bluuebunny/crossref_metadata_2025 huggingface dataset:
Biofouling of Polyamide Membranes: Fouling Mechanisms, Current Mitigation and Cleaning Strategies, and Future Prospects
Authors: Kucera Jane
Published: August 2019

Reverse osmosis and nanofiltration systems are continuously challenged with biofouling of polyamide membranes that are used almost exclusively for these desalination techniques. Traditionally, pretreatment and reactive membrane cleanings are employed as biofouling control methods. This in-depth review paper discusses the mechanisms of membrane biofouling and effects on performance. Current industrial disinfection techniques are reviewed, including chlorine and other chemical and non-chemical alternatives to chlorine. Operational techniques such as reactive membrane cleaning are also covered. Based on this review, there are three suggested areas of additional research offering promising, polyamide membrane-targeted biofouling minimization that are discussed. One area is membrane modification. Modification using surface coatings with inclusion of various nanoparticles, and graphene oxide within the polymer or membrane matrix, are covered. This work is in the infancy stage and shows promise for minimizing the contributions of current membranes themselves in promoting biofouling, as well as creating oxidant-resistant membranes. Another area of suggested research is chemical disinfectants for possible application directly on the membrane. Likely disinfectants discussed herein include nitric oxide donor compounds, dichloroisocyanurate, and chlorine dioxide. Finally, proactive cleaning, which aims to control the extent of biofouling by cleaning before it negatively affects membrane performance, shows potential for low- to middle-risk systems.
An Isotropic Model for Cyclic Plasticity Calibrated on the Whole Shape of Hardening/Softening Evolution Curve
Authors: Srnec Novak Jelena , De Bona Francesco , Benasciutti Denis
Published: August 2019

This work presents a new isotropic model to describe the cyclic hardening/softening plasticity behavior of metals. The model requires three parameters to be evaluated experimentally. The physical behavior of each parameter is explained by sensitivity analysis. Compared to the Voce model, the proposed isotropic model has one more parameter, which may provide a better fit to the experimental data. For the new model, the incremental plasticity equation is also derived; this allows the model to be implemented in finite element codes, and in combination with kinematic models (Armstrong and Frederick, Chaboche), if the material cyclic hardening/softening evolution needs to be described numerically. As an example, the proposed model is applied to the case of a cyclically loaded copper alloy. An error analysis confirms a significant improvement with respect to the usual Voce formulation. Finally, a numerical algorithm is developed to implement the proposed isotropic model, currently not available in finite element codes, and to make a comparison with other cyclic plasticity models in the case of uniaxial stress and strain-controlled loading.
Metallic Slit-Plate Dampers: Damage Evaluation with Metal Magnetic Memory Technique and Application to Structures with Rocking Columns
Authors: Abarkane Chihab , Ríos-García German , Gale-Lamuela David , Rescalvo Francisco , Gallego Antolino , Benavent-Climent Amadeo
Published: August 2019

Inelastic deformation of metallic materials is one of the most effective mechanisms for the dissipation of energy input to a structure by an earthquake. Metallic dampers are special devices that resort to this source of energy dissipation, proving to be a cost-efficient solution for the seismic protection of structures. Two important issues arise when implementing metallic dampers in real structures: (1) Inelastic deformations cause damage that must be quantified after an earthquake to decide upon their eventual replacement; (2) dampers must possess an energy dissipation capacity large enough to endure severe earthquakes. This paper focuses on a particular type of metallic damper consisting of slit-plates made of stainless steel, applied to reinforced concrete frames with rocking columns at the first story. In particular, a new damage index based on the metallic magnetic memory (MMM) method is proposed and validated experimentally to quantify the damage of slit plate dampers subjected to cyclic loadings. Further, the seismic response of a frame with rocking columns that incorporate the damper is obtained to demonstrate that it can endure severe earthquakes without failing, and to emphasize the relevance of the proposed MMM damage index that would make its replacement after a severe earthquake unnecessary.
Microfluidic-Based Biosensor for Sequential Measurement of Blood Pressure and RBC Aggregation Over Continuously Varying Blood Flows
Authors: Kang Yang Jun
Published: August 2019

Aggregation of red blood cells (RBCs) varies substantially depending on changes of several factors such as hematocrit, membrane deformability, and plasma proteins. Among these factors, hematocrit has a strong influence on the aggregation of RBCs. Thus, while measuring RBCs aggregation, it is necessary to monitor hematocrit or, additionally, the effect of hematocrit (i.e., blood viscosity or pressure). In this study, the sequential measurement method of pressure and RBC aggregation is proposed by quantifying blood flow (i.e., velocity and image intensity) through a microfluidic device, in which an air-compressed syringe (ACS) is used to control the sample injection. The microfluidic device used is composed of two channels (pressure channel (PC), and blood channel (BC)), an inlet, and an outlet. A single ACS (i.e., air suction = 0.4 mL, blood suction = 0.4 mL, and air compression = 0.3 mL) is employed to supply blood into the microfluidic channel. At an initial time (t < 10 s), the pressure index (PI) is evaluated by analyzing the intensity of microscopy images of blood samples collected inside PC. During blood delivery with ACS, shear rates of blood flows vary continuously over time. After a certain amount of time has elapsed (t > 30 s), two RBC aggregation indices (i.e., SEAI: without information on shear rate, and erythrocyte aggregation index (EAI): with information on shear rate) are quantified by analyzing the image intensity and velocity field of blood flow in BC. According to experimental results, PI depends significantly on the characteristics of the blood samples (i.e., hematocrit or base solutions) and can be used effectively as an alternative to blood viscosity. In addition, SEAI and EAI also depend significantly on the degree of RBC aggregation. In conclusion, on the basis of three indices (two RBC aggregation indices and pressure index), the proposed method is capable of measuring RBCs aggregation consistently using a microfluidic device.
Investigation of Possible Leaching Control Mechanisms for Chromium and Vanadium in Electric Arc Furnace (EAF) Slags Using Combined Experimental and Modeling Approaches
Authors: Neuhold Simone , van Zomeren André , Dijkstra Joris J. , van der Sloot Hans A. , Drissen Peter , Algermissen David , Mudersbach Dirk , Schüler Susanne , Griessacher Thomas , Raith Johann G. , Pomberger Roland , Vollprecht Daniel
Published: August 2019

