Standard Rolling Research Articles

Comparative analysis of non-standardised aging methods for asphalt binder against standard laboratory aging and natural field aging

ABSTRACT This research investigates non-standardised and natural field aging methods, in comparison with standardised ones. Aging in the Rotational Viscometer (RV) for 24 hours was studied. Pressure Aging Vessel (PAV) aging time and film thickness were changed and compared with standard rolling thin film oven (RTFO) and field-aged binders. Finally, a conventional binder preserved from external conditions was tested over 24 months. Results showed that PAV-aged binders may exhibit greater susceptibility to changes captured by RV. The study also noted a higher increase in viscosities at lower shear rates over time in the RV. However, rheological results did not align with RV findings across all binders. Altering asphalt film thickness in the PAV from 32.5 mm to 25 ± 1 mm has a comparable effect to standard RTFO when the original binder is aged directly in the PAV for the same period of time. The recovered asphalt binder from a 15-year-old pavement showed similarities to 25–30 hours for high-temperature measures, and 55 hours for fatigue parameters indicating inconsistency between laboratory and filed aging. Finally, chemical changes indicated by carbonyl index showed that after 24 months of controlled environmental conditions, a conventional binder exhibited only 44% increase in the index compared to RTFO.

Rolling bearing fault diagnosis method based on wavelet packet logarithmic energy map

Aiming at the fault diagnosis problem of rolling bearings, a diagnosis method based on wavelet packet logarithmic energy map is proposed. Firstly, a new wavelet packet node logarithmic energy formula is improved and proposed to overcome the shortcomings of cumbersome parameter determination and strong subjectivity in the traditional wavelet packet energy formula, improve the recognition of high-frequency faults and the distinction of low-frequency fault categories, so as to fully extract the initial time-frequency domain features; secondly, the Gram angle and field idea is used to realize the conversion from one-dimensional features to two-dimensional image features, so as to construct the logarithmic energy map feature based on wavelet packet, which further considers the spatial information between adjacent features, thereby optimizing the initial time-frequency domain features and improving the significance of the obtained features. On this basis, the residual network is used to improve the accuracy of fault diagnosis classification results. Finally, through the simulation verification of the standard rolling bearing data set of Case Western Reserve University, it can be seen that the fault diagnosis model constructed by the proposed method has high diagnostic accuracy and strong generalization ability.

ChromaFlash: Snapshot Hyperspectral Imaging Using Rolling Shutter Cameras

Hyperspectral imaging captures scene information across narrow, contiguous bands of the electromagnetic spectrum. Despite its proven utility in industrial and biomedical applications, its ubiquity has been limited by bulky form factors, slow capture times, and prohibitive costs. In this work, we propose a generalized approach to snapshot hyperspectral imaging that only requires a standard rolling shutter camera and wavelength-adjustable lighting. The crux of this approach entails using the rolling shutter as a spatiotemporal mask, varying incoming light quicker than the camera's frame rate in order for the captured image to contain rows of pixels illuminated at different wavelengths. An image reconstruction pipeline then converts this coded image into a complete hyperspectral image using sparse optimization. We demonstrate the feasibility of this approach by deploying a low-cost system called ChromaFlash, which uses a smartphone's camera for image acquisition and a series of LEDs to change the scene's illumination. We evaluated ChromaFlash through simulations on two public hyperspectral datasets and assessed its spatial and spectral accuracy across various system parameters. We also tested the real-world performance of our prototype by capturing diverse scenes under varied ambient lighting conditions. In both experiments, ChromaFlash outperformed state-of-the-art techniques that use deep learning to convert RGB images into hyperspectral ones, achieving snapshot performance not demonstrated by prior attempts at accessible hyperspectral imaging.

