Free Wheel Research Articles

MOVEMENT DATA ANALYSIS AS A NOVEL PREDICTIVE TECHNOLOGY FOR TENDON REPAIR

Digital Ventilated Cages (DVC) offer an innovative technology to obtain accurate movement data from a single mouse over time [1]. Thus, they could be used to determine the occurrence of a tendon damage event as well as inform on tissue regeneration [2,3]. Therefore, using the mouse model of tendon experimental damage, in this study it has been tested whether the recovery of tissue microarchitecture and of extracellular matrix (ECM) correlates with the motion data collected through this technology.Mice models were used to induce acute injury in Achilles tendons (ATs), while healthy ones were used as control. During the healing process, the mice were housed in DVC cages (Tecniplast) to monitor animal welfare and to study biomechanics assessing movement activity, an indicator of the recovery of tendon tissue functionality. After 28 days, the AT were harvested and assessed for their histological and immunohistochemical properties to obtain a total histological score (TSH) that was then correlated to the movement data.DVC cages showed the capacity to distinguish activity patterns in groups from the two different conditions. The data collected showed that the mice with access to the mouse wheel had a higher activity as compared to the blocked wheel group, which suggests that the extra movement during tendon healing improved motion ability. The histological results showed a clear difference between different analyzed groups. The bilateral free wheel group showed the best histological recovery, offering the highest TSH score, thus confirming the results of the DVC cages and the correlation between movement activity and structural recovery.Data obtained showed a correlation between TSH and the DVC cages, displaying structural and movement differences between the tested groups. This successful correlation allows the usage of DVC type cages as a non-invasive method to predict tissue regeneration and recovery.Acknowledgements: This research is part of the P4FIT project ESR13, funded by the H2020-ITN-EJD MSCA grant agreement No.955685.

Diagnostics of the airless wheel by the combined method

For construction and road machinery, tubeless tires made on the basis of elastic polyurethanes are being used more often. The diagnosis of airless tires made of elastic polymer materials in order to determine the conditions of their safe operation is becoming more and more relevant. The use of roller stands does not give accurate results, because the round support surface of the rollers introduces distortion. A method of obtaining basic parameters and characteristics on simple stands is proposed. Use their values for tire research and diagnostics in software environments such as Ansys, Solidworks, AutoCad. For the designed and manufactured sample of an airless wheel on the stands, the dependences of the change in the static radius of the wheel depending on the load and the change in the deflection of the wheel depending on the lateral force at different loads on the wheel were obtained. They became the basis for the initial parameters and characteristics of the wheel modeled in the Solidworks environment. Its properties were simulated for three cases of wheel rolling: “driven wheel”, “driving wheel” and “free wheel”. The obtained results show that the most difficult mode is the movement of the wheel on the deformable support base. In this mode, the opposite sides of the spokes work in tension and compression when blowing the spokes to a vertical state. The values of stress do not exceed the critical allowable ones during rupture or during compression for polyurethane. Therefore, it can be diagnosed that the wheel is in satisfactory condition.

Research on a tubeless tire for a mobile robot

Airless tires are used not only in cars, but also in vehicles used in the construction, road, forestry, and robotics industries. In order to develop the construction of an airless tire, its optimization at the stage of their design, a comprehensive method of researching the operational properties of an airless tire is proposed. The methodology includes stress-strain analysis, modal and thermal analysis of an airless tire using three-dimensional modeling using the finite element method. The airless tire was studied in the following modes of uniform movement of the wheel on a solid base: driven wheel; driving wheel; free wheel; neutral wheel; brake wheel. An example of the study of an airless tire of a mobile robot is given.

Digital Twin for a Multifunctional Technology of Flexible Assembly on a Mechatronics Line with Integrated Robotic Systems and Mobile Visual Sensor-Challenges towards Industry 5.0.