In this study, possible leaching control mechanisms for Cr and V in electric arc furnace slags were investigated by using a multi-methodological approach. Aside from chemical and mineralogical bulk analyses, special emphasis was given to surface investigations of the slags prior to and after leaching. In addition, pH dependence leaching tests were performed and the obtained data were evaluated with hydrogeochemical models. Investigations revealed that Cr and V are mainly bound in spinel and wuestite as well as minor amounts of olivine. Spinel and wuestite do not dissolve during water leaching for 48 h, whereas, depending on the composition of olivine, this phase either dissolves and releases V and Cr congruently, or does not dissolve but may hydrate. Melilite may also hydrate, but neither V nor Cr were detected in this phase. It appears that leached V is subsequently adsorbed onto these newly hydrated phases. The combination of the applied methods further showed that the abundance of calcium silicates, spinel, and wuestite is influenced by the FeO/SiO2 and CaO/SiO2 ratio in the slag. Therefore, it is assumed that the leaching of V and Cr can be minimized by changing these ratios to favor the formation of Fe bearing calcium silicate and spinel instead of wuestite.
Automated SEM Mineral Liberation Analysis (MLA) with Generically Labelled EDX Spectra in the Mineral Processing of Rare Earth Element Ores
Authors: Schulz Bernhard , Merker Gerhard , Gutzmer Jens
Published: August 2019

Many rare earth element (REE) deposits have experienced multistage geological enrichment processes resulting in REE bearing mineral assemblages of considerable complexity and variability. Automated scanning electron microscopy (SEM) mineral liberation analysis of such REE ores is confronted by the difficult assignment of energy-dispersive X-ray (EDX) spectra to REE mineral names. To overcome and bypass this problem, a generic and reliable labelling of EDX reference spectra obtained from REE-bearing minerals based on their contents of Si, Ca, F and P in a bulk normalised analysis is proposed. The labelled spectra are then combined into groups of REE-P (~monazite), REE-Ca-Si-P (~britholite), REE-Ca-F (~synchysite) and REE-F (~bastnaesite, parisite, fluocerite). Mixed spectra with low counts for REE from minute REE mineral grains are combined into a separate group. This classification scheme is applied to automated SEM mineral liberation analysis (MLA) data from beneficiation products by comminution and multistage flotation of REE carbonatite ores. Mineral modes, mineral grain size distribution, mineral liberation, mineral locking and mineral grade versus recovery curves based on the analysis of >200,000 particles in a sample can be recognised and interpreted in virtual grain size fractions. The approach as proposed here will allow future process mineralogical studies of REE deposits to be robust and comparable.
Predicting Missing Seismic Velocity Values Using Self-Organizing Maps to Aid the Interpretation of Seismic Reflection Data from the Kevitsa Ni-Cu-PGE Deposit in Northern Finland
Authors: Junno Niina , Koivisto Emilia , Kukkonen Ilmo , Malehmir Alireza , Montonen Markku
Published: August 2019

We use self-organizing map (SOM) analysis to predict missing seismic velocity values from other available borehole data. The site of this study is the Kevitsa Ni-Cu-PGE deposit within the mafic-ultramafic Kevitsa intrusion in northern Finland. The site has been the target of extensive seismic reflection surveys, which have revealed a series of reflections beneath the Kevitsa resource area. The interpretation of these reflections has been complicated by disparate borehole data, particularly because of the scarce amount of available sonic borehole logs and the varying practices in logging of borehole lithologies. SOM is an unsupervised data mining method based on vector quantization. In this study, SOM is used to predict missing seismic velocities from other geophysical, geochemical, geological, and geotechnical data. For test boreholes, for which measured seismic velocity logs are also available, the correlation between actual measured and predicted velocities is strong to moderate, depending on the parameters included in the SOM analysis. Predicted reflectivity logs, based on measured densities and predicted velocities, show that some contacts between olivine pyroxenite/olivine websterite-dominant host rocks of the Kevitsa disseminated sulfide mineralization—and metaperidotite—earlier extensively used “lithology” label that essentially describes various degrees of alteration of different olivine pyroxenite variants—are reflective, and thus, alteration can potentially cause reflectivity within the Kevitsa intrusion.
Polymineralic Inclusions in Megacrysts as Proxies for Kimberlite Melt Evolution—A Review
Authors: Bussweiler Yannick
Published: August 2019

