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Research on the Method of Evaluating the Pore Throat Structure of Rock Microscopically Based on the 3D Pore Network Model of Digital Core
Get PDFIn order to solve the problems of time-consuming, poor repeatability and inability to directly reflect the pore structure of the core by traditional experimental methods to obtain the reservoir parameters, a method was proposed to study the pore structure of inner core using digital core and pore network model. Firstly, the core CT scan image is processed by filtering and denoising, threshold segmentation and pore-throat network skeleton extraction. Then, the digital core and pore network model are constructed by digital image technology and maximum sphere algorithm, and the core physical parameters are statistically analyzed. Finally, a digital core pore network model is used to simulate oil-water two-phase flow. The results show that the digital core pore network model can better reflect the real core pore space characteristics and accurately reflect the pore throat distribution and morphology characteristics. Through practical application, the 3D pore network model of a digital core can accurately reflect the core's microporosity and throat structure and fully understand the mechanism of fluid flow in porous media, which has high application value. In addition, the method can be repeated many times, which is time-consuming and controllable and makes up for the limitations of conventional physical experiments
Design and Performance Characteristics of a Hybrid Photovoltaic-Thermal Regeneration System under Indoor and Outdoor Solar Radiation Conditions of Thunder Bay, Ontario
Get PDFNumerous energy sources continuously emit large amounts of waste energy into the earth's atmosphere. Significant losses, nearly 85% of the incident light on a PV panel, are either reflected from the PV surface, accounting for up to 20%, or dissipated as heat. In this work, a novel lab-scale hybrid photovoltaic-thermal regeneration (HPVT-R) system is designed, constructed, and tested to restore some of the reflection losses in the PV system. The new HPVT-R system design permits the PV and thermal co-systems to perform autonomously while revitalizing some of the reflection losses by hybridization. Thorough testing of the HPVT-R system was performed under lab-scale indoor simulated light and outdoor solar radiation conditions in Thunder Bay, Ontario. The HPVT-R system regenerated approximately 14 % of the reflected light in these tests, transforming it into electrical power and heat. Under the solar-simulated lights, the indoor test setup regenerated around 17 mW of electric power from the reflected light accounting for slightly less than 1% of more electric power per unit PV surface area. However, the outdoor solar radiation tests rejuvenated nearly 137 mW of electric power, accounting for approximately 3% more electric power per unit PV surface area, with a conversion efficiency of nearly 7%. Regarding heat energy, the HPVT-R system regenerated approximately 34% more in indoor and outdoor performances entirely from the reflected light. This research investigates the performance aspects of the HPVT-R system operated under different working conditions
Validation of Solar Dehydrator for Food Drying Applications: A Granny Smith Apple Study
Get PDFFood loss is a global issue that may be alleviated with effective dehydration strategies. Solar dehydration, rather than traditional sun-drying, is one method that could allow for the safe, efficient preservation of food materials. In this study, passive solar dehydration was achieved using a psychrometric chamber to model the environment of sub-Saharan Africa, where the temperature was the major focus (24.3 °C to 29.4 °C). A mass decrease of 88.56% was achieved within 9 hours. Microbial testing (total aerobic bacteria, Gram-negative bacteria, and total yeasts and molds) demonstrated no difference (all negative) between food stored at 4 °C and dehydrated food, indicating that the dehydrator introduced no new contamination. A 16.0% decrease in vitamin C (VC) concentration was observed due to the lability of VC. Insight into the visual appeal of the food samples was provided by measuring browning values, where it was found that dehydrated green apples are significantly less brown than the sample exposed to air for the same length of time. Passive solar dehydrators could provide a simple method to reduce food waste and maintain nutritional content and visual appeal
Soft Computing Under Uncertain Knowledge
Get PDFThe early publications in the theory of fuzzy sets by Zadeh and Goguen show the intention to generalize the classical notion of a set and to accommodate the fuzziness that is contained in human language, namely human judgement, evaluation, and decisions. This article aims to show several approaches that allow effective treatment of uncertain, inaccurate, or unknown knowledge. On the one hand, a brief review of the theoretical background for these different paradigms is provided. On the other hand, the different extensions of soft sets are justified in the application to decision making. We pay special attention to applications in the medical sciences and provide a study case for biological signaling pathways
