272 results on '"depth filter"'
Search Results
2. Leveraging mathematical models for optimizing filter utility at manufacturing scale.
- Author
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Rose, Steven, Dhingra, Ashna, Joseph, Adrian, and Coffman, Jon
- Abstract
In the production of biopharmaceuticals depth filters followed by sterile filters are often employed to remove residual cell debris present in the feed stream. In the back drop of a global pandemic, supply chains associated with the production of biopharmaceuticals have been constrained. These constraints have limited the available amount of depth filters for the manufacture of biologics. This has placed manufacturing facilities in a difficult position having to choose between running processes with reduced number of depth filters and risking a failed batch or the prospect of plants going into temporary shutdown until the depth filter resources are replenished. This communication describes a modeling based method that leverages manufacturing scale filtration data to predict the depth filter performance with a reduced number of filters and an increased operational flux. This method can be used to quantify the acceptable level of area reduction before which the filtration process performance is affected. This enables facilities to manage their filter inventory avoiding potential plant shutdowns and reduces the risks of negative depth filter performance. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Depth filter material process interaction in the harvest of mammalian cells.
- Author
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Parau, Maria, Pullen, James, and Bracewell, Daniel G.
- Subjects
HARVESTING ,MANUFACTURING processes ,DIATOMACEOUS earth ,CHO cell ,MASS transfer - Abstract
Upstream advances have led to increased mAb titers above 5 g/L in 14‐day fed‐batch cultures. This is accompanied by higher cell densities and process‐related impurities such as DNA and Host Cell Protein (HCP), which have caused challenges for downstream operations. Depth filtration remains a popular choice for harvesting CHO cell culture, and there is interest in utilizing these to remove process‐related impurities at the harvest stage. Operation of the harvest stage has also been shown to affect the performance of the Protein A chromatography step. In addition, manufacturers are looking to move away from natural materials such as cellulose and Diatomaceous Earth (DE) for better filter consistency and security of supply. Therefore, there is an increased need for further understanding and knowledge of depth filtration. This study investigates the effect of depth filter material and loading on the Protein A resin lifetime with an industrially relevant high cell density feed material (40 million cells/ml). It focuses on the retention of process‐related impurities such as DNA and HCP through breakthrough studies and a novel confocal microscopy method for imaging foulant in‐situ. An increase in loading of the primary‐synthetic filter by a third, led to earlier DNA breakthrough in the secondary filter, with DNA concentration at a throughput of 50 L/m2 being more than double. Confocal imaging of the depth filters showed that the foulant was pushed forward into the filter structure with higher loading. The additional two layers in the primary‐synthetic filter led to better pressure profiles in both primary and secondary filters but did not help to retain HCP or DNA. Reduced filtrate clarity, as measured by OD600, was 1.6 fold lower in the final filtrate where a synthetic filter train was used. This was also associated with precipitation in the Protein A column feed. Confocal imaging of resin after 100 cycles showed that DNA build‐up around the outside of the bead was associated with synthetic filter trains, leading to potential mass transfer problems. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. Recognition and Positioning of Fresh Tea Buds Using YOLOv4-lighted + ICBAM Model and RGB-D Sensing.
- Author
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Guo, Shudan, Yoon, Seung-Chul, Li, Lei, Wang, Wei, Zhuang, Hong, Wei, Chaojie, Liu, Yang, and Li, Yuwen
- Subjects
STEREO vision (Computer science) ,OBJECT recognition (Computer vision) ,BUDS ,STEREOSCOPIC cameras ,TEA ,RECOGNITION (Psychology) - Abstract
To overcome the low recognition accuracy, slow speed, and difficulty in locating the picking points of tea buds, this paper is concerned with the development of a deep learning method, based on the You Only Look Once Version 4 (YOLOv4) object detection algorithm, for the detection of tea buds and their picking points with tea-picking machines. The segmentation method, based on color and depth data from a stereo vision camera, is proposed to detect the shapes of tea buds in 2D and 3D spaces more accurately than using 2D images. The YOLOv4 deep learning model for object detection was modified to obtain a lightweight model with a shorter inference time, called YOLOv4-lighted. Then, Squeeze-and-Excitation Networks (SENet), Efficient Channel Attention (ECA), Convolutional Block Attention Module (CBAM), and improved CBAM (ICBAM) were added to the output layer of the feature extraction network, for improving the detection accuracy of tea features. Finally, the Path Aggregation Network (PANet) in the neck network was simplified to the Feature Pyramid Network (FPN). The light-weighted YOLOv4 with ICBAM, called YOLOv4-lighted + ICBAM, was determined as the optimal recognition model for the detection of tea buds in terms of accuracy (94.19%), recall (93.50%), F1 score (0.94), and average precision (97.29%). Compared with the baseline YOLOv4 model, the size of the YOLOv4-lighted + ICBAM model decreased by 75.18%, and the frame rate increased by 7.21%. In addition, the method for predicting the picking point of each detected tea bud was developed by segmentation of the tea buds in each detected bounding box, with filtering of each segment based on its depth from the camera. The test results showed that the average positioning success rate and the average positioning time were 87.10% and 0.12 s, respectively. In conclusion, the recognition and positioning method proposed in this paper provides a theoretical basis and method for the automatic picking of tea buds. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
5. Detection of Green Asparagus Using Improved Mask R-CNN for Automatic Harvesting.
- Author
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Liu, Xiangpeng, Wang, Danning, Li, Yani, Guan, Xiqiang, and Qin, Chengjin
- Subjects
- *
HARVESTING , *ASPARAGUS , *COMPUTER vision , *DEEP learning , *WEATHER - Abstract
Advancements in deep learning and computer vision have led to the discovery of numerous effective solutions to challenging problems in the field of agricultural automation. With the aim to improve the detection precision in the autonomous harvesting process of green asparagus, in this article, we proposed the DA-Mask RCNN model, which utilizes the depth information in the region proposal network. Firstly, the deep residual network and feature pyramid network were combined to form the backbone network. Secondly, the DA-Mask RCNN model added a depth filter to aid the softmax function in anchor classification. Afterwards, the region proposals were further processed by the detection head unit. The training and test images were mainly acquired from different regions in the basin of the Yangtze River. During the capturing process, various weather and illumination conditions were taken into account, including sunny weather, sunny but overshadowed conditions, cloudy weather, and daytime greenhouse conditions as well as nighttime greenhouse conditions. Performance experiments, comparison experiments, and ablation experiments were carried out using the five constructed datasets to verify the effectiveness of the proposed model. Precision, recall, and F1-score values were applied to evaluate the performances of different approaches. The overall experimental results demonstrate that the balance of the precision and speed of the proposed DA-Mask RCNN model outperform those of existing algorithms. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
6. Natural Zeolite for The Purification of Saline Groundwater and Irrigation Potential Analysis.
- Author
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Mkilima, Timoth, Devrishov, Davud, Assel, Kydyrbekova, Ubaidulayeva, Nurbala, Tleukulov, Almas, Khassenova, Alissa, Yussupova, Nargiza, and Birimzhanova, Dinara
- Subjects
- *
SALINE irrigation , *ZEOLITES , *WATER purification , *IRRIGATION water , *COLUMNS , *WATER filtration , *GROUNDWATER purification - Abstract
Groundwater is one of the main sources of water for irrigation used worldwide. However, the application of the resource is threatened by the possibility of high saline levels, especially in low-lying coastal regions. Furthermore, the lack of readily accessible materials for successful treatment procedures makes the purification of such water a constant challenge. Based on the fact that natural zeolite is one of the easily accessible and relatively cheap filter materials, this study examined the potential use of high-salinity groundwater filtered by natural zeolite for irrigation. Zeolite-filled filters at two different depths (0.5 m and 1 m) were studied. The samples were collected from the low-lying areas of Dar es Salaam City, Tanzania. The study observed that when the raw groundwater samples were exposed to the 0.5 m column depth, sodium (Na+) had the lowest removal efficiency at 40.2% and calcium (Ca2+) had the highest removal efficiency at 98.9%. On the other hand, magnesium (Mg2+) had the lowest removal efficiency, at about 61.2%, whereas potassium (K+) had up to about 99.7% removal efficiency from the 1 m column depth treatment system. Additionally, from the salinity hazard potential analysis, most of the samples fell within C4 (based on the electrical conductivity), which is a "very high salinity" class, and based on the quality it means the water cannot be directly applied for irrigation purposes. From the 0.5 m column depth, most of the samples fell within C3 (the "high salinity" class), and from the 1 m column depth most of the samples fell within C1 ("low salinity" class). The findings of this study offer some valuable insight into the prospective use of natural zeolite for the filtration of saline groundwater before its application for irrigation. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
7. The Realtime Indoor Localization Unmanned Aerial Vehicle
- Author
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Zhou, Yimin, Yu, Zhixiong, Ma, Zhuang, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Prates, Raquel Oliveira, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Sun, Fuchun, editor, Liu, Huaping, editor, and Fang, Bin, editor
- Published
- 2021
- Full Text
- View/download PDF
8. Recognition and Positioning of Fresh Tea Buds Using YOLOv4-lighted + ICBAM Model and RGB-D Sensing
- Author
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Shudan Guo, Seung-Chul Yoon, Lei Li, Wei Wang, Hong Zhuang, Chaojie Wei, Yang Liu, and Yuwen Li
- Subjects
tea buds ,YOLOv4 ,attention mechanism ,intelligent recognition ,depth filter ,picking point ,Agriculture (General) ,S1-972 - Abstract
To overcome the low recognition accuracy, slow speed, and difficulty in locating the picking points of tea buds, this paper is concerned with the development of a deep learning method, based on the You Only Look Once Version 4 (YOLOv4) object detection algorithm, for the detection of tea buds and their picking points with tea-picking machines. The segmentation method, based on color and depth data from a stereo vision camera, is proposed to detect the shapes of tea buds in 2D and 3D spaces more accurately than using 2D images. The YOLOv4 deep learning model for object detection was modified to obtain a lightweight model with a shorter inference time, called YOLOv4-lighted. Then, Squeeze-and-Excitation Networks (SENet), Efficient Channel Attention (ECA), Convolutional Block Attention Module (CBAM), and improved CBAM (ICBAM) were added to the output layer of the feature extraction network, for improving the detection accuracy of tea features. Finally, the Path Aggregation Network (PANet) in the neck network was simplified to the Feature Pyramid Network (FPN). The light-weighted YOLOv4 with ICBAM, called YOLOv4-lighted + ICBAM, was determined as the optimal recognition model for the detection of tea buds in terms of accuracy (94.19%), recall (93.50%), F1 score (0.94), and average precision (97.29%). Compared with the baseline YOLOv4 model, the size of the YOLOv4-lighted + ICBAM model decreased by 75.18%, and the frame rate increased by 7.21%. In addition, the method for predicting the picking point of each detected tea bud was developed by segmentation of the tea buds in each detected bounding box, with filtering of each segment based on its depth from the camera. The test results showed that the average positioning success rate and the average positioning time were 87.10% and 0.12 s, respectively. In conclusion, the recognition and positioning method proposed in this paper provides a theoretical basis and method for the automatic picking of tea buds.