Polymineralic inclusions in megacrysts have been reported to occur in kimberlites worldwide. The inclusions are likely the products of early kimberlite melt(s) which invaded the pre-existing megacryst minerals at mantle depths (i.e., at pressures ranging from 4 to 6 GPa) and crystallized or quenched upon emplacement of the host kimberlite. The abundance of carbonate minerals (e.g., calcite, dolomite) and hydrous silicate minerals (e.g., phlogopite, serpentine, chlorite) within polymineralic inclusions suggests that the trapped melt was more volatile-rich than the host kimberlite now emplaced in the crust. However, the exact composition of this presumed early kimberlite melt, including the inventory of trace elements and volatiles, remains to be more narrowly constrained. For instance, one major question concerns the role of accessory alkali-halogen-phases in polymineralic inclusions, i.e., whether such phases constitute a common primary feature of kimberlite melt(s), or whether they become enriched in late-stage differentiation processes. Recent studies have shown that polymineralic inclusions react with their host minerals during ascent of the kimberlite, while being largely shielded from processes that affect the host kimberlite, e.g., the assimilation of xenoliths (mantle and crustal), degassing of volatiles, and secondary alteration. Importantly, some polymineralic inclusions within different megacryst minerals were shown to preserve fresh glass. A major conclusion of this review is that the abundance and mineralogy of polymineralic inclusions are directly influenced by the physical and chemical properties of their host minerals. When taking the different interactions with their host minerals into account, polymineralic inclusions in megacrysts can serve as useful proxies for the multi-stage origin and evolution of kimberlite melt/magma, because they can (i) reveal information about primary characteristics of the kimberlite melt, and (ii) trace the evolution of kimberlite magma on its way from the upper mantle to the crust.
Amphiphilic Block Copolymer PCL-PEG-PCL as Stationary Phase for Capillary Gas Chromatographic Separations
Authors: Sun Tao , Shuai Xiaomin , Ren Kaixin , Jiang Xingxing , Chen Yujie , Zhao Xinyu , Song Qianqian , Hu Shaoqiang , Cai Zhiqiang
Published: August 2019

This work presents the first example of utilization of amphiphilic block copolymer PCL-PEG-PCL as a stationary phase for capillary gas chromatographic (GC) separations. The PCL-PEG-PCL capillary column fabricated by static coating provides a high column efficiency of 3951 plates/m for n-dodecane at 120 °C. McReynolds constants and Abraham system constants were also determined in order to evaluate the polarity and possible molecular interactions of the PCL-PEG-PCL stationary phase. Its selectivity and resolving capability were investigated by using a complex mixture covering analytes of diverse types and positional, structural, and cis-/trans-isomers. Impressively, it exhibits high resolution performance for aliphatic and aromatic isomers with diverse polarity, including those critical isomers such as butanol, dichlorobenzene, dimethylnaphthalene, xylenol, dichlorobenzaldehyde, and toluidine. Moreover, it was applied for the determination of isomer impurities in real samples, suggesting its potential for practical use. The superior separation performance demonstrates the potential of PCL-PEG-PCL and related block copolymers as stationary phases in GC and other separation technologies.
Transformation Mechanisms of Chemical Ingredients in Steaming Process of Gastrodia elata Blume
Authors: Li Yun , Liu Xiao-Qian , Liu Shan-Shan , Liu Da-hui , Wang Xiao , Wang Zhi-Min
Published: August 2019

To explore the transformation mechanisms of free gastrodin and combined gastrodin before and after steaming of Gastrodia elata (G. elata), a fresh G. elata sample was processed by the traditional steaming method prescribed by Chinese Pharmacopoeia (2015 version), and HPLC-ESI-TOF/MS method was used to identify the chemical composition in steamed and fresh G. elata. Finally, 25 components were identified in G. elata based on the characteristic fragments of the compounds and the changes of the 25 components of fresh and steamed G. elata were compared by the relative content. Hydrolysis experiments and enzymatic hydrolysis experiments of 10 monomer compounds simulating the G. elata steaming process were carried out for the first time. As a result, hydrolysis experiments proved that free gastrodin or p-hydroxybenzyl alcohol could be obtained by breaking ester bond or ether bond during the steaming process of G. elata. Enzymatic experiments showed that steaming played an important role in the protection of gastrodin, confirming the hypothesis that steaming can promote the conversion of chemical constituents of G. elata—inhibiting enzymatic degradation. This experiment clarified the scientific mechanism of the traditional steaming method of G. elata and provided reference for how to apply G. elata decoction to some extent.
LC-MS Analysis of Serum for the Metabolomic Investigation of the Effects of Pulchinenoside b4 Administration in Monosodium Urate Crystal-Induced Gouty Arthritis Rat Model
Authors: Lyu Shang , Ding Ruowen , Liu Peng , OuYang Hui , Feng Yulin , Rao Yi , Yang Shilin
Published: August 2019