Quantifying Ageing of 35-50 and 70-100 Asphalts Using Fourier Transform Infrared Spectroscopy and Dynamic Shear Rheometer Measurements

In this study, Dynamic Shear Rheometer (DSR) and Fourier Transform Infrared (FTIR) spectroscopy tests were performed on 35-50 and 70-100 penetration-graded asphalts. Both tests were performed on specimens at three different ageing states: unaged, short-term aged using the standard rolling thin film oven (RTFO) device, and long term aged by placing RTFO residue in the pressure aging vessel (PAV) apparatus. The tests were accomplished to quantify how ageing affects the results of both tests, namely the complex shear modulus for the DSR test and the carbonyl, sulfoxide, and ageing indices for the FTIR spectroscopy test. Both sets of measurements confirm that the harder asphalt stays harder than the softer asphalt after undergoing ageing, but the rate of hardness is higher for the softer asphalt. For instance, on average, PAV ageing was found to increase the amplitude of the shear complex modulus, from the unaged state, by 4.3 times and by 6.2 times for the 35-50 and 70-100 asphalts, respectively. It was also found that ageing decreases the phase angle for asphalt and the decrease is more pronounced for the softer asphalt (70-100) than the harder one (35-50). This was attributed to more maltenes content in the softer asphalt that transform into asphaltenes during ageing. Correlation coefficient between FTIR signals from the same samples revealed that FTIR spectroscopy as used in this research has an excellent repeatability. The repeatability was also confirmed using measures of dispersion such as the coefficient of variation, which was found not to exceed the 1.2%. The 35-50 asphalt was found to have more C=O and S=O links than the 70-100 asphalt since it showed more absorbance in the carbonyl and sulfoxide bands. These links are thought to make the asphalt physically harder. An analysis of variance study revealed that ageing is a statistically significant factor as measured using ageing indices calculated from FTIR spectroscopy data with the index AIFTIR being the most sensitive to ageing among all considered indices. Empirical power equations with high coefficient of determination values were established to predict DSR results from FTIR index values, which was possible since both types of measurements show the same trend with ageing.

Perancangan Sistem Proteksi Eksternal Penyalur Petir di Workshop PT. Bukaka Teknik Utama Balikpapan

Abstract— PT Bukaka Teknik Utama is currently building a fairly spacious workshop building with a length of 60m, a height of 15m and a width of 20m which almost the entire building is made of steel. Considering that thunder days in the city of Balikpapan are quite high, which is as high as 227 per year, the building is vulnerable to lightning strikes. Therefore, to avoid the impact of the lightning strike effect, an external lightning protection system is needed. The method to be used in determining lightning protection is the rolling ball method. Because the shape of the building has a horse gable type the protection level is at level IV with a protection radius of 100.9m and is able to protect lightning currents up to 234.89 kA. After simulation using Sparkta software, the standard rolling ball method NFPA 780 and BS 7430 obtained detailed risk assessment calculation results which are quite safe.

Evaluation of friction calculation methods for rolling bearings

In gearboxes, rolling bearing power losses often make up a large amount of the total gearbox power losses. Therefore, an exact calculation of rolling bearing power losses is very important for resource and energy efficient gearbox design. The state of the art offers numerous friction calculation methods with different levels of detail to calculate power losses of rolling bearings. Bearing manufacturers like SKF and Schaeffler offer popular bearing-based/global calculation methods for standard rolling bearings. Contact-based/local calculation methods can consider a wider application field by generalization of tribological relations, which enables its application to e.g. hybrid bearings or non-standard bearings. The different methods may yield widely differing results. For its validation, measurement results are required. In this study, a broad comparison of calculation results with substantial measurement results is shown. Based on the validation a classification of the calculation methods is derived, which provides guidance for the design engineer to choose the appropriate method for the respective application. Contact-based/local calculation methods have the potential to predict friction in rolling bearings precisely.

Effect of variation of cold-rolling strain-paths on the microstructure, texture and mechanical properties of alloy Ni-16Cr-8Fe