- Published
- 2023
- Full Text
- View/download PDF
9. Analysis of fouling and breakthrough of process related impurities during depth filtration using confocal microscopy.
- Author
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Parau, Maria, Johnson, Thomas F., Pullen, James, and Bracewell, Daniel G.
- Subjects
CONFOCAL microscopy ,DIATOMACEOUS earth ,FOULING ,CELL culture ,CELL survival - Abstract
Titer improvement has driven process intensification in mAb manufacture. However, this has come with the drawback of high cell densities and associated process related impurities such as cell debris, host cell protein (HCP), and DNA. This affects the capacity of depth filters and can lead to carryover of impurities to protein A chromatography leading to early resin fouling. New depth filter materials provide the opportunity to remove more process related impurities at this early stage in the process. Hence, there is a need to understand the mechanism of impurity removal within these filters. In this work, the secondary depth filter Millistak+ X0HC (cellulose and diatomaceous earth) is compared with the X0SP (synthetic), by examining the breakthrough of DNA and HCP. Additionally, a novel method was developed to image the location of key impurities within the depth filter structure under a confocal microscope. Flux, tested at 75, 100, and 250 LMH was found to affect the maximal throughput based on the max pressure of 30 psi, but no significant changes were seen in the HCP and DNA breakthrough. However, a drop in cell culture viability, from 87% to 37%, lead to the DNA breakthrough at 10% decreasing from 81 to 55 L/m2 for X0HC and from 105 to 47 L/m2 for X0SP. The HCP breakthrough was not affected by cell culture viability or filter type. The X0SP filter has a 30%–50% higher max throughput depending on viability, which can be explained by the confocal imaging where the debris and DNA are distributed differently in the layers of the filter pods, with more of the second tighter layer being utilized in the X0SP. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
10. SDF-SLAM: Semantic Depth Filter SLAM for Dynamic Environments
- Author
-
Linyan Cui and Chaowei Ma
- Subjects
Dynamic scenes ,depth filter ,semantic segmentation ,simultaneous localization and mapping ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Simultaneous Localization and Mapping (SLAM) has been widely applied in computer vision and robotics. For the dynamic environments which are very common in the real word, traditional visual SLAM system faces significant drop in localization and mapping accuracy due to the static world assumption. Recently, the semantic visual SLAM systems towards dynamic scenes have gradually attracted more and more attentions, which use the semantic information of images to help remove dynamic feature points. Existing semantic visual SLAM systems commonly detect the dynamic feature points by the semantic prior, geometry constraint or the combine of them, then map points corresponding to dynamic feature points are removed. In the visual SLAM framework, pose calculation is essentially around the 3D map points, so the essence of improving the accuracy of visual SLAM system is to build a more accurate and reliable map. These existing semantic visual SLAM systems are actually adopting an indirect way to acquire reliable map points, and several drawbacks exist. In this paper, we present SDF-SLAM: Semantic Depth Filter SLAM, a visual semantic SLAM system towards dynamic environments, which utilizes the technology of depth filter to directly judge whether a 3D map point is dynamic or not. First, the semantic information is integrated into the original pure geometry SLAM system by the semantic optical flow method to perform reliable map initialization. Second, design the semantic depth filter that satisfies the Gaussian Uniform mixture distribution to describe the inverse depth of each map point. Third, updating the inverse depth of 3D map point in a Bayesian estimation framework, and dividing the 3D map point into active one or inactive one. Last, only the active map points are utilized to achieve robust camera pose tracking. Experiments on TUM dataset demonstrate that our approach outperforms original ORB-SLAM2 and other state-of-the-art semantic SLAM systems.
- Published
- 2020
- Full Text
- View/download PDF
11. Detection of Green Asparagus Using Improved Mask R-CNN for Automatic Harvesting
- Author
-
Xiangpeng Liu, Danning Wang, Yani Li, Xiqiang Guan, and Chengjin Qin
- Subjects
agricultural automation ,green asparagus detection ,DA-Mask RCNN ,depth filter ,different weather ,illumination conditions ,Chemical technology ,TP1-1185 - Abstract
Advancements in deep learning and computer vision have led to the discovery of numerous effective solutions to challenging problems in the field of agricultural automation. With the aim to improve the detection precision in the autonomous harvesting process of green asparagus, in this article, we proposed the DA-Mask RCNN model, which utilizes the depth information in the region proposal network. Firstly, the deep residual network and feature pyramid network were combined to form the backbone network. Secondly, the DA-Mask RCNN model added a depth filter to aid the softmax function in anchor classification. Afterwards, the region proposals were further processed by the detection head unit. The training and test images were mainly acquired from different regions in the basin of the Yangtze River. During the capturing process, various weather and illumination conditions were taken into account, including sunny weather, sunny but overshadowed conditions, cloudy weather, and daytime greenhouse conditions as well as nighttime greenhouse conditions. Performance experiments, comparison experiments, and ablation experiments were carried out using the five constructed datasets to verify the effectiveness of the proposed model. Precision, recall, and F1-score values were applied to evaluate the performances of different approaches. The overall experimental results demonstrate that the balance of the precision and speed of the proposed DA-Mask RCNN model outperform those of existing algorithms.
- Published
- 2022
- Full Text
- View/download PDF
12. Natural Zeolite for The Purification of Saline Groundwater and Irrigation Potential Analysis
- Author
-
Timoth Mkilima, Davud Devrishov, Kydyrbekova Assel, Nurbala Ubaidulayeva, Almas Tleukulov, Alissa Khassenova, Nargiza Yussupova, and Dinara Birimzhanova
- Subjects
groundwater ,salinity ,sodium adsorption ratio ,depth filter ,natural zeolite ,Organic chemistry ,QD241-441 - Abstract
Groundwater is one of the main sources of water for irrigation used worldwide. However, the application of the resource is threatened by the possibility of high saline levels, especially in low-lying coastal regions. Furthermore, the lack of readily accessible materials for successful treatment procedures makes the purification of such water a constant challenge. Based on the fact that natural zeolite is one of the easily accessible and relatively cheap filter materials, this study examined the potential use of high-salinity groundwater filtered by natural zeolite for irrigation. Zeolite-filled filters at two different depths (0.5 m and 1 m) were studied. The samples were collected from the low-lying areas of Dar es Salaam City, Tanzania. The study observed that when the raw groundwater samples were exposed to the 0.5 m column depth, sodium (Na+) had the lowest removal efficiency at 40.2% and calcium (Ca2+) had the highest removal efficiency at 98.9%. On the other hand, magnesium (Mg2+) had the lowest removal efficiency, at about 61.2%, whereas potassium (K+) had up to about 99.7% removal efficiency from the 1 m column depth treatment system. Additionally, from the salinity hazard potential analysis, most of the samples fell within C4 (based on the electrical conductivity), which is a “very high salinity” class, and based on the quality it means the water cannot be directly applied for irrigation purposes. From the 0.5 m column depth, most of the samples fell within C3 (the “high salinity” class), and from the 1 m column depth most of the samples fell within C1 (“low salinity” class). The findings of this study offer some valuable insight into the prospective use of natural zeolite for the filtration of saline groundwater before its application for irrigation.
