System identification and pid control of toothbrush simulator system

Toothbrush simulator was invented for industry and dentist researchers to do research related to plaque removal. The toothbrush simulator system repeatedly has a problem in achieving the desired speed control. The brushing movement is inconsistence and stops eventually if there is a force exerted on the toothbrush holder. Further research is required to increase the reliability and controllability of the speed response achievable from the toothbrush simulator system. In this study, a PID controller is designed and embedded in the system. A real-time experiment has been conducted on the real system via the Matlab Simulink environment to construct the model. The model parameters are optimized with model order 2, 3 and 4 where each model order has been analyzed for ten (10) times iteration by the genetic algorithm in obtaining the accurate transfer function. The model has been validated through correlation analysis. The PID controller was tuned through the PID tuner and Ziegler-Nichols method. Simulated and real-time system response from both tuning methods was compared. The simulated response with the selected PID controller is then compared with the response from the real-time experiment. The closed-loop system without controller was compared with the response with the PID controller. The PID controller was then deployed into the real system by uploaded into the microcontroller. The brushing simulator remote control was created to control the desired speed through a smartphone. Genetic algorithm model based on model order 4 has been selected as the best model as it able to achieve the minimum MSE value of 0.0176 and past all the validation tests. The selected PID parameters was from PID tuner tuning method with gain values of; Kp= 17.9287, Ki= 40.751 and Kd= -0.52705. Both results of simulation and real-time tests were compared, and they show about similar performances. The controlled system response had achieved all five desired speed of 175, 195, 215, 235 and 255 rpm with the percentage of improvement 67%, 65%, 65%, 65%, and 68%. Throughout this study, a genetic algorithm model based and tuned PID controller parameters has been applied to the real system improvised in better system response

Effect of Toothbrushing On Shade and Surface Roughness of Extrinsically Stained Pressable Ceramics

Statement of problem The effect of toothbrushing on extrinsically stained pressable ceramic materials is unknown. Purpose The purpose of this in vitro study was to investigate the effects of toothbrushing on the shade and surface roughness of extrinsically stained, pressable ceramics. Material and Methods Two materials, leucite-based (IPS Empress Esthetic [EE]; Ivoclar Vivadent AG) and lithium disilicate-based ceramic (IPS e.max Press [EP]; Ivoclar Vivadent AG), were studied. For each material, 24 disk-shaped specimens, 10 mm (diameter)×3 mm (height) were fabricated. Three different methods (n=8) of applying extrinsic stains were performed on each material: glazed only (G, control group); stained then glazed (SG); and stained and glazed together (T). The specimens were brushed with a multistation brushing machine under a load of 1.96 N at a rate of 90 strokes per minute with a soft and straight toothbrush (Oral-B #35) and a 1:1 toothpaste and distilled water slurry. Shade and roughness were measured at baseline and at 72, 144, 216, and 288 hours, which is equivalent to 3, 6, 9, and 12 years of simulated toothbrushing for 2 minutes twice a day. A repeated measures ANOVA with staining technique as a fixed factor was used to evaluate shade and roughness (α=.05). Results For EE groups, no significant change was found after 12 years of simulated toothbrushing regarding shade and surface roughness, irrespective of staining techniques (P\u3e.05). However, EP groups demonstrated a significant shade change and an increase in surface roughness after 12 years of simulated toothbrushing. Shade change was found to depend on the method of applying stain. For the EP-SG technique, a significant shade change was observed only at the 9- to 12-year interval (P=.047). However, the EP-T technique demonstrated a significant difference in shade between baseline and 3 years (P=.005) and in the 6- to 9-year interval (P=.005). Surface roughness was only significantly affected at baseline and 3 years for the EP-T group (P=.005). Conclusions For the shade and surface roughness of the EE groups, no statistically significant difference was found after 12 years of toothbrushing, irrespective of the staining technique. The shade and surface roughness of the EP groups were significantly statistically affected by toothbrushing time; only shade changes were found to depend on technique

Deep VLA Observations of the Cluster 1RXS J0603.3+4214 in the Frequency Range of 1–2 GHz