Gouty arthritis (GA) is commonly caused by deposition of monosodium urate (MSU) crystals within the joint capsule, bursa, cartilage, bone, or other periarticular tissues after chronic hyperuricemia. Clinically, GA is characterized by acute episodes of joint inflammation, which is most frequently encountered in the major joints, and also has a significant impact on quality of life. Pulchinenoside b4(P-b4) has a wide range of biological activities, including antitumor, anti-inflammatory, antiviral and immunomodulatory activities. Currently, the anti-GA activity and metabolomic profiles after being treated by P-b4 have not been reported. In this paper, for the first time, we have performed a non-targeted metabolomics analysis of serum obtained from an MSU crystal-induced GA rat model intervened by P-b4, using ultra-performance liquid chromatography coupled to quadrupole time-of-flight tandem mass spectrometry. In this study, the main pharmacodynamics of different dosing methods and dosages of P-b4 was firstly investigated. Results have shown that P-b4 possesses high anti-inflammatory activity. These results demonstrated changes in serum metabolites with 32 potential biomarkers. Arachidonic acid, sphingolipid, and glycerophospholipid metabolism are considered to be the most relevant metabolic pathway with P-b4 treatment effect in this study. Moreover, the changes of metabolites and the self-extinction of model effects within 24 h reveals important information for GA diagnostic criteria: The regression of clinical symptoms or the decline of some biochemical indicators cannot be regarded as the end point of GA treatment. Furthermore, our research group plans to conduct further metabolomics research on the clinical course of GA.
In Vitro Analysis of the Effects of ITER-Like Tungsten Nanoparticles: Cytotoxicity and Epigenotoxicity in BEAS-2B Cells
Authors: Uboldi Chiara , Sanles Sobrido Marcos , Bernard Elodie , Tassistro Virginie , Herlin-Boime Nathalie , Vrel Dominique , Garcia-Argote Sébastien , Roche Stéphane , Magdinier Fréderique , Dinescu Gheorghe , Malard Véronique , Lebaron-Jacobs Laurence , Rose Jerome , Rousseau Bernard , Delaporte Philippe , Grisolia Christian , Orsière Thierry
Published: August 2019

Tungsten was chosen as a wall component to interact with the plasma generated by the International Thermonuclear Experimental fusion Reactor (ITER). Nevertheless, during plasma operation tritiated tungsten nanoparticles (W-NPs) will be formed and potentially released into the environment following a Loss-Of-Vacuum-Accident, causing occupational or accidental exposure. We therefore investigated, in the bronchial human-derived BEAS-2B cell line, the cytotoxic and epigenotoxic effects of two types of ITER-like W-NPs (plasma sputtering or laser ablation), in their pristine, hydrogenated, and tritiated forms. Long exposures (24 h) induced significant cytotoxicity, especially for the hydrogenated ones. Plasma W-NPs impaired cytostasis more severely than the laser ones and both types and forms of W-NPs induced significant micronuclei formation, as shown by cytokinesis-block micronucleus assay. Single DNA strand breaks, potentially triggered by oxidative stress, occurred upon exposure to W-NPs and independently of their form, as observed by alkaline comet assay. After 24 h it was shown that more than 50% of W was dissolved via oxidative dissolution. Overall, our results indicate that W-NPs can affect the in vitro viability of BEAS-2B cells and induce epigenotoxic alterations. We could not observe significant differences between plasma and laser W-NPs so their toxicity might not be triggered by the synthesis method.
Terbium Functionalized Schizochytrium-Derived Carbon Dots for Ratiometric Fluorescence Determination of the Anthrax Biomarker
Authors: Zhang Lina , Wang Zhanwei , Zhang Jingbo , Shi Changliang , Sun Xiaoli , Zhao Dan , Liu Baozhong
Published: August 2019

Efficient and instant detection of biological threat-agent anthrax is highly desired in the fields of medical care and anti-terrorism. Herein, a new ratiometric fluorescence (FL) nanoprobe was elaborately tailored for the determination of 2,6-dipicolinic acid (DPA), a biomarker of anthrax spores, by grafting terbium ions (Tb3+) to the surface of carbon dots (CDs). CDs with blue FL were fabricated by a simple and green method using schizochytrium as precursor and served as an FL reference and a supporting substrate for coordination with Tb3+. On account of the absorbance energy transfer emission effect (AETE), green emission peaks of Tb3+ in CDs-Tb nanoprobe appeared at 545 nm upon the addition of DPA. Under optimal conditions, good linearity between the ratio FL intensity of F545/F445 and the concentrations of DPA was observed within the experimental concentration range of 0.5–6 μM with the detection limit of 35.9 nM, which is superior to several literature studies and significantly lower than the infectious dosage of the Bacillus anthracis spores. Moreover, the CDs-Tb nanoprobe could sensitively detect DPA in the lake water sample. This work offers an efficient self-calibrating and background-free method for the determination of DPA.
The Problem of Hospital Malnutrition in the African Continent
Authors: Blaauw Renée , Achar Esther , Dolman Robin C , Harbron Janetta , Moens Merel , Munyi Faith , Nyatefe Dzifa , Visser Janicke
Published: August 2019