- Published
- 2022
- Full Text
- View/download PDF
13. Dense point cloud map construction based on stereo VINS for mobile vehicles.
- Author
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Wen, Shuhuan, Liu, Xin, Zhang, Hong, Sun, Fuchun, Sheng, Miao, and Fan, Shaokang
- Subjects
- *
POINT cloud , *OPTICAL flow , *STEREOSCOPIC cameras , *CAMERA movement , *ALGORITHMS , *AIR filters - Abstract
[Display omitted] • We implement more accurate optical flow tracking by the assistance of IMU. We use the rotated tracked points obtained by an IMU to initialize the estimation of the optical flow, and this can improve the reliability of the initial feature points. To obtain accurate feature matching, a stereo baseline constraint and ring matching are used to remove outlier points. The experiments show that the information fused with a stereo camera and an IMU achieves real-time optical flow tracking and more accurate feature matching than the LK optical flow method. Compared with the feature matching method in ORB-SLAM3, the proposed method is more lightweight and faster. • We develop a high-precision SLAM framework that integrates stereo vision and an IMU to tackle the problem of pose inaccuracy that results from the fast movement of a stereo camera and insufficient view overlap between frames. We build a new objective function based on VINS to reduce the complexity of the computation. We adopt a sliding window to ensure the real time performance of the system, and the marginalized information is added as a prior in the objective function. The experimental results demonstrate that the localization accuracy of the proposed SLAM framework is better than that of OKVIS, VINS-Mono and VINS-Fusion. • We propose a fast method for constructing dense point maps to estimate depth values based on stereo vision and an IMU. The depth value computed by SGBM (semi-global block matching) is regarded as the initial value to update the depth of the deep filter, which can improve the convergence rate. We further adopt the TSDF (truncated signed distance function) to fuse the depth images obtained by stereo matching and build a dense map. The experiments show that the proposed stereo dense reconstruction method can obtain a deeper image, less convergence time for the estimated picture and fewer updating frames than the REMODE (probabilistic, monocular dense reconstruction) method. Mobile vehicles require accurate localization and dense mapping for motion planning. In this paper, we propose a dense map construction algorithm based on a light-and-fast stereo visual-inertial navigation system (VINS). A tightly coupled nonlinear optimization method is used to calculate the position of adjacent keyframes. An optical flow tracking method fused with IMU information and ring matching constraints is used to improve the matching accuracy and speed of the feature points. In addition, we obtain the pose and depth values using the semi-global block matching (SGBM) method, which are used as the initial values of the depth filter to update the depth image and improve the convergence speed. Then, we further use the Truncated Signed Distance Function (TSDF) method to construct the dense map. We compare our algorithm with state-of-the-art algorithms on the EuRoc dataset and then compare the estimated depth image using the proposed algorithm and the point cloud construction with the probabilistic monocular dense reconstruction (REMODE). The experiments show that the proposed algorithm can obtain more accurate localization than VINS and OKVIS, as well as a faster tracking speed, a better depth map, a lower convergence time for the estimated image and a lower number of updated frames than REMODE. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
14. Manufacturing of Proteins and Antibodies: Chapter Downstream Processing Technologies
- Author
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Turner, Richard, Joseph, Adrian, Titchener-Hooker, Nigel, Bender, Jean, Belkin, Shimshon, Editorial Board Member, Bley, Thomas, Editorial Board Member, Bohlmann, Jörg, Editorial Board Member, Gu, Man Bock, Editorial Board Member, Hu, Wei Shou, Editorial Board Member, Mattiasson, Bo, Editorial Board Member, Seitz, Harald, Editorial Board Member, Zeng, An-Ping, Editorial Board Member, Zhong, Jian-Jiang, Editorial Board Member, Kiss, Bob, editor, Gottschalk, Uwe, editor, and Pohlscheidt, Michael, editor
- Published
- 2018
- Full Text
- View/download PDF
15. Faster R–CNN–based apple detection in dense-foliage fruiting-wall trees using RGB and depth features for robotic harvesting.
- Author
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Fu, Longsheng, Majeed, Yaqoob, Zhang, Xin, Karkee, Manoj, and Zhang, Qin
- Subjects
- *
COMPUTER vision , *APPLES , *APPLE orchards , *CONVOLUTIONAL neural networks , *ROBOTICS , *FRUIT trees , *ORCHARDS , *VISION - Abstract
Apples in modern orchards with vertical-fruiting-wall trees are comparatively easier to harvest and specifically suitable for robotic picking, where accurate apple detection and obstacle-free access are fundamentally important. However, field images have complex backgrounds because of the presence of nontarget trees and fruit in adjacent rows. An outdoor machine vision system was developed with a low-cost Kinect V2 sensor to improve the accuracy of apple detection by filtering the background objects using depth features. A total of 800 set images were acquired in a commercial fruiting-wall Scifresh apple orchard with dense-foliage canopy. Images were collected in both daytime and nighttime with artificial light. The sensor was kept at 0.5 m to the tree canopies. A depth threshold of 1.2 m was used to remove background. Two Faster R–CNN based architectures ZFNet and VGG16 were employed to detect the Original-RGB and the Foreground-RGB images. Results showed that the highest average precision (AP) of 0.893 was achieved for the Foreground-RGB images with VGG16, which cost 0.181 s on average to process a 1920 × 1080 image. AP values for the Foreground-RGB images with ZFNet and VGG16 were both higher than those of the Original-RGB images. The results indicated that the use of a depth filter to remove background trees improved fruit detection accuracy by 2.5% and that only a minimal difference was found in processing speed between two image datasets. The proposed technique and results are expected to be applicable for robotic harvesting on fruiting-wall apple orchards. • An RGB-D sensor (Kinect v2) was applied to filter background using depth features. • Apples in dense-foliage fruiting wall tree were detected by ZFNet and VGG16. • The highest average precision of 0.893 achieved on depth filtered images with VGG16. • Using depth-filter to remove background improved fruit detection accuracy by 2.5%. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
16. A Confidence Weighted Real-Time Depth Filter for 3D Reconstruction
- Author
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Shao, Zhenzhou, Shi, Zhiping, Qu, Ying, Guan, Yong, Wei, Hongxing, Tan, Jindong, Rannenberg, Kai, Editor-in-chief, Sakarovitch, Jacques, Series editor, Goedicke, Michael, Series editor, Tatnall, Arthur, Series editor, Neuhold, Erich J., Series editor, Pras, Aiko, Series editor, Tröltzsch, Fredi, Series editor, Pries-Heje, Jan, Series editor, Whitehouse, Diane, Series editor, Reis, Ricardo, Series editor, Furnell, Steven, Series editor, Furbach, Ulrich, Series editor, Gulliksen, Jan, Series editor, Rauterberg, Matthias, Series editor, Shi, Zhongzhi, editor, Vadera, Sunil, editor, and Li, Gang, editor
- Published
- 2016
- Full Text
- View/download PDF
17. CONTROL SYSTEM OF A TEST RIG FOR THE PRE-TREATMENT OF WATER USING DEPTH FILTERS.
- Author
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WOJUTYŃSKI, Jacek, SICZEK, Mariusz, STANISŁAWEK, Ewa, and KOWALIK-KLIMCZAK, Anna
- Subjects
TESTING equipment ,WATER purification equipment ,WASTEWATER treatment ,SEPARATION (Technology) ,FILTERS & filtration - Abstract
Copyright of Journal of Machine Construction & Maintenance is the property of Institute for Sustainable Technologies - National Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2019
18. A critical review on cleanroom filtration
- Author
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Monica Puri Sikka and Mandira Mondal
- Subjects
Pollutant ,Materials science ,business.industry ,Materials Science (miscellaneous) ,Airflow ,Industrial and Manufacturing Engineering ,law.invention ,Indoor air quality ,law ,Cleanroom ,Management of Technology and Innovation ,Depth filter ,Business and International Management ,Process engineering ,business ,Air quality index ,Filtration ,Air filter - Abstract
Purpose Cleanrooms are highly controlled enclosed rooms where air quality is monitored and ensured to have less contamination according to standard cleanliness level. Air filters are used to optimize indoor air quality and remove air pollutants. Filter media and filtering system are decided as per requirement. Depth filter media are mostly used in cleanroom filtrations. This paper aims to present a comprehensive review of the evolution of cleanroom filter media. It evaluates the advantages and disadvantages of air filter media. It is also studied which air filters have additional properties such as anti-microbial properties, anti-odour properties and chemical absorbent. Development and innovation of air filters and filtration techniques are necessary to improve the performance via the synergistic effect and it can be a possible avenue of future research. Design/methodology/approach This paper aims to drive the future of air filter research and development in achieving high-performance filtration with high filtration efficiency, low operational cost and high durability. Air pollutants are classified into three types: suspended particles, volatile organic pollutants and microorganisms. Technologies involved in purification are filtration, water washing purification, electrostatic precipitation and anion technology. They purify the air by running it through a filter medium that traps dust, hair, pet fur and debris. As air passes through the filter media, they function as a sieve, capturing particles. The fibres in the filter medium provide a winding path for airflow. There are different types of air filters such as the high-efficiency particulate air filter, fibreglass air filter and ultra-low particulate air filter. Findings Emerging filtration technologies and filters such as nanofibres, filters with polytetrafluoroethylene membrane are likely to become prevalent over the coming years globally. The introduction of indoor air filtration with thermal comfort can be a possible avenue of future research along with expanding indoor environment monitoring and improving air quality predictions. New air filters and filtration technologies having better performance with low cost and high durability must be developed which can restrict multiple types of pollutants at the same time. Originality/value The systematic literature review approach used in this paper highlights the emerging trends and issues in cleanroom filtration in a structured and thematic manner, enabling future work to progress as it will continue to develop and evolve.
