以Al_2O_3为黏结剂制备的Pt-WO_3/ZrO_2/Al_2O_3催化剂上的正庚烷异构化

采用挤条法制备了一系列以Al_2O_3为黏结剂的Pt-WO3/ZrO2/Al_2O_3(PtWZA)催化剂,在微型固定床装置上评价了正庚烷在PtWZA上的异构化性能。主要考察了黏结剂Al_2O_3质量分数、WO3质量分数和焙烧温度对PtWZA催化剂物化性质和异构化性能的影响,并采用XRD、氮气吸附-脱附、Py-FTIR等手段对催化剂的晶相结构、比表面积和酸性进行了表征。结果表明:Al_2O_3的引入明显影响催化剂的异构化活性,且对活性的影响不仅与Al_2O_3质量分数有关,而且与WO3质量分数也紧密相关。对于含较低WO3质量分数的Pt15WZA而言,添加少量Al_2O_3(质量分数为2%)导致催化活性大幅度提高;而WO3质量分数提高到20%时,添加质量分数为2%的Al_2O_3对Pt20WZA的活性影响不大。当Al_2O_3的质量分数提高到15%时,Pt15WZA与Pt20WZA的活性大大下降。提高WO3质量分数显著提高了PtWZ15A的异构化活性。升高焙烧温度有利于提高Pt20WZ10A催化剂活性,过高的焙烧温度导致催化剂活性大幅度下降,较为适宜的温度为800～850℃。

Microstructural evaluation and nanohardness of an AlCoCuCrFeNiTi high-entropy alloy

An AlCoCuCrFeNiTi high-entropy alloy(HEA) was prepared by mechanical alloying and sintering to study the effect of Ti addition to the widely studied AlCoCuCrFeNi system. The structural and microstructural characteristics were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), and transmission electron microscopy(TEM). The formation of four micrometric phases was detected: a Cu-rich phase with a face-centered cubic(fcc) structure, a body-centered cubic(bcc) solid solution with Cu-rich plate-like precipitates(fcc), an ordered bcc phase, and a tetragonal structure. The XRD patterns corroborate the presence of a mixture of bcc-, fcc-, and tetragonal-structured phases. The Vickers hardness of the alloy under study was more than twice that of the AlCoCuCrFeNi alloy. Nanoindentation tests were performed to evaluate the mechanical response of the individual phases to elucidate the relationship between chemical composition, crystal structure, and mechanical performance of the multiphase microstructure of the AlCoCuCrFeNiTi HEA.

Benchmarking Approach to Compare Web Applications Static Analysis Tools Detecting OWASP Top Ten Security Vulnerabilities

To detect security vulnerabilities in a web application,the security analyst must choose the best performance Security Analysis Static Tool(SAST)in terms of discovering the greatest number of security vulnerabilities as possible.To compare static analysis tools for web applications,an adapted benchmark to the vulnerability categories included in the known standard Open Web Application Security Project(OWASP)Top Ten project is required.The information of the security effectiveness of a commercial static analysis tool is not usually a publicly accessible research and the state of the art on static security tool analyzers shows that the different design and implementation of those tools has different effectiveness rates in terms of security performance.Given the significant cost of commercial tools,this paper studies the performance of seven static tools using a new methodology proposal and a new benchmark designed for vulnerability categories included in the known standard OWASP Top Ten project.Thus,the practitioners will have more precise information to select the best tool using a benchmark adapted to the last versions of OWASP Top Ten project.The results of this work have been obtaining using widely acceptable metrics to classify them according to three different degree of web application criticality.

不同温度下MoO_3在KOH介质中的溶解动力学（英文）

通过改变体系的温度、KOH浓度和粒径,研究合成的MoO_3在氢氧化钾(KOH)介质中的溶解动力学,考察搅拌速率和和反应剂种类(如氢氧化钡、氢氧化钙和氢氧化钠等)的影响。实验是在一个可以控制温度和搅拌速率的反应器中进行的。结果表明,钼华的溶解反应生成了钼酸钾(K_2MoO_4),而没有中间化合物生成。温度(6~80°C)、KOH浓度(0.0005~0.025 mol/L)和粒径(5~40mm)对MoO_3的溶解影响显著。在温度80°C、KOH浓度0.01 mol/L、反应时间0.25 h的条件下,钼的回收率最大,达67.5%。在接近水的冰点的最低温度(6°C)下,反应45 min后,钼的回收率为17.8%。建立了KOH环境中MoO_3溶解的动力学方程,表明扩散是通过多孔层进行的。计算得到活化能为47.81 k J/mol,KOH浓度的反应级数为1.0,与粒径的平方成反比,并得到了动力学方程。MoO_3是辉钼矿精矿(MoS_2)氧化的产物,它的溶解导致钼的回收率低,这主要是因为CaCO_3和Cr(Mo_4)_3等杂质消耗了KOH。

