ARTICLE | doi:10.20944/preprints201705.0116.v1
Subject: Engineering, Mechanical Engineering Keywords: thermal runaway; big-data platform; battery systems; electric vehicles; National Service and Management Center for Electric Vehicles
Online: 16 May 2017 (03:18:57 CEST)
This paper presents a thermal runaway prognosis scheme based on the big-data platform and entropy method for battery systems in electric vehicles. It can simultaneously realize the diagnosis and prognosis of thermal runaway caused by the temperature fault through monitoring battery temperature during vehicular operations. A vast quantity of real-time voltage monitoring data was collected in the National Service and Management Center for Electric Vehicles (NSMC-EV) in Beijing to verify the effectiveness of the presented method. The results show that the proposed method can accurately forecast both the time and location of the temperature fault within battery packs. Furthermore, a temperature security management strategy for thermal runaway is proposed on the basis of the Z-score approach and the abnormity coefficient is set to make real-time precaution of temperature abnormity.
ARTICLE | doi:10.20944/preprints202211.0150.v1
Subject: Engineering, Automotive Engineering Keywords: China; Electric vehicle; Development bottleneck; French Standardization; Enlightenment
Online: 8 November 2022 (09:18:21 CET)
The problems of operating range and costs are the two most critical bottlenecks restricting the extensive application of electric vehicles at home and abroad. There are also some prominent problems in China's electric vehicles, such as slow improvement of electric vehicle's operating range, difficulty in charging, slow charging, low utilization efficiency of charging resources, and high battery cost for electric vehicles, which lead to poor competitiveness of electric vehicles compared with traditional internal combustion engine (I.C.E.) vehicles. This paper analyzes the key factors restricting the development and popularization of electric vehicles in China from the aspects of strategic policy, sales situation and self problems. Through summarizing the experience and lessons of French standardization development strategy and electric vehicle development mode, this paper puts forward the hypothesis leading the development of electric vehicles through standardization to enhance their competitiveness, gives the specific suggestions, and briefly analyzes the feasibility from the aspects of product situation. The research content of this paper provides a certain basis and ideas for the future research work.
ARTICLE | doi:10.20944/preprints202310.1812.v1
Subject: Social Sciences, Education Keywords: social needs; curriculum chains; curriculum energy efficiency space; student ability space; dynamic evolution; control
Online: 27 October 2023 (13:27:06 CEST)
Curriculum teaching is the basic unit to realize the cultivation and achievement of students’ ability in undergraduate colleges, and it is very important to investigate the influence mechanism of the curriculum system on the achievement states of students' ability. This paper first puts forward the theoretical system and framework of curriculum chains, and constructs a “double-energy and double-space” (DEDS) which consist of the curriculum energy efficiency space and student ability space respectively. Investigating the space-time transformation relationship of curriculum chains in the DEDS, the forward transformation model, inverse transformation model and the rheological model of the achievement states in the curriculum energy efficiency space and student ability space are established. Studying the dynamic evolution mechanism of curriculum chains within the DEDS, the dynamic evolution model, which presents the relationship between achievement states of curriculum energy efficiency/students' ability and curriculum/students' dynamic potential, are established; the control methods of courses/students' dynamic potential based on the proposed dynamic evolution model are developed to ensure the achievements of the graduates’ social ability; the evaluation and detection methods of achievement states of curriculum chains in DEDS are proposed to obtain the actual achievement states of curriculum energy efficiency and students’ ability, and this will provide effective input for the control of curriculums/students’ dynamic potential; the planning and design methods of curriculum chains facing social needs are presented, which can provide theoretical basis for the formulation of the talent training scheme and curriculum system in colleges and universities.
ARTICLE | doi:10.20944/preprints202304.0734.v1
Subject: Computer Science And Mathematics, Computer Networks And Communications Keywords: Federated Learning; Node Selection; Deep Reinforcement Learning; Multi-Objective; Model Performance
Online: 23 April 2023 (03:02:36 CEST)
As a new distributed machine learning (ML) approach, federated learning (FL) shows the great potential to preserve data privacy by enabling distributed data owners to collaboratively build a global model without sharing their raw data. However, the heterogeneity in terms of data distribution and hardware configurations make it hard to select participants from the thousands of nodes. In this paper, we propose a multi-objective node selection approach to improve time-to-accuracy performance while resisting malicious nodes. We firstly design a deep reinforcement learning assisted FL framework. Then the problem of multi-objective node selection under this framework is formulated as a Markov decision process (MDP), which aims to reduce the training time and improve model accuracy simultaneously. Finally, a deep Q-netwok (DQN) based algorithm is proposed to efficiently solve the optimal set of participants for each iteration. Simulation results show that the proposed method not only significantly improves the accuracy and training speed of FL, but has stronger robustness to resist malicious nodes.