This study aims to determine the prevalence of risk of malnutrition on admission and discharge in African hospitals, and to identify the association with selected indicators. In this multi-center prospective cohort study, adult patients from hospitals in South Africa, Kenya, and Ghana were screened on admission and discharge and contacted 3 months post-discharge. Relevant morbidity and mortality outcomes were assessed. At risk of malnutrition was indicated if NRS-2002 score ≥3. Adult patients (n = 2126; 43.11 years, IQR: 31.95–55.60; 52.2% female) were screened on admission and 61% were identified as at risk of malnutrition. The proportion of at-risk patients for the three hospitals in Kenya and Ghana (66.2%) were significantly higher than that of the three South African hospitals (53.7%) (Chi2 = 31.0; p < 0.001). Discharge risk of malnutrition was 71.2% (n = 394). Mean length of stay (LOS) was 6.46 ± 5.63 days. During hospitalization, 20.6% lost ≥5% body weight, 18.8% were referred for nutrition support, and discharge BMI (23.87 ± 7.38 kg/m2) was significantly lower than admission BMI (24.3 ± 7.3 kg/m2) (p < 0.001). Admission nutrition risk was associated with lower admission and discharge BMI (p < 0.001), longer LOS (p < 0.001), increased 3-month re-admission rates (Chi2 = 1.35; p = 0.245) and increased mortality (Chi2 = 21.68; p < 0.001). Nearly two-thirds of patients were at risk of malnutrition on admission. This was associated with longer LOS and greater hospital mortality. The nutritional status of patients deteriorated during hospitalization. Routine screening practices with appropriate nutrition support action should be implemented as a matter of urgency.
Study on the Electrospinning of Gelatin/Pullulan Composite Nanofibers
Authors: Wang Yuanduo , Guo Ziyang , Qian Yongfang , Zhang Zhen , Lyu Lihua , Wang Ying , Ye Fang
Published: August 2019

In this study, gelatin and pullulan were successfully prepared as a novel type of protein–polysaccharide composite nanofibrous membrane by electrospinning at room temperature with deionized water as the solvent. The effects of gelatin content on the properties of the solution, as well as the morphology of the resultant nanofibers, were investigated. Scanning electron microscopy (SEM) was utilized to observe the surface morphology. Fourier transform infrared spectroscopy (FTIR) was used to study the interaction between gelatin and pullulan. Incorporation of pullulan with gelatin will improve the spinnability of the mixed aqueous solution due to lower surface tension. Moreover, the conductivity of the solution had a greater effect on the fiber diameters, and the as-spun fibers became thinner as the viscosity and the surface tension increased due to the addition of the polyelectrolyte gelatin. Gelatin and pullulan formed hydrogen bonds, and the intermolecular hydrogen bonds increased while the intramolecular hydrogen bond decreased, which resulted in better mechanical properties. The electrospun gelatin/pullulan nanofibers could mimic both the structure and the composition of the extracellular matrix, and thus could be applied in tissue engineering.
Preparation of Methacrylate-Based Polymers Modified with Chiral Resorcinarenes and Their Evaluation as Sorbents in Norepinephrine Microextraction
Authors: Castillo-Aguirre Alver , Maldonado Mauricio
Published: August 2019

Aminomethylation reactions between chiral amino compounds (S)-(-)-1-phenylethylamine and l-proline with tetranonylresorcinarene and tetra-(4-hydroxyphenyl)resorcinarene in presence of formaldehyde were studied. The reaction between l-proline and resorcinarenes generated regioselectively chiral tetra-Mannich bases, due to the molecular incorporation of the fragment of the chiral amino acid. On the other hand, tetranonylresorcinarene and (S)-(-)-1-phenylethylamine formed regio- and diasteroselectively chiral tetrabenzoxazines, both by chiral auxiliary functionalization and by the transformation of the molecular structure that confers inherent chirality. The products obtained were characterized using IR, 1H-NMR, 13C-NMR, COSY, HMQC, and HMBC techniques. The reaction of (S)-(-)-1-phenylethylamine with tetra-(4-hydroxyphenyl)resorcinarene did not proceed under the experimental conditions. Once the chiral aminomethylated tetra-(4-hydroxyphenyl)resorcinarene was obtained, the chemical modification of poly(GMA–co–EDMA) was studied, and the results showed an efficient incorporation of the aminomethylated compound. For the physical modification, chiral aminomethylated tetranonylresorcinarenes were employed, finding that the incorporation of modified resorcinarenes occurs, but with less efficiency than that observed using chemical modification. The modified polymers were characterized via FT-IR, scanning electron microscopy imaging, and elemental analysis. Finally, polymers modified with chiral resorcinarenes were used as sorbents in norepinephrine microextraction; for practical purposes, artificial urine was prepared and used. To perform the microextraction, the decision was made to use the modern rotating-disk sorptive extraction technique (RDSE), because of its analytical attributes as a green, or eco-friendly, technique. According to the results, the method preliminarily validated for the determination of norepinephrine in artificial urine shows that the modified polymer with chiral derivative of tetra-(4-hydroxyphenyl)resorcinarene worked effectively as a new sorbent phase for the quantitative microextraction of norepinephrine, exhibiting high stability and homogeneity of composition and structure within the working range.
Global Ancestry and Cognitive Ability
Authors: Lasker Jordan , Pesta Bryan J. , Fuerst John G. R. , Kirkegaard Emil O. W.
Published: August 2019