Empirical Mode Decomposition and a Bidirectional LSTM Architecture Used to Decode Individual Finger MI-EEG Signals
Get PDFBrain-Computer Interface (BCI) paradigms based on Motor Imagery Electroencephalogram (MI-EEG) signals have been developed because the related signals can be generated voluntarily to control further applications. Researches using strong and stout limbs MI-EEG signals reported performing significant classification rates for BCI applied systems. However, MI-EEG signals produced by imagined movements of small limbs present a real classification challenge to be effectively used in BCI systems. It is due to a reduced signal level and increased noisy distorted effects. This study aims to decode individual right-hand fingers’ imagined movements for BCI applications, using MI-EEG signals from C3, Cz, P3, and Pz channels. For this purpose, the Empirical Mode Decomposition (EMD) preprocesses the non-stationary and non-linear EEG signals to finally use a Bidirectional Long Short-Term Memory (BiLSTM) to classify corresponding feature sequences. An average accuracy of 98.8 % was achieved for ring-finger movements decoding using k-fold cross-validation on a public dataset (Scientific-Data). The obtained results support that the proposed framework can be used for BCI control applications
Semantic Segmentation to Extract Coronary Arteries in Invasive Coronary Angiograms
Get PDFAccurate semantic segmentation of each coronary artery using invasive coronary angiography (ICA) is important for stenosis assessment and coronary artery disease (CAD) diagnosis. In this paper, we propose a multi-step semantic segmentation algorithm based on analyzing arterial segments extracted from ICAs. The proposed algorithm firstly extracts the entire arterial binary mask (binary vascular tree) using a deep learning-based method. Then we extract the centerline of the binary vascular tree and separate it into different arterial segments. Finally, by extracting the underlying arterial topology, position, and pixel features, we construct a powerful coronary artery segment classifier based on a support vector machine. Each arterial segment is classified into the left coronary artery (LCA), left anterior descending (LAD), and other types of arterial segments. The proposed method was tested on a dataset with 225 ICAs and achieved a mean accuracy of 70.33% for the multi-class artery classification and a mean intersection over union of 0.6868 for semantic segmentation of arteries. The experimental results show the effectiveness of the proposed algorithm, which provides impressive performance for analyzing the individual arteries in ICAs
A Conjecture Congenetic with Fermat’s Last Theorem
Get PDFWe propose the conjecture that for any positive integers r and n with n > 2, there do not exist 2r + 1 consecutive positive integers in natural order such that the sum of n-th powers of the first r + 1 integers equals the sum of n-th powers of the subsequent r integers, i.e., there are no positive integers r, m and n, where r < m and n > 2, satisfying (m – r)n + (m – r + 1)n + … + mn = (m + 1)n + (m + 2)n + … + (m + r)n. We prove that the conjecture is true for the cases n = 3 and n = 4. We also verified by using Mathematica that the conjecture is true for the cases 3 < n < 10 and m < 5000
Evaluation of an Automated Truck Wash Modified with a Two-Stage Decontamination System for Sanitizing Transport Trucks At Large Farms or Animal Contaminant Facilities
Get PDFAn automated truck wash study was conducted at a large layer hen facility to determine the effectiveness of a modified decontamination system for sanitizing semi-trucks and other farm vehicles. The commercial automated power washing system was modified with a fixed gantry that applied a chlorine dioxide (ClO2) disinfectant rinse as the truck exited the biosecurity facility. The truck decontamination study included the primary study plus one smaller Bacillus atrophaeus spore study, as well as air and water sampling. The goal of the field study was to determine the effectiveness of a two-stage automated decontamination system for sanitizing a large, semi-tractor trailer. The primary study objective was to evaluate two power washing techniques (power wash only with a surfactant or power wash with surfactant and a ClO2 rinse). The second objective was to evaluate the decontamination methods on four coupon materials (glass, painted metal, plastic, rubber) to determine the effectiveness of the two-stage wash system on inoculated coupons. The third objective was to determine the effectiveness of the decontamination methods on coupon locations on the truck (front windshield, middle side of trailer, undercarriage). The fourth objective was to determine the effectiveness of the decontamination methods on coupon surface type (coupons coated with or without synthetic grime).
