Pad Temperature Research Articles

Numerical study of thermal comfort and energy efficiency about electrically heated footwear under a cold environment

PurposeThe paper aims to reveal the relationship among energy efficiency, thermal comfort and thermal regulation of electrically heated footwear and to investigate influencing factors on the energy efficiency and thermal comfort.Design/methodology/approachA finite volume model was proposed to simulate the two-dimensional heat transfer in electrically heated footwear (EHF) under an extremely cold condition. The model domain consists of three-layer footwear materials, a heating pad, a sock material, an air gap and skin tissues. Model predictions were verified by experimental data from cold-contact exposure. Then the influencing factors on the energy efficiency and thermal comfort were investigated through parametric analysis.FindingsThe paper demonstrated that the skin temperature control (STC) mode provided superior thermal comfort compared to the heating pad temperature control (HPTC) mode. However, the energy efficiency for the HPTC mode with a heating temperature of 38 °C was 18% higher than the STC mode. The energy efficiency of EHF while reaching the state of thermal comfort was strongly determined by the arrangement and connection of heating elements, heating temperature, thickness and thermal conductivity of footwear materials.Originality/valueThe findings obtained in this paper can be used to engineer the EHF that provides optimal thermal comfort and energy efficiency in cold environments.

Next-Gen Lubrication: Water-cooled thrust bearings in conjunction with nano fluid lubricant

Thrust bearing finds application as a key element for heavy duty machines such as hydro-power plants (vertical shaft), submarines, steam engines, cement plant-ball mills (horizontal shaft) etc. Bearing temperature is a primary factor that affects the performance of hydrodynamic thrust bearings. Thermal deformation, misalignment, reduction in minimum oil film thickness and subsequent drop in load carrying capacity, are some of the manifestations related to high bearing temperatures. The present study attempts to decrease the bearing temperature by utilizing novel hybrid bearing set up. It involves the integration of water-cooled pads coupled with nanoparticle-infused lubricant films. This approach represents a convergence of two key technologies aimed at addressing the thermal effects linked with elevated temperatures generated during the operation of bearings. This study utilizes computational simulations to evaluate the effect of integrated thrust pad design on performance characteristics like pressure, temperature, and thermal deformation of a thrust bearing. The simulation results of new integrated design confirm (i) enhancement in pressure values e.g. maximum pressure increases from 5.6 MPa to 6.5 MPa (ii) reduction of pad temperature values e.g. maximum pad temperature value reduces from 85℃ to 70℃ (iii) reduction of pad thermal deformation values e.g. maximum pad thermal deformation value reduces from 36.5 µm to 22.3 µm. By leveraging the direct cooling effect of embedded cooling circuitry and the enhanced thermophysical properties of nanoparticles, this novel configuration promises to unlock new levels of efficiency and reliability in thrust bearing operation.

Alleviating thermal challenges in hydrodynamic bearings: A novel approach through thrust bearing pads with embedded cooling circuitry and deep recess

At high speeds minimization of operating temperature is the critical design objective in hydrodynamic thrust bearings. During the high speed operations of heavy duty machines high temperatures are generated in thrust bearings due to vigorous viscous shearing of lubricant oil film. Under such circumstances thermal effects gain critical importance. Consequences of thermal effects include pad deformation, increased wear, material degradation etc. in hydrodynamic bearings. This research explores a pioneering approach to mitigate thermal challenges by integrating deep recesses and cooling circuitry in thrust bearing pads. The integrated design facilitates enhanced heat dissipation and load carrying capacity along with optimized lubrication process. In this study CFD (CFX) simulation code is used to numerically evaluate the effect of hybrid bearing configuration (conventional thrust pad equipped with deep recess and embedded cooling circuitry) on the performance parameters of thrust bearing. The simulation results confirm an appreciable decrease in maximum pad temperature and thermal pad deformation. The maximum pad temperature decreased from 85℃ to 71℃. Similarly value of thermal pad deformation decreased from 36 µm to 24 µm. The outcomes hold promise for enhancing the thermal performance of existing machinery and inspiring the development of next-generation thrust bearing systems, marking a transformative advancement in the field of mechanical engineering.