Using data from the Philadelphia Neurodevelopmental Cohort, we examined whether European ancestry predicted cognitive ability over and above both parental socioeconomic status (SES) and measures of eye, hair, and skin color. First, using multi-group confirmatory factor analysis, we verified that strict factorial invariance held between self-identified African and European-Americans. The differences between these groups, which were equivalent to 14.72 IQ points, were primarily (75.59%) due to difference in general cognitive ability (g), consistent with Spearman’s hypothesis. We found a relationship between European admixture and g. This relationship existed in samples of (a) self-identified monoracial African-Americans (B = 0.78, n = 2,179), (b) monoracial African and biracial African-European-Americans, with controls added for self-identified biracial status (B = 0.85, n = 2407), and (c) combined European, African-European, and African-American participants, with controls for self-identified race/ethnicity (B = 0.75, N = 7,273). Controlling for parental SES modestly attenuated these relationships whereas controlling for measures of skin, hair, and eye color did not. Next, we validated four sets of polygenic scores for educational attainment (eduPGS). MTAG, the multi-trait analysis of genome-wide association study (GWAS) eduPGS (based on 8442 overlapping variants) predicted g in both the monoracial African-American (r = 0.111, n = 2179, p < 0.001), and the European-American (r = 0.227, n = 4914, p < 0.001) subsamples. We also found large race differences for the means of eduPGS (d = 1.89). Using the ancestry-adjusted association between MTAG eduPGS and g from the monoracial African-American sample as an estimate of the transracially unbiased validity of eduPGS (B = 0.124), the results suggest that as much as 20%–25% of the race difference in g can be naïvely explained by known cognitive ability-related variants. Moreover, path analysis showed that the eduPGS substantially mediated associations between cognitive ability and European ancestry in the African-American sample. Subtest differences, together with the effects of both ancestry and eduPGS, had near-identity with subtest g-loadings. This finding confirmed a Jensen effect acting on ancestry-related differences. Finally, we confirmed measurement invariance along the full range of European ancestry in the combined sample using local structural equation modeling. Results converge on genetics as a potential partial explanation for group mean differences in intelligence.
Time Series of Landsat Imagery Shows Vegetation Recovery in Two Fragile Karst Watersheds in Southwest China from 1988 to 2016
Authors: Pei Jie , Wang Li , Wang Xiaoyue , Niu Zheng , Kelly Maggi , Song Xiao-Peng , Huang Ni , Geng Jing , Tian Haifeng , Yu Yang , Xu Shiguang , Wang Lei , Ying Qing , Cao Jianhua
Published: August 2019

Since the implementation of China’s afforestation and conservation projects during recent decades, an increasing number of studies have reported greening trends in the karst regions of southwest China using coarse-resolution satellite imagery, but small-scale changes in the heterogenous landscapes remain largely unknown. Focusing on two typical karst regions in the Nandong and Xiaojiang watersheds in Yunnan province, we processed 2,497 Landsat scenes from 1988 to 2016 using the Google Earth Engine cloud platform and analyzed vegetation trends and associated drivers. We found that both watersheds experienced significant increasing trends in annual fractional vegetation cover, at a rate of 0.0027 year−1 and 0.0020 year−1, respectively. Notably, the greening trends have been intensifying during the conservation period (2001–2016) even under unfavorable climate conditions. Human-induced ecological engineering was the primary factor for the increased greenness. Moreover, vegetation change responded differently to variations in topographic gradients and lithological types. Relatively more vegetation recovery was found in regions with moderate slopes and elevation, and pure limestone, limestone and dolomite interbedded layer as well as impure carbonate rocks than non-karst rocks. Partial correlation analysis of vegetation trends and temperature and precipitation trends suggested that climate change played a minor role in vegetation recovery. Our findings contribute to an improved understanding of the mechanisms behind vegetation changes in karst areas and may provide scientific supports for local afforestation and conservation policies.
Refugee Camp Monitoring and Environmental Change Assessment of Kutupalong, Bangladesh, Based on Radar Imagery of Sentinel-1 and ALOS-2
Authors: Braun Andreas , Fakhri Falah , Hochschild Volker
Published: August 2019

Approximately one million refugees of the Rohingya minority population in Myanmar crossed the border to Bangladesh on 25 August 2017, seeking shelter from systematic oppression and persecution. This led to a dramatic expansion of the Kutupalong refugee camp within a couple of months and a decrease of vegetation in the surrounding forests. As many humanitarian organizations demand frameworks for camp monitoring and environmental impact analysis, this study suggests a workflow based on spaceborne radar imagery to measure the expansion of settlements and the decrease of forests. Eleven image pairs of Sentinel-1 and ALOS-2, as well as a digital elevation model, were used for a supervised land cover classification. These were trained on automatically-derived reference areas retrieved from multispectral images to reduce required user input and increase transferability. Results show an overall decrease of vegetation of 1500 hectares, of which 20% were used to expand the camp and 80% were deforested, which matches findings from other studies of this case. The time-series analysis reduced the impact of seasonal variations on the results, and accuracies between 88% and 95% were achieved. The most important input variables for the classification were vegetation indices based on synthetic aperture radar (SAR) backscatter intensity, but topographic parameters also played a role.
Automatic Regularization of TomoSAR Point Clouds for Buildings Using Neural Networks
Authors: Zhou Siyan , Li Yanlei , Zhang Fubo , Chen Longyong , Bu Xiangxi
Published: August 2019