ARTICLE | doi:10.20944/preprints202007.0163.v1
Subject: Engineering, Mechanical Engineering Keywords: Shape memory polymer; LCD; Transparency; High shape recovery rate; Fast responsive
Online: 9 July 2020 (01:58:31 CEST)
In this study, we report a new epoxy acrylate based shape memory polymer(SMP) fabricated by Liquid crystal display (LCD) Stereolithographic 3D printing. The printed 3D object has a high resolution and high transparency in visible light region. The uniaxial tensile tests showed enhanced tensile toughness and tunable mechanical properties. The fix-recovery and cycle tests indicated high shape recovery properties including high shape recovery rate and excellent cycling stability. In addition, a smart electrical valve actuator was fabricated that can be used in fast heat or electricity responsive electrical circuits. LCD 3D printing provides a low-cost and high efficient way to fabricate fast responsive SMP, which can be used in wide applications in various fields on aerospace engineering, biomedical devices, soft robots and electronic devices.
ARTICLE | doi:10.20944/preprints201911.0309.v1
Subject: Engineering, Bioengineering Keywords: in vitro diagnostics; microfluidics; full integration; lab-on-a-chip; pathogen detection
Online: 26 November 2019 (09:56:47 CET)
Microfluidics is facing critical challenges in the quest of miniaturizing, integrating, and automating in vitro diagnostics, including the increasing complexity of assays, the gap between the macroscale world and the microscale devices, and the diverse throughput demands in various clinical settings. Here a “3D extensible” microfluidic design paradigm that consists of a set of basic structures and unit operations was developed for constructing any application-specific assay. Four basic structures- check valve (in), check valve (out), double-check valve (in and out), and on-off valve, were designed to mimic basic acts in biochemical assays. By combining these structures linearly, a series of unit operations can be readily formed. We then proposed a “3D extensible” architecture to fulfill the needs of the function integration, the adaptive “world-to-chip” interface, and the adjustable throughput in the X, Y, and Z directions, respectively. To verify this design paradigm, we developed a fully integrated loop-mediated isothermal amplification microsystem that can directly accept swab samples and detect Chlamydia trachomatis automatically with a sensitivity one order higher than that of the conventional kit. This demonstration validated the feasibility of using this paradigm to develop integrated and automated microsystems in a less risky and more consistent manner.
ARTICLE | doi:10.20944/preprints201801.0142.v2
Subject: Environmental And Earth Sciences, Waste Management And Disposal Keywords: ater-borne; iodine excess; impairement; control and prevention
Online: 8 February 2018 (15:21:11 CET)
Since the water-borne iodine excessive goiter was firstly found and reported in 19 in Hebei Province, it was confirmed successively. The national water-borne investigation carried out in 2005 demarcated the water-borne iodine excess areas and water-borne iodine excess endemial areas. The high iodine water well was found In 129 counties of 11 provinces, about 30.98 million people of threatened population lived in water-borne iodine excess areas and water borne iodine excess endemial areas. In these areas, the measures of prevention and control was effectively implemented. In 2016, the new standard of iodine excess area was issued, the iodine excess areas redrawed, and in these areas, non-iodized salt should be supplied and the drinking water should be gradually improved of water, and to control the damage of water-borne iodine excess at an early date
ARTICLE | doi:10.20944/preprints202305.1318.v1
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: starch gel; adhesive; flame-retardancy
Online: 18 May 2023 (09:51:50 CEST)
Starch being renewable and biodegradable is a viable resource for developing sustainable and environmentally friendly materials. This work explores the potential of starch/Ca2+ gels based on waxy corn starch (WCS), normal corn starch (NCS), and two high-amylose corn starches, G50 (55% amylose content) and G70 (68% amylose content) as flame-retardant adhesives. Being stored at 57% relative humidity for up to 30 days, the G50/Ca2+ and G70/Ca2+ gels are stable without water absorption or retrogradation. The starch gels with increasing amylose content displayed increased cohesion, as reflected by significantly higher tensile strength and fracture energy. All the four starch-based gels show good adhesive properties on corrugated paper. For wooden boards, because of the slow diffusion of the gels, the adhesive abilities are weak initially but improve with storage extension. After storage, the adhesive abilities of the starch-based gels are almost the same except for G70/Ca2+, which is peeled off from the wood surface by itself. Moreover, all the starch/Ca2+ gels exhibit excellent flame retardancy with limiting oxygen index (LOI) values all around 60. This work demonstrates a facile method to prepare starch-based flame-retardant adhesives simply by gelating starch with a CaCl2 solution, which can be used in paper or wood products.
ARTICLE | doi:10.20944/preprints202309.2078.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Soil phosphorus availability; Dissolved organic matter; Organic fertilizer; Competitive adsorption; Molecular weight
Online: 3 October 2023 (03:36:39 CEST)
Dissolved organic matter (DOM) derived from organic fertilizers may increase soil phosphorus (P) availability. However, the frequently observed correlation between soil P availability and dissolved organic carbon (DOC) content has led to an excessive focus on DOC content at the expense of DOM properties. The present study investigated the influence of DOM characteristics on soil P availability by using a 6-year field experiment and microcosms of P sorption in paddy soil. Our results showed that partial replacement of chemical P fertilizer with manure or crop straw increased P fertilizer-use efficiency, even when decreasing chemical P input by 34 %, compared to normal chemical fertilization. The microcosm experiment demonstrated that DOM properties, rather than total DOC content, determine soil P sorption capacity, despite the significant correlation between DOC content and P availability observed in the field experiment. Manure-DOM exerted stronger inhibitory effects on P sorption than straw-DOM, and high molecular weight (HMW)-fractionated DOM exerted stronger inhibitory effects on P sorption than low-molecular-weight-fractionated DOM by 16-20%. The mechanism was rooted in the HMW DOM with unique characteristics (e.g., strong aromaticity, hydrophobicity, abundant humic-like components, carboxyl groups, and benzene ring structures) competing for soil P sorption sites (e.g., reduction in specific surface area and micropore volume), decreasing the soil surface charge (e.g., zeta potential), and thereby suppressing P sorption in paddy soil. Our study points out a promising avenue for regulating organic matter properties with organic fertilization to improve P use efficiency in agricultural soils.
ARTICLE | doi:10.20944/preprints202101.0303.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Controlling Nutritional Status Score; Hemorrhagic stroke; Nutrition screening; Prognosis; Modified Rankin Scale
Online: 15 January 2021 (16:08:15 CET)
Controlling Nutritional Status (CONUT) Score is useful for the nutritional screening. We aimed to explore whether the CONUT score may predict a 3-month functional outcome in hemorrhagic stroke (AHS). Totally, 349 patients with incident AHS were consecutively recruited, and their malnutrition risks were determined using a high CONUT score of ≥ 2. Poor functional outcomes were defined as the modified Rankin Scale (mRS) score of ≥ 3 at 3 months. A total of 328 patients (mean age, 60.4 ± 12.83 years; 66.8% male) were included, 172 (52.40%) patients at malnutrition risk and 104 (31.7%) patients with a poor prognosis. High-CONUT patients had lower total lymphocyte counts and total cholesterol levels than low-CONUT patients (p < 0.001 and p = 0.012). At 3-month post discharge, patients with malnutrition risk had higher hospitalization costs (p = 0.021), lower Barthel Index (p = 0.001), and more infectious complications (p = 0.002) than those without, and there was a greater risk for poor functional outcomes in the high-CONUT compared with the low-CONUT patients at admission (adjusted odds ratio: 2.32, 95% confidence interval: 1.28-4.17). High-CONUT scores predict a 3-month poor prognosis in AHS, which may help identify the AHS patients who need additional nutritional managements.
ARTICLE | doi:10.20944/preprints201702.0044.v2
Subject: Engineering, Energy And Fuel Technology Keywords: dielectric properties; microwave; zinc sulfide concentrate
Online: 14 February 2017 (07:45:08 CET)
Microwave technology has a potential application in the extraction of zinc from sulphide ores, knowledge of the dielectric properties of these ores plays a major role in the microwave design and simulation for any process. The dielectric properties of zinc sulfide concentrate for two different apparent densities—1.54 and 1.63 g/cm3—have been measured by using the resonance cavity perturbation technique at 915 and 2450 MHz during the roasting process for the temperature ranging from room temperature to 850 °C. The variations of dielectric constant, the dielectric loss factor, the dielectric loss tangent and the penetration depth with the temperature, frequency and apparent density have been investigated numerically. The results indicate that the dielectric constant increases as the temperature increases and temperature has a pivotal effect on the dielectric constant, while the dielectric loss factor has a complicated change and all of the temperature, frequency and apparent density have a significant impact to dielectric loss factor. Zinc sulfide concentrate is high loss material from 450 to 800 °C on the basis of theoretical analyses of dielectric loss tangent and penetration depth, its ability of absorbing microwave energy would be enhanced by increasing the apparent density as well. The experimental results also have proved that zinc sulfide concentrate is easy to be heated by microwave energy from 450 to 800 °C. In addition, the experimental date of dielectric constant and loss factor can be fitted perfectly by Boltzmann model and Gauss model, respectively.