chloride, and zinc fluoride.

The instantaneous transmission ratio of a driveshaft composed of a tripod joint and a fixed constant velocity joint

The paper presents a procedure to assess the instantaneous transmission ratio, in a generic configuration, of a driveshaft equipped with a tripod joint and a constant velocity joint of the fixed type. This mechanical transmission is used, for example, in automobiles to connect each half shaft of the differential to a driving wheel. After highlighting that the usual approach to evaluating the instantaneous transmission ratio is conceptually flawed, the paper proposes an original procedure to correctly assess the transmission ratio. The paper also proves that the considered driveshaft is homokinetic whenever the axes of the two end shafts are parallel. Numerical examples show application of the proposed procedure to case studies.

Dissecting dynamic plant virus synergism in mixed infections of poleroviruses, umbraviruses, and tombusvirus-like associated RNAs.

Mixed infections of a plant infecting polerovirus, umbravirus, and/or tombusvirus-like associated RNAs (tlaRNAs) produce unique virus disease complexes that exemplify "helper-dependence" interactions, a type of viral synergism that occurs when a "dependent" virus that lacks genes encoding for certain protein products necessary for it to complete its infection cycle can utilize complementary proteins encoded by a co-infecting "helper" virus. While much research has focused on polerovirus-umbravirus or polerovirus-tlaRNA interactions, only recently have umbravirus-tlaRNA interactions begun to be explored. To expand on the limited understanding of umbravirus-tlaRNA interactions in such disease complexes, we established various co-infection pairings of the polerovirus turnip yellows virus (TuYV), the umbravirus carrot mottle virus (CMoV), and three different tlaRNAs-carrot red leaf virus aRNAs (CRLVaRNAs) gamma and sigma, and the TuYVaRNA ST9-in the model plant Nicotiana benthamiana, then investigated the effects of these different co-infections on tlaRNA systemic movement within the host, and on virus accumulation, and aphid and mechanical transmission of each of these viruses. We found that CMoV alone could support systemic movement of each of the tlaRNAs, making this the second report to demonstrate such an interaction between an umbravirus and tlaRNAs. We also report for the first time that CMoV could also impart mechanical transmissibility to the tlaRNAs sigma and ST9, and that co-infections of either of these tlaRNAs with both TuYV and CMoV increased the efficiency with which TuYV could be mechanically co-transmitted with CMoV.