In this work, the effect of variation of cold-rolling strain-paths (one-directional (U), two-stage cross (T), and multi-stage cross (M) rolling) on the evolution of microstructure as well as texture and their correlation with mechanical properties of alloy Ni-16Cr-8Fe has been studied. The overall texture strengthens while increasing rolling reductions from 30-to-50 and 50-to-90 % in all the strain-paths. In U strain-path, two of the standard rolling components—copper and brass—are strengthened significantly, while in T and M strain-paths only brass component strengthens. The overall texture has strong relationship with the brass-component of β-fibre irrespective of the strain-paths used during cold-rolling. The strain-path plays an important role in the changeover of texture from metal- to alloy-type, unlike what was previously thought that lowering of alloy’s stacking fault energy is the only reason. The yield (σYS) and tensile (σUTS) strength of 90 % rolled samples are significantly higher in U as compared to T and M strain-paths. The flow curves of 90 % rolled alloy follow Ludwigson-relationship with negative deviation in all the strain-paths. Regardless of the strain-paths, the area of yield locus ellipse increases as the rolling reductions are increased from 30-to-50 and 50-to-90 % and bear a good relationship with the overall texture. The average in-plane anisotropy in yield stress is observed to be highest in U strain-path. The theory of relative resolved shear stress of fcc slip systems in presence of highest intensity texture component well explains the variation in the values of in-plane anisotropies.

Comparison of Different Standard Test Methods for Evaluating Greases for Rolling Bearings under Vibration Load or at Small Oscillation Angles

Rolling bearings operated at small oscillation angles or exposed to vibrations during standstill show typical damage after only a short period of operation. This can be false brinelling damage, so-called standstill marks or classic fretting damage (fretting corrosion, tribo-oxidation). It is important to differentiate here according to the amplitude-ratio x/2b, which indicates the ratio between the rolling element Motion (x) and the Hertzian contact half-axis (b). Depending on this ratio, suitable laboratory test methods must be used to test the lubricating grease practically for the particular application. For this purpose, the Fafnir wear test, according to the standard of the American Society for Testing and Materials ASTM D4170, is also listed in the current high-performance multi-use specification of the National Lubricating Grease Institute (NLGI) as a release test for lubricating greases. In Europe, the SNR-FEB2 test is frequently used, which is also required to release greases in the blade bearings of wind turbines, among other things. In the case of standstill marks due to very small oscillation angles or vibrations, the Mannheim Tribology Competence Center (KTM) has developed a special test now established in the industry. The oscillating angles vary in these three different standard tests in the range from ±6° in the Fafnir test to ±3° in the SNR-FEB2 test to ±0.5° in the KTM standstill marking test; the x-to-2b ratios range from 5.5 (Fafnir) to 3.4 (SNR) to 0.5 (KTM). This paper will explain the scientific basis for these special operating and test conditions and compare test results of specially prepared model greases in these three standard rolling bearing tests, two test variations and a classical fretting test under oscillating sliding friction (ASTM D7594). The paper’s main objective is to show that the suitability of grease for such an application depends strongly on the prevailing operating conditions. Different tests in this field are, therefore, not interchangeable. Good results in one test do not automatically mean good results in a similar test at first glance. Therefore, selecting the right test for the application is important.

Research on the Cause and Control Method of Edge Warping Defect during Hot Finishing Rolling

Different from the cross-section profile defects caused by uneven roll wear or external forces during hot finishing rolling, the edge warping defect often occurs and has special local characteristics. However, the cause and control method of edge warping are still unclear. By superposition calculating the roll shape, it is found that the high-order comprehensive roll gap contour formed by the superposition of the bathtub-shaped roll thermal contour and parabolic original roll shape is the main cause of strip edge warping. To ensure that the comprehensive roll gap contour is parabolic rather than the original roll shape, the target curve of the comprehensive roll contour in the form of a parabola is determined according to the amplitude of the middle position of the comprehensive roll contour of the last strip in a standard rolling unit, and then subtract the thermal contour curve of the last strip to obtain the desired curve of the antithermal original roll shape. In theory and application, the optimization of the original roll shape can effectively avoid the occurrence of edge warping defect.