在碱性体系中用NH_4OH浸出赤铜矿（英文）

在酸性条件下,赤铜矿是一种难浸出的氧化物,最大浸出率仅为50%。本文作者研究在氨性介质中浸出赤铜矿的可行性。所研究的实验条件为液固比(120:1～400:1mL/g)、溶液搅拌速度(0～950r/min)、温度(10～45°C)和NH_4OH浓度(0.05～0.15mol/L)。此外,还对不同的氨性试剂(NH_4F和(NH_4)_2SO_4)的作用进行分析。实验是在带有加热套和冷凝器的2L反应器中进行的。最重要的结果是,在pH10.5、NH_4OH浓度0.10mol/L、浸出温度45°C、浸出时间4 h、搅拌速度850 r/min、液固比400:1的条件下,达到82%的最大浸出率。这一结果与溶液中四氨合铜离子(Cu(NH_3)_4^(2-))的形成使得铜不会生成沉淀有关。液固比和溶液搅拌速度是提高赤铜矿浸出率的关键参数。虽然最大浸出率是在较高温度下实现的,但在接近水冰点的温度下也发生了显著的浸出,4h浸出率达17.9%。随着NH_4OH浓度的增大和粒径的减小,Cu_2O的浸出率增大。本文研究两种氨性试剂(NH_4F和(NH_4)_2SO_4),与氢氧化铵相比,它们对铜的浸出率较低。Cu_2O浸出的动力学符合表面化学反应模型,相对于氢氧化铵浓度的反应级数为1.8,表观反应速率常数与颗粒半径成反比。在10～45°C温度范围内,计算得到的活化能为44.36 kJ/mol。

Visual grading criteria for Japanese larch ( Larix kaempferi ) structural timber from Spain

Larch wood is structurally classifi ed in many countries as one of conifers with the highest load-bearing capacity(strength class of C30).The Spanish visual classifi cation regulation only assigns a strength class to 4 pine woods:Laricio pine(Pinus nigra Arn.var.Salzmannii),Silvestre pine(Pinus sylvestris L.),Radiata pine(Pinus radiata D.Don),and Pinaster pine(Pinus pinaster Ait.).This work adds to the number of structurally characterised species by creating a visual classifi cation table for Japanese larch wood(Larix kaempferi(Lamb.)Carr.)which diff erentiates between 2 visual classes,MEG-1 and MEG-2.Characteristic strength values were calculated for each class(fk,MEG-1=31.80 MPa,f k,MEG-2=24.55 MPa),mean module of elasticity(E 0,mean,MEG-1=13,082 MPA,E 0,mean,MEG-2=12,320 MPA)and density(ρk,MEG-1=456.6 kg m−3,ρk,MEG-2=469.1 kg m−3),before fi nally assigning a strength class of C30 to visual class MEG-1,and a strength class of C24 to visual class MEG-2.

Fabrication of paper-based devices for in vitro tissue modeling

Paper devices have recently attracted considerable attention as a class of cost-effective cell culture substrates for various biomedical applications.The paper biomaterial can be used to partially mimic the in vivo cell microenvironments mainly due to its natural three-dimensional characteristic.The paper-based devices provide precise control over their structures as well as cell distributions,allowing recapitulation of certain interactions between the cells and the extracellular matrix.These features have shown great potential for the development of normal and diseased human tissue models.In this review,we discuss the fabrication of paper-based devices for in vitro tissue modeling,as well as the applications of these devices toward drug screening and personalized medicine.It is believed that paper as a biomaterial will play an essential role in the field of tissue model engineering due to its unique performances,such as good biocompatibility,eco-friendliness,cost-effectiveness,and amenability to various biodesign and manufacturing needs.