Performance Analysis of Thermal and Surface Roughness Effect of Slider Bearings with Unsteady Fluid Film Lubricant Using Finite Element Method

The streamline upwind Petrov‐Galerkin (SUPG) finite element method was used in this study to investigate the thermal and surface roughness effects on an inclined slider bearing with an unsteady fluid film. One‐dimensional transverse and longitudinal surface roughness models were considered with the supposition that roughness is stochastic and has a Gaussian random distribution. For simplicity of numerical computation, the irregularity caused by the texture of the surface is transformed into a regular domain. The bearing performance of the combined effect is lower than the thermal and surface roughness effects of the one‐dimensional longitudinal surface roughness for all modified Reynolds numbers of nonparallel slider bearings; this means that for nonparallel (w = 0.4) between the surface roughness effect and the combined effect condition, there is a decrease of 13% in load‐carrying capacity performance and a minimal change in friction force, respectively. However, in the case of nonparallel one‐dimensional transverse type slider bearings, the bearing performance of the thermal effect is lower than the combined and surface roughness effects for all modified Reynolds numbers, where between the combined effect and the thermal effect condition, there is a reduction of 19% in load‐carrying capacity performance and 2% in friction force practically for all changed Reynolds values, respectively. Furthermore, the combined effects at various temperatures have been investigated. As a result, in both longitudinal and transverse models, in the case of the pad temperature being lower than the slider, the load‐carrying capacity performance is higher than in other cases for nonparallel slider bearings, whereas when the slider temperature is lower than the pad temperature, the drag frictional force is the leading one in both models. In general, considering surface texture and inertial effects will increase the performance of a slider. The results obtained are displayed using figures and tables.

Short-term cocoa bioflavanol supplementation does not improve cold-induced vasodilation in young healthy adults.

Cold-induced vasodilation (CIVD) is an oscillatory rise in blood flow to glabrous skin that occurs in cold-exposed extremities. Dietary flavanols increase bioavailable nitric oxide, a proposed mediator of CIVD through active vasodilation and/or withdrawal of sympathetic vascular smooth muscle tone. However, no studies have examined the effects of flavanol intake on extremity skin perfusion during cold exposure. We tested the hypothesis that acute and 8-day flavanol supplementation would augment CIVD during single-digit cold water immersion (CWI). Eleven healthy adults (24 ± 6years; 10M/1F) ingested cocoa flavanols (900mg/day) or caffeine- and theobromine-matched placebo for 8days in a double-blind, randomized, crossover design. On Days 1 and 8, CIVD was assessed 2h post-treatment. Subjects immersed their 3rd finger in warm water (42°C) for 15min before CWI (4°C) for 30min, during which nail bed and finger pad skin temperature were measured. Flavanol ingestion had no effect on CIVD frequency (Day 1, Flavanol: 3 ± 2 vs. Placebo: 3 ± 2; Day 8, Flavanol: 3 ± 2 vs. Placebo: 3 ± 1) or amplitude (Day 1, Flavanol: 4.3 ± 1.7 vs. Placebo: 4.9 ± 2.6°C; Day 8, Flavanol: 3.9 ± 1.9 vs. Placebo: 3.9 ± 2.0°C) in the finger pad following acute or 8-day supplementation (P > 0.05). Furthermore, average, nadir, and apex finger pad temperatures during CWI were not different between treatments on Days 1 or 8 of supplementation (P > 0.05). Similarly, no differences in CIVD parameters were observed in the nail bed following supplementation (P > 0.05). These data suggest that cocoa flavanol ingestion does not alter finger CIVD. Clinical Trial Registration Clinicaltrials.gov Identifier: NCT04359082. April 24, 2020.

The effect of misalignment on the performance of tilting pad thrust bearing with TEHD coupling model and turbulence model

A thermoelastohydrodynamic (TEHD) coupling model is developed to study the static performance of a heavy-duty tilting pad thrust bearing (TPTB) under the effect of axis misalignment. To ensure the validity in calculating thermoelastic deformation, the calculation accuracy of the mechanical and thermal deformations used in the TEHD model is verified by the finite element method (FEM). The influence of the TEHD model on the flow state prediction is determined using different axial loads, and the numerical analysis of turbulence model and centrifugal inertia term on the bearing pad temperature is conducted at various operating rotation speeds. Compared with the aligned bearing performance, the characteristic distribution of each bearing pad under different misaligned angles is obtained. The effect of misalignment will cause local overheating of the thrust-bearing pads, especially for the heavy-duty TPTD. The results of this study can help to improve the prediction accuracy of heavy-duty TPTB characteristics and avoid harmful misalignment effects. Therefore, it is necessary to consider the effects of misalignment, turbulence, and thermoelastic deformation in the design and analysis of thrust bearings.