Relationship between thermoreversible and irreversible aging in rejuvenated asphalt binder

Rejuvenators are now widely used to restore performance of aged asphalt. A critical factor that controls performance of pavements in service is age hardening of the binder. Hence, both reversible and irreversible processes need to be accounted for in order to ensure durable designs. Thermoreversible processes are affected by irreversible aging, but how the two interact remains largely unexplored for rejuvenated binders. A straight Cold Lake PG 58-28 binder was blended with castor oil residue (COR), soybean oil residue (SOR) and petroleum-based aromatic oil (ARO) rejuvenators. Standard Extended Bending Beam Rheometer (EBBR, AASHTO TP 122) tests were conducted to assess thermoreversible aging. Non-isothermal crystallization kinetics were investigated using Modulated Differential Scanning Calorimetry (MDSC) and Thermogravimetric Analysis (TGA). Standard Rolling Thin-Film Oven (RTFO) followed by 20 h of Pressure Aging Vessel (PAV) conditioning proved sufficient to differentiate thermoreversible aging tendencies. However, EBBR grade losses increased significantly upon extended aging. Rejuvenated compositions fared worse in comparison to straight Cold Lake binder. Three-day grade losses for the PG 58-28 ranged from 1.8 °C (unaged) to 9 °C (100 h PAV). In contrast, the ARO blend lost 0.8 °C (unaged) increasing to a significant 15 °C (100 h PAV).

Verhalten von Kurvenrollen unter verschiedenen Querschlupfbedingungen

With the aid of the universal orthogonal two-disk tribometer „MopeD Qs2STg500“, a new application-oriented method is developed for testing stud type track roller materials and lubricants under various running conditions. The tests are carried out under circulating oil lubrication. This laboratory test method is used to map cam roller gears from a wide range of industrial applications, such as gear changes on lathes in series production or the implementation of cyclic motion profiles on automatic machines. The wear tests are carried out on two different axial cam materials with cam rollers made of the standard rolling bearing steel 100Cr6.

New rolling horizon optimization approaches to balance short-term and long-term decisions: An application to energy planning

The planning of complex systems such as energy systems calls for multiple and recurrent operational decisions depending on the present situation as well as future trends. Such decisions can be optimized with rolling-horizon approaches where most immediate decisions are fixed, based on current previsions, while next decisions are made at further optimization steps with updated information. In this paper, focus on cases where long-term decisions have to be balanced with detailed short-term decisions to insure operational realism. On such problems, standard rolling horizon approaches are hard to solve due to the substantial increase of the temporal dimension. To overstep this issue, new approaches to balance short and long-term decisions. Two modelling approaches, based on aggregated time steps, are proposed and tested on an energy production problem where energy can be stored seasonally. Approaches are compared to benchmarks approaches (myopic and a posteriori optimization), and a sensitivity analysis is performed. Both approaches are promising and correspond to different compromises between the model complexity, computation times and solution quality.

Low-cost camera-based pulsed and modulated continuous wave laser detection for laser-based optical communications

A novel, low-cost, camera-based method of detecting a single nanosecond (ns) laser pulse and kHz modulated continuous wave and pulsed lasers has been developed. The detector uses a simple optical modification to a standard rolling shutter color camera combined with image processing techniques to distinguish lasers from other illumination sources and extract a laser’s wavelength and pulse repetition frequency. In addition, the detector is also capable of detecting a single ns laser pulse at any given time. Such a detector has applications in free-space optical communications (FSO comms) as a low-cost broadband method of extracting information from multiple sources and as a detector of laser range finders. A low-cost prototype (≈£600) has been developed using entirely off-the-shelf components and assessed in laboratory and field trial conditions, with the ability to measure laser wavelengths to ±5 nm and pulse repetition frequencies to within ±5 % at a distance of 660 m. In the laboratory, the prototype was also able to detect each of the 1000 pulses generated by a 10 Hz 10 ns 532-nm pulsed laser, as well as 100 pulses sent at random intervals, highlighting its capability to detect a ns pulse at any given time. This novel technology offers a low-cost method of detecting lasers and extracting their pulse repetition frequencies, with a wide field of view and high spatial resolution. Ultimately, this technology has applications in FSO comms for between vehicles or platforms of interest, with a capability of communicating with multiple targets simultaneously.

