161 research outputs found

    Maillard reactions in Spray dryers

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    Spray drying has been widely used in many areas, including the production of spray-dried dairy products. The combination of high protein and reducing sugars makes dairy products subject to Maillard reactions during spray drying. Therefore, it is important to investigate the kinetics of Maillard reactions in spray dryers. This thesis has started with investigating the kinetics of Maillard reactions in spray dryers with different feed compositions and inlet gas temperatures. The extent of the Maillard reactions was evaluated based on fluorometric and colourimetric methods. Proteins in the feed were found to play an important role in the reaction kinetics. Results from the laboratory-scale spray dryer suggested the particle residence time distribution (RTD) also plays a pivotal role, which determines the reaction time. A measurement system has been developed to measure the RTD of different spray dryers. Experimental results showed that the later designs of the dryers have advantages over earlier designs, mainly in terms of particle-to-gas residence ratios. Fluctuations observed in signals also demonstrated the potential connection between drying chamber geometry and the wall deposition and re-entrainment processes. Apart from experimental works, this thesis has also developed mathematical models based on different modelling approaches for predicting the Maillard reactions kinetics in spray dryers. In general, prediction results are comparable to the experimental data measured earlier in this thesis, which is a significant improvement over similar models developed in other studies. The performance of the distributed-parameter model is better compared with the lumped-parameter model, though the effects of component segregation were only approximated. In summary, this thesis has systematically investigated Maillard reactions in spray dryers from an engineering point of view

    Absolute Wrong Makes Better: Boosting Weakly Supervised Object Detection via Negative Deterministic Information

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    Weakly supervised object detection (WSOD) is a challenging task, in which image-level labels (e.g., categories of the instances in the whole image) are used to train an object detector. Many existing methods follow the standard multiple instance learning (MIL) paradigm and have achieved promising performance. However, the lack of deterministic information leads to part domination and missing instances. To address these issues, this paper focuses on identifying and fully exploiting the deterministic information in WSOD. We discover that negative instances (i.e. absolutely wrong instances), ignored in most of the previous studies, normally contain valuable deterministic information. Based on this observation, we here propose a negative deterministic information (NDI) based method for improving WSOD, namely NDI-WSOD. Specifically, our method consists of two stages: NDI collecting and exploiting. In the collecting stage, we design several processes to identify and distill the NDI from negative instances online. In the exploiting stage, we utilize the extracted NDI to construct a novel negative contrastive learning mechanism and a negative guided instance selection strategy for dealing with the issues of part domination and missing instances, respectively. Experimental results on several public benchmarks including VOC 2007, VOC 2012 and MS COCO show that our method achieves satisfactory performance.Comment: 7 pages, 5 figure

    BLAT: Bootstrapping Language-Audio Pre-training based on AudioSet Tag-guided Synthetic Data

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    Compared with ample visual-text pre-training research, few works explore audio-text pre-training, mostly due to the lack of sufficient parallel audio-text data. Most existing methods incorporate the visual modality as a pivot for audio-text pre-training, which inevitably induces data noise. In this paper, we propose BLAT: Bootstrapping Language-Audio pre-training based on Tag-guided synthetic data. We utilize audio captioning to generate text directly from audio, without the aid of the visual modality so that potential noise from modality mismatch is eliminated. Furthermore, we propose caption generation under the guidance of AudioSet tags, leading to more accurate captions. With the above two improvements, we curate high-quality, large-scale parallel audio-text data, based on which we perform audio-text pre-training. Evaluation on a series of downstream tasks indicates that BLAT achieves SOTA zero-shot classification performance on most datasets and significant performance improvement when fine-tuned on downstream tasks, suggesting the effectiveness of our synthetic data

    Micro-Clearance Oil Film Temperature Field Characteristics of High Speed and Heavy Type Hydrostatic Thrust Bearing under Extreme Operating Conditions

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    To explore the micro-clearance oil film temperature field characteristics of hydrostatic thrust bearings under operating conditions of high speed and heavy load, a mathematical model of micro-clearance oil film is established. According to the principle of computational fluid dynamics, the relationship between load capacity and rotational speed is calculated, and the model is solved using the finite volume method. The micro-clearance oil film temperature field is also investigated and tested to verify the theoretical analysis. The results show that the rotational speed is coupled with the load-carrying capacity of hydrostatic thrust bearings. When the extreme operating conditions are between 0t-228.9r/min and 4t-214.9r/min, the oil film maximum temperature increases slowly with the load increase and rotational speed decrease, and the average temperature decreases slowly. On the other hand, when the extreme operating conditions are between 4t-214.9r/min and 32t-78.9r/min, the maximum temperature and the average temperature slowly decrease as the load increases and the rotational speed decreases; the influence of rotational speed is greater than that of load, and the temperature rise of the upstream side is sharper than that of the downstream side

    Pollutant diffusion in multiple-face tunnel construction: theoretical analysis and numerical validation