Investigation of Brake Pad Wear Effect due to Temperature Generation Influenced by Brake Stepping Count on Different Road Terrains

The use of vehicles in Malaysia has become a need and important to commute to the workplace and commercial business transportation. This necessity resulted in an increase in the number of cars on the road that eventually increase the number of accidents that resulted in the loss of life which is also one of the leading killers in Malaysia. Deriving from this phenomenon, car maintenance especially brake systems has become imperative that eventually become the main objective of this research to investigate the effect of different road terrains to brake pad wear. The experimental vehicle is operated in two different road terrains namely hilly and flat roads and each road terrain is set to complete 1000km of investigation traveled distance. Three main investigation parameters are brake pad thickness wear, the temperature generated from rubbing the brake pad with the rotor, and the brake force applied on the brake pedal. A CANedge external onboard diagnostic (OBD) logger is used to collect real-time data on the relevant parameters from the vehicle’s ECU for analysis. The result from the experiments found that the average brake pad wear rate during hilly roads is 53% higher than that of flat roads. Likewise, brake pad temperature generation on a hilly road is 34% higher than that on a flat road. However, the brake pedal force applied during braking is 60% higher on flat roads compared to on hilly roads. From the findings, data from the vehicle OBD2 and the brake pad wear can be analyzed to provide an electronic signal for indication of timely maintenance for the brake pad.

Steam allocation for SAGD: Multi-pad multi-criteria short and long-term real-time performance management

Optimizing steam allocation is critical for long-term performance goals in Steam-Assisted Gravity Drainage (SAGD) recovery. The steam supply mainly contributes to the economics, steam chamber conformance, greenhouse gas emissions, and ultimate bitumen recovery. Therefore, SAGD real-time optimization (RTO) must balance steam chamber development and economics to achieve long-term goals. However, in RTO, general-purpose optimization algorithms decide based on short-term responses, unlike long-term optimization processes. Using economic Key Performance Indicators (KPI) such as Net Present Value (NPV) in a single objective, the RTO determines the smallest amount of steam that results in the highest economic returns. Injecting a small amount of steam reduces steam chamber heat loss, growth, and long-term ultimate bitumen recovery. As a result, a suitable selection of critical KPIs is required to balance the development and economics of the steam chamber.This work presents a study of multiple combinations of SAGD KPIs for a multi-pad real-time steam allocation. The KPI combinations used in this study are NPV, cumulative steam-oil-ratio (cSOR), recovery factor (RF), and average pad temperature (aveTemp). A Box-Jenkins-based data-driven model simulates the SAGD recovery process, and a first principle simulator is used as a substitute for an actual reservoir. The Alternating Direction Method of Multipliers (ADMM) is proposed for multi and many-objective optimization for real-time steam allocation across multiple pads. A compromise programming approach guides the decision-makers choice of the optimum control setpoints of the non-dominated solutions on each horizon. At the end of three and half years of RTO, the optimal KPI combination is ranked based on the aggregated performance of NPV, cSOR, and RF of SAGD multi-pad steam allocation. A synthetic Western Canadian reservoir model with four pads and 33 well pairs developed from publicly available data is used for this study.The aggregated performance of this study's results showed that joint optimization of an economic and a steam chamber growth KPIs of two is better than a combination of three or four. The choice of the joint economic and steam chamber growth KPIs depends on the average pad temperature at the start of RTO to achieve optimal fluid balance in the long term. cSOR or NPV with RF joint KPI performs optimally at average pad temperatures above 90 °C, while cSOR or NPV with aveTemp below 90 °C at the start of RTO to achieve injected and produced fluid balance. Optimum economic return, recovery, and greenhouse gas emission of the SAGD process are achieved with cSOR KPI as the primary economic objective.