Reappraisal of the ASTM/AASHTO Standard Rolling Device Method for Plastic Limit Determination of Fine-Grained Soils

Given its apparent limitations, various attempts have been made to develop alternative testing approaches to the standardized rolling-thread plastic limit (PLRT) method (for fine-grained soils), targeting higher degrees of repeatability and reproducibility. Among these, device-rolling techniques, including the method described in ASTM D4318/AASHTO T90 standards, based on original work by Bobrowski and Griekspoor (BG) and which follows the same basic principles as the standard thread-rolling (by hand) test, have been highly underrated by some researchers. To better understand the true potentials and/or limitations of the BG method for soil plasticity determination (i.e., PLBG), this paper presents a critical reappraisal of the PLRT–PLBG relationship using a comprehensive statistical analysis performed on a large and diverse database of 60 PLRT–PLBG test pairs. It is demonstrated that for a given fine-grained soil, the BG and RT methods produce essentially similar PL values. The 95% lower and upper (water content) statistical agreement limits between PLBG and PLRT were, respectively, obtained as −5.03% and +4.51%, and both deemed “statistically insignificant” when compared to the inductively-defined reference limit of ±8% (i.e., the highest possible difference in PLRT based on its repeatability, as reported in the literature). Furthermore, the likelihoods of PLBG underestimating and overestimating PLRT were 50% and 40%, respectively; debunking the notion presented by some researchers that the BG method generally tends to greatly underestimate PLRT. It is also shown that the degree of underestimation/overestimation does not systematically change with changes in basic soil properties; suggesting that the differences between PLBG and PLRT are most likely random in nature. Compared to PLRT, the likelihood of achieving consistent soil classifications employing PLBG (along with the liquid limit) was shown to be 98%, with the identified discrepancies being cases that plot relatively close to the A-Line. As such, PLBG can be used with confidence for soil classification purposes.

Preliminary rolling noise measurements toward the design of a standard rolling noise device

The tapping machine has long existed as the primary standard method for measuring the performance of floors in buildings in response to structure-borne noise. However, other sources of structure-borne noise exist. One of these is rolling noise: such as a trolley rolling across the floor in an indoor building environment. Because the sound profile of indoor rolling noise is substantially different than that of impact noise, the techniques developed to reduce the latter may not necessarily be effective at reducing the former. To this end, a means of repeatably measuring indoor rolling noise is needed. Here the results of a study on indoor rolling noise are presented, identifying the various characteristics of this type of excitation which until now have been left unexplored. The proposal for a standard rolling device is also put forth: a machine which may be capable of characterizing a floor’s performance with regards to indoor rolling noise. A series of indoor rolling noise tests were conducted in order to characterize the range of sound profiles that various indoor rolling items are capable of producing, as well as identify how the different characteristics govern the shape of the sound profile produced. Just as the standard tapping machine assesses a floor’s performance in response to impact noise, a standard rolling machine may assess a floor’s performance in response to rolling noise.

Impact of Data Preparation in Freezing of Gait Detection Using Feature-Less Recurrent Neural Network

Many studies showed the feasibility of detecting Freezing of Gait (FOG) of Parkinson’s patients by using several numbers of inertial sensors worn on the body and in back-end computing power. This work uses machine learning approaches for analyzing the data of one single body-worn inertial sensor system to classify and detect FOG. Long-Short-Term-Memory (LSTM) is employed as the FOG detection algorithm and the Daphnet (FOG and normal gait) dataset provides the data for model training and testing in this paper. The model considers raw data from three channels of the acceleration sensor mounted on the patient’s shank and ignores all other data from other sensors. The model is patient dependent and uses sensitivity and specificity metrics to evaluate the model’s performance. In this paper, we propose a novel padding method that is applied to the windows of FOG and non-FOG with zero overlaps on the training set and adapts the padding to the individual regions. This method produces windows of only one type of data and label. The proposed padding method reduces the padding amount by two orders of magnitude compared to bigger batch sizes in the sequence splitting method offered by MATLAB 2019a. The padding amount is independent of the batch size. Raw data is fed to the model in the testing mode without any pre-processing or data transformation. The standard rolling window generates fixed-size windows for the test set without overlap and the higher amount of FOG or Normal walking data which defines the label of the individual window. The model for one-second long windows applied in this work outperformed the literature results with a sensitivity of 92.57% and a specificity of 95.62% compared to 82% and 94% reported by Masiala et al.