- Published
- 2021
19. Engineering cellulose fibre inorganic composites for depth filtration and adsorption.
- Author
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Onur, Aysu, Ng, Aaron, Garnier, Gil, and Batchelor, Warren
- Subjects
- *
CELLULOSE , *ENGINEERING , *POLYAMIDES , *EPICHLOROHYDRIN , *PORE size distribution - Abstract
Depth type composite filters are porous materials heavily loaded with adsorbents and can remove contaminants from liquids by combining mechanical entrapment and adsorption. There is still a need for developing high performance filters by controlling the internal structure at micro and nano level. In this study, highly fibrillated nanocellulose (NC) with increased surface area was used as partial substitute for the fibre matrix to tailor the filter structure as well as the adsorption and filtration performance. Polyamide-amine-epichlorohydrin (PAE) was added both to adjust the charge of medium and provide wet strength. Filters were fabricated by embedding perlite particles into the cellulose fibre matrix by papermaking technique. The structure of composites was characterized for pore size distribution and surface morphology. Adsorption and filtration characteristics were quantified using two model dyes and silicon dioxide particles. Adsorption was found to be electrostatically controlled and dependent on the charge of the dye molecules and the filter medium. The addition of NC doubled the removal of a cationic dye by increasing the surface area and the available negative charges; it however decreased the removal of an anionic dye by 75%. PAE addition decreased the adsorption of the cationic methylene blue dye, while increasing the adsorption of the anionic metanil yellow dye. Rejection by filtration of 1 µm particles was over 90% for all filters. This study demonstrates that highly fibrillated NC fibres combined with a cationic wet strength polyelectrolyte can be used to tailor the filter structure and properties. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
20. Multi-layered nonwoven filter media for capture of nanoparticles in HVAC systems
- Author
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Young-Ok Park, Kwang-Deuk Kim, and Naim Hasolli
- Subjects
business.product_category ,Materials science ,General Chemical Engineering ,Nanoparticle ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,law.invention ,Aerosol ,Sphere packing ,020401 chemical engineering ,law ,Depth filter ,Microfiber ,Fiber ,Particle size ,0204 chemical engineering ,Composite material ,0210 nano-technology ,business ,Filtration - Abstract
Two samples of multi-layered depth filter media and single layers were prepared for this study. Filtration performance of these samples was evaluated using lab scale test unit with KCl as test aerosol. Filter media samples were composed of three layers, two of them of meltblown fiber layers and one of thermal-bonded microfiber layer. A commercial filter media was used as reference sample to compare the filtration performance. Quality factors were calculated in addition to evaluate the overall filtration performance of the new composite filter media. The results indicate a satisfactory filtration efficiency of the media M2U, over 90% for the studied particle size range. Compared to reference media, new media M2U shows better performance, especially for the particle size greater than 50 nm. Charged (M2U) and uncharged (M2U-2) composite media were tested and results compared with theory calculations. Due to upstream layer of high packing density, the loading tests reveal a tendency of clogging for media M2U. Both media, M1U and M2U, exhibit better filtration performance compared to the reference media RefM and could be applied for collection of nanoparticles in HVAC system by replacing the high grade efficiency filters.
- Published
- 2021
21. Robust multivariate estimation based on statistical depth filters
- Author
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Claudio Agostinelli and Giovanni Saraceno
- Subjects
Statistics and Probability ,Multivariate statistics ,Mathematics - Statistics Theory ,Statistics Theory (math.ST) ,62G35 62G05 ,01 natural sciences ,010104 statistics & probability ,Case-wise contamination ,Dimension (vector space) ,0502 economics and business ,Statistics ,FOS: Mathematics ,0101 mathematics ,Statistical depth functions ,050205 econometrics ,Mathematics ,05 social sciences ,Robust statistics ,Filters ,Filter (signal processing) ,Contamination ,Missing data ,Cell-wise contamination ,Data set ,Outlier ,Depth filter ,Statistics, Probability and Uncertainty - Abstract
In the classical contamination models, such as the gross-error (Huber and Tukey contamination model or Case-wise Contamination), observations are considered as the units to be identified as outliers or not. This model is very useful when the number of considered variables is moderately small. Alqallaf et al. [2009] shows the limits of this approach for a larger number of variables and introduced the Independent contamination model (Cell-wise Contamination) where now the cells are the units to be identified as outliers or not. One approach to deal, at the same time, with both type of contamination is filter out the contaminated cells from the data set and then apply a robust procedure able to handle case-wise outliers and missing values. Here we develop a general framework to build filters in any dimension based on statistical data depth functions. We show that previous approaches, e.g. Agostinelli et al. [2015a] and Leung et al. [2017], are special cases. We illustrate our method by using the half-space depth., Comment: 25 pages, 11 figures. TEST (2021)
- Published
- 2021
22. New application of depth filters for the immobilization of Candida antarctica lipase B.
- Author
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Schreiber, Sarah, Scheper, Thomas, Beutel, Sascha, Thiefes, Axel, Schuldt, Ute, and Dähne, Lars
- Subjects
- *
LIPASE biotechnology , *CANDIDA , *IMMOBILIZED enzymes , *FILTERS & filtration , *POLYANIONS - Abstract
The objective of this study was to use for the first time depth filters, which are usually intended for clarification of cell culture broth, as a direct immobilization support/matrix for industrially relevant enzymes. With this method, it is not only possible to immobilize pure enzymes; it can be also used for capturing recombinant enzymes directly out of culture supernatant. Therefore, the depth filters were coated with different anionic and cationic polymer layers by Layer-by-Layer (LbL) technology. The immobilization behavior of the model enzyme Candida antarctica lipase B (CalB) was examined. Optimal conditions for lipase immobilization were found for anionic surfaces with Poly (allylamin hydrochlorid) (PAH)/Poly (sodium-4-styrene sulfonate) (PSS) coating in 20 mM acetate buffer pH 4. Stability studies showed that immobilized CalB is 1.7-fold more stable when storage is carried out in buffer at 4 °C, compared to storage in buffer at room temperature or storage after drying at 30 °C for 24 h. The calculated half-life period is 108 days until half of the activity was lost. Furthermore, the possibility of direct capture of the CalB either from sonicated culture broth ( Escherichia coli) or from cell-free supernatant was tested. Filter blocking prevented the immobilization of lipase from sonicated culture broth, but immobilization from cell-free supernatant could be performed successfully at moderate biomass content (OD = 7.0). [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
23. Ash depth filter sanitation eliminates all bacteria and makes source-separated urine waste sterile
- Author
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Sarah Copley, Theppawut Israsena Na Ayudhya, Michael Witty, Raja Al-Bahou, and Nin N. Dingra
- Subjects
Sanitation ,Waste management ,biology ,Depth filter ,Public Health, Environmental and Occupational Health ,Environmental science ,Urine ,Development ,biology.organism_classification ,Pollution ,Waste Management and Disposal ,Bacteria ,Water Science and Technology - Abstract
Remote houses cannot use sewerage systems and so they must make their own arrangements for waste disposal. A solution is the use of ash depth filters which simultaneously trap nitrogen and phosphorus from human waste streams and all bacteria during long periods (750 ml per day for more than 6 weeks) of operation by filtration under gravity. Bacteria entering the filtration system, those trapped by the filter and the living material which eventually emerges if the system is operated till it eventually fails, are characterized. Reduction of bacterial numbers is achieved by two mechanisms: physical filtration and chemical sanitation.
- Published
- 2020
24. Novel combinatorial extensions to breakthrough curve modeling of an adsorption column — Depth filtration hybrid process
- Author
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Ehsan Salehi, Yaser Darvishi, and Mahdi Askari
- Subjects
Work (thermodynamics) ,General Chemical Engineering ,02 engineering and technology ,Mechanics ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Volumetric flow rate ,Adsorption ,law ,Filter (video) ,Hybrid system ,Depth filter ,0210 nano-technology ,Filtration ,Mathematics ,Concentration polarization - Abstract
This work introduces novel scenarios for the breakthrough curve modeling of an adsorption column/depth filtration hybrid system. Four well-known theoretical breakthrough models including Thomas, Adams–Bohart, Yoon–Nelson, and BDST were employed to describe the normalized concentration profiles. In the first approach, the theoretical models were combined for better estimation of the breakthrough curves and the Thomas/Yoon–Nelson and Thomas/BDST combinations were obtained as the best extensions. In the second approach, an adsorption-transport model was developed for the depth filter to obtain the transient concentration gradient across the filter medium thickness. The model was then combined with the theoretical breakthrough models to predict the adsorption column breakthrough curves. Results revealed that a decrease in the feed flowrate and filter pore size could intensify the concentration polarization on the filter surface. Both model extensions could successfully approximate the breakthrough curves of the hybrid system with more than 99% agreement with the experimental data, while the prediction accuracy of the original breakthrough models seldom exceeds 93%.