Development of brake activity measurement method for heavy-duty vehicles

ABSTRACT Tailpipe PM (particulate matter) emissions have been reduced due to decades of tightening regulations, however non-tailpipe PM emissions are not regulated and are expected to become a significant source of traffic-related PM emissions. Previous studies have focused on emission measurement from laboratory and track tests. Their findings suggest brake wear PM emission rates are dependent on brake activity. Therefore, it is important to characterize brake emissions by first understanding the real-world brake activity from many different vehicle vocations and driving conditions. The goal of the current study is to establish a test method and analysis for brake activity measurements of heavy-duty vehicles. In this study, brake fluid pressure and brake pad temperature were measured for a heavy-duty vehicle during chassis and on-road driving tests. The chassis tests consisted of the Central Business District (CBD) cycle representative of a repetitive stop-and-go driving pattern of a bus, and the Urban Dynamometer Driving Schedule (UDDS) cycle representative of urban driving conditions of heavy-duty vehicles. The on-road tests consisted of a local Riverside City route focused on urban roads at low vehicle speeds with frequent braking, while the second route from Riverside City to Victorville focused on highway driving and downhill braking. The brake pad temperature of the triplicate CBD cycle gradually increased linearly with a slope of 2.3°C/min and the temperature per kinetic energy lost during braking increased by 2.3 × 10−5°C/J for the CBD cycle. The UDDS cycles had the largest kinetic energy loss between 3.2 × 103 to 3.0 × 105 J in the histogram. The local Riverside city route brake temperature increased by 2.0°C/min. The kinetic energy loss for the on-road tests were one order of magnitude larger than that of the dynamometer tests due to brake events occurring under higher speeds. Implications: The non-tailpipe source contributions to traffic related particulate matter (PM) emissions have surpassed that of tailpipe emissions. The results of this work provide a measurement method to obtain brake activity information for a heavy-duty vehicle, which is critical estimating emission inventory accurately.

Study on the Influence of Rotational Speed and Pad Temperature of Pumped-Storage Set on Oil Mist Leakage of Thrust Bearing

The accumulation of oil mist in the thrust bearings poses a threat to the safety of the unit, leading to financial and environmental losses. To investigate the generation and influencing factors of oil mist in the oil tank of the thrust bearing in a pumped-storage power station, a novel numerical simulation method is proposed for calculating the oil–oil mist–air multi-phase flow based on the VOF model, RNG k−ε turbulence model, and Lee model. The proposed numerical method’s reliability is verified using field operation data. The effects of rotational speed and pad temperature on the formation of oil mist inside the oil tank were examined from two perspectives of internal and external oil leaks. The research revealed two accumulation areas where oil mist is generated and accumulated: between the thrust head and the oil-retaining ring and near the oil slinger. The former causes external oil leaks due to pressure differences, while the latter causes internal oil leaks due to the rotor blast effect. An increase in temperature and rotational speed exacerbates the formation of oil mist. Furthermore, an increase in speed decreases the pressure change rate at the wall of the inner tank (external oil leaks) by 5.95% and at the oil slinger (internal leaks) by 44.64%. Consequently, compared to external oil leaks, internal oil leaks are more likely to occur.

Suppressive effects of a transient receptor potential melastatin 8 (TRPM8) agonist on hyperthermia-induced febrile seizures in infant mice.

Background: Febrile seizures (FSs) are the most frequent type of seizures in infancy and childhood. Epileptiform discharges (EDs) on electroencephalogram at the time of first FS recurrence can increase the risk of epilepsy development. Therefore, inhibition of EDs is important. Recently, WS-3, a transient receptor potential melastatin 8 (TRPM8) agonist, reportedly suppressed penicillin G-induced cortical-focal EDs. However, the effects of TRPM8 agonists on FSs remain unknown. In this study, we aimed to clarify the effects of the TRPM8 agonist, and the absence of TRPM8 channels, on hyperthermia-induced FS by analyzing the fast ripple band. Methods: Hyperthermia (43°C for 30min) induced by a heating pad caused FSs in postnatal day 7 wild-type (WT) and TRPM8 knockout (TRPM8KO) mice. FSs were defined as EDs occurring during behavioral seizures involving hindlimb clonus and loss of the righting reflex. Mice were injected with 1% dimethyl sulfoxide or 1mM WS-3 20min before the onset of hyperthermia, and electroencephalograms; movies; and rectal, brain and heating pad temperatures were recorded. Results: In wild-type mice, WS-3 reduced the fast ripple amplitude in the first FS without changing rectal and brain temperature thresholds. In contrast, the anti-FS effect induced by the TRPM8 agonist was not observed in TRPM8KO mice and, compared with wild-type mice, TRPM8 deficiency lowered the rectal and brain temperature thresholds for FSs, exacerbated the fast ripple amplitude, and prolonged the duration of the initial FS induced by hyperthermia. Conclusion: Our findings suggest that TRPM8 agonists can be used to treat hyperthermia-induced FSs.