Driving cycle construction and combined driving cycle prediction for fuzzy energy management of electric vehicles

Energy management strategies (EMSs) play an important role in battery electric vehicles (BEVs). However, the efficiency of an EMS is significantly affected by the driving cycle (DC). On the one hand, because of the differences in driving type, torque characteristics, and speed response of BEVs differ from those of internal combustion-powered vehicles. Meanwhile, on the other hand, typical DCs that are widely used as evaluation indexes cannot reflect changes in the road slope and the driving characteristics of BEVs in a specific city. To solve this problem, a novel EMS based on combined DC prediction (CDCP) is proposed, and three efforts are made. First, a large volume of driving data is collected based on a BEV. The DC for a specific city is constructed using the principal component analysis and K-means cluster algorithm combined with 15 characteristic parameters of speed, acceleration, slope, and running state rate. Second, CDCP is adopted to overcome the disadvantage that the speed cannot be predicted initially using standard rolling prediction. The state transmission matrix based on the constructed DC is employed to predict the speed when the vehicle starts to run. Third, a fuzzy EMS that considers the CDCP is proposed in order to adapt to the real-time changes of DCs. Compared with the other predictions, the simulation results show that the proposed EMS has a longer driving range and lower energy consumption rate.

Behaviors of asphalt under certain aging levels and effects of rejuvenation

Aging has an undesirable effect on asphalt properties, which can be restored by rejuvenation. In this study, neat asphalt was aged by the standard rolling thin-film oven (RTFO) test with varying times to obtain asphalts at different levels of aging; these asphalts were then rejuvenated to their original penetration grade. Analysis of the asphalt fractions, Fourier-transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM) were employed to investigate the evolution of the distributions of SARA fractions, the functional groups, and the microstructures during aging and rejuvenation. Physical and rheological properties were tested to evaluate the pavement performance of the asphalts. The results showed that aging can convert the aromatics to resins and further to asphaltenes, and increase the carbonyl and sulfoxide contents due to oxidation. Consequently, the micelle number and proportion in the colloidal structure increased at the micro-scale, and the penetration and ductility decreased while the softening point increased at the macro-scale. These trends were more evident at increased aging levels. A rejuvenator with a high content of aromatics can adjust the fractions and dilute the aggregated micelles in aged asphalt, thus achieving the thermodynamically reversible process of the asphaltenes and resins being converted to saturates and aromatics; this balances the fraction distribution and restabilizes the colloidal structure. The performance-related properties were basically restored to their unaged levels. Comparing the results of the aged asphalts from the laboratory and field, the ductility and asphaltene content of the latter cannot be restored to their original level, though other properties can be, which indicates the complex service conditions of asphalt in the field.

Method of Speed Mode Correction of Rolling Pipes in the Reduction Mill

The article develops one of the main directions of improving the technology of pipe rolling on a reduction-stretching mill, in order to reduce the end crop. The article describes a speed adjustment technique of the reduction mill, when rolling the front end and back end of pipes, the length of which corresponds to the length of the thickness of ends of the finished pipe. A distinctive feature of the technique is the calculation of volume of the thickness end, which must be reduced by an adjusted value, when rolling the end area in the head stands. The sequence of technological calculations and the results of industrial testing of pipe reduction by standard rolling modes, and modes calculated by the proposed technique, are given. An analysis of the results of industrial testing showed the possibility of reducing the mass of the thickness ends by no less than 7%.

Исследование деформации обечайки с вафельным подкреплением при вальцевании и разработка метода компенсации отклонений формы

When the waffle panel of AMg6 alloy rolls into the cylindrical shell, a shape defect occurs. Manual elimination of this defect causes local irregularities on butt welded edges of the waffle shell. This leads to difficulties in the process of welding by friction welding with mixing of shells in the section of fuel tanks. It is necessary, on the basis of computer analysis and existing theories, to determine the stresses in the waffle shell that cause internal deformations that result in a general shape error, and to derive patterns under which external influence on the geometry of the mold at the time of bending is possible. The proposed campaign will make it possible to determine auxiliary technological elements for setting standard rolling equipment for defective rolling of wafer shells of missile fuel tanks with various geometric versions of reinforcements. It, in turn, will increase the efficiency of forming shells and the quality of welds when they are welded