Mesenchymal stromal cells (MSC) hold great promise for tissue engineering applications and cell‐based therapies. Large cell doses (>1 × 106 cells kg−1) and Good Manufacturing Practices ...(GMP)‐compliant processes are however required for clinical purposes. Here, a serum‐ and xenogeneic‐free (S/XF) microcarrier‐based culture system is established for the expansion of human umbilical cord matrix (UCM)‐ and adipose tissue (AT)‐derived MSC using the Vertical‐Wheel system (PBS‐0.1 MAG; PBS Biotech). UCM and AT MSC are expanded to maximum cell densities of 5.3 ± 0.4 × 105 cell mL−1 (n = 3) and 3.6 ± 0.7 × 105 cell mL−1 (n = 3), respectively, after 7 days of culture, while maintaining their identity, according to standard criteria. An economic evaluation of the process transfer from T‐flasks to PBS‐0.1 MAG shows a reduction in the costs associated with the production of a dose for an average 70 kg adult patient (i.e., 70 million cells). Costs decrease from $17.0 K to $11.1 K for UCM MSC and from $21.5 K to $11.1 K for AT MSC, proving that the transition to Vertical‐Wheel reactors provides a cost‐effective alternative for MSC expansion. The present work reports the establishment of a scalable and cost‐effective culture platform for the manufacturing of UCM and AT MSC in a S/XF microcarrier‐based system.
Purpose
– The purpose of this paper is to investigate the failure-driven capacity consumption of wheels on the track, to determine whether there are some relations to vehicle wheel configurations ...that show a larger amount of failures, and to ascertain the influence of the temperature and the travelling direction of the train on the number of events. This information can be used to develop prognostic health management so that more track capacity can be gained without modifications, re-building or re-investments.
Design/methodology/approach
– This paper presents a study of 1,509 warning and alarm events concerning train wheels. The data come from the infrastructure manager's wheel defect detectors and wheel profile measurement system. These data have been analysed and processed to find patterns and connections to different vehicles, travelling directions and temperatures.
Findings
– Lower temperatures increase the probability of wheels having high vertical forces. Trains with different wheel configurations show different results. With high vertical forces, the probability of wheel failures at axles 6 and 7 is high for locomotives with two bogies and three axles in each bogie (2×3). All these findings can be used to develop the maintenance, monitoring and inspection principles for wheels.
Practical implications
– The inspection of wheels to detect failures needs to be more frequent on days and in seasons with lower temperatures. The wheel inspection should be performed more frequently at axles 6 and 7 for locomotives with a 2×3 wheel configuration. The inspection and monitoring of wheels need to be carried out more carefully for trains travelling south, to avoid a large amount of wheels with high force levels rolling in the southern direction.
Originality/value
– The analysis carried out in this paper identifies important factors that correlate with the high occurrence of wheel defects. It also proposes a conceptual e-maintenance model for the combination of wheel condition monitoring data from different system. The value of this study is the provision of information to support prognostic and health management system to support proactive maintenance.
This study explores the capacity of the morphology analysis for railway wheel flat fault detection. A dynamic model of vehicle systems with 56 degrees of freedom was set up along with a wheel flat ...model to calculate the dynamic responses of axle box. The vehicle axle box vibration signal is complicated because it not only contains the information of wheel defect, but also includes track condition information. Thus, how to extract the influential features of wheels from strong background noise effectively is a typical key issue for railway wheel fault detection. In this paper, an algorithm for adaptive multiscale morphological filtering (AMMF) was proposed, and its effect was evaluated by a simulated signal. And then this algorithm was employed to study the axle box vibration caused by wheel flats, as well as the influence of track irregularity and vehicle running speed on diagnosis results. Finally, the effectiveness of the proposed method was verified by bench testing. Research results demonstrate that the AMMF extracts the influential characteristic of axle box vibration signals effectively and can diagnose wheel flat faults in real time.
•An adaptive multiscale morphological filter (AMMF) is proposed.•The impacts of speed and track for wheel flat fault detection are investigated.•AMMF is applied to detect the wheel fault using simulation and lab test signals.