SIMULASI KARAKTERISTIK AKUSTIK MENGGUNAKAN APLIKASI METODE ELEMEN HINGGA PADA MATERIAL KOMPOSIT HAZELNUT, PINEAPPLE, ALUMINIUM YANG DIGUNAKAN SEBAGAI KAMPAS REM PADA SEPEDA MOTOR

Brake pads are an important factor in braking, so it is necessary to study the noise and acoustic characteristics of the brake pads using the acoustic simulation method to obtain sound pressure level results, determine the acoustic characteristics of the simulation, compare the noise results in the simulation with experimental testing. The simulated composite brake lining material uses a composition of hazelnut shell, pineapple leaf fiber, aluminum, polyurethane. Researchers used simulations with the application of the finite element method in the form of 3D modeling to analyze the parameters applied. The parameters are material data, mesh size, acoustic region, physics region, force, mass source. The simulation results of the acoustic characteristics of composite brake linings with a load of 500grams obtained a minimum noise at 500rpm rotation with a distance of 15cm of 3.88dB and the maximum noise occurs with a load of 750grams at 900 rpm rotation with a distance of 5cm of 11.54dB. The average sound pressure level value using the simulation method is smaller than the experimental method at 500rpm, 700rpm, 900rpm, a load of 500grams and 750grams, a distance of 5cm, 10cm, 15cm. This could be caused by parameters that were not included in the simulation, such as vibration on the test equipment, brake pad temperature, setup errors or calibration of experimental method measuring devices. The overall percent error of the simulation results at 500rpm, 700rpm, 900rpm, 500gram and 750gram loads, distances of 5cm, 10cm, 15cm, the result percent error are not up to 12%.

Theoretical and Experimental Comparisons for Rotordynamic Coefficients of a Multiscratched Tilting Pad Journal Bearing

Abstract This paper presents a thermo-elasto-hydrodynamics model (TEHD) based on a mass conservative generalized Reynolds equation, coupled with three-dimensional (3D) energy equation for the oil film, and a full 3D thermo-mechanical model for the pads. The model uses a regularization technique to consider film thickness discontinuities created by scratches. The numerical results are compared to the experimental results obtained from a rocker-backed, five tilting pads journal bearing (TPJB) with single and multiple scratches. The numerical model achieved good agreement, especially with respect to pad temperatures and dynamic coefficients. Discrepancies were observed at low speed but only on the stiffness in the load direction. The numerical model shows a significant drop in the pressure field at the location of the scratches, and a significant pressure rise between two consecutive scratches accompanied by a decrease in film thickness.

A Study of Moisture Sorption-Desorption and Its Influence on the Dynamic Modulus and Friction Coefficient of Copper-Free Brake Pads

<div class="section abstract"><div class="htmlview paragraph">The moisture sorption-desorption kinetics of copper-free brake pads was studied in detail. The sorption-desorption behavior is dependent on the environmental temperature and humidity. At 24 °C under 54% RH, the sorption increases rapidly for a week or so identified as the first stage of sorption, enters the second stage of negligible weight gain for a month and then the third stage of rapid sorption again. With increasing moisture sorption, the pad thickness increases through the 3 stages and the dynamic modulus also increases through the 3 stages. Friction materials lose moisture rapidly at 130°C and behave like desiccants. The sorption-desorption phenomenon significantly influences the friction coefficient -- a higher moisture content leading to lower friction coefficients. It is demonstrated that the rising friction coefficient for the half a dozen braking stops at the beginning of every brake testing in general is due to moisture desorption caused by rising pad temperatures. The pads become a reservoir for releasing moisture for a long period of time during testing. As many standardized brake test procedures do not specify the moisture content of the pads, brake test repeatability and reproducibility become problematic. Also, friction material property measurements for quality control becomes problematic as the moisture content is not specified or considered. For modeling and simulation of brake friction, vibration and noise, the moisture sorption-desorption effects will have to be incorporated for reliable outcomes.</div></div>