A digital twin for a multifunctional technology for flexible manufacturing on an assembly, disassembly, and repair mechatronics line (A/D/RML), assisted by a complex autonomous system (CAS), is presented in the paper. The hardware architecture consists of the A/D/RML and a six-workstation (WS) mechatronics line (ML) connected to a flexible cell (FC) and equipped with a six-degree of freedom (DOF) industrial robotic manipulator (IRM). The CAS has in its structure two driving wheels and one free wheel (2DW/1FW)-wheeled mobile robot (WMR) equipped with a 7-DOF robotic manipulator (RM). On the end effector of the RM, a mobile visual servoing system (eye-in-hand MVSS) is mounted. The multifunctionality is provided by the three actions, assembly, disassembly, and repair, while the flexibility is due to the assembly of different products. After disassembly or repair, CAS picks up the disassembled components and transports them to the appropriate storage depots for reuse. Disassembling or repairing starts after assembling, and the final assembled product fails the quality test. The virtual world that serves as the digital counterpart consists of tasks assignment, planning and synchronization of A/D/RML with integrated robotic systems, IRM, and CAS. Additionally, the virtual world includes hybrid modeling with synchronized hybrid Petri nets (SHPN), simulation of the SHPN models, modeling of the MVSS, and simulation of the trajectory-tracking sliding-mode control (TTSMC) of the CAS. The real world, as counterpart of the digital twin, consists of communication, synchronization, and control of A/D/RML and CAS. In addition, the real world includes control of the MVSS, the inverse kinematic control (IKC) of the RM and graphic user interface (GUI) for monitoring and real-time control of the whole system. The "Digital twin" approach has been designed to meet all the requirements and attributes of Industry 4.0 and beyond towards Industry 5.0, the target being a closer collaboration between the human operator and the production line.

Comparative Analysis Multi-Robot Formation Control Modeling Using Fuzzy Logic Type 2 – Particle Swarm Optimization

Multi-robot is a robotic system consisting of several robots that are interconnected and can communicate and collaborate with each other to complete a goal. With physical similarities, they have two controlled wheels and one free wheel that moves at the same speed. In this Problem, there is a main problem remaining in controlling the movement of the multi robot formation in searching the target. It occurs because the robots have to create dynamic geometric shapes towards the target. In its movement, it requires a control system in order to move the position as desired. For multi-robot movement formations, they have their own predetermined trajectories which are relatively constant in varying speeds and accelerations even in sudden stops. Based on these weaknesses, the robots must be able to avoid obstacles and reach the target. This research used Fuzzy Logic type 2 – Particle Swarm Optimization algorithm which was compared with Fuzzy Logic type 2 – Modified Particle Swarm Optimization and Fuzzy Logic type 2 – Dynamic Particle Swarm Optimization. Based on the experiments that had been carried out in each environment, it was found that Fuzzy Logic type 2 - Modified Particle Swarm Optimization had better iteration, time and resource and also smoother robot movement than Fuzzy Logic type 2 – Particle Swarm Optimization and Fuzzy Logic Type 2 - Dynamic Particle Swarm Optimization.

Communication and Control of an Assembly, Disassembly and Repair Flexible Manufacturing Technology on a Mechatronics Line Assisted by an Autonomous Robotic System

This paper aims to describe modeling and control in what concerns advanced manufacturing technology running on a flexible assembly, disassembly and repair on a mechatronic line (A/D/RML) assisted by an Autonomous Robotic System (ARS), two robotic manipulators (RM) and visual servoing system (VSS). The A/D/RML consists of a six workstations (WS) mechatronics line (ML) connected to a flexible cell (FC) equipped with a 6-DOF ABB industrial robotic manipulator (IRM) and an ARS used for manipulation and transport. A hybrid communication and control based on programmable logic controller (PLC) architecture is used, which consists of two interconnected systems that feature both distributed and centralized topology, with specific tasks for all the manufacturing stages. Profinet communication link is used to interconnect and control FC and A/D/RML. The paper also discusses how to synchronize data between different field equipment used in the industry and the control systems. Synchronization signals between the master PLC and ARS is performed by means of Modbus TCP protocol and OPC UA. The structure of the ARS consists of a wheeled mobile robot (WMR) with two driving wheels and one free wheel (2DW/1FW) equipped with a 7-DOF RM. Trajectory tracking sliding-mode control (TTSMC) is used to control WMR. The end effector of the ARS RM is equipped with a mobile eye-in-hand VSS technology for the precise positioning of RM to pick and place the workparts in the desired location. Technology operates synchronously with signals from sensors and from the VSS HD camera. If the workpiece does not pass the quality test, the process handles it by transporting back from the end storage unit to the flexible cell where it will be considered for reprocessing, repair or disassembling with the recovery of the dismantled parts. The recovered or replaced components are taken over by the ARS from disassembling location and transported back to the dedicated storage warehouses to be reused in the further assembly processes.

Exercise reduces pain behavior and pathological changes in dorsal root ganglia induced by systemic inflammation in mice

Emerging research indicates that physical activity can ameliorate chronic pain, but the underlying mechanisms are still largely obscure. In particular, little is known on the mechanisms behind exercise-induced analgesia in the setting of inflammatory pain. In our previous studies on systemic inflammation in mice using lipopolysaccharide (LPS) administration, we characterized satellite glial cells (SGCs) and neurons in dorsal root ganglia (DRG). We found that a week post-LPS injection, the sensitivity to mechanical stimulation was lowered, SGCs were activated and coupling among SGCs increased 3 to 4.5-fold. In the present work, we examined the effects of exercise (free wheel running) on tactile sensitivity and on pathological changes in mouse DRG in the LPS model. We found that exercise prevented tactile hypersensitivity, and also reversed the cellular changes in the DRG induced by LPS that were listed above. We propose that the analgesic effect of exercise is at least partly mediated by reversing the pathological changes in SGCs.

Robotic wheel structures and their industrial applications based on motion simulations

The following work was done to analyze mobile structures with different arrangements of wheels. Software package Solidworks was utilized in modeling and analysis of the structures. Eight mobile structures were built by rearranging the placement of both driven and free wheels. Each structure has its own unique placement of wheels, hence giving the opportunity to understand the influence of the wheels’ placement on the functionality of the whole structure in terms of speed, stability, and other parameters. Therefore, eight mobile structures were analyzed, and the results were gathered. Adding more driven wheels or free wheels does not improve the performance of the mobile structures. The outcomes of the results illustrated that structure 6 tends to be more positive in terms of energy consumption, torque, and stability. Hence, adding more driven wheels does not improve the performance of the mobile structures.

Multifunctional Technology of Flexible Manufacturing on a Mechatronics Line with IRM and CAS, Ready for Industry 4.0

A communication and control architecture of a multifunctional technology for flexible manufacturing on an assembly, disassembly, and repair mechatronics line (A/D/RML), assisted by a complex autonomous system (CAS), is presented in the paper. A/D/RML consists of a six-work station (WS) mechatronics line (ML) connected to a flexible cell (FC) equipped with a six-degree of freedom (DOF) industrial robotic manipulator (IRM). The CAS has in its structure two driving wheels and one free wheel (2 DW/1 FW)-wheeled mobile robot (WMR) equipped with a 7-DOF robotic manipulator (RM). On the end effector of the RM, a mobile visual servoing system (eye-in-hand VSS) is mounted. The multifunctionality is provided by the three actions, assembly, disassembly, and repair, while the flexibility is due to the assembly of different products. After disassembly or repair, CAS picks up the disassembled components and transports them to the appropriate storage depots for reuse. Technology operates synchronously with signals from sensors and eye-in-hand VSS. Disassembling or repairing starts after assembling and the final assembled product fails the quality test. Due to the diversity of communication and control equipment such as PLCs, robots, sensors or actuators, the presented technology, although it works on a laboratory structure, has applications in the real world and meets the specific requirements of Industry 4.0.

