Application of computer vision for roller operation management

Compaction is the last and possibly the most important phase in construction of asphalt concrete (AC) pavements. Compaction densifies the loose (AC) mat, producing a stable surface with low permeability. The process strongly affects the AC performance properties. Too much compaction may cause aggregate degradation and low air void content facilitating bleeding and rutting. On the other hand too little compaction may result in higher air void content facilitating oxidation and water permeability issues, rutting due to further densification by traffic and reduced fatigue life. Therefore, compaction is a critical issue in AC pavement construction.;The common practice for compacting a mat is to establish a roller pattern that determines the number of passes and coverages needed to achieve the desired density. Once the pattern is established, the roller\u27s operator must maintain the roller pattern uniformly over the entire mat.;Despite the importance of uniform compaction to achieve the expected durability and performance of AC pavements, having the roller operator as the only mean to manage the operation can involve human errors.;With the advancement of technology in recent years, the concept of intelligent compaction (IC) was developed to assist the roller operators and improve the construction quality. Commercial IC packages for construction rollers are available from different manufacturers. They can provide precise mapping of a roller\u27s location and provide the roller operator with feedback during the compaction process.;Although, the IC packages are able to track the roller passes with impressive results, there are also major hindrances. The high cost of acquisition and potential negative impact on productivity has inhibited implementation of IC.;This study applied computer vision technology to build a versatile and affordable system to count and map roller passes. An infrared camera is mounted on top of the roller to capture the operator view. Then, in a near real-time process, image features were extracted and tracked to estimate the incremental rotation and translation of the roller. Image featured are categorized into near and distant features based on the user defined horizon. The optical flow is estimated for near features located in the region below the horizon. The change in roller\u27s heading is constantly estimated from the distant features located in the sky region. Using the roller\u27s rotation angle, the incremental translation between two frames will be calculated from the optical flow. The roller\u27s incremental rotation and translation will put together to develop a tracking map.;During system development, it was noted that in environments with thermal uniformity, the background of the IR images exhibit less featured as compared to images captured with optical cameras which are insensitive to temperature. This issue is more significant overnight, since nature elements are not able to reflect the heat energy from sun. Therefore to improve roller\u27s heading estimation where less features are available in the sky region a unique methodology that allows heading detection based on the asphalt mat edges was developed for this research. The heading measurements based on the slope of the asphalt hot edges will be added to the pool of the headings measured from sky region. The median of all heading measurements will be used as the incremental roller\u27s rotation for the tracking analysis.;The record of tracking data is used for QC/QA purposes and verifying the proper implementation of the roller pattern throughout a job constructed under the roller pass specifications.;The system developed during this research was successful in mapping roller location for few projects tested. However the system should be independently validated

Paleoecology and Sedimentary Environments of the Oligo-Miocene Deposits of the Asmari Formation (Qeshm Island, SE Persian Gulf)

The Asmari Formation is composed of limestones, marly limestones, and marls, whose subsurface thickness in this region is about 148 m. Two assemblage zones have been recognized through the distribution of large foraminifera in the study area, indicating a Late Oligocene (Chattian)-Early Miocene (Aquitanian) age. The gradual facies changes and the lacking of turbiditic deposits show that the Asmari Formation was deposited in a carbonate ramp environment. Based on the depositional textures and petrographical studies, characterizing gradual shallowing upward trends of an open marine carbonate ramp, three distinct depositional settings have been recognized: lagoon, barrier, and open marine. MF1 was characterized by the occurrence of hyaline benthic and planktonic foraminifera representing distal middle ramp and below the storm wave base of other ramp. Paleolatitudinal reconstructions based on skeletal grains suggest that carbonate sedimentation of the Asmari Formation took place in tropical waters within the photic zone

Investigation of pouring temperature and holding time for semisolid metal feedstock production

Semisolid metal (SSM) processing, as a kind of new technology that exploits forming of alloys between solidus and liquidus temperatures, has attracted great attention from investigators for its thixotropic behaviour as well as having advantages in reducing porosity, macrosegregation, and forming forces during shaping process. Various techniques are employed to produce feedstock with fine globular microstructures, and direct thermal method is one of them. In this paper, the effect from different pouring temperatures and holding times using a direct thermal method on microstructure and hardness of aluminium alloy 6061 is presented. Molten aluminium alloy 6061 was poured into a cylindrical copper mould and cooled down to the semisolid temperature before being quenched in water at room temperature. The effect of different pouring temperatures of 660 °C, 680 °C, 700 °C, and holding time of 20 s, and 60 s on the microstructure of aluminium alloy 6061 were investigated. From the micrographs, it was found that the most globular structures were achieved at processing parameters of 660 °C pouring temperature and 60 s holding time. The highest density and hardness of the samples were found at the same processing parameters. It can be concluded that the most spheroidal microstructure, the highest density, and the hardness were recorded at lower pouring temperature and longer holding time

Nephroprotective effect of Gallic acid against mercuric chloride (HgCl2) induced damage in rats

