High molecular weight carboxymethyl cellulose binder to enhance integrity of silicon anodes for Li-ion batteries

Department of Energy Engineering (Battery Science and Technology)Today, considerable interest for eco-friendly and renewable energy systems has been increased toward. Among sustainable energy systems, lithium-ion batteries have been treated as a promising energy device for high-energy batteries. Among anode materials, silicon has attracted attention as a promising candidate for high-energy LIBs due to its high theoretical capacity. However, electrochemical reactions of silicon materials normally result in electrode failure, which cause cell degradation due to massive volume changes upon cycling. To resolve problems, many researchers have studied outstanding binders, which are efficient to sustain the mechanical integrity of electrodes and electrical conductivity, leading to improved electrochemical performances. Herein, we discuss recent works and main issues for functional binders and provide binding mechanisms in terms of chemical and physical features. The relationship between chain lengths of CMC binders and enhanced electrochemical performances of silicon-graphite composite anodes is discussed in detail.clos

Analytical Model for Deflections of Bonded Posttensioned Concrete Slabs

This paper presents a finite element analysis approach to evaluate the flexural behavior of posttensioned two-way slabs depending on the tendon layout. A finite element model was established based on layered and degenerated shell elements. Nonlinearities of the materials are considered using the stress-strain relationships for concrete, reinforcing steel, and prestressing tendons. Flexural testing of the posttensioned two-way slabs was conducted to validate the developed analytical process. Comparing the analytical results with the experimental results in terms of deflections, it showed generally good agreements. Also a parametric study was performed to investigate the effects of different types of tendon layout

The long-term effects of the fenestration in patients with extracardiac Fontan circulation—a multicenter Korean cohort study based on national Fontan registry

IntroductionThe long-term effects of fenestration in patients with Fontan circulation remain unclear. We aim to evaluate the fenestration impact on early and late outcomes in patients with extracardiac Fontan (ECF) using a propensity score matching analysis.MethodsWe performed an extensive retrospective multicenter clinical data review of the Korean Fontan registry and included 1,233 patients with surgical ECF (779 fenestrated, 454 non-fenestrated). Demographics, baseline, and follow-up data were collected and comprehensively analyzed. Patients were divided into two groups according to the baseline presence or absence of surgical fenestration. Subsequently, patients were sub-divided according to the fenestration status at the last follow-up. Propensity-score matching was performed to account for collected data between the 2 groups using a multistep approach. The primary outcomes were survival and freedom from Fontan failure (FFF). We also looked at postoperative hemodynamics, cardiopulmonary exercise test results, oxygen saturations, and functional status.ResultsAfter propensity-score matching (454 matched pairs), there was no difference in survival or FFF between the 2 groups. However, ECF patients with baseline fenestration had significantly lower oxygen saturation (p = 0.001) and lower functional status (p < 0.001). Patients with fenestration had significantly longer bypass times, higher postoperative central venous pressure, higher postoperative left atrial pressure, and less prolonged pleural effusion in the early postoperative period. The propensity score matching according to the fenestration status at the last follow-up (148 matched pairs) showed that patients with a persistent fenestration had significantly lower oxygen saturation levels (p < 0.001). However there were no intergroup differences in the functional status, survival and FFF.ConclusionsOur results showed no long-term benefits of the Fenestration in terms of survival and FFF. Patients with persistent fenestration showed oxygen desaturation but no difference in exercise intolerance was shown between the 2 groups

The Application of Terrestrial Light Detection and Ranging to Forest Resource Inventories for Timber Yield and Carbon Sink Estimation