- Published
- 2020
25. Facile and simultaneous separation of nitrogen, phosphorus and bacteria from urine by using ash depth filters which harvest ammonium and phosphate as Struvite Enriched Ash
- Author
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Michael Witty, Nin N. Dingra, Raja Al-Bahou, Theppawut Israsena Na Ayudhya, and Sarah Copley
- Subjects
Chromatography ,biology ,Chemistry ,Public Health, Environmental and Occupational Health ,Urine ,Development ,biology.organism_classification ,Phosphate ,Pollution ,Nitrogen phosphorus ,chemistry.chemical_compound ,Struvite ,Depth filter ,Ammonium ,Waste Management and Disposal ,Bacteria ,Water Science and Technology - Abstract
Ash depth filters were developed which can simultaneously remove nitrogen, phosphorus and bacteria from human waste streams while simultaneously maintaining a flow rate which is acceptable for domestic use processing urine from one individual for 1 month if the filter bed has a volume of approximately 3 l. Nitrogen and phosphorus depletion is achieved by the formation of Struvite Enriched Ash, which can subsequently be used as a slow-release garden fertilizer. Depth filtration and sanitation by high pH removed all detectable bacteria from this home-based system.
- Published
- 2020
26. SDF-SLAM: Semantic Depth Filter SLAM for Dynamic Environments
- Author
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Chaowei Ma and Linyan Cui
- Subjects
0209 industrial biotechnology ,General Computer Science ,Computer science ,Feature extraction ,Optical flow ,Initialization ,02 engineering and technology ,Simultaneous localization and mapping ,Semantics ,020901 industrial engineering & automation ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,Point (geometry) ,Computer vision ,depth filter ,business.industry ,General Engineering ,Dynamic scenes ,semantic segmentation ,Visualization ,020201 artificial intelligence & image processing ,Artificial intelligence ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,business ,lcsh:TK1-9971 ,simultaneous localization and mapping - Abstract
Simultaneous Localization and Mapping (SLAM) has been widely applied in computer vision and robotics. For the dynamic environments which are very common in the real word, traditional visual SLAM system faces significant drop in localization and mapping accuracy due to the static world assumption. Recently, the semantic visual SLAM systems towards dynamic scenes have gradually attracted more and more attentions, which use the semantic information of images to help remove dynamic feature points. Existing semantic visual SLAM systems commonly detect the dynamic feature points by the semantic prior, geometry constraint or the combine of them, then map points corresponding to dynamic feature points are removed. In the visual SLAM framework, pose calculation is essentially around the 3D map points, so the essence of improving the accuracy of visual SLAM system is to build a more accurate and reliable map. These existing semantic visual SLAM systems are actually adopting an indirect way to acquire reliable map points, and several drawbacks exist. In this paper, we present SDF-SLAM: Semantic Depth Filter SLAM, a visual semantic SLAM system towards dynamic environments, which utilizes the technology of depth filter to directly judge whether a 3D map point is dynamic or not. First, the semantic information is integrated into the original pure geometry SLAM system by the semantic optical flow method to perform reliable map initialization. Second, design the semantic depth filter that satisfies the Gaussian Uniform mixture distribution to describe the inverse depth of each map point. Third, updating the inverse depth of 3D map point in a Bayesian estimation framework, and dividing the 3D map point into active one or inactive one. Last, only the active map points are utilized to achieve robust camera pose tracking. Experiments on TUM dataset demonstrate that our approach outperforms original ORB-SLAM2 and other state-of-the-art semantic SLAM systems.
- Published
- 2020
27. Impact of micro and macroporous TFF membranes on product sieving and chromatography loading for perfusion cell culture
- Author
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Nuno D.S. Pinto, William N. Napoli, and Mark Brower
- Subjects
0106 biological sciences ,0301 basic medicine ,Cell Culture Techniques ,Bioengineering ,CHO Cells ,01 natural sciences ,Applied Microbiology and Biotechnology ,law.invention ,Cross-flow filtration ,03 medical and health sciences ,Bioreactors ,Cricetulus ,law ,Cricetinae ,010608 biotechnology ,Bioreactor ,Animals ,Filtration ,Chromatography ,Chemistry ,Antibodies, Monoclonal ,Membranes, Artificial ,Equipment Design ,Microporous material ,Permeation ,030104 developmental biology ,Membrane ,Depth filter ,Chromatography column ,Chromatography, Liquid ,Biotechnology - Abstract
Bioprocess intensification can be achieved through high cell density perfusion cell culture with continuous protein capture integration. Protein passage and cell retention are commonly accomplished using tangential flow filtration systems consisting of microporous membranes. Significant challenges, including low efficiency and decaying product sieving over time, are commonly observed in these cell retention devices. Here, we demonstrate that a macroporous membrane overcomes the product sieving challenges when comparing to several other membrane chemistries and pore sizes within the microporous range. This way, variable chromatography column loading is avoided. The macroporous membrane yielded a 13,000 L/m2 volumetric throughput. The membrane's cut-off size results in an increased permeate turbidity due to particles passage, such as cell debris, through pores ranging from 1 to 4 µm. In addition, successful chromatography column plugging mitigation was achieved by employing depth filtration before the chromatographic step. Depth filtration volumetric throughputs were between 600 and 1,000 L/m2 . Combing a macroporous cell retention device with a depth filter not only provided an alternative to address the challenge of undesired long protein residence times in the bioreactor due to product sieving decay, but also exhibited a throughput increase, making the integration of multicolumn capture chromatography with a perfusion cell culture a more robust process.
- Published
- 2019
28. Mechanisms of Leukodepletion by Filtration
- Author
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Steneker, Ingeborg, Pietersz, Ruby N. I., Reesink, Henk W., Sweeney, Joseph, and Heaton, Andrew
- Published
- 1995
- Full Text
- View/download PDF
29. Regulatory Issues for Bioaerosols
- Author
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Sayre, Philip, Burckle, John, Macek, Gregory, LaVeck, Gerald, Lighthart, Bruce, editor, and Mohr, Alan Jeff, editor
- Published
- 1994
- Full Text
- View/download PDF
30. Investigating the Influence of Column Depth on the Treatment of Textile Wastewater Using Natural Zeolite
- Author
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Ubaidulayeva Nurbala, Lyazzat Tastanova, Kulyash Meiramkulova, Mansur B. Khusainov, Abdilda Meirbekov, Nurgul Nurmukhanbetova, Timoth Mkilima, Amanbek Zandybay, and Toghan Mashan
- Subjects
textile production contaminants ,Pharmaceutical Science ,Organic chemistry ,natural zeolite ,textile wastewater treatment ,depth filtration ,water quality ,Article ,Analytical Chemistry ,law.invention ,QD241-441 ,law ,Drug Discovery ,Physical and Theoretical Chemistry ,Filtration ,Total suspended solids ,Chemical oxygen demand ,Total dissolved solids ,Pulp and paper industry ,Filter (aquarium) ,Wastewater ,Chemistry (miscellaneous) ,Depth filter ,Molecular Medicine ,Environmental science ,Sewage treatment - Abstract
Textile industry production processes generate one of the most highly polluted wastewaters in the world. Unfortunately, the field is also challenged by the availability of relatively cheap and highly effective technologies for wastewater purification. The application of natural zeolite as a depth filter offers an alternative and potential approach for textile wastewater treatment. The performance of a depth filter treatment system can be deeply affected by the column depth and the characteristics of the wastewater to be treated. Regrettably, the information on the potential of these filter materials for the purification of textile wastewater is still scarce. Therefore, this study investigated the potential applicability of natural zeolite in terms of column depth for the treatment of textile wastewater. From the analysis results, it was observed that the filtration efficiencies were relatively low (6.1 to 13.7%) for some parameters such as total dissolved solids, electrical conductivity, chemical oxygen demand, and sodium chloride when the wastewater samples were subjected to the 0.5 m column depth. Relatively high efficiency of 82 and 93.8% was observed from color and total suspended solids, respectively, when the wastewater samples were subjected to the 0.5 m column depth. Generally, the 0.75 m column depth achieved removal efficiencies ranging from 52.3% to 97.5%, whereas the 1 m column depth achieved removal efficiencies ranging from 86.9% to 99.4%. The highest removal efficiency was achieved with a combination of total suspended solids and 1 m column depth (99.4%). In summary, the treatment approach was observed to be highly effective for the removal of total suspended solids, with a 93.8% removal efficiency when the wastewater was subjected to the 0.5 m column depth, 97.5% for 0.75 m column depth, and 99.4% for 1 m column depth. Moreover, up to 218.233 mg of color per g of the filter material was captured. The results derived in this study provide useful information towards the potential applicability of natural zeolite in the textile wastewater treatment field.