EVALUATION OF POSSIBILITIES TO IMPROVE FUNCTIONALITY OF BRAKE PADS THROUGH MODIFICATION OF THE HEAT DISSIPATION METHOD

From a social perspective, providing motor vehicle users with high quality brake lining assemblies, which additionally help to prevent the braking system from overheating by dissipating heat into the atmosphere, is a matter of great importance. Overheated brakes may cause failure of the braking system and, as a result, lead to a car accident. Heat dissipation during operation helps to cool the braking system and prevent overheating. The article presents two patented brake pad structural solutions – anisotropic and ventilated brake pads – designed to boost the effectiveness of heat dissipation. The tests described in the article were performed using the T-33 inertia dynamometer developed at the Łukasiewicz – Institute for Sustainable Technologies in response to a demand presented by a Polish brake pad manufacturer. As part of the tests, various functional properties of the newly-designed and classic brake pads (i.e. the friction coefficient, the temperature of the brake pad, and the wear of the brake pad and brake disc) were compared. From the tests it follows that the new pads with the heat dissipation system have an advantage over classic pads, depending on the method of brake pad’s material and structural modification.

0083 A Thermoregulated Pillow Improves Sleep: Results from Real-Life Data

Abstract Introduction Sleep is regulated by homeostatic mechanisms and circadian rhythms.Thermal environment is one of the most important factors that can affect human sleep. This real-life study aims to evaluate the effects of temperature regulation on sleep quality using a thermoregulated pillow. Methods The Moona device has been used to control the temperature of a pillow pad from 64°F to 95°F. Users with more than 7 uses of the device and who completed the initial questionnaire (18 profile questions) participated in this study from October 2019 to July 2021. Participants rated their sleep quality on a scale of 1 to 5. Comparison between the sleep quality before the first use and the average of the last seven uses of the device has been done. A survey has been sent to all users from June to November 2021. To date, 206 answers have been collected including 32 users who reported having been diagnosed with insomnia. Improvement of their insomnia has been assessed by a 5-point scale (from ‘much better’ to ‘much worse’). Statistical analyses have been performed on Python 3.7. Mean comparisons have been measured by student t-test. Results The sleep quality significantly increased with the use of the device from 2.6/5 to 3.7/5 (p<0.001) in the general population (N=620). This significant difference has been also measured in several subgroups who have temperature issues. That is the case for overweight/obese users (N=321, from 2.6/5 to 3.7/5, p<0.001), women over 45 (N=97, from 2.4/5 to 3.6/5, p<0.001) and users who feel hot during the night more than several times a week (N=523, from 2.5/5 to 3.8/5, p<0.001). Moreover, 30 out of 32 insomniacs have reported an improvement of their insomnia since using this active cooling pillow pad. Conclusion The present study findings showed that an active thermoregulated pillow could improve sleep of insomnia patients and several subgroups of patients with issues at controlling temperature at night. Support (If Any)

EFFECT OF BRAKING DISTANCE AND ROAD CONDITIONS ON BRAKE PAD TEMPERATURE ON 150 CC MOTORCYCLE

Road safety is the right of all road users. However, the reality is that the high number of deaths is still caused by accidents while driving on the road. One of the contributing factors to these accidents is the lack of warning signs when the braking system malfunctions. This study aims to monitor the temperature during braking and provide an early warning safety system for motorcycle riders based on the ESP32 microcontroller and the MAX6675 thermocouple type-K temperature sensor module. The method in this study, employed a quantitative experimental approach by conducting experiments on three types of road terrains: flat road, gentle downhill road, and steep downhill road. Braking was performed at intervals of 30 meters, with a final braking distance of 300 meters. The findings of this study indicate that the distance and road conditions have an impact on the increase in brake pad temperature. The experiments showed a significant temperature increase at a braking distance of 300 meters, with values of 99.75°C on flat roads, 115.50°C on gentle downhill roads, and 129.00°C on steep downhill roads.
 