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    As the length of the tunnel continues to increase, it will be common for a single fan to undertake the ventilation of two or more tunnel faces. However, the construction of multiple faces in a single tunnel will lead to a complex construction environment in the tunnel, the mutual interference of ventilation, and difficulty in discharging pollutants. Based on the simultaneous construction of multiple tunnel faces in a single tunnel, this study analyzed the transport law of pollutants. The diffusion laws of carbon monoxide and dust in multiple-face tunnels under different working conditions were obtained by numerical simulation. It was found that when both sides of the tunnel are ventilated at the same time, the airflow in the tunnel is spiral, the vortex zone will appear near both sides of the face, and the vortex and unstable airflow will appear at the intersection with the inclined shaft. The airflow in the non-equal-length tunnel at both sides is more disordered than that in the equal-length tunnel, and there will be a wider range of eddy currents at the intersection. The change of dust diffusion in the non-equal-length tunnel at both sides is not obvious, and the length of the multiple-face tunnel has little effect on dust settlement and diffusion. The research results are of great significance for improving the construction environment of tunnel faces and improving the working conditions of personnel

    A position-aware transformer for image captioning

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    Image captioning aims to generate a corresponding description of an image. In recent years, neural encoder-decoder models have been the dominant approaches, in which the Convolutional Neural Network (CNN) and Long Short Term Memory (LSTM) are used to translate an image into a natural language description. Among these approaches, the visual attention mechanisms are widely used to enable deeper image understanding through fine-grained analysis and even multiple steps of reasoning. However, most conventional visual attention mechanisms are based on high-level image features, ignoring the effects of other image features, and giving insufficient consideration to the relative positions between image features. In this work, we propose a Position-Aware Transformer model with image-feature attention and position-aware attention mechanisms for the above problems. The image-feature attention firstly extracts multi-level features by using Feature Pyramid Network (FPN), then utilizes the scaled-dot-product to fuse these features, which enables our model to detect objects of different scales in the image more effectively without increasing parameters. In the position-aware attention mechanism, the relative positions between image features are obtained at first, afterwards the relative positions are incorporated into the original image features to generate captions more accurately. Experiments are carried out on the MSCOCO dataset and our approach achieves competitive BLEU-4, METEOR, ROUGE-L, CIDEr scores compared with some state-of-the-art approaches, demonstrating the effectiveness of our approach

    Is world view neutral education possible and desirable? : A Christian response to liberal arguments.

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    The main object of this thesis is to find out why it so often is assumed that education can and should be neutral between world views, and to argue against this. It is also discussed what the world view basis of the common school should be when neutrality is impossible. The idea of a common school that inculcates common values without taking a stand between different religions and secular world views, is central in today's idea of liberal education. It is argued here that however thin the common basis for the school is, certain world view presuppositions will always be conveyed, at least implicitly. It is easier to see the world view presuppositions in one account of education if it is contrasted with another. An account is given of Christian education, emphasizing its view of reality and human nature, the meaning of life and the corresponding purpose of education. Contrasted with this, an analysis of J. White's and K. Strike's accounts of education based on common values only, shows that they both convey world view presuppositions that are incompatible with a Christian view and therefore not neutral. The argument of incompatibility is strengthened by a discussion of T. H. McLaughlin's three different accounts of common, world view neutral education, Catholic education, and liberal religious education. Several kinds of argument for the possibility and desirability of world view neutral education are analysed, and it is claimed that none of them is valid. Some imply a shallow understanding of religion, others a biased view of education. It is argued that liberal education in many ways is more likely to indoctrinate than Christian education IS. Finally, it is argued that it is desirable to have Christian education in state schools, and the degree to which this is possible is discussed

    Assessing the Quality of Reports about Randomized Controlled Trials of Acupuncture Treatment on Diabetic Peripheral Neuropathy

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    BACKGROUND: To evaluate the reports' qualities which are about randomized controlled trials (RCTs) of acupuncture treatment on Diabetic Peripheral Neuropathy (DPN). METHODOLOGY/PRINCIPAL FINDINGS: Eight databases including The Cochrane Library(1993-Sept.,2011), PubMed (1980-Sept., 2011), EMbase (1980-Sept.,2011), SCI Expanded (1998-Sept.,2011), China Biomedicine Database Disc (CBMdisc, 1978-Sept., 2011), China National Knowledge Infrastructure (CNKI, 1979-Sept., 2011 ), VIP (a full text issues database of China, 1989-Sept., 2011), Wan Fang (another full text issues database of China 1998-Sept., 2011) were searched systematically. Hand search for further references was conducted. Language was limited to Chinese and English. We identified 75 RCTs that used acupuncture as an intervention and assessed the quality of these reports with the Consolidated Standards for Reporting of Trials statement 2010 (CONSORT2010) and Standards for Reporting Interventions Controlled Trials of Acupuncture 2010(STRICTA2010). 24 articles (32%) applied the method of random allocation of sequences. No article gave the description of the mechanism of allocation concealment, no experiment applied the method of blinding. Only one article (1.47%) could be identified directly from its title as about the Randomized Controlled Trials, and only 4 articles gave description of the experimental design. No article mentioned the number of cases lost or eliminated. During one experiment, acupuncture syncope led to temporal interruption of the therapy. Two articles (2.94%) recorded the number of needles, and 8 articles (11.76%) mentioned the depth of needle insertion. None of articles reported the base of calculation of sample size, or has any analysis about the metaphase of an experiment or an explanation of its interruption. One (1.47%) mentioned intentional analysis (ITT). CONCLUSIONS/SIGNIFICANCE: The quality of the reports on RCTs of acupuncture for Diabetic Peripheral Neuropathy is moderate to low. The CONSORT2010 and STRICTA2010 should be used to standardize the reporting of RCTs of acupuncture in future
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