New non-destructive method for testing the strength of cement mortar material based on vibration frequency of steel bar: Theory and experiment

Timely and accurately obtaining the strength of pouring material, e.g., concrete, cement mortar, is of great significance for engineering construction. In this paper, a non-destructive, economical and accurate strength detection method that suites for on-site using is proposed for the steel bar cement mortar material. The method based on the relationship between the vibration frequency of the steel bar and the properties of the mortar material, which is obtained by solving the Euler-Bernoulli beam problem. Both Particle Flow Code (PFC) software simulation (calibrated) and Split Hopkinson pressure Bar experiment on test samples of cement mortar and steel bar were performed to verify the theoretically obtained relationship. Studies on samples of various aggregate ratio further confirmed such correspondence. Results show that the dynamic stiffness of the cement mortar material dominates the calculation of the vibration frequency of steel bar, while the combined effect of the density, length, elastic modulus, inertia moment of the steel bar can be safely ignored. A single-valued mapping relation exists in between the dynamic stiffness coefficient and the Uniaxial Compressive Strength (UCS) of the cement mortar sample, i.e., increased dynamic stiffness coefficient with increasing UCS. Both experimental and predicted results showed a linear relationship between the vibration frequency of the steel bar and the strength of the mortar material. Fitted linear relations were proposed with coefficients depending on sample size and aggregate ratio and might serve as a good indicator for the strength of the mortar material. Further studies on the effect of internal defects of the mortar materials as well as on samples of more size and aggregate ratio are required to make the proposed method a practical too

microRNA-144/451 decreases dendritic cell bioactivity via targeting interferon-regulatory factor 5 to limit DSS-induced colitis

The microRNAs miR-144/451 are highly conserved miRNA that is strongly induced during erythropoiesis. Despite the biological functions of miR-144/451 have been extensively studied in erythropoiesis and tumorigenesis, few studies have been conducted in immune responses. In this study, we showed that miR-144/451-/- DCs exhibit increased activation. Mechanistically, the miR-144 directly targets the 3`-UTR of IRF5 and represses the expression of IRF5 in DCs. Ectopic expression of miR-144/451 by lentiviruses downregulates the levels of IRF5 and suppresses DCs function. In addition, knockdown of IRF5 by shRNA significantly inhibits activities of the miR-144/451-/- DCs. Expression of miR144/451 was decreased in DCs from both patients with IBD and mice with DSS-colitis compared with controls. Human PBMC derived DCs were downregulated expression of miR144/451 after LPS stimulation. In the DSS-induced colitis mice model, we showed that ablation of the miR-144/451 gene causes severe colitis, and their DCs from both periphery and MLN expressed higher co-stimulatory molecules and pro-inflammatory cytokines than wild-type mice. In addition, DCs isolated from miR-144/451-/- mice transfusion exacerbates mice colitis. In the bone marrow transplanted chimeric mice model, we show that miR-144/451-/- bone marrow transplantation deteriorated DSS-induced colitis. At last, we treat the mice with miR-144/451 delivered by chitosan nanoparticles revealing protective effects in DSS-induced colitis mice. Thus, our results reveal a novel miR144/451-IRF5 pathway in DCs that protects experimental colitis. The manipulation of miR-144/451 expression and DCs activation in IBD patients may be a novel therapeutic approach for the treatment of inflammatory diseases

Efficient rule engine for smart building systems

In smart building systems, the automatic control of devices relies on matching the sensed environment information to customized rules. With the development of wireless sensor and actuator networks (WSANs), low-cost and self-organized wireless sensors and actuators can enhance smart building systems, but produce abundant sensing data. Therefore, a rule engine with ability of efficient rule matching is the foundation of WSANs based smart building systems. However, traditional rule engines mainly focus on the complex processing mechanism and omit the amount of sensing data, which are not suitable for large scale WSANs based smart building systems. To address these issues, we build an efficient rule engine. Specifically, we design an atomic event extraction module for extracting atomic event from data messages, and then build a ?-network to acquire the atomic conditions for parsing the atomic trigger events. Taking the atomic trigger events as the key set of MPHF, we construct the minimal perfect hash table which can filter the majority of the unused atomic event with O (1) time overhead. Moreover, a rule engine adaption scheme is proposed to minimize the rule matching overhead. We implement the proposed rule engine in a practical smart building system. The experimental results show that the rule engine can perform efficiently and flexibly with high data throughput and large rule set. 2014 IEEE.Scopus2-s2.0-8492937871

Flame-retardant thermoelectric responsive coating based on poly(3,4-ethylenedioxythiphene) modified metal–organic frameworks

Poly(3,4-ethylenedioxythiophene) (PEDOT) is introduced on the surface of a metal–organic framework material by solvothermal method to prepare nanorods (TE@Zn-MOFs) with both flame retardant and thermoelectric properties. Data from cone calorimeter and TG-IR show that TE@Zn-MOFs effectively improves the flame retardant and smoke suppression properties of epoxy-based coatings. At a high TE@Zn-MOFs content of 10 wt%, the coating oxygen index increased from 18.2% to 29.0%, the total smoke release decreased from 25.26 to 22.60 m2, and the V-0 level was achieved in vertical combustion classification. Moreover, PEDOT enables epoxy-based coatings to output a certain current value at different heating temperatures (50–200°C). This work demonstrates that MOFs with flexible and variable structures can serve as effective flame retardants for epoxy-based coatings and endow coatings with fire warning characteristics, providing a way to develop multifunctional coatings for different application scenarios

Non-limit passive soil pressure on rigid retaining walls

This paper aims to reveal the depth distribution law of non-limit passive soil pressure on rigid retaining wall that rotates about the top of the wall (rotation around the top (RT) model). Based on Coulomb theory, the disturbance degree theory, as well as the spring-element model, by setting the rotation angle of the wall as the disturbance parameter, we establish both a depth distribution function for sand and a nonlinear depth distribution calculation method for the non-limit passive soil pressure on a rigid retaining wall under the RT model, which is then compared with experiment. The results suggest that under the RT model: the non-limit soil pressure has a nonlinear distribution; the backfill disturbance degree and the lateral soil pressure increase with an increase in the wall rotation angle; and, the points where the resultant lateral soil pressure acts on the retaining wall are less than 2/3 of the height of the wall. The soil pressure predicted by the theoretical calculation put forward in this paper are quite similar to those obtained by the model experiment, which verifies the theoretical value, and the engineering guidance provided by the calculations are of significance. Keywords: RT model, Rigid wall, Non-limit passive soil pressure, Spring element, Genetic algorith

Low-grade malignant myofibroblastic sarcoma of the larynx: a case report

Low-grade myofibroblastic sarcoma (LGMS) is a rare malignant mesenchymal tumor derived from myofibroblasts. It is commonly identified in the head and neck, and particularly in the oral cavity, but rarely in the larynx. In this case report, we describe a patient who presented with hoarseness and underwent electronic fiber laryngoscopy, which revealed a neoplasm on the surface of his left vocal cord. The vocal cord tumor was resected under general anesthesia, and a malignant LGMS was diagnosed on postoperative pathologic examination. The results of immunohistochemical staining of the sections for vimentin (diffuse +), actin (partial +), and desmin (−) were consistent with this diagnosis. The patient recovered well after the surgery, and there was no recurrence of the neoplasm

Influence of alkali metal amides on the catalytic activity of manganese nitride for ammonia decomposition

Strong promoting effect of alkali metal amides, i.e., LiNH2, NaNH2 and KNH2, on the catalytic activity of manganese nitride (MnN) for ammonia decomposition has been demonstrated, which is evidenced by ca. 100 K drop in onset temperature and by ca. 50-60 kJ mol(-1) reduction in apparent activation energy as compared with the neat MnN. The order of promotion capability of alkali metal amides can be ranked as LiNH2 > KNH2 >= NaNH2, either in term of NH3 conversion rate or turnover frequency (TOF), which is distinctly different from that of conventional alkali metal oxides or hydroxides, i.e., K > Na > Li. This phenomenon suggests that the promoting mechanism of alkalis depends on their chemical forms. When alkalis are in the form of amide or imide, they may function as co-catalysts by participating in the catalytic circle directly rather than by executing electronic promotion influence on transition metals. (C) 2016 Elsevier B.V. All rights reserved

Identifying active concentrations of biopolymers for enhancing membrane nanofiltration performance: from bench-scale tests to real production considerations

In the last decades, membrane-based nanofiltration (NF) technique has been widely applied for safe and high-quality drinking water production worldwide. NF membrane fouling has become one of the main obstacles in its application due to high operation cost, and thus numerous efforts have been made. However, there is still a large disconnect between academic findings and their applications. Hence, novel approaches for further exploitation and application are required based on feasibility of implementation. In this work, an optimized design of membrane-based NF plants was proposed, inspired by natural biopolymers present in feed water of NF unit. Specifically, we found beneficial functions of biopolymers, including NF membrane fouling alleviation and effluent quality improvement; these advantages could only be "activated" under a certain concentration range of biopolymers (0-1 mg C/L here), and less or more is not acceptable. This indicated that a NF unit is better to follow a microfiltration (MF) (instead of ultrafiltration (UF) which removes biopolymers) process during which natural biopolymers could be remained; also, this approach is suggested to be valid across different seasons when biopolymers' concentrations could be controlled within an "activated" range by mixing MF and UF permeates. Furthermore, three representative reference biopolymers with different, confirmed spatial structures and molecular weight (MW) were used to elucidate the micro-level functions of natural biopolymers on NF membranes, suggesting that cake layer structures shaped by various biopolymers determine the resulting NF performance. Overall, this innovative proposal is expected to be considered and adopted towards more energy-efficient NF technology for drinking water supply.We thank China Postdoctoral Science Foundation (No. 2018M641497), Beijing Natural Science Foundation (No. 8192042), National Natural Science Foundation of China (No. 51108444), and Key Research and Development Plan of the Ministry of Science and Technology (No. 2019YFD1100104 and No. 2019YFC1906501) for the financial support of the work

Ammonia Decomposition with Manganese Nitride-Calcium Imide Composites as Efficient Catalysts

Ammonia has high gravimetric and volumetric hydrogen densities and is, therefore, considered a promising carrier for the production of COx-free molecular H-2 for forthcoming energy systems. Alkaline earth metals are generally regarded as structural promoters of catalysts and employed in numerous catalytic processes. Here, we report that calcium imide (CaNH) has a strong synergistic effect on Mn6N5 in catalyzing the decomposition of NH3, leading to a ca. 40% drop in apparent activation energy. At 773K, the H-2 formation rate over a Mn6N5-11CaNH composite catalyst is about an order of magnitude higher than that of Mn6N5 and comparable to the highly active Ni/SBA-15 and Ru/Al2O3 catalysts. Analysis by means of temperature-programmed decomposition (TPD), X-ray diffraction (XRD), and X-ray absorption near edge spectroscopy (XANES) reveal that CaNH participates in the catalysis via forming a [Ca6MnN5]-like intermediate, thus altering the reaction pathway and energetics. A two-step catalytic cycle, accounting for the synergy between CaNH and Mn6N5, is proposed