 Keywords: early warning sign; ESP32 microcontroller; temperature monitoring; temperature sensor; road safety.

Characterization of brake particles emitted from non-asbestos organic and low-metallic brake pads under normal and harsh braking conditions

The physicochemical characteristics of micro- and nano-sized brake particles emitted from non-asbestos organic (NAO) and low-metallic (LM) brake pads were investigated under normal and harsh braking conditions using a brake dynamometer. Under normal braking conditions, 28% and 12% of the total wear mass of brake pad and disc was emitted as PM10 and PM2.5, respectively. Overall, the LM pad emitted 4 times higher brake wear PM than the NAO pad. There was no difference in the morphology of brake wear particles (BWPs) according to pad type from the two pad types. BWPs emitted from the NAO pad were mainly composed of Fe oxide and potassium hexatitanate particles, whereas BWPs from the LM pad were almost entirely of Fe oxide particles. Even when the critical pad temperature was not reached, nanoparticles 80–200 nm in size were emitted from both pad types, and the emission concentration of the LM pad was 3–4 times higher than that of the NAO pad. When the pad temperature exceeded the critical temperature by repeated harsh braking, high particle number (PN) concentrations of volatile nanoparticles were measured. Brake nanoparticles 10–50 nm in size formed out of 10 nm sized particles through volatilization and nucleation. Notably, the PN concentration of volatile NAO pad nanoparticles was 3–4 times higher than that of LM pad nanoparticles due to a higher organic fraction in NAO pads. Volatile nanoparticles smaller than 50 nm could be efficiently removed using volatile particle removers such as an evaporation tube and a catalytic stripper, and the evaporation tube had a higher removal efficiency of volatile nanoparticle than the catalytic stripper. Scanning transmission electron microscopy and energy dispersive spectroscopy analysis showed that nanoparticles of size around 50 nm were round and adhered to larger particles.

Influence of Brake Pad Properties to Braking Characteristics

In this research, field and laboratory testing of three commercially available brake pads with the lowest, mid-dle, and highest price were performed. Complex field testing, where brake pads were tested in real extreme conditions on a loaded van vehicle and laboratory tests were performed. The field testing intended to investigate the temperatures that occur during the braking process and to determine the stopping distance, deceleration, and stopping time separately on the type of brake pads. Labo-ratory tests included the determination of the friction co-efficient according to ASTM G77, the structure of brake pad surfaces before and after the testing, and quantitative chemical analysis of brake pads. The aim of this study was to determine the influence of brake pad temperature on braking time depending on their purchase prices. The obtained results show a significant difference between the temperature, friction coefficient, chemical composi-tion, and braking time of the brake pads and their price.

The agreement of rectal temperature with gingival, ocular and metacarpal pad temperatures in clinically healthy dogs

ABSTRACT Aims To compare alternative methods of recording body temperature (BT) with rectal temperature (RT) in clinically healthy dogs. Methods This prospective study included 97 healthy mixed-breed dogs (43 females and 54 males). The gingival temperature (GT) was collected by using a human non-contact, infrared forehead thermometer, while ocular temperature (OT) and metacarpal pad temperature (MPT) were obtained with an infrared thermal camera. The degree of agreement was determined using the Bland–Altman method, with RT considered as the reference temperature. Results A total of 382 readings were obtained from four different anatomical regions. The mean difference and their 95% limits of agreement for the differences between RT−GT, RT−OT, and RT−MPT were 0.18°C (−0.95°C–1.32°C), 0.79°C (−0.45°C–2.04°C), and 0.50°C (−0.63°C–1.62°C), respectively. The GT, OT, and MPT values were within ±0.5°C of RT for 65.9%, 19.5%, and 52.5% of dogs, respectively. Conclusions and clinical relevance Although GT, OT, and MPT were a quick way to estimate BT in dogs, these measurements were not comparable with RT. The GT measurement achieved the best agreement with RT measurement (lowest bias and the highest proportion of measurements within ±0.5°C). The GT could be considered an option for monitoring changes to body temperature in clinically healthy dogs where RT measurement is not possible.