Analysis of buckling failure in continuously welded railway tracks

Continuously welded rails (CWR) are sensitive to thermal and train loads which could destabilize the track and cause buckling. The study of track buckling in the literature, however, is mostly focused on static analysis of CWR tracks under thermal loads. Yet in reality, train dynamic loads in lateral, vertical and longitudinal directions can have a major impact on track buckling behaviour. Moreover, track and wheel defects can aggravate the dynamic train track interaction loads, and reduce the safety against track buckling. The aim of this paper is to have an in-depth comparison of static and dynamic track buckling by employing a multi-body train-track dynamic model and a 3D finite element track model. Various scenarios are elaborated, base scenario dealing with static thermal analysis, dynamic analysis for a steady motion of a wagon with constant speed, dynamic analysis for a wagon with defect free wheels during braking, and dynamic analysis for a wagon with out of round defect wheels during braking. For each scenario, a sensitivity analysis of relevant parameters is also presented. Based on the results, it is concluded that train loads can significantly change the buckling temperature, as well as the safe temperature. For a severe braking of a wagon with out of round wheel defect of order 3, buckling temperature is almost 5.5 °C less than that of the static case. The drop for safe temperature in this case is 6.7 °C.

Free Wheel, Free Will! The Effects of Bikeshare Systems on Urban Commuting Patterns in the U.S.

AbstractUrban bikeshare systems have become increasingly popular in the U.S. in recent years. In this paper, I examine the effects of bikeshare systems on patterns of commuting to and from work in U.S. cities. To study this, I link cities across 2008 through 2016 American Community Survey (ACS) data and estimate the effects of bikeshare systems using both individual‐level ACS records and city panel data. Event‐study estimates suggest that bikeshare systems lead to a rise in bicycle commuting to and from work, and the effects of bikeshare systems are statistically and economically significant. I also find evidence of modal shifts after the introduction of bikeshare systems: While bicycle commuting rates increase, there is a decline in automobile commuting to and from work.

The Effect of Wheel Exercise on Functional Indices of Cachexia in Tumor-bearing Mice.

Cancer-related fatigue and muscle wasting have received significant attention over the last few decades with the goal of establishing interventions that can improve cancer patient life quality and survival. Increased physical activity has shown to reduce cancer-associated fatigue and has been proposed as a promising therapeutic to attenuate cancer-induced wasting. However, significant gaps remain in our understanding of how physical activity affects the compositional and functional changes that initiate muscle wasting. The purpose of the current study was to determine the effect of wheel exercise on body composition and functional indices of cancer cachexia before the development of significant wasting. Thirteen-week-old male Apc (MIN) and C57BL/6 (B6) mice were given free wheel access (W) or a locked wheel (Sed) for 5 wk. Wheel activity was reduced in the MIN compared with B6; however, wheel access increased complex II expression in isolated skeletal muscle mitochondria regardless of genotype. Wheel access had no effect on tumor burden or plasma interleukin-6 in the MIN. MIN-W increased body weight and lean mass compared with MIN-Sed, and there was a direct correlation between wheel distance and lean mass change. MIN-W increased grip strength and treadmill time to fatigue compared with MIN-Sed. Within MIN-W mice, skeletal muscle fatigability was only improved in high runners (>60 min·d). Our results suggest that there were therapeutic benefits of increased activity related to body composition, behavior, and whole-body function that were not dependent on exercise duration; however, there was an exercise threshold needed to improve skeletal muscle fatigability in tumor-bearing mice. Interestingly, wheel access was able to improve compositional and functional outcomes without mitigating tumor number or size.

CIRCADIAN PATTERNS OF FREE-WHEEL RUNNING IN YOUNG AND OLD MICE

The mammalian circadian clock operates on a 24-hour cycle and regulates physiological, endocrine, and metabolic responses to changes in the environment. Aging disrupts this circadian process, increasing risk for development of age-associated diseases. Free-wheel running is not only an indicator of circadian rhythm, but also a strong predictor of survival from age-related diseases (i.e. cardiovascular disease). Thus, understanding the impact of age on free-wheel running can lead to a better understanding of disease progression. We analyzed free wheel running in both male and female C57BL/6J mice at young (3-6 months) and old (18-21 months) ages exposed to standard 12h light/dark cycle. Running wheel data was recorded hourly for 10 days. As expected, young female mice ran more than male mice, and old mice ran less than young mice. Regulation of wheel running demonstrated that older mice of both sexes had a delayed start time in activity patterns. Young mice began running immediately at lights off (signaling the start of their active period) and ran consistently throughout the dark phase with peak activity in the first 2 hours. In contrast, older mice had a delayed response to light with peak activity not occurring until hours 4-6 of the dark cycle and nightly activity ending 2 hours before lights on. Ongoing work will assess the central (brain) and peripheral (muscle, cardiac) regulation of free-wheel running in aging. Together, we demonstrate the importance of studying molecular mechanisms underlying circadian misalignment in older individuals to identify ways to combat age-associated disease with circadian misalignment.