The present work explores the application of nanofluids (NFs) in small quantity lubrication (SQL) mode by suspending eco-friendly Silver and Zinc oxide nanoparticles in deionized water. These ...nanoparticles have already been established as eco-friendly by several researchers. Hence these NFs may be termed as environmentally sustainable, and the present work is the first attempt to use such NFs in environment-friendly grinding of Inconel 718 (IN718) superalloy. The NFs have been supplied into the grinding zone using an in-house developed SQL setup. The results of the grinding process using NFs have been compared with the outcomes of grinding experiments under dry, wet and SQL with soluble oil. Ground surface integrity, wheel topography, and chip morphology have been investigated with the help of Scanning electron microscopy, Energy-dispersive X-ray spectroscopy, Atomic force microscopy and Stereo Zoom microscopy micrographs. The NFs have been characterized through measurements of zeta potential, hydrodynamic diameter, thermal conductivity, dynamic viscosity, and contact angles in relation to IN718 surface. From the present study, it can be concluded that application of NFs resulted in minimization of grinding forces, coefficient of friction, and improvement in the ground surface integrity. Zinc oxide based NFs have shown better grinding responses mainly because of improved lubrication behavior. It is primarily due to better spreadability that has induced stable lubricious film at the contacting surfaces even at a higher temperature. The findings of this work can be regarded as a first step towards the green and sustainable grinding of high strength superalloys.
In order to develop the high-efficiency and precision machining technique of TiCp/Ti - 6Al-4V particulate reinforced titanium matrix composites （PTMCs）, high-speed grinding experiments were conducted ...using the single-layer electroplated cubic boron nitride （CBN） wheel and brazed CBN wheel, respectively. The comparative grinding performance was studied in terms of grinding force, grinding temperature, grinding-induced surface features and defects. The results display that the grinding forces and grinding temperature obtained with the brazed CBN wheel are always lower than those with the electroplated CBN wheel. Though the voids and microcracks are the dominant grinding-induced surface defects, the brazed CBN wheel produces less surface defects compared to the electroplated wheel according to the statistical analysis results. The max mum materials removal rate with the brazed CBN wheel is much higher than that with the electroplated one. All above indicate that the single-layer brazed CBN super-abrasive wheel is more suitable for high-speed grinding of PTMCs than the electroplated counterpart.
Pseudomonas aeruginosa is an opportunistic bacteria; adaptation in different environments makes them very aggressive and life-threatening pathogens for humans,
especially patients who suffer from ...weak immunity. This study aimed to evaluate
the gene expression of each mexA and mexB gene in Pseudomonas aeruginosa
isolates, which were isolated from clinical samples; screening of efflux pumps in
multidrug P. aeruginosa phenotypically was done by the Cather wheel method.
Study genes expression of efflux pump genes under ciprofloxacin antibiotic stress
and Et. Br were done in different concentrations of cip and EtBr. One hundred and
ten (110) isolates of Pseudomonas spp. were collected from different hospitals in
Baghdad city, (50) isolates of Pseudomonas aeruginosa identified and confirmed
were done. The results appeared according to the type of clinical sources the fiftyisolate distributed as 35 (70 %) burns swab samples, 10 (20 %) from wounds
swabs, and 5 (10 %) from ear discharge. The results of mexA Ct values ranged
from 32.1 to 36.79 with an average of 34.337, and the results of mexB Ct values
ranged from 14.74 to 19.96 with an average of 16.791 compared to the rpsL (Ct =
11.14) reference gene. The results showed that the mean of Ct of gene expression
was noticed when put under stress of Et.Br. + CIP and CIP in mexA were 37.195
and 34.702, respectively, compared to control 34.337; on the other hand, the gene
expression between both treatments was over-expressed in the treatment of CIP 32
compared to CIP+Et.Br. The Cather wheel method expression results were noticed
when stressed, Et.Br. + CIP and CIP in mexB gene expression were 19.626 and
18.872, respectively, compared to control 16.791. In conclusion, compared to the
control, both treatments did not induce the expression of mexB genes; on the other
hand, the gene expression between both treatments was expressed in the treatment
of CIP 32 compared to CIP+Et.Br.
Keywords: Pseudomonas aeruginosa, mexA, mexB, Cather Wheel.
Low adhesion in the wheel/rail contact is a problem for the rail industry in Great Britain as it causes significant scheduling and safety issues. Applying sand to the wheel/rail contact is used to ...mitigate against low adhesion however, there is not a consensus on what makes a “good” particle for restoring adhesion, especially with regards to when the particle has entered the wheel/rail contact. The aim of this work was to investigate what particle characteristics had the greatest effect on wheel/rail adhesion and surface conditions, using a process of particle characterisation, tribological testing and statistical modelling. Particle size, shape, and hardness were all found to affect tribological performance. This knowledge can help guide future changes to sanding operations.