Flexural Performance of I-Joist Fabricated with Glue-Laminated Bamboo and <i>Gmelina arborea</i>Plywood

The search for efficient and versatile structural elements, leads to the fabrication of I-joists (6.5 cm × 18.5 cm × 600 cm (width × depth × length) with glue-laminated bamboo (Guada angustifolia) in the flanges and Gmelina arborea 12-mm structural plywood in the web. The results showed a modulus of rupture (MOR) of 39.45 MPa and an effective modulus of elasticity (MOE) of 17.05 GPa. Shearing in the glue line was 5.95 MPa and the lamination strength was 6.45 MPa. Structural design values averaged 9.43 MPa for bending and 4.72 MPa in shear according to Costa Rican structural standards. Both resistance value (flexure and shear) were considered satisfactory for structural proposes and I-joists fabricated with bamboo and G. arborea plywood are comparable with the Andean classification group “C” structural grade. The use of this I-joist was also shown in roofing and flooring systems. This beam can be used in allowable spans from 2 to 4 m in span for flooring systems and from 5 to 7 m for roofing applications.

Surfactant-Enhanced Washing of Soils Contaminated with Wasted-Automotive Oils and the Quality of the Produced Wastewater

An old automotive industrial site located at Mexico City with many years of operation and contaminated with heavy oil hydrocarbons, particularly spent oils, was assessed for restoration using the surfactant enhanced soil washing (SESW) process. The main goal of this study was to characterize the contaminated soil in terms of TPHs, BTEX, PAHs, and metals contents as well as microbiologically (total heterotrophs and specific degrading microorganisms). We also aimed to determine the surfactant type and concentration to be used in the SESW process for the automotive waste oil contaminated soil. At the end, sixteen kg of contaminated soil were washed and the produced wastewater (approximately 40 L) was characterized in terms of COD, BOD;solids, and other physico-chemical parameters. The soil contained about 14,000 mg of TPH/kg soil (heavy fraction), 0.13 mg/kg of benzo (k) fluoranthene and 0.07 mg/kg of benzo (a) pyrene as well as traces of some metals. Metals concentrations were always under the maximum concentration levels suggested by Mexican regulations. 15 different surfactants were used to identify the one with the capability to achieve the highest TPH removal. Surfactants included 5 anionics, 2 zwitterionic, 5 nonionics and 3 natural gums. Sulfopon 30 at a concentration of 0.5% offered the best surfactant performance. The TPH removals employing the different surfactants were in the range from 38% to 68%, in comparison to the soil washing with water (10% of TPH removal). Once the surfactant was selected, 70 kg of soil were washed and the resulting water contained approximately 1300 mg/L of COD, 385 mg/L of BOD (BOD/COD = 0.29), 122 mg/L of MBAS, and 212 mg/L of oil and greases, among other contaminants.

Metallography of an Underground Oil Pipeline

The purpose of this article is to show a metallographic analysis of an underground pipeline taken out of operation upon failure. The pipeline had an 8.89 cm (3.5”) diameter and a 7 mm thickness. The study was based on a 45 cm long pipe sample, visibly and entirely corroded, with a fish-mouth crack along its length. The work contributes to finding new ways to prevent structural failure, which has high-impact consequences from the point of view of production, damage to property, pollution, and risks to human live. Through this analysis the knowledge on behavior of failures in terrestrial ducts has been extended. Development of the research included metallographic, chemical, and mechanical tests on the sample in order to know the composition of the material, its strength and its physical conditions upon taking it out of operation. After the analysis of the laboratory tests, the physical and chemical features were compared to existing national and international regulations, which allowed a specific characterization of the conditions of the sample. In accordance with the regulations, the grade of the pipe was between ×65 and ×70. Tensile testing was carried out to obtain mechanical properties in order to corroborate the grade of pipeline steel and complement the metallographic analysis.

Fractal interpolation:a sequential approach

Fractal interpolation is a modern technique to fit and analyze scientific data.We develop a new class of fractal interpolation functions which converge to a data generating(original)function for any choice of the scaling factors.Consequently,our method offers an alternative to the existing fractal interpolation functions(FIFs).We construct a sequence of-FIFs using a suitable sequence of iterated function systems(IFSs).Without imposing any condition on the scaling vector,we establish constrained interpolation by using fractal functions.In particular,the constrained interpolation discussed herein includes a method to obtain fractal functions that preserve positivity inherent in the given data.The existence of Cr--FIFs is investigated.We identify suitable conditions on the associated scaling factors so that-FIFs preserve r-convexity in addition to the Cr-smoothness of original function.