Novel Design and Analysis of Free Electric 2.2 Machine

As per the data provided by the governments of Bihar, Uttar Pradesh and Assam, 82.84 per cent, 72.97 percent and 62.93 percent of their rural households, respectively, are still without any access to electricity. Every Machine to perform its function needs electricity, therefore electricity is the basic backbone which is needed to drive even a small machine. It has become a necessary piece of development that has led to the rise of other development.500 million people are still left without electricity. This paper aims at designing a machine which will use electro-mechanical energy of the body to generate free electricity for the basic needs and is eco-friendly i.e.it will not cause any kind of pollution. The Free Electric 2.0 machine is created, which works on a normal and simple principle of an electrical dynamo. The basic idea is, whenever the machine is paddled, it results in rotation of a free wheel. The free wheel is connected to a shaft and the shaft is connected to another free wheel on the other side. This free wheel is connected to a wheel which is connected to generator. Power thus produced is stored in a battery and can be used for the basic necessities like lightning bulbs, fan and charging mobiles. The major necessity of this type of machine are in places which are very hostile or places which doesn’t have a power grid line setup. It can also be used in places which are prone to disaster. Having this device at our homes will provide electricity for at least the basic necessities

Design and control of a novel all-terrains wearable vehicle

PurposeThis paper aims to design and control of a novel compact transportation system called the “wearable vehicle”. The wearable vehicle allows for traversing all types of terrains while transporting one's luggage in a comfortable and efficient manner.Design/methodology/approachThe proposed design consists of a lower limb exoskeleton carrying two motorized wheels and two free wheels installed alongside its feet. This paper presents a detailed description of the system with its preliminary design and finite element analysis. Moreover, the system has been optimally designed to decrease wearable vehicle’s total weight, consequently leading to a reduction in motor size. Finally, two controllers have been designed to achieve stable operation of the wearable vehicle while walking. A PD controller with gravity compensation has been designed to ensure that the wearable vehicle tracks human motion, while a PID controller has been designed to ensure that the zero moment point is close to the center of the system’s support polygon.FindingsExperimental tests were carried out to check the wearable vehicle concept. The obtained results prove the feasibility of the proposed wearable vehicle from the design, dynamics and control viewpoints.Practical implicationsThis proposed wearable vehicle’s purpose is for traveling faster with less effort than normal walking. When a human comes across a flat open ground, the wearable vehicle can be used as a vehicle. However, when a human enters crowded traffic, an unstructured area or other obstacles like stairs, the vehicle can be switched into walking mode.Originality/valueThe wearable vehicle has seven DOFs exoskeletons, two motorized wheels, two free wheels and a foldable seat. It is used as a vehicle via its motorized and free wheels to travel fast with minimal effort. In addition, the human can switch easily into walking mode, if there is unstructured terrain to be traversed. Furthermore, an illustration of system's mechanisms and main feature parameters are presented to become acquainted with the ultimate benefits of the new system.

P6372Does modification of activity regimes optimize the effect of high physical activity on hypertensive heart disease?