New technologies are utilized to improve forest management, but they require the collection and analysis of digital data. This study assessed the applicability of using light detection and ranging (LiDAR) devices for the examination of forest resource inventories to obtain digital forest resource information. Two terrestrial LiDARs, a backpack laser scanner (BPLS) and a terrestrial laser scanner (TLS) were used and compared with the traditional method to identify which was optimal. The findings showed that the TLS single-scan method was least accurate due to occlusion. The TLS multi-scan method and the BPLS showed high levels of accuracy for the height and diameter at breast height (DBH) estimates in most sample plots. However, the BPLS underestimated height to a greater extent than the other methods in a sloped plot (24°). Nevertheless, the efficiency of the BPLS was 2.8 times higher than that of the TLS when considering the amount of time spent on completing all indoor and outdoor tasks. Thus, these results prove that the utilization of LiDAR devices increases the efficiency of data collection and overcomes the limitations of existing methods. Moreover, they provide accurate information that will be a basis for forest management plans, the estimation of biomass, and the transaction of forest products

The Application of Terrestrial Light Detection and Ranging to Forest Resource Inventories for Timber Yield and Carbon Sink Estimation

New technologies are utilized to improve forest management, but they require the collection and analysis of digital data. This study assessed the applicability of using light detection and ranging (LiDAR) devices for the examination of forest resource inventories to obtain digital forest resource information. Two terrestrial LiDARs, a backpack laser scanner (BPLS) and a terrestrial laser scanner (TLS) were used and compared with the traditional method to identify which was optimal. The findings showed that the TLS single-scan method was least accurate due to occlusion. The TLS multi-scan method and the BPLS showed high levels of accuracy for the height and diameter at breast height (DBH) estimates in most sample plots. However, the BPLS underestimated height to a greater extent than the other methods in a sloped plot (24°). Nevertheless, the efficiency of the BPLS was 2.8 times higher than that of the TLS when considering the amount of time spent on completing all indoor and outdoor tasks. Thus, these results prove that the utilization of LiDAR devices increases the efficiency of data collection and overcomes the limitations of existing methods. Moreover, they provide accurate information that will be a basis for forest management plans, the estimation of biomass, and the transaction of forest products

Straining Behavior of Mortar Reinforced by Cold Drawn Crimped and Dog-Bone-Shaped Fibers under Monotonic and Cyclic Compressions

The straining behavior of the shape memory alloy (SMA) fibers-reinforced mortar was investigated in this study by the monotonic compressive and cyclic compressive tests. Two types of SMA fibers with a crimped and dog-bone shape were used due to the high pullout resistance capacity, which guaranteed that the fibers and mortar matrix were composited well. The plain mortar was mixed with two different compositions to create the higher elastic modulus mortar matrix and the lower elastic modulus mortar matrix compared with the elastic modulus of SMA fibers. The results of the experimental test indicated that the non-heated SMA fibers could control the strains in both elastic and plastic phases; in which, the crimped fiber was more effective in precracking due to the higher composite capacity while the dog-bone-shaped fiber had a higher effect in post-cracking. After heating, the dog-bone-shaped fiber slipped more than that of the crimped fiber; thus, the heated crimped fiber was more effective than the heated dog-bone-shaped fiber in controlling strains after cracking. The effect of SMA fibers on the elastic modulus depended on both the elastic modulus of mortar matrix and the property of SMA fibers. In the plastic phase, the fibers were effective on reducing the speed of damage in monotonic case. An equation using reinforcing index was suggested for damage evolution in the cyclic case

Effect of Chlorides on Conductivity and Dielectric Constant in Hardened Cement Mortar: NDT for Durability Evaluation

Dielectric constant and conductivity, the so-called EM properties (electromagnetic), are widely adopted for NDT (Nondestructive Technique) in order to detect damage or evaluate performance of concrete without damage to existing RC (reinforced concrete). Among deteriorating agents, chloride ion is considered as one of the most critical threats due to rapid penetration and direct effect on steel corrosion. In the work, cement mortar samples with 3 w/c (water-to-cement) ratios and 4 levels of chloride addition are considered. Conductivity and dielectric constant are measured in the normal frequency range. They increase with strength of mortar and more chloride ions due to denser pore formation. Furthermore, the behaviors of measured EM property are investigated with carbonation velocity and strength, which shows an attempt of application to durability evaluation through EM measurement

A quantitative analysis of spontaneous alternation behaviors on a Y-maze reveals adverse effects of acute social isolation on spatial working memory