- Published
- 2021
31. A scale-down mimic for mapping the process performance of centrifugation, depth and sterile filtration.
- Author
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Joseph, Adrian, Kenty, Brian, Mollet, Michael, Hwang, Kenneth, Rose, Steven, Goldrick, Stephen, Bender, Jean, Farid, Suzanne S., and Titchener‐Hooker, Nigel
- Abstract
ABSTRACT In the production of biopharmaceuticals disk-stack centrifugation is widely used as a harvest step for the removal of cells and cellular debris. Depth filters followed by sterile filters are often then employed to remove residual solids remaining in the centrate. Process development of centrifugation is usually conducted at pilot-scale so as to mimic the commercial scale equipment but this method requires large quantities of cell culture and significant levels of effort for successful characterization. A scale-down approach based upon the use of a shear device and a bench-top centrifuge has been extended in this work towards a preparative methodology that successfully predicts the performance of the continuous centrifuge and polishing filters. The use of this methodology allows the effects of cell culture conditions and large-scale centrifugal process parameters on subsequent filtration performance to be assessed at an early stage of process development where material availability is limited. Biotechnol. Bioeng. 2016;113: 1934-1941. © 2016 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
32. Robust Depth Filter Sizing for Centrate Clarification.
- Author
-
Lutz, Herb, Chefer, Kate, Felo, Michael, Cacace, Benjamin, Hove, Sarah, Wang, Bin, Blanchard, Mark, Oulundsen, George, Piper, Rob, and Zhao, Xiaoyang
- Subjects
FILTERS & filtration ,INSULATING materials ,CELLULOSE insulation ,MAMMALIAN cell cycle ,CURRENT good manufacturing practices - Abstract
Cellulosic depth filters embedded with diatomaceous earth are widely used to remove colloidal cell debris from centrate as a secondary clarification step during the harvest of mammalian cell culture fluid. The high cost associated with process failure in a GMP (Good Manufacturing Practice) environment highlights the need for a robust process scale depth filter sizing that allows for (1) stochastic batch-to-batch variations from filter media, bioreactor feed and operation, and (2) systematic scaling differences in average performance between filter sizes and formats. Matched-lot depth filter media tested at the same conditions with consecutive batches of the same molecule were used to assess the sources and magnitudes of process variability. Depth filter sizing safety factors of 1.2-1.6 allow a filtration process to compensate for random batch-to-batch process variations. Matched-lot depth filter media in four different devices tested simultaneously at the same conditions was used with a common feed to assess scaling effects. All filter devices showed <11% capacity difference and the Pod format devices showed no statistically different capacity differences. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
33. High-resolution imaging of depth filter structures using X-ray computed tomography
- Author
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Francesco Iacoviello, John H. Welsh, Daniel G. Bracewell, T.F. Johnson, and Paul R. Shearing
- Subjects
Length scale ,0303 health sciences ,Materials science ,Pixel ,Macropore ,Mechanical Engineering ,Mineralogy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Tortuosity ,03 medical and health sciences ,Mechanics of Materials ,Filter (video) ,Depth filter ,General Materials Science ,Tomography ,0210 nano-technology ,Porosity ,030304 developmental biology - Abstract
A multiple length scale approach to the imaging and measurement of depth filters using X-ray computed tomography is described. Three different filter grades of varying nominal retention ratings were visualized in 3D and compared quantitatively based on porosity, pore size and tortuosity. Positional based analysis within the filters revealed greater voidage and average pore sizes in the upstream quartile before reducing progressively through the filter from the center to the downstream quartile, with these results visually supported by voidage distance maps in each case. Flow simulation to display tortuous paths that flow may take through internal voidage were examined.Digital reconstructions were capable of identifying individual constituents of voidage, cellulose and perlite inside each depth filter grade, with elemental analysis on upstream and downstream surfaces confirming perlite presence. Achieving an appropriate pixel size was of particular importance when optimizing imaging conditions for all grades examined. A 3 µm pixel size was capable of representing internal macropores of each filter structure; however, for the finest grade, an improvement to a 1 µm pixel size was required in order to resolve micropores and small perlite shards. Enhancing the pixel size resulted in average porosity measurements of 70% to 80% for all grades. Graphical abstract
- Published
- 2021
34. Optimization of Flocculation in Connection with Various Solid-Liquid Separation Processes
- Author
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Tambo, Norihito, Hahn, Hermann H., editor, and Klute, Rudolf, editor
- Published
- 1990
- Full Text
- View/download PDF
35. Application of Microporous Filtration in Single‐Use Systems
- Author
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Christian Julien and Chuck Capron
- Subjects
Single use ,Materials science ,Chemical engineering ,law ,Depth filter ,Microporous material ,Filtration ,law.invention - Published
- 2019
36. Control of antibody high and low molecular weight species by depth filtration‐based cell culture harvesting
- Author
-
Deqiang Yu, Zheng Jian Li, Mukesh Mayani, Yuanli Song, Sanchayita Ghose, and Zhizhuo Xing
- Subjects
0106 biological sciences ,0301 basic medicine ,Bioengineering ,CHO Cells ,Plasma protein binding ,01 natural sciences ,Applied Microbiology and Biotechnology ,law.invention ,Hydrophobic effect ,03 medical and health sciences ,Cricetulus ,Adsorption ,law ,010608 biotechnology ,Animals ,Filtration ,Chromatography ,Chemistry ,Antibodies, Monoclonal ,food and beverages ,dBc ,Molecular Weight ,030104 developmental biology ,Membrane ,Depth filter ,Biotechnology ,Protein adsorption - Abstract
Depth filtration-based harvesting is widely used in mAb manufacturing to remove cell and process-related impurities. However, it has not been studied on control of product-related impurities, which are very critical for product quality. In this article, we studied the interactions of depth filter with high and low molecular weight species (HMWs and LMWs) for their direct removal from cell culture. The process parameters (filter, loading, temperature, and flux) were evaluated for adsorption of HMWs and LMWs by depth filters. The adsorption is significantly dependent on filter media and loading capacity and is mainly on the basis of hydrophobic interaction during harvesting. The HMW and LMW species were characterized as HMW1, HMW2, LMW1, and LMW2. The increasing binding from LMW2 to LMW1, HMW1, and HMW2 is correlated with their increasing hydrophobicity score. Adsorption using enriched HMW sample demonstrated similar total protein binding capacity (36-40 g/m2 ) between depth filters D0HC and X0HC. However, X0HC has stronger HMW binding than D0HC (71% vs 43% of bound protein), indicating more hydrophobic interaction in X0HC. HMW2 DBC on X0HC reached 12 g/m2 , similar to protein binding on hydrophobic interaction membrane adsorbers. Further study showed LMW can induce HMW formation. This study provides a critical understanding of HMW and LMW interaction with depth filters. The strategy of HMW and LMW control by depth filtration-based harvesting was implemented successfully in mAb manufacturing.
- Published
- 2019
37. Impact of depth filtration on disulfide bond reduction during downstream processing of monoclonal antibodies from CHO cell cultures
- Author
-
Fann John C, Zhong-Hua Gao, Jon Therriault, Smith Laura R, Robert Mallett, Cameron Miller, Brian W. O’Mara, Gautam Nayar, Manju Kuruganti, John Cisney, and Jeffrey D Meyer
- Subjects
0106 biological sciences ,0301 basic medicine ,Lysis ,Thioredoxin reductase ,Bioengineering ,Dehydrogenase ,CHO Cells ,01 natural sciences ,Applied Microbiology and Biotechnology ,03 medical and health sciences ,chemistry.chemical_compound ,Cricetulus ,010608 biotechnology ,Animals ,Humans ,Disulfides ,chemistry.chemical_classification ,Downstream processing ,Chinese hamster ovary cell ,Antibodies, Monoclonal ,030104 developmental biology ,chemistry ,Depth filter ,Biophysics ,Thiol ,Oxidation-Reduction ,Filtration ,Nicotinamide adenine dinucleotide phosphate ,Biotechnology - Abstract
Monoclonal antibody interchain disulfide bond reduction was observed in a Chinese Hamster Ovary manufacturing process that used single-use technologies. A similar reduction has been reported for processes that involved high mechanical shear recovery unit operations, such as continuous flow centrifugation and when the clarified harvest was stored under low dissolved oxygen (DO) conditions (Trexler-Schmidt et al., 2010. Biotechnology and Bioengineering, 106(3), 452-461). The work described here identifies disposable depth filtration used during cell culture harvest operations as a shear-inducing unit operation causing cell lysis. As a result, reduction of antibody interchain disulfide bonds was observed through the same mechanisms described for continuous flow centrifugation. Small-scale depth-filtration models were developed, and the differential pressure (Δ P) of the primary depth filter was identified as the key factor contributing to cell lysis. Strong correlations of Δ P and cell lysis were generated by measuring the levels of lactate dehydrogenase and thiol in the filtered harvest material. A simple risk mitigation strategy was implemented during manufacturing by providing an air overlay to the headspace of a single-use storage bag to maintain sufficient DO in the clarified harvest. In addition, enzymatic characterization studies determined that thioredoxin reductase and glucose-6-phosphate dehydrogenase are critical enzymes involved in antibody reduction in a nicotinamide adenine dinucleotide phosphate (NADP + )/NADPH-dependent manner.
- Published
- 2019
38. Influence of flow alterations on bacteria retention during microfiltration
- Author
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Dominic Büning, Volkmar Thom, Milan Polakovič, Christina Grote, Alexander Helling, Matthias Wessling, and Mathias Ulbricht
- Subjects
biology ,Chemistry ,Microfiltration ,Chemie ,Filtration and Separation ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Volumetric flow rate ,Membrane ,Pulmonary surfactant ,Chemical engineering ,Depth filter ,Particle ,General Materials Science ,Physical and Theoretical Chemistry ,Turbidity ,0210 nano-technology ,Bacteria - Abstract
Microfiltration membranes retain bacteria predominantly by size-exclusion. However, some empirical data points towards the fact, that alterations in flow rate as well as changes in the quality of adhesive interactions between the membrane surface and the bacteria can affect their retention. For parvo virus retaining normal flow virus-filters, systematic investigations have been undertaken to characterize the impact of flow alterations as well as modulations of particle-membrane interactions on virus particle retention. For depth filters used, e.g., for the clarification of fermentation broths, it is well known that alterations in flow rate typically lead to elevated levels of turbidity. This work adopts the acquired knowledge from virus- and depth-filters and investigates their applicability for bacteria retention by microfiltration membranes. It presents particle retention data for mycoplasma and Gram-negative and Gram-positive bacteria. Single layer flat sheet PES model microfiltration membranes with maximum pore sizes varying from 0.3 to 1.5 µm and an overall low retention were used in order to easily detect and differentiate their retention properties for the different particle species. The event of particle breakthrough is elucidated depending on the adsorptive character of the membrane surface, the pore size, and changes in flow rate including the interruption of flow. Moreover, this work investigates how the chemical and physical solution properties influence bacterial retention. These properties include the temperature of the fluid, the presence of a surfactant, the salt concentration and the pH. Flow interruptions using B. diminuta were also applied to commercially available PES sterilizing-grade microfiltration membranes showing no bacterial breakthrough.