Analysing changes in spatial point patterns:A proposal using data from a forest thinning experiment

Spatial patterns reveal critical features at the individual and community levels.However,how to evaluate changes in spatial characteristics remains largely unexplored.We assess spatial changes in spatial point patterns by augmenting current statistical functions and indices.We fitted functions to describe unmarked and marked(tree size)spatial patterns using data from a large-scale silvicultural experiment in southern Chile.Furthermore,we compute the mingling index to represent spatial tree diversity.We proffer the pair correlation function difference before and after treatment to detect changes in the unmarked-point pattern of trees and the semivariogram-ratio to evaluate changes in the marked-point pattern.Our research provides a quantitative assessment of a critical aspect of forest heterogeneity:changes in spatial unmarked and marked-point patterns.The proposed approach can be a powerful tool for quantifying the impacts of disturbances and silvicultural treatments on spatial patterns in forest ecosystems.

Extremal Coalitions for Influence Games Through Swarm Intelligence-Based Methods

An influence game is a simple game represented over an influence graph(i.e.,a labeled,weighted graph)on which the influence spread phenomenon is exerted.Influence games allow applying different properties and parameters coming from cooperative game theory to the contexts of social network analysis,decision-systems,voting systems,and collective behavior.The exact calculation of several of these properties and parameters is computationally hard,even for a small number of players.Two examples of these parameters are the length and the width of a game.The length of a game is the size of its smaller winning coalition,while the width of a game is the size of its larger losing coalition.Both parameters are relevant to know the levels of difficulty in reaching agreements in collective decision-making systems.Despite the above,new bio-inspired metaheuristic algorithms have recently been developed to solve the NP-hard influence maximization problem in an efficient and approximate way,being able to find small winning coalitions that maximize the influence spread within an influence graph.In this article,we apply some variations of this solution to find extreme winning and losing coalitions,and thus efficient approximate solutions for the length and the width of influence games.As a case study,we consider two real social networks,one formed by the 58 members of the European Union Council under nice voting rules,and the other formed by the 705 members of the European Parliament,connected by political affinity.Results are promising and show that it is feasible to generate approximate solutions for the length and width parameters of influence games,in reduced solving time.

Systematic Approach for Web Protection Runtime Tools’Effectiveness Analysis

Web applications represent one of the principal vehicles by which attackers gain access to an organization’s network or resources.Thus,different approaches to protect web applications have been proposed to date.Of them,the two major approaches are Web Application Firewalls(WAF)and Runtime Application Self Protection(RASP).It is,thus,essential to understand the differences and relative effectiveness of both these approaches for effective decisionmaking regarding the security of web applications.Here we present a comparative study between WAF and RASP simulated settings,with the aim to compare their effectiveness and efficiency against different categories of attacks.For this,we used computation of different metrics and sorted their results using F-Score index.We found that RASP tools scored better than WAF tools.In this study,we also developed a new experimental methodology for the objective evaluation ofweb protection tools since,to the best of our knowledge,nomethod specifically evaluates web protection tools.

Near shore seismic movements induced by seaquakes using the boundary element method

This study quantifies seismic amplifications in near-shore arising from seaquakes. Within the Boundary Element Method, boundary elements are used to irradiate waves and force densities obtained for each element. Huygens′ Principle is implemented since the diffracted waves are constructed at the boundary from which they are radiated, which is equivalent to Somigliana′s theorem. Application of boundary conditions leads to a system of integral equations of the Fredholm type of second kind and zero order. Several numerical configurations are analyzed： The first is used to verify the present formulation with ideal sea floor configurations to estimate seismic amplifications. With the formulation verified, simple slope configurations are studied to estimate spectra of seismic motions. It is found that P-waves can produce seismic amplifications from 1.2 to 3.9 times the amplitude of the incident wave. SV-waves can generate seismic amplifications up to 4.5 times the incident wave. Another relevant finding is that the highest amplifications are at the shore compared to the ones at the sea floor.

Structure, Electronic Properties and Chemical Bonding in Bis(1H-imidazolium-κN^3)silver(Ⅰ) Nitrate from Periodic DFT Computations

Using the first-principles density functional theory calculations within the genera- lized gradient approximation we study the bis（1H-imidazolium-kN3）silver（I） nitrate molecular crystal. A number of different exchange-correlation functionals are considered for a possible treatment of the system. Perdew-Burke-Emzerhof （PBE） GGA exchange-correlation ftmctionals are found to be adequate for our system. The obtained results show that it is possible to reproduce very well the geometry of at least some molecular crystals if computational parameters are chosen adequately. In addition to the reproducing crystal structure of the bis（1H-imidazolium-kN3）silver（I） nitrate in close agreement with the available experimental data, the present work reports analysis on the chemical bonding in the material and gives total and partial density of states of this system.