Tomographic SAR (TomoSAR) is a remote sensing technique that extends the conventional two-dimensional (2-D) synthetic aperture radar (SAR) imaging principle to three-dimensional (3-D) imaging. It produces 3-D point clouds with unavoidable noise that seriously deteriorates the quality of 3-D imaging and the reconstruction of buildings over urban areas. However, existing methods for TomoSAR point cloud processing notably rely on data segmentation, which influences the processing efficiency and denoising performance to a large extent. Inspired by regression analysis, in this paper, we propose an automatic method using neural networks to regularize the 3-D building structures from TomoSAR point clouds. By changing the point heights, the surface points of a building are refined. The method has commendable performance on smoothening the building surface, and keeps a precise preservation of the building structure. Due to the regression mechanism, the method works in a high automation level, which avoids data segmentation and complex parameter adjustment. The experimental results demonstrate the effectiveness of our method to denoise and regularize TomoSAR point clouds for urban buildings.
Payload for Contact Inspection Tasks with UAV Systems
Authors: González-deSantos L. M. , Martínez-Sánchez J. , González-Jorge H. , Ribeiro M. , de Sousa J. B. , Arias P.
Published: August 2019

This paper presents a payload designed to perform semi-autonomous contact inspection tasks without any type of positioning system external to the UAV, such as a global navigation satellite system (GNSS) or motion capture system, making possible inspection in challenging GNSS- denied sites. This payload includes two LiDAR sensors which measure the distance between the UAV and the target structure and their inner orientation angle. The system uses this information to control the approaching of the UAV to the structure and the contact between both, actuating over the pitch and yaw signals. This control is performed using a hybrid automaton with different states that represent all the possible UAV status during the inspection tasks. It uses different control strategies in each state. An ultrasonic gauge has been used as the inspection sensor of the payload to measure the thickness of a metallic sheet. The sensor requires a stable contact in order to collect reliable measurements. Several tests have been performed on the system, reaching accurate results which show it is able to maintain a stable contact with the target structure.
Cooperative Unmanned Aerial System Reconnaissance in a Complex Urban Environment and Uneven Terrain
Authors: Stodola Petr , Drozd Jan , Mazal Jan , Hodický Jan , Procházka Dalibor
Published: August 2019

Using unmanned robotic systems in military operations such as reconnaissance or surveillance, as well as in many civil applications, is common practice. In this article, the problem of monitoring the specified area of interest by a fleet of unmanned aerial systems is examined. The monitoring is planned via the Cooperative Aerial Model, which deploys a number of waypoints in the area; these waypoints are visited successively by unmanned systems. The original model proposed in the past assumed that the area to be explored is perfectly flat. A new formulation of this model is introduced in this article so that the model can be used in a complex environment with uneven terrain and/or with many obstacles, which may occlude some parts of the area of interest. The optimization algorithm based on the simulated annealing principles is proposed for positioning of waypoints to cover as large an area as possible. A set of scenarios has been designed to verify and evaluate the proposed approach. The key experiments are aimed at finding the minimum number of waypoints needed to explore at least the minimum requested portion of the area. Furthermore, the results are compared to the algorithm based on the lawnmower pattern.
A Novel Demodulation Analysis Technique for Bearing Fault Diagnosis via Energy Separation and Local Low-Rank Matrix Approximation
Authors: Lv Yong , Ge Mao , Zhang Yi , Yi Cancan , Ma Yubo
Published: August 2019

Bearing fault diagnosis is of utmost importance in the maintenance of mechanical equipment. The collected fault vibration signal generally presents a modulated nature due to the special structure and dynamic characteristics of the bearings. This paper introduces a novel demodulation analysis technique via energy separation and local low-rank matrix approximation (LLORMA) to address this type of signal. The amplitude envelope and instantaneous frequency of the signal can be calculated via an energy separation algorithm based on the Teager energy operator. We can confirm the bearing faults by comparing the peak frequencies of the Fourier spectrum of the amplitude envelope and instantaneous frequency with the theoretical bearing fault-related frequencies. However, this algorithm is only suitable for handling single-component signals. In addition, the powerful background noise has a serious effect on the demodulation results. To tackle these problems, a new signal decomposition method based on LLORMA is proposed to decompose the signal into several single-components and eliminate the noise simultaneously. After that, the single-component signal representing the fault characteristics can be identified via the high frequency feature of the modulated signal. The analysis of the simulated signal and the bearing outer race fault signal collected from a bearing-gear fault test rig indicate that the proposed technique has an excellent diagnostic performance for bearing fault signals.
Review on Smart Gas Sensing Technology
Authors: Feng Shaobin , Farha Fadi , Li Qingjuan , Wan Yueliang , Xu Yang , Zhang Tao , Ning Huansheng
Published: August 2019

With the development of the Internet-of-Things (IoT) technology, the applications of gas sensors in the fields of smart homes, wearable devices, and smart mobile terminals have developed by leaps and bounds. In such complex sensing scenarios, the gas sensor shows the defects of cross sensitivity and low selectivity. Therefore, smart gas sensing methods have been proposed to address these issues by adding sensor arrays, signal processing, and machine learning techniques to traditional gas sensing technologies. This review introduces the reader to the overall framework of smart gas sensing technology, including three key points; gas sensor arrays made of different materials, signal processing for drift compensation and feature extraction, and gas pattern recognition including Support Vector Machine (SVM), Artificial Neural Network (ANN), and other techniques. The implementation, evaluation, and comparison of the proposed solutions in each step have been summarized covering most of the relevant recently published studies. This review also highlights the challenges facing smart gas sensing technology represented by repeatability and reusability, circuit integration and miniaturization, and real-time sensing. Besides, the proposed solutions, which show the future directions of smart gas sensing, are explored. Finally, the recommendations for smart gas sensing based on brain-like sensing are provided in this paper.
A Sensor for Broken Wire Detection of Steel Wire Ropes Based on the Magnetic Concentrating Principle
Authors: Zhang Yiqing , Jing Luyang , Xu Weixiao , Zhan Weixia , Tan Jiwen
Published: August 2019