We report L-band VLA observations of 1RXS J0603.3+4214, a cluster that hosts a bright radio relic, known as the Toothbrush, and an elongated giant radio halo. These new observations allow us to study the surface brightness distribution down to one arcsec resolution with very high sensitivity. Our images provide an unprecedented detailed view of the Toothbrush, revealing enigmatic filamentary structures. To study the spectral index distribution, we complement our analysis with published LOFAR and GMRT observations. The bright `brush' of the Toothbrush shows a prominent narrow ridge to its north with a sharp outer edge. The spectral index at the ridge is in the range $-0.70\leq\alpha\leq-0.80$. We suggest that the ridge is caused by projection along the line of sight. With a simple toy model for the smallest region of the ridge, we conclude that the magnetic field is below $5\,\rm\mu G$ and varies significantly across the shock front. Our model indicates that the actual Mach number is higher than that obtained from the injection index and agrees well with the one derived from the overall spectrum, namely ${\cal M}=3.78^{+0.3}_{-0.2}$. The radio halo shows an average spectral index of $\alpha=-1.16\pm0.05$ and a slight gradient from north to south. The southernmost part of the halo is steeper and possibly related to a shock front. Excluding the southernmost part, the halo morphology agrees very well with the X-ray morphology. A power-law correlation is found between the radio and X-ray surface brightnessComment: 23 pages, 21 figures, accepted for publication in Ap

Consideration for care for your patient with cerebral palsy

Cerebral palsy (CP) is a common developmental neurological disorder affecting about 2-3 children out of 1,000. CP is the result of infant brain damage or abnormal development resulting in impaired muscle control, coordination, tone, reflex, posture, and balance. These patients are unable to control motor movements of their muscles of mastication and facial expression, causing excessive drooling, clenching, bruxism, and other oral health-related issues. This lack of motor control affects their ability to swallow and often limits these patients to a liquid diet. This can lead to vitamin deficiencies and result in further developmental problems. As an example, a deficiency in vitamin D may lead to osteoporosis, which manifests in the oral cavity as periodontal disease. Even into adulthood, these individuals are often reliant on the care of others. It becomes the caregiver’s responsibility to ensure the individual with cerebral palsy is receiving consistent and effective oral hygiene, and to monitor the oral tissues for signs of disease or injury. The researchers reviewed primary and secondary literature published after 2014 on the subjects of cerebral palsy, general health considerations, and oral care. The aim of this investigation focuses on unique issues faced by patients with cerebral palsy, and how to effectively educate caregivers on risks and proper techniques for providing oral hygiene to these individuals.https://scholarscompass.vcu.edu/denh_student/1001/thumbnail.jp

Challenges to our understanding of radio relics: X-ray observations of the Toothbrush cluster

The cluster 1RXS J0603.3+4214 is a merging galaxy cluster that hosts three radio relics and a giant radio halo. The northern relic, the Toothbrush, is 1.9-Mpc long and has an unusual linear morphology. According to simple diffusive shock acceleration theory, its radio spectral index indicates a Mach number of 3.3-4.6. Here, we present results from a deep XMM-Newton observation of the cluster. We observe two distinct cluster cores that have survived the merger. The presence of three shocks at or near the locations of the radio relics is confirmed by density and temperature discontinuities. However, the observation poses several puzzles that challenge our understanding of radio relics: (i) at the Toothbrush, the shock Mach number is not larger than 2, in apparent conflict with the shock strength predicted from the radio spectrum; (ii) at the Toothbrush, the shock front is, in part, spatially offset from the radio emission; (iii) at the eastern relic, we detect a temperature jump corresponding to a Mach number of approximately 2.5, but there is no associated surface brightness discontinuity. We discuss possible explanations for these findings.Comment: 14 pages, 15 figures; submitted to MNRA

Particle motion and stain removal during simulated abrasive tooth cleaning

Stain removal from teeth is important both to prevent decay and for appearance. This is usually achieved using a filament-based toothbrush with a toothpaste consisting of abrasive particles in a carrier fluid. This work has been carried out to examine how these abrasive particles interact with the filaments and cause material removal from a stain layer on the surface of a tooth. It is important to understand this mechanism as while maximum cleaning efficiency is required, this must not be accompanied by damage to the enamel or dentine substrate. In this work simple abrasive scratch tests were used to investigate stain removal mechanism of two abrasive particles commonly used in tooth cleaning, silica and perlite. Silica particles are granular in shape and very different to perlite particles, which are flat and have thicknesses many times smaller than their width. Initially visualisation studies were carried out with perlite particles to study how they are entrained into a filament/counterface contact. Results were compared with previous studies using silica. Reciprocating scratch tests were then run to study how many filaments have a particle trapped at one moment and are involved in the cleaning process. Stain removal tests were then carried out in a similar manner to establish cleaning rates with the two particle types. Perlite particles were found to be less abrasive than silica. This was because of their shape and how they were entrained into the filament contacts and loaded against a counterface. With both particles subsurface damage during stain removal was found to be minimal. A simple model was built to predict stain removal rates with silica particles, which gave results that correlated well with the experimental data