Combinatorial Method with Static Analysis for Source Code Security in Web Applications

Security weaknesses in web applications deployed in cloud architectures can seriously affect its data confidentiality and integrity.The construction of the procedure utilized in the static analysis tools of source code security differs and therefore each tool finds a different number of each weakness type for which it is designed.To utilize the possible synergies different static analysis tools may process,this work uses a new method to combine several source codes aiming to investigate how to increase the performance of security weakness detection while reducing the number of false positives.Specifically,five static analysis tools will be combined with the designed method to study their behavior using an updated benchmark for OWASP Top Ten Security Weaknesses(OWASP TTSW).The method selects specific metrics to rank the tools for different criticality levels of web applications considering different weights in the ratios.The findings show that simply including more tools in a combination is not synonymous with better results;it depends on the specific tools included in the combination due to their different designs and techniques.

MMALE—A Methodology for Malware Analysis in Linux Environments

In a computer environment,an operating system is prone to malware,and even the Linux operating system is not an exception.In recent years,malware has evolved,and attackers have become more qualified compared to a few years ago.Furthermore,Linux-based systems have become more attractive to cybercriminals because of the increasing use of the Linux operating system in web servers and Internet of Things(IoT)devices.Windows is the most employed OS,so most of the research efforts have been focused on its malware protection rather than on other operating systems.As a result,hundreds of research articles,documents,and methodologies dedicated to malware analysis have been reported.However,there has not been much literature concerning Linux security and protection from malware.To address all these new challenges,it is necessary to develop a methodology that can standardize the required steps to perform the malware analysis in depth.A systematic analysis process makes the difference between good and ordinary malware analyses.Additionally,a deep malware comprehension can yield a faster and much more efficient malware eradication.In order to address all mentioned challenges,this article proposed a methodology for malware analysis in the Linux operating system,which is a traditionally overlooked field compared to the other operating systems.The proposed methodology is tested by a specific Linux malware,and the obtained test results have high effectiveness in malware detection.

Chiral Maxwell’s Equations as Two Spinor System: Dirac and Majorana Neutrino

This work clarifies the relation between Maxwell, Dirac and Majorana neutrino equations presenting an original way to derive the Dirac and neutrino equation from the chiral electrodynamics leading, perhaps, to novel conception in the mass generation by electromagnetic fields. In the present article, it is shown that Maxwell equations can be written in the same form as the two components Dirac and neutrino equations, that is the vector representation of electromagnetic theory can be factorized into a pair of two-component spinor field equations. We propose a simple approach with the electric field E parallel to the magnetic field H. Our analysis is based on the chiral or Weyl form of the Maxwell equations in a chiral vacuum. This theory is a new quantum mechanics (QM) interpretation for Dirac and neutrino equation. The below research proves that the QM of particles represents the electrodynamics of the curvilinear closed chiral waves. Electromagnetic properties of neutrinos are discussed.

Fast Single Image Haze Removal Method for Inhomogeneous Environment Using Variable Scattering Coefficient

The images capture in a bad environment usually loses its fidelity and contrast.As the light rays travel towards its destination they get scattered several times due to the tiny particles of fog and pollutants in the environment,therefore the energy gets lost due to multiple scattering till it arrives its destination,and this degrades the images.So the images taken in bad weather appear in bad quality.Therefore,single image haze removal is quite a bit tough task.Significant research has been done in the haze removal algorithm but in all the techniques,the coefficient of scattering is taken as a constant according to the homogeneous atmosphere but in real time this does not happen.Therefore,this paper introduces a simple and efficient method so that the scattering coefficient becomes variable according to the inhomogeneous environment.Then,this research aims to remove the haze with the help of a fast and effective algorithm i.e.,Prior Color Fading,according to the inhomogeneous environmental properties.Thereby,to filter the depth map,the authors used a weighted guided image filtering which removes the drawbacks of guided image filter.Afterwards the scattering coefficient is made variable according to the inhomogeneous atmosphere and then the Simple Color Balance Algorithm is applied so that the readability property of images can be increased.The proposed method tested on various general outdoor images and synthetic hazy images and analyzed on various parameters Mean Square Error(MSE),Root Mean Square Error(RMSE),Peak Signal to Noise Ratio(PSNR),Mean Structural Similarity(MSSIM)and the Universal Objective Quality Index(UQI).Experimental results for the proposed method show that the proposed approach provides better results as compared to the state-of-the-art haze removal algorithms.