Abstract Aims and background Spontaneously hypertensive rats (SHR) are a suitable model of essential hypertension and allow analyze the progression of hypertension and hypertension-dependent end-organ damage. In this model, acute improvement of physical activity (free running wheel activity) exerts known beneficial effects (such as lowering oxidative stress). However, these initial beneficial effects are lost during the continuation of high physical activity and translate into mal-adaptive processes, suggesting that not any high physical activity exerts beneficial effects. It has been hypothesized that the skeletal muscle release myokines, that contribute to the beneficial effects of exercise. However, myokines, such as IL-6, are induced by an acute increase in work load not by continuous work load. Therefore, we analyzed whether modification of high physical activity, i.e. intermittent free running wheel activity, modify the long-term impact on long lasting hypertension. Methods 38 female SHR aged 6 weeks (pre-hypertensive state) were randomly allocated to one of the following groups: Sedentary (S; standard holding condition) imitating the condition of sedentary life style, high activity (HA; life-long free running wheel) imitating the condition of active life style, temporary activity (TA; 6 months free running wheel and 3 months sedentary) imitating the loss of active life style during ageing, and finally intermittent activity (IA; 10 months repetitive access to running wheels every 4 weeks) imitating altered workloads. All rats were sacrificed at the age of 10 months. Results IA was the only treatment regime that effectively lowered blood pressure (P syst: 186±11 vs. 165±6 mmHg), improved ejection fraction (EF: 56±5 vs. 63±2%), and displayed clear molecular profile of adaptive myocardial hypertrophy rather than mal-adaptive hypertrophy. Moreover, only IA reduced the number of circulating monocytes (377±102 vs. 220±16 /μl), a cell population that immigrated in the left ventricle. The number of monocytes was directly correlated with the expression of MMP12, BNP, ANP, biglycan, collagen-1, actinin, β-MHC, and somatstatin but inversely related to β-adrenoceptor, Glut-4, and UCP3 expression. Finally, IA increased the skeletal expression of IL-6 and decreased the renal expression of AT1 receptors. Conclusion The data confirm the previous findings that not all type of physical activity beneficially affects hypertensive-dependent disease. In contrast, the data support the hypothesis that alterations in work load are required triggering the release of myokines from the skeletal muscle and identify the amount of circulating monocytes as a main trigger of mal-adaptive hypertrophy in these rats. The data are important with respect to optimize life style suggestions for patients with essential hypertension. Acknowledgement/Funding DFG (ERAGON and SFB 1213)

Ensuring permissible level of gas turbine dynamic loading in operation by means of standard engine control devices

To solve the fatigue resistance problems of gas turbine engine elements using the existing principles of regulation based on the use of safe load factors for various loading schemes we suggest exercising controlled influence upon the loading sources in operation using a system of automatic control and standard devices for engine monitoring. The article discusses the use of this approach to minimize the dynamic loading of the LPC (low pressure compressor) blades of afterburning turbojet engines installed on supersonic aircraft, as well as to combat oscillatory combustion in combustion chambers with shock actuation of free wheel clutches and self-induced oscillation in the helicopter transmission system. Besides, it is shown that the monitoring of GTE (gas turbine engine) dynamic load should be accompanied by improving the efficiency of the on-board engine diagnostic system. It is impossible to reduce the probability of target drop-out or faulty actuation of the existing standard means and facilities of such systems down to the required level without applying an individual approach to the determination of permissible levels of adjustable diagnostic parameters.

Self-Paced Free-Running Wheel Mimics High-Intensity Interval Training Impact on Rats' Functional, Physiological, Biochemical, and Morphological Features.