Introduction: Mercury has hematotoxic, hepatotoxic, neurotoxic, nephrotoxic and genotoxic effects. Tissue damage induced by mercuric chloride (HgCl2) is associated with the promotion of oxidative stress. In this study, Gallic acid (GA), as potent antioxidant compound, was examined against mercuric chloride (HgCl2)-induced kidney injury in Wistar rats. Methods and Results: In this experimental study, animals were divided into five groups (n=7). Groups 1 and 2 respectively received normal saline (2 ml/kg, orally.) and HgCl2 (0.4 mg/kg, orally) for 28 consecutive days. Group 3 only received GA (200 mg/kg, orally) for 28 consecutive days. Groups 4 and 5 received orally GA at doses of 50 and 200 mg/kg, respectively, one hour after administration of HgCl2 for 28 consecutive days. Then On the 29th day, the rats were sacrificed, and blood samples were collected to determine biochemical parameters such as serum creatinine (Cr) and blood urea nitrogen (BUN) levels. For oxidative stress evaluation, malondialdehyde (MDA) and reduced glutathione (GSH) levels and also catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity were evaluated in left kidney tissue. The right kidney was used for histological examination. The results obtained from our study showed a significant increase in the levels of MDA, Cr and BUN, and decrease of GSH, CAT and SOD after ingestion of HgCl2 (p<0.05). Pre-treatment with GA showed diminished in the levels of MDA, Cr and BUN and enhanced of GSH, CAT, GPx and SOD activity (p<0.05). Additionally the nephroprotective effect of the GA was established by the histological evaluation of the kidneys. Conclusions: Our results indicate that GA has protective effect against HgCl2-induced renal damage probably by scavenging free radicals, reducing the oxidative stress, and increasing the antioxidant defense mechanism

Thermal analysis of 6061 wrought aluminium alloy using cooling curve analysis-computer aided (CCA-CA) method

The objective of this work was to investigate the effect of different cooling rates on microstructure and solidification parameters of 6061 wrought aluminium alloy. Wrought Al6061 were heated and melted at temperature of 800°C in a graphite crucible. A thermocouple was placed at the centre of molten under different conditions. Solidification characteristics are recognized from cooling curve and its first derivative curves which have been plotted using thermal analysis technique. In this study, molten were solidify in different airflow conditions. The results of thermal analysis show that the characteristics of Al6061 are influenced by cooling rate. The cooling rates in this experiment ranged from 1.3 to 2.4 °C/s and increasing the cooling rate affects the solidification parameters. Images of microstructures were taken to present its relation with cooling rates

Targeted Fluoromagnetic Nanoparticles for Imaging of Breast Cancer MCF-7 Cells

Purpose: To achieve simultaneous imaging and therapy potentials, targeted fluoromagnetic nanoparticles were synthesized and examined in human breast cancer MCF-7 cells. Methods: Fe3O4 nanoparticles (NPs) were synthesized through thermal decomposition of Fe(acac)3. Then, magnetic nanoparticles (MNPs) modified by dopamine-poly ethylene glycol (PEG)-NH2; finally, half equivalent fluorescein isothiocyanate (FITC) and half equivalent folic acid were conjugated to one equivalent of it. The presence of Fe3O4-DPA-PEG-FA/FITC in the folate receptor (FR) positive MCF-7 cells was determined via fluorescent microscopy to monitor the cellular interaction of MNPs. Results: FT-IR spectra of final compound confirmed existence of fluorescein on folic acid grafted MNPs. The Fe3O4-DPA-PEG-FA/FITC NPs, which displayed a size rang about 30-35 nm using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), were able to actively recognize the FR-positive MCF-7 cells, but not the FR-negative A549 cells. Conclusion: The uniform nano-sized Fe3O4-DPA-PEG-FA/FITC NPs displayed great potential as theranostics and can be used for targeted imaging of various tumors that overexpress FR

Viscosity measurements in semi-solid metal processing: Current status and recent developments

Semi-solid metal processing (SSMP) is an ideal method of producing high-quality products with fewer defects in casting technology. Viscosity is the most important physical and chemical property for the flow behaviour of the SSMP. Currently, there are several approaches, both theoretical and experimental, to evaluate the viscosity of semi-solid metals. This paper comprehensively reviews the single point and multi-point viscometry for SSMP. Features, similarities, and limitations ofdifferent viscometers for SSMP applications are then compared. The effect of influencing factors on the viscosity behaviour of SSMP is also highlighted. The importance of the non-dendritic globular microstructure and the instantaneous drop in viscosity caused by the scattering of solid particles during SSMP are explained. It is expected that the study will assist the researcher in identifying the best method of viscosity measurement during SSMP

Effect of degassing addition on the solidification of nickel aluminum bronze

The effect of degassing agent addition on the solidification of Nickel Aluminum Bronze was investigated. The complex relationship between the development of the alloy solidification and its thermal analysis in Nickel Aluminum Bronze was obtained by using data logger. This experiment describes the characterization of thermal analysis in Nickel Aluminum Bronze which was interpret using solidification cooling curve. With this method, the differences of temperature points during solidification were clearly evidenced. The results show a solidification cooling curve directly affected by percentage of degassing agent added in molten Nickel Aluminum Bronze alloy. There is distribution of temperature point after solidification from melting. As for degassing treatment, higher degassing addition on the Nickel Aluminum Bronze decreased the solidification temperature point