- Published
- 2019
39. Effect of filtration on elimination of turbidity and changes in volatile compounds concentrations in plum distillates
- Author
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Mateusz Różański, Katarzyna Pielech-Przybylska, Piotr Patelski, Urszula Dziekońska-Kubczak, and Maria Balcerek
- Subjects
0106 biological sciences ,Organoleptic ,Cold storage ,Raw material ,01 natural sciences ,Fruit distillate ,law.invention ,Turbidity ,0404 agricultural biotechnology ,law ,010608 biotechnology ,medicine ,Filtration ,Chromatography ,Chemistry ,04 agricultural and veterinary sciences ,040401 food science ,Fatty acid esters ,Volume (thermodynamics) ,Depth filter ,Volatile compounds ,Original Article ,Food Science ,Activated carbon ,medicine.drug - Abstract
The purpose of this study was to investigate the effect of alcoholic strength by volume (ASV) and storage conditions on turbidity in plum brandies. Different types of filter sheet were also tested for their effects on turbidity, as well as on the chemical composition and organoleptic characteristics of the distillates. The raw materials used were two plum distillates with initial ASVs of 76.77% v/v and 81.92% v/v. The distillates were diluted to alcohol contents of 37.5%, 40% and 50% v/v and stored under various conditions for 64 days. Filtration was performed using two depth filter sheets, with nominal retention rates of 0.40–0.48 μm and 0.80 μm, or with an activated carbon-based filter sheet. The lowest turbidity was observed in samples stored at ambient temperature with an ASV of 50% v/v. Reducing the alcohol content and storage temperature caused turbidity to increase. Samples prepared from distillate with an initial alcohol content of 76.77% v/v were characterized by significantly higher turbidity than those produced from spirit with an initial ASV of 81.92% v/v. Lowering the storage temperature resulted in a larger decrease in the concentration of volatile compounds after filtration. Use of an activated carbon filter sheet caused the greatest decrease in the majority of volatiles. Use of a filter sheet with a nominal retention rate of 0.80 μm led to the greatest improvement in the organoleptics of the tested plum distillates.
- Published
- 2019
40. A Comprehensive Investigation of Depth Filter Functionality for a Colloidal Silica Slurry Used for Semiconductor Manufacturing Process
- Author
-
Young Gil Yoo, Manhee Lee, Sunho Moon, Inkyung Park, Hyungil Lee, and Yunseo Jang
- Subjects
0209 industrial biotechnology ,Materials science ,Colloidal silica ,02 engineering and technology ,Condensed Matter Physics ,Industrial and Manufacturing Engineering ,Electronic, Optical and Magnetic Materials ,law.invention ,020901 industrial engineering & automation ,law ,Chemical-mechanical planarization ,Depth filter ,Zeta potential ,Slurry ,Particle ,Wafer ,Electrical and Electronic Engineering ,Composite material ,Filtration - Abstract
We report a comprehensive study on depth filter functionality by using a slurry, colloidal silica, used for chemical mechanical polishing process in semiconductor manufacturing. We show that the depth filters with nominal pore size ranging from 0.1 $\mu \text{m}$ to 0.5 $\mu \text{m}$ selectively reduces the concentration of ‘large’ particles up to 80%, and maintains other critical properties of slurry including solid content ratio, mean diameter of particles, pH, zeta potential, and conductivity. Furthermore, we find the particle size-dependent filter efficiency, and the stable and allowable pressure drop across the filters. The depth filtration efficiently reduces the large particle concentration in slurry, and thus could be useful for suppressing the associated manufacturing defects such as micro-scratches and pits on the polished wafers.
- Published
- 2019
41. Poly(L-lactic acid) Depth Filter Membrane Prepared by Nonsolvent-Induced Phase Separation with the Aid of a Nonionic Surfactant
- Author
-
Yuki Shibuya, Masayuki Taniguchi, Takaaki Tanaka, Akihito Ochiai, Hiromi Minbu, and Haruki Mizuno
- Subjects
Poly l lactic acid ,Membrane ,Chemical engineering ,Chemistry ,General Chemical Engineering ,Depth filter ,Nonionic surfactant ,General Chemistry - Published
- 2019
42. DNA retention on depth filters
- Author
-
Xuankuo Xu, Nripen Singh, Zheng Jian Li, Steven J. Traylor, Ohnmar Khanal, Abraham M. Lenhoff, Sanchayita Ghose, and Chao Huang
- Subjects
Lysis ,Filtration and Separation ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,DNA extraction ,Article ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,chemistry ,Ionic strength ,law ,Depth filter ,Fluorescence microscope ,Nucleic acid ,Biophysics ,General Materials Science ,Physical and Theoretical Chemistry ,0210 nano-technology ,DNA ,Filtration - Abstract
Depth filtration is a commonly-used bioprocessing unit operation for harvest clarification that reduces the levels of process- and product-related impurities such as cell debris, host-cell proteins, nucleic acids and protein aggregates. Since depth filters comprise multiple components, different functionalities may contribute to such retention, making the mechanisms by which different impurities are removed difficult to decouple. Here we probe the mechanisms by which double-stranded DNA (dsDNA) is retained on depth filter media by visualizing the distribution of fluorescently-labeled retained DNA on spent depth filter discs using confocal fluorescence microscopy. The extent of DNA displacement into the depth filter was found to increase with decreasing DNA length with increasing operational parameters such as wash volume and buffer ionic strength. Finally, using 5ethynyl-2'-deoxyuridine (EdU) to label DNA in dividing CHO cells, we showed that Chinese hamster ovary (CHO) cellular DNA in the lysate supernatant migrates deeper into the depth filter than the lysate re-suspended pellet, elucidating the role of the size of the DNA in its form as an impurity. Apart from aiding DNA purification and removal, our experimental approaches and findings can be leveraged in studying the transport and retention of nucleic acids and other impurities on depth filters at a small scale.
- Published
- 2019
43. Nanoparticles capture on cellulose nanofiber depth filters
- Author
-
Anja Huch, Patryk Spera, Tanja Zimmermann, and Houssine Sehaqui
- Subjects
Materials science ,Polymers and Plastics ,Organic Chemistry ,technology, industry, and agriculture ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Nanocellulose ,chemistry.chemical_compound ,Membrane ,Chemical engineering ,chemistry ,Filter (video) ,Nanofiber ,Depth filter ,Materials Chemistry ,Surface charge ,Cellulose ,0210 nano-technology - Abstract
A self-standing filter with a porosity of 80% is prepared from naturally abundant cellulose biopolymer in its native state by water-based cationization and freeze-drying processes. The positive surface charge of the filter in a wide pH range favors its interaction with various nanoparticles (NPs), while its tortuous sheet structure builds a contact between cellulose nanofibers (CNF) and the NPs, and hinders them to pass through the filter. Unlike membranes used for the retention of NPs and viruses, the separation in the CNF filter is not only limited to its surface but occurs also in its interior even when the NPs are orders of magnitude smaller than the filter pores. Additional functionalities added to the filter enlarge the spectrum of NPs it can separate. NPs supported onto the filter can thereafter be utilized for the reduction of harmful chemicals into their benign form. The present filter concept may not only address shortcomings of the current membrane systems, but could offer a disruptive technology for the sustainable and universal water purification.
- Published
- 2018
44. Modeling flux in tangential flow filtration using a reverse asymmetric membrane for Chinese hamster ovary cell clarification
- Author
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Parag Patel, S. Ranil Wickramasinghe, Xianghong Qian, Da Zhang, and Daniel Strauss
- Subjects
Microscopy, Confocal ,Materials science ,Fouling ,Biofouling ,Membrane fouling ,Membranes, Artificial ,CHO Cells ,Permeation ,Models, Biological ,Cross-flow filtration ,Barrier layer ,Bioreactors ,Cricetulus ,Membrane ,Chemical engineering ,Hollow fiber membrane ,Cricetinae ,Depth filter ,Animals ,Filtration ,Biotechnology - Abstract
Tangential flow filtration is advantageous for bioreactor clarification as the permeate stream could be introduced directly to the subsequent product capture step. However, membrane fouling coupled with high product rejection has limited its use. Here, the performance of a reverse asymmetric hollow fiber membrane where the more open pore structure faces the feed stream and the barrier layer faces the permeate stream has been investigated. The open surface contains pores up to 40 μm in diameter while the tighter barrier layer has an average pore size of 0.4 μm. Filtration of Chinese hamster ovary cell feed streams has been investigated under conditions that could be expected in fed batch operations. The performance of the reverse asymmetric membrane is compared to that of symmetric hollow fiber membranes with nominal pore sizes of 0.2 and 0.65 μm. Laser scanning confocal microscopy was used to observe the locations of particle entrapment. The throughput of the reverse asymmetric membrane is significantly greater than the symmetric membranes. The membrane stabilizes an internal high permeability cake that acts like a depth filter. This stabilized cake can remove particulate matter that would foul the barrier layer if it faced the feed stream. An empirical model has been developed to describe the variation of flux and transmembrane pressure drop during filtration using reverse asymmetric membranes. Our results suggest that using a reverse asymmetric membrane could avoid severe flux decline associated with fouling of the barrier layer during bioreactor clarification.