The primary study evaluated 48 decontamination treatments to assess their ability to inactivate the MS2 bacteriophage, which is the viral surrogate selected for the study. The results show that the two-stage decontamination treatments increased log10 reduction of the MS2 phage. Log10 reduction increased an average of 247% and 118% for the non-grimed and grimed coupons, respectively, when comparing the automated wash with and without ClO2 rinse across all locations and material types. The average log10 reduction increased from 0.94 to 1.89 for the automated wash and the automated wash + ClO2 rinse, respectively, for the grimed coupons, across all coupon locations and materials. The average log10 reduction increased from 1.23 to 2.17 for the automated wash without ClO2 and the automated wash + ClO2 rinse, respectively, for the non-grimed coupons, across all coupon locations and materials. These results show that combining the ClO2 disinfectant rinse with the automated power wash increased viral efficacy by an average of one log (grimed coupons). Evaluation of the two-stage tuck decontamination system confirms that combining a power wash with a disinfectant rinse increases the ability of the system to sanitize transport trucks and increase farm biosecurity.
Field Response of Tephritid Fruit Flies (Diptera) to Fruit Juice of Some Botanicals and Implications for Bio-Rationale Pest Management in Sudan
Get PDFFruit flies belonging to the order Tephritidae are the most notorious pests that attack various fruit and vegetable species, causing severe economic losses. Guava orchards at Elfaki Hashim; North of Khartoum, (Khartoum State) and Elsawagi Elgenobia (Kassala State) in the middle and east of Sudan respectively were selected to assess the response of some Tephritids to water extracts (WE) of mango, guava, apple, cucumber, and ready-made juice of mango (Crystal®; Crystal Industrial Co. Ltd, Araak Group; [email protected]) against Torula yeast (a standard fruit fly attractant) and water (control) baited in locally made traps. The trial was performed as Randomized Complete Block Design (RCBD) replicated 3 times for 5 consecutive weeks at each site. Highly significant differences were recorded between attractants and the interaction between attractants and times (weeks) on trapping different species of fruit flies. Five species of fruit flies; Ceratitis capitata, Bactrocera dorsalis, Zeugodacus cucurbitae, Ceratitis cosyra, and Ceratitis quinaria, were found to respond positively to all tested materials at both sites. The greatest number of C. capitata flies was caught by traps equipped with ready-made Crystal® mango juice at the Elfaki Hashim site. The mean number of B. dorsalis attracted to the WEs of mango and guava at Elsawagi Elgenobia site was statistically identical to that of the same species lured to Torula yeast, 83.7, 70.3, and 111.5 flies /trap/week, respectively. Attractants extracted from botanicals are cost-free and easily prepared by farmers for mass trapping of fruit flies. More studies regarding active ingredients, doses, and the number of traps utilized per area should be considered
Revolutionizing Fuel Cell Efficiency with Non-Metallic Catalysts for Oxygen Reduction Reactions
Get PDFPlatinum-based catalysts are widely used in oxygen reduction reactions, but platinum’s high cost and low reserves have restricted their sustainable development. With continuous in-depth research, it has been found that metal-free catalysts also have better catalytic activity in oxygen reduction reactions and have great potential for development due to the low cost and abundant reserves of metal-free catalysts, which has become a hot research direction. This paper reviews the application of metal-free catalysts in oxygen reduction reactions, including heteroatom-doped carbon-based catalysts, polymeric nitrogen catalysts, and emerging carbon catalysts. This work provides insights into developing non-platinum catalysts for oxygen reduction reactions by comparing the catalytic activity, selectivity, and prolonged stability