Free-running wheel (FRW) is an animal exercise model that relies on high-intensity interval moments interspersed with low-intensity or pauses apparently similar to those performed in high-intensity interval training (HIIT). Therefore, this study, conducted over a 12-weeks period, aimed to compare functional, thermographic, biochemical and morphological skeletal and cardiac muscle adaptations induced by FRW and HIIT. Twenty-four male Wistar rats were assigned into three groups: sedentary rats (SED), rats that voluntarily exercise in free wheels (FRW) and rats submitted to a daily HIIT. Functional tests revealed that compared to SED both FRW and HIIT increased the ability to perform maximal workload tests (MWT-cm/s) (45 ± 1 vs. 55 ± 2 and vs. 65 ± 2). Regarding thermographic assays, FRW and HIIT increased the ability to lose heat through the tail during MWT. Histochemical analyzes performed in tibialis anterior (TA) and soleus (SOL) muscles showed a general adaptation toward a more oxidative phenotype in both FRW and HIIT. Exercise increased the percentage of fast oxidative glycolytic (FOG) in medial fields of TA (29.7 ± 2.3 vs. 44.9 ± 4.4 and vs. 45.2 ± 5.3) and slow oxidative (SO) in SOL (73.4 ± 5.7 vs. 99.5 ± 0.5 and vs. 96.4 ± 1.2). HITT decreased fiber cross-sectional area (FCSA-μm2) of SO (4350 ± 286.9 vs. 4893 ± 325 and vs. 3621 ± 237.3) in SOL. Fast glycolytic fibers were bigger across all the TA muscle in FRW and HIIT groups. The FCSA decrease in FOG fibers was accompanied by a circularity decrease of SO from SOL fibers (0.840 ± 0.005 vs. 0.783 ± 0.016 and vs. 0.788 ± 0.010), and a fiber and global field capillarization increase in both FRW and HIIT protocols. Moreover, FRW and HIIT animals exhibited increased cardiac mitochondrial respiratory control ratio with complex I-driven substrates (3.89 ± 0.14 vs. 5.20 ± 0.25 and vs. 5.42 ± 0.37). Data suggest that FRW induces significant functional, physiological, and biochemical adaptations similar to those obtained under an intermittent forced exercise regimen, such as HIIT.

Wear damage of out-of-round wheels in rail wagons under braking

Periodic deviation of the diameter of wheel across its circumference is referred to as the out-of-round (OOR) defect that can cause significant damages to wheel – rail interface, affect the service life of various components of the vehicle/track system and the safety of trains. Under braking, OOR defect may exacerbate these damages; to uncover such exacerbation, a multi-body dynamic simulation model in a fixed coordinate system for wagons containing new/ defect free or OOR wheels subject to braking torques has been formulated and validated using a dataset in the literature. Using the validated model, the effects of the repetition order (single or multiple deviations of diameter) of OOR defect and the severity of application of braking torques to wheel wear has been examined. It has been found that under constant speed, the normal contact force increased with the repetition order. The OOR defect dominated the normal contact force with a dynamic impact force factor of 1.48, whilst the new/ defect free wheels exhibited negligible impact force. It is shown that the effect of OOR defect is significant for wear of wheels under normal braking whist under wheel skid, braking torque dominates wear. Wheel unloading ratio is shown to be a better indicator for the determination of risk to derailment, than the commonly used Nadal's derailment quotient where the wheel contains OOR defect.

Voluntary wheel running reduces colon inflammation in female but not male mice fed a high-fat diet

The influence of diet and exercise on intestinal mucus and the spatial organisation of the microbiota is poorly understood. Though, it has been observed that the spatial organisation of the microbiota can be altered extensively in Crohn’s disease and ulcerative colitis. This study aims to investigate the pathophysiological events in mouse colon that are associated with a high fat diet and lack of exercise. Forty-eight, 6-week old C57BL/6NTac male and female mice were fed a normal or high-fat diet for 12 weeks and randomly assigned to free wheel running or sedentary groups. After 12 weeks, animals were sacrificed and distal colon tissue sections with and without faecal material were fixed for histomorphometric analysis, immunohistochemistry for cyclooxygenase-2 and mucin-2, or fluorescent in situ hybridization with the universal bacterial probe EUB338 (5’-GCTGCCTCCCGTAGGAGT-3’). Goblet cell counts and distance between the microbiota and epithelial surface were determined using ImageJ software. All mice had a normal colon morphology except for high-fat fed female mice who ran, demonstrating a reduction of goblet cells that approached significance and a reduced mucin-2 expression. Voluntary wheel running attenuated high-fat diet induced COX-2 expression in female mice only. The distance between the microbiota and epithelial surface remained the same. Taken together, these results show that voluntary wheel running protect against high-fat diet-induced inflammation in the distal colon of female mice and responses to changes in host behaviour may differ between sex.