Impact analysis of BGP sessions for prioritization of maintenance operations

When a limited number of network operