采用LIMPET测试混凝土强度的试验研究

在钢筋混凝土结构服役寿命中,混凝土强度是联系结构安全性的重要指标。较为准确地检测混凝土质量,对于结构物而言是十分重要的。进行了英国女王大学研发的LIMPET混凝土强度监测设备对于中国混凝土的适用性验证。采用LIMPET拔出试验仪和液压式万能试验机对几种国内常用混凝土强度的试件进行测试,对数据进行统计分析之后,总结出国内常用混凝土的LIMPET拔出强度与轴心抗压强度之间的相关关系曲线,对现场评估结构物中混凝土强度提供相关依据,也为LIMPET仪器在中国的标准化提供试验支持。     

Ensemble Machine Learning Based Identification of Pediatric Epilepsy

Epilepsy is a type of brain disorder that causes recurrent seizures. It is the second most common neurological disease after Alzheimer’s. The effects of epilepsy in children are serious, since it causes a slower growth rate and a failure to develop certain skills. In the medical field, specialists record brain activity using an Electroencephalogram (EEG) to observe the epileptic seizures. The detection of these seizures is performed by specialists, but the results might not be accurate due to human errors; therefore, automated detection of epileptic pediatric seizures might be the optimal solution. This paper investigates the detection of epileptic seizures by applying supervised machine learning techniques. The techniques applied on the data of patients with ages seven years and below from children’s hospital boston massachusetts institute of technology (CHB-MIT) scalp EEG database of epileptic pediatric signals. A group of Naïve Bayes (NB), Support vector machine (SVM), Logistic regression (LR), k-nearest neighbor (KNN), Linear discernment (LD), Decision tree (DT), and ensemble learning methods were applied to the classification process. The results demonstrated the outperformance of the present study by achieving 100% for all parameters using the Ensemble learning model in contrast to state-of-the-art studies in the literature. Similarly, the SVM model achieved performance with 98.3% for sensitivity, 97.7% for specificity, and 98% for accuracy. The results of the LD and LR models reveal the lower performance i.e., the sensitivity at 66.9%–68.9%, specificity at 73.5%–77.1%, and accuracy at 70.2%–73%.     

Olive oil composition as a function of nitrogen,phosphorus and potassium plant nutrition

BACKGROUND: Macronutrients play fundamental roles in processes affecting olive oil productivity and are expected to influence oil composition. A necessary step in optimal nutrient application management for olives is an understanding of the relationship between olive tree nutritional status and oil quality parameters. We studied the independent effects of N, P and K concentrations in irrigation solution on the oil quality of ‘Barnea’ olives by applying a wide range of macronutrient concentrations under highly controlled conditions. RESULTS: Oil composition was significantly influenced by P and N levels, while K levels had only a minor effect. Unsaturation levels were unaffected by the treatments but, within the unsaturated fatty acids, the levels of PUFA increased compared to those of MUFA. Specifically, levels of the MUFA C18:1, polyphenol content and peroxide values decreased while levels of the PUFA C18:3 increased in response to higher doses of N and P. CONCLUSION: Decreased MUFA and polyphenol levels coupled with increased omega‐3 levels demonstrated a potential negative influence on oil profile alongside increased nutritional benefits. The sum effects on oil yield and composition should be considered in designing of nutrient application management strategies for olive orchards. Copyright © 2009 Society of Chemical Industry     

Effects of polyphenols from Caralluma fimbriata on acrylamide formation and lipid oxidation—An integrated approach of nutritional quality and degradation of fried food

The objective of this study was to investigate the utilization of Caralluma fimbriata an edible succulent cactus as natural antioxidants for retarding acrylamide formation, lipid oxidation, and the degradation of bioactive compounds in French fries due to frying at 190°C. The fresh Caralluma fimbriata extract exhibited the highest phenolic content of 96.4 ± 0.1 mg gallic acid equivalent/g when the raw potato extract showed significantly 27.4 ± 0.3 mg GAE/g before frying. The Caralluma fimbriata extract had the higher flavonoid content of 54.4 ± 0.1 mg of Quercetin equivalent/g, while the raw potato had 38.8 ± 0.2 mg of Quercetin equivalent/g. The total flavonols and flavanols in Caralluma fimbriata were signi?cantly high, and those were found to be 27.6 ±0.8 mg Quercetin Equivalent/g and 19.1 ±0.6 mg Catechin equivalent/g, respectively, and, eventually, higher than potato extract. These bioactive compounds are easily degraded due to frying at high temperatures. The Caralluma fimbriata extract retards the formation of acrylamide precursors in potato, primary and secondary oxidation products, and the degradation of polyphenols after the immersion treatment. The Caralluma fimbriata extract was found to be more effective against acrylamide level (42.5 μg/kg) in French fries. The Caralluma fimbriata treated sample exhibited comparatively better oxidative stability during holding time with highest overall acceptability than the sample treated with butylated hydroxyanisole, distilled water (control) and raw potato (without treatment). The results will provide scientific basis in the use of Caralluma fimbriata as natural antioxidant against acrylamide formation and the oxidative deterioration of bioactive compounds.     

A machine vision approach to the grading of crushed aggregate

The grading of crushed aggregate is carried out usually by sieving. We describe a new image-based approach to the automatic grading of such materials. The operational problem addressed is where the camera is located directly over a conveyor belt. Our approach characterizes the information content of each image, taking into account relative variation in the pixel data, and resolution scale. In feature space, we find very good class separation using a multidimensional linear classifier. The innovation in this work includes (i) introducing an effective image-based approach into this application area, and (ii) our supervised classification using wavelet entropy-based features.     

Multi-level lot sizing in material requirements planning: an empirical investigation

The research report in this paper was a result of a recent article by Yelle [8]. He reports computational results using all combinations of four single level heuristic lot sizing rules, which are applied sequentially to a two level problem in a Material Requirements Planning (MRP) environment. To test the impact of the different combinations of these lot sizing rules he employed six different demand patterns for the end-items which range from level demand to demand which is intermittent throughout the planning horizon. In our research we utilized the same data as Yelle and conducted a more extensive analysis by adding (a) two more recent and powerful single level heuristic rules, namely, the least unit cost heuristic and Silver and Meal's least-cost per period heuristic, (b) the very well known single level optimum method of Wagner-Whitin[7], and (c) a multi-level heuristic proposed recently by McLaren and Whybark [4]. The results show a significant improvement in many cases over the best solutions reported by Yelle.Further in this paper, we also provide a much simpler mathematical formulation of the multi-level lot sizing problem than found in the literature. This formulation was advantageously used to determine optimum solutions using IBM's Mathematical Programming System Extended (MPSX) to the aforementioned problems.     

Application of porous membrane-protected micro-solid-phase extraction combined with HPLC for the analysis of acidic drugs in wastewater

This report describes the use of a porous membrane-protected micro-solid-phase extraction (micro-SPE) procedure to extract acidic drugs from wastewater that are then determined by high-performance liquid chromatography with ultraviolet detection. The micro-SPE device consists of C18 sorbent held within a membrane envelope made of polypropylene. Ketoprofen and ibuprofen were selected as model compounds, and extraction parameters were optimized. Correlation coefficients of 0.9980 and 0.9953 were obtained for ketoprofen and ibuprofen, respectively, across a concentration range of 1-250 microg/L. Relative extraction recoveries were between 94 and 112%. The relative standard deviation of the analytical method ranged between 2 and 10%, respectively. The method detection limits for these target analytes in wastewater ranged from 0.03 to 0.08 microg/L. When compared to conventional solid-phase extraction (SPE), this new method showed better detection limits with good reproducibility. The results shows that this micro-SPE technique is a feasible alternative to multistep SPE for the extraction of analytes in complex samples.     

In Situ Cross-Calibration of In-Fiber Bragg Grating and Electrical Resistance Strain Gauges for Structural Monitoring Using an Extensometer

This study addresses the direct calibration of optical fiber strain sensors used for structural monitoring and is carried out in situ. The behavior of fiber-Bragg-grating-based sensor systems when attached to metal bars, in a manner representative of their use as reinforcement bars in structures, was examined and their response calibrated. To ensure the validity of the measurements, this was done using an extensometer with a further calibration against the response of electrical resistance strain gauges, often conventionally used, for comparison. The results show a repeatable calibration generating a suitable geometric factor of extension to strain for these sensors, to enable accurate strain data to be obtained when the fiber-optic sensor system is in use in structural monitoring applications.     

Stimulus-Responsive Smart Nanoparticles-Based CRISPR-Cas Delivery for Therapeutic Genome Editing

The innovative research in genome editing domains such as CRISPR-Cas technology has enabled genetic engineers to manipulate the genomes of living organisms effectively in order to develop the next generation of therapeutic tools. This technique has started the new era of “genome surgery”. Despite these advances, the barriers of CRISPR-Cas9 techniques in clinical applications include efficient delivery of CRISPR/Cas9 and risk of off-target effects. Various types of viral and non-viral vectors are designed to deliver the CRISPR/Cas9 machinery into the desired cell. These methods still suffer difficulties such as immune response, lack of specificity, and efficiency. The extracellular and intracellular environments of cells and tissues differ in pH, redox species, enzyme activity, and light sensitivity. Recently, smart nanoparticles have been synthesized for CRISPR/Cas9 delivery to cells based on endogenous (pH, enzyme, redox specie, ATP) and exogenous (magnetic, ultrasound, temperature, light) stimulus signals. These methodologies can leverage genome editing through biological signals found within disease cells with less off-target effects. Here, we review the recent advances in stimulus-based smart nanoparticles to deliver the CRISPR/Cas9 machinery into the desired cell. This review article will provide extensive information to cautiously utilize smart nanoparticles for basic biomedical applications and therapeutic genome editing.     

Electromagnetic interference shielding properties of graphene quantum-dots reinforced poly(vinyl alcohol)/polypyrrole blend nanocomposites

Graphene quantum dots (GQDs) reinforced poly(vinyl alcohol) (PVA)/polypyrrole (WPPy) nanocomposite films with various GQDs loadings were synthesized using the versatile solvent casting method. The structural and morphological properties of PVA/WPPy/GQDs nanocomposite films were investigated by employing Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The thermogravimetric analysis revealed enhanced thermal stability of synthesized nanocomposites while enhanced dielectric properties were also observed. The maximum dielectric constant value for PVA/WPPy/GQDs nanocomposite films was observed to be ε = 6,311.85 (50 Hz, 150°C). The electromagnetic interference (EMI) shielding effectiveness (SE) of nanocomposite films was determined in the X-band (8–12 GHz) and Ku-band (12–18 GHz) frequency region. The EMI SE was found to be increased from 0.8 dB for the pure PVA film to 9.8 dB for the PVA/WPPy/GQDs nanocomposite film containing 10 wt% GQDs loading. The enhanced EMI shielding efficiency of nanocomposite films has resulted from the homogenous dispersion of GQDs in PVA/WPPy blend nanocomposites. Thus, the prepared nanocomposites are envisioned to utilize as a lightweight, flexible, and low-cost material for EMI shielding applications.