•Multiple types of particle used in the sanding process characterised.•Tribological tests assessing the impact of sand on leaf layers.•Effect of particle characteristics on friction in high pressure interface.•Effect of particle characteristics on surface roughness in high pressure interface.
Detailed investigations of white etching layers (WELs) formed on rails and wheels are of utmost importance to improve railway safety. This calls for lab-generated WELs with well-comparable ...characteristics to conduct further testing such as in twin-disc experiments. In this work, laser surface treatments were applied on wheel steels to induce thermally induced WELs. To evaluate the influence of the initial deformation state of the sample, undeformed and severely plastically deformed ER7 wheel steels were selected. In this study, it is shown that surface temperatures of > 640 °C lead to thermally induced WELs, with differences based on the initial deformation state. The thermally induced WELs are compared to a field-WEL present on an ex-service railway wheel. Results indicate that the WEL induced by laser treatment on an initially deformed wheel material provides the best match with the field-WEL. The most distinct difference is a grain size gradient within the outermost 30 µm of the field-WEL caused by deformation after the formation in service. This study clearly shows that the variation in initial microstructures and laser process parameters leads to differences in microstructural characteristics of thermally induced WELs and must be considered when imitating and testing WELs in laboratories.
Animals including humans execute motor behavior to reach their goals. For this purpose, they must choose correct strategies according to environmental conditions and shape many parameters of their ...movements, including their serial order and timing. To investigate the neurobiology underlying such skills, we used a multi‐sensor equipped, motor‐driven running wheel with adjustable sequences of foothold pegs on which mice ran to obtain water reward. When the peg patterns changed from a familiar pattern to a new pattern, the mice had to learn and implement new locomotor strategies in order to receive reward. We found that the accuracy of stepping and the achievement of water reward improved with the new learning after changes in the peg‐pattern, and c‐Fos expression levels assayed after the first post‐switch session were high in both dorsolateral striatum and motor cortex, relative to post‐switch plateau levels. Combined in situ hybridization and immunohistochemistry of striatal sections demonstrated that both enkephalin‐positive (indirect pathway) neurons and substance P‐positive (direct pathway) neurons were recruited specifically after the pattern switches, as were interneurons expressing neuronal nitric oxide synthase. When we blocked N‐methyl‐D‐aspartate (NMDA) receptors in the dorsolateral striatum by injecting the NMDA receptor antagonist, D‐2‐amino‐5‐phosphonopentanoic acid (AP5), we found delays in early post‐switch improvement in performance. These findings suggest that the dorsolateral striatum is activated on detecting shifts in environment to adapt motor behavior to the new context via NMDA‐dependent plasticity, and that this plasticity may underlie forming and breaking skills and habits as well as to behavioral difficulties in clinical disorders.
Mice were trained to perform new, complex stepping patterns required by re‐arranged peg‐patterns in the step‐wheel task. c‐Fos expression demonstrated that striatal projection neurons of both direct and indirect pathways, together with nNOS‐positive striatal interneurons, were activated in the first session with exposure to a new peg‐pattern. Experiments with intrastriatal infusion of the NMDA blocker AP5 showed that the striatal plasticity was recruited at the earliest stage of learning.
In this paper, a new extension coordinated controller was proposed for driving stability and handling performance of four wheel independent drive electric vehicles. The proposed controller has three ...levels. The upper control level uses a new extension coordinated controller to find the weights of a active front wheel steering controller (AFS) and a direct yaw moment controller (DYC). Moreover, considering the different vehicle speed, the road adhesion coefficient and the wheel steering angle, a phase plane method was used to provide the dynamic stability boundary for the switching control strategy of AFS and DYC. The medium control level used the triple-step nonlinear method to calculate the additional front wheel angle and additional yaw moment required by the lower control level. The additional front wheel angle and additional yaw moment was applied to the steering motor and the four wheel drive motor, respectively. In order to obtain the target wheel force, the four wheel drive torque was optimized based on a quadratic programming method. The proposed extension coordinated controller was performed in the CarSim/Simulink co-simulation platform, hardware-in-loop (HIL) and vehicle test. The results showed that the proposed controller can effectively improved both the stability and handling performance.
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