Abstract Animals tend to alternate between different choices, which requires the ability to remember recent choices. The Y-maze spontaneous alternation test is widely used in various animal models for assessing short-term memory, and its precise evaluation depends upon the accurate determination of the arm visit sequence. However, an objective method for defining arm visits is lacking owing to uncertainty regarding the extent to which an animal must go into the arm to be considered visited. Here, we conducted quantitative analyses on mice behavior in the Y-maze while systematically varying the arm visit threshold and assessed the effect of acute social isolation on spatial working memory. Our results revealed that 24-h social isolation significantly reduced spontaneous alternation rate when the arm threshold was set at the distal part of the arm. Furthermore, the memory of the recently visited arms faded away faster in the socially isolated mice. However, other behavioral factors were comparable to those of the group-housed mice, indicating a specific impairment of short-term memory. Our findings suggest that the location of arm visit threshold is critical for the precise evaluation of short-term memory, and our study provides a method for comprehensively and systematically assessing spontaneous alternation behavior in the Y-maze

An Improved Blind Kriging Surrogate Model for Design Optimization Problems

Surrogate modeling techniques are widely employed in solving constrained expensive black-box optimization problems. Therein, Kriging is among the most popular surrogates in which the trend function is considered as a constant mean. However, it also encounters several challenges related to capturing the overall trend with a relatively limited number of function evaluations as well as searching feasible points with complex or discontinuous feasible regions. To address this above issue, this paper presents an improved surrogate blind Kriging (IBK) and a combined infill strategy to find the optimal solution. According to enhancing the prediction accuracy of metamodels of objective and constraints, the high-order effects of regression function in the blind Kriging are identified by promising a variable selection technique. In addition, an infill strategy is developed based on the probability of feasibility, penalization, and constrained expected improvement for updating blind Kriging metamodels of the objective and constraints. At each iteration, two infill sample points are allocated at the positions to achieve improvement in optimality and feasibility. The IBK metamodels are updated by the newly-added infill sample points, which leads the proposed framework search to rapidly converge to the optimal solution. The performance and applicability of the proposed model are tested on several numerical benchmark problems via comparing with other metamodel-based constrained optimization methods. The obtained results indicate that IBK generally has a greater efficiency performance and outperforms the competitors in terms of a limited number of function evaluations. Finally, IBK is successfully applied to structural design optimization. The optimization results show that IBK is able to find the best feasible design with fewer evaluation functions compared with other studies, and this demonstrates the effectiveness and practicality of the proposed model for solving the constrained expensive black-box engineering design optimization problems

Dietary Glutamic Acid Modulates Immune Responses and Gut Health of Weaned Pigs

Dietary glutamic acid (GLU) is used as a feed additive because of its functional characteristics that may affect the growth performance and health of pigs. This study was carried out to determine the effects of dietary GLU on growth performance, nutrient digestibility, immune responses, and intestinal health of weaned pigs. A total of ninety-six weaned pigs (8.07 ± 1.17 kg of body weight; 28 days of age) were assigned to two dietary treatments (8 pigs/pen; 6 replicates/treatment) in a randomized complete block design (block: body weight): (1) a typical weaner diet (CON) and (2) CON supplemented with 0.5% GLU. The experimental period was for 4 weeks. All data and sample collections were performed at the specific time points during the experimental period. Pigs fed GLU had higher average daily gain and average daily feed intake for the first two weeks and nutrient digestibility than pigs fed CON. In addition, dietary GLU increased villus height to crypt depth ratio, number of goblet cells, and ileal gene expression of claudin family and occludin compared with CON, but decreased serum TNF-α and IL-6 and ileal gene expression of TNF-α. Moreover, pigs fed GLU had increased relative composition of bacterial communities of genus Prevotella and Anaerovibrio and decreased genus Clostridium and Terrisporobacter compared with those fed CON. This study suggests that dietary GLU influences growth performance and health of weaned pigs by modulating nutrient digestibility, intestinal morphology, ileal gene expression of tight junction proteins and cytokines, immune responses, and microbial community in the gut