- Published
- 2021
45. Multipurpose Oil Filter Systems for Innovative Drivetrains and e-Axles
- Author
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Richard Bernewitz, Claudia Wagner, Marius Panzer, Alexander Wöll, and Anna-Lena Winkler
- Subjects
Computer science ,business.industry ,Oil filter ,Drivetrain ,Grid ,law.invention ,Oil pump ,Filter (video) ,law ,Depth filter ,Lubrication ,Process engineering ,business ,Filtration - Abstract
Changing drivetrain architectures and designs such as highly integrated e-Axles and hybrid transmissions require different filtration solutions. Not only the requirements towards oil cleanliness and differential pressure of the lubrication and cooling circuit become more challenging, but also the dielectric and electric oil properties and the insulating function, for instance, come more and more into focus. To protect all system components starting from the oil pump MANN+HUMMEL developed a new generation of filters using their depth filter media MULTIGRADE eM-CO. The new concept increases the degrees of freedom for the development of the lubrication circuit significantly. Offering an ultra-compact and flexible installation space, lowest differential pressure or highest filtration efficiencies for system reliability. The new MANN+HUMMEL filter media portfolio MULTIGRADE eM-CO offers filter media with excellent properties and a gradient structure that provides a high dust holding capacity at a low differential pressure. Customized numerical development tools are supporting the media development by analyzing and optimizing the structure and the filtration performance. To multiply these advantages and to add further benefits for the customers a new generation of pleated suction-side filters has been developed. With up to 60% higher filter area the new concept uses the given installation space to the maximum. A 3D structured drainage grid keeps the media performance at a maximum level over the whole filter life. The latest computational fluid dynamics (CFD) analysis tools are used to optimize the differential pressure of the housing even in challenging installation spaces. Special oil drying units are applied to minimize water induced increase of conductivity. This allows the dielectric properties of the oils to be kept constant and even water sensitive oils can be used for the applications. With this knowledge and expertise, MANN+HUMMEL developed a sensor-supported oil management system with intelligent cooling function and integrated oil drying for highest oil quality over the entire life of the system.
- Published
- 2021
46. Influence of the Precoat Layer on the Filtration Properties and Regeneration Quality of Backwashing Filters
- Author
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Patrick Morsch, Hermann Nirschl, Marco Gleiß, and Volker Bächle
- Subjects
Materials science ,Backwashing ,cellulose fibres ,02 engineering and technology ,law.invention ,precoat filtration ,precoat layer ,Chemical engineering ,020401 chemical engineering ,law ,filter regeneration ,backwash filtration ,0204 chemical engineering ,Composite material ,filter aids ,Filtration ,particle layer ,filter media resistance ,021001 nanoscience & nanotechnology ,filter cake resistance ,turbidity ,Volumetric flow rate ,TK1-9971 ,Filter cake ,Membrane ,Filter (video) ,Depth filter ,ddc:660 ,Electrical engineering. Electronics. Nuclear engineering ,0210 nano-technology ,Layer (electronics) - Abstract
For solid–liquid separation, filter meshes are still used across large areas today, as they offer a cost-effective alternative, for example, compared to membranes. However, particle interaction leads to a continuous blocking of the pores, which lowers the flow rate of the mesh and reduces its lifetime. This can be remedied by filter aids. In precoat filtration, these provide an already fully formed filter cake on the fabric, which acts as a surface and depth filter. This prevents interaction of the particles to be separated with the mesh and thus increases the service life of the mesh. In this work, the influence of a precoat layer with different fibre lengths of cellulose on the filtration behavior is investigated. A satin with a pore size of 11 µm is used as the filter medium. The effects of the precoat layer on the filter media resistance, the filter cake resistance, the turbidity impact, and the regenerability of the fabrics are investigated. This study shows an overview of the suitability of various cellulose fibres based on different aspects as filter aids for particles in ultrafine filtration.
- Published
- 2021
47. Making Sense of Occluded Scenes using Light Field Pre-processing and Deep-learning
- Author
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Suranga Seneviratne, Sakila S. Jayaweera, Chamith Wijenayake, Chamira U. S. Edussooriya, Namalka Liyanage, and Kalana Abeywardena
- Subjects
Computer science ,business.industry ,Deep learning ,020206 networking & telecommunications ,02 engineering and technology ,Sense (electronics) ,Object (computer science) ,Depth filter ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Computer vision ,Artificial intelligence ,business ,Light field - Abstract
A combined approach of low-complexity light field depth filtering and deep learning is proposed for object classification in the presence of partial occlusions. The proposed approach exploits depth information embedded in multi-perspective four-dimensional (4-D) light fields via low-complexity 4-D sparse depth filtering and deep-learning. The proposed 4-D depth filter, designed using numerical optimization techniques by formulating as an l 1 − l ∞ minimization problem, is shown to outperform typical light field refocusing based on 4-D shift-sum averaging filters. Experiments conducted using a light field dataset acquired by a Lytro camera verify 45% and 27% better performance in terms of object classification accuracy compared to the cases when no depth filtering is employed and standard shift-sum refocusing is employed, respectively.
- Published
- 2020
48. Depth filtration application of nanofibrillated cellulose-mesoporous silica nanoparticle composites as double-layer membranes
- Author
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Yvonne Hora, Humayun Nadeem, Warren Batchelor, Benjamin Wey Xien Chin, Simin Miri, and Philip C. Andrews
- Subjects
Materials science ,Process Chemistry and Technology ,Polyethylene glycol ,Mesoporous silica ,Pollution ,Polyelectrolyte ,chemistry.chemical_compound ,Adsorption ,Membrane ,chemistry ,Selective adsorption ,Depth filter ,Chemical Engineering (miscellaneous) ,Cellulose ,Composite material ,Waste Management and Disposal - Abstract
The adsorption capacity of cellulose membranes without modification is negligible for water treatment. Therefore, enhancing cellulose adsorption capacity via cost-effective approaches is required. Double-layer membranes with a nanofibrillated cellulose (NFC) membrane and an in-situ produced NFC-mesoporous silica nanoparticles (MSN) depth filter layers were produced. The membranes were tailored to improve size rejection and saturated adsorption capacity (SAC) by altering the gram per meter square (gsm) of the depth filter layer. The higher SAC of double-layer membranes was achieved by increasing the depth filter layer gsm and because of the significantly lower porosity of double-layer membranes compared to NFC-MSN single-layer membranes. The optimized membrane for methylene blue (MB) showed the SAC of 107 mg per g of MSN. The membrane could be modified with polyethyleneimine (PEI) or polyamide amine-epichlorohydrin (PAE) resin as cationic charged polyelectrolytes for the selective adsorption of anionic molecules of metanil yellow (MY). The membrane modified with PEI had 41 times higher SAC than unmodified specimens toward MY. Optimized double-layer membranes for size rejection, including 30 gsm composite layer, were produced by reducing the NFC fibre diameter via higher homogenization and drying the NFC layer before adding the depth filter layer. The optimized double-layer membrane had a polyethylene glycol (PEG) molecular weight cut-off (MWCO) of 200 kDa. These membranes manufactured by cost-effective materials have great potential of scale-up for membrane manufacturing for water treatment. The combination of good adsorption and size rejection makes a unique material that should be explored further.
- Published
- 2022
49. Intersection between engineering mechanics and supervised learning for modelling clogging dynamics in depth filters
- Author
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Alvin Wei Ze Chew
- Subjects
Clogging ,Theoretical computer science ,Intersection ,Computer science ,Dynamics (music) ,Depth filter ,Supervised learning ,Applied mechanics - Published
- 2020
50. Monocular Dense 3D Reconstruction Algorithm Based on Inverse Depth Filter
- Author
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Long Zhao and Jingyun Duo
- Subjects
Monocular ,Computer science ,Robustness (computer science) ,3D reconstruction ,Depth filter ,Probability distribution ,Inverse ,Reconstruction algorithm ,Algorithm ,Smoothing - Abstract
In this paper, an inverse depth filter based real-time monocular 3D dense reconstruction algorithm is proposed. We construct the Gaussian-uniformly mixed probability distribution model by fusing the right and wrong observations in inverse depth filter, which effectively solves the “long tail” problem in conventional depth filter. Then a fast smoothing method is adopted to reduce the effects of noises and false observations, which greatly improves the accuracy and robustness of our method. Experiments are designed to evaluate the accuracy and effectiveness of the proposed algorithm, and the results show that our algorithm has good 3D dense reconstruction performance and high computational accuracy.
- Published
- 2020
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