Electromagnetic testing is the most widely used technique for the inspection of steel wire ropes. As one of the electromagnetic detecting approaches, the magnetic flux leakage (MFL) method has the best effect for the detection of broken wires. However, existing sensors based on MFL method still have some problems. (1) The size of the permanent magnet exciter is usually designed according to experience or rough calculation, and there is not enough depth analysis for its excitation performance; (2) Since the detectable angular range for a single Hall component is limited, Hall sensor arrays are often employed in the design of MFL sensors, which will increase the complexity of the subsequent signal processing due to the extensive use of Hall components; (3) Although the new magneto-resistance sensor has higher sensitivity, it is difficult to be applied in practice because of the requirement of the micron-level lift-off. To solve these problems, a sensor for the detection of broken wires of steel wire ropes based on the principle of magnetic concentration is developed. A circumferential multi-circuit permanent magnet exciter (CMPME) is employed to magnetize the wire rope to saturation. The traditional Hall sensor array is replaced by a magnetic concentrator to collect MFL. The structural parameters of the CMPME are optimized and the performance of the magnetic concentrator is analyzed by the finite element method. Finally, the effectiveness of the designed sensor is verified by wire breaking experiment. 1–5 external broken wires, handcrafted on the wire rope with a diameter of 24 mm, can be clearly identified, which shows great potential for the inspection of steel wire ropes.
Intelligent 3D Perception System for Semantic Description and Dynamic Interaction
Authors: Teixeira Marco , Nogueira Rafael , Dalmedico Nicolas , Santos Higor , Arruda Lucia , Neves-Jr Flavio , Pipa Daniel , Ramos Julio , Oliveira Andre
Published: August 2019

This work proposes a novel semantic perception system based on computer vision and machine learning techniques. The main goal is to identify objects in the environment and extract their characteristics, allowing a dynamic interaction with the environment. The system is composed of a GPU processing source and a 3D vision sensor that provides RGB image and PointCloud data. The perception system is structured in three steps: Lexical Analysis, Syntax Analysis and finally an Analysis of Anticipation. The Lexical Analysis detects the actual position of the objects (or tokens) in the environment, through the combination of RGB image and PointCloud, surveying their characteristics. All information extracted from the tokens will be used to retrieve relevant features such as object velocity, acceleration and direction during the Syntax Analysis step. The anticipation step predicts future behaviors for these dynamic objects, promoting an interaction with them in terms of collisions, pull, and push actions. As a result, the proposed perception source can assign relevant information to mobile robots, not only about distances as traditional sensors, but about other environment characteristics and object behaviors. This novel perception source introduces a new class of skills to mobile robots. Experimental results obtained with a real robot are presented, showing the proposed perception source efficacy and potential.
A Displacement Sensor Based on a Normal Mode Helical Antenna
Authors: Xue Songtao , Yi Zhuoran , Xie Liyu , Wan Guochun , Ding Tao
Published: August 2019

This paper presents a passive displacement sensor based on a normal mode helical antenna. The sensor consists of an external helical antenna and an inserting dielectric rod. First, the perturbation theory is adopted to demonstrate that both the electric intensity and magnetic intensity have a noticeable gradient change within the in-and-out entrance of the helical antenna, which will cause the sensor to experience a resonant frequency shift. This phenomenon was further verified by numerical simulation using the Ansoft high frequency structure simulator (HFSS), and results show the linear correlation between the retrieved resonant frequency and the displacement. Two sets of proposed sensors were fabricated. The experiments validated that the resonant frequency shifts are linearly proportional to the applied displacement, and the sensing range can be adjusted to accommodate the user’s needs.
Guide for Climate-Resilient Cities: An Urban Critical Infrastructures Approach
Authors: Lomba-Fernández Cinta , Hernantes Josune , Labaka Leire
Published: August 2019

Climate change (CC) is one of the most challenging issues ever faced, as it affects every system worldwide at any scale. Urban areas are not an exception. Extreme weather-related events have seriously affected urban areas in recent years, and they have a significant impact on the welfare of people. According to UN projections, by 2050 more than 68% of the world’s population could be concentrated in urban areas. Additionally, daily life in urban areas is highly dependent on certain critical services and products provided by critical infrastructures (CIs). Therefore, it is especially relevant to understand how CC affects urban CIs in order to develop mechanisms to improve their capacity to handle crises derived from CC. In this context, resilience-based strategies provide a holistic approach, considering both predictable and unpredictable threats. This paper proposes a guide for assessing and enhancing the resilience level of cities against CC, considering urban CIs as key agents in improving the city’s capacity to face and recover from CC-related crises. The guide was developed through a co-creation process in which two cities in the Basque Country (Spain) worked together with CI providers and other relevant stakeholders in the resilience-building process. The resulting guide is to be used by city stakeholders at a strategic level, providing them with: (1) a qualitative assessment of the city’s current resilience level in the CC context; (2) better knowledge about urban CI sectors, their interdependency relationships and the chain of impacts due to cascading effects in the short, medium and in the long term and; (3) a set of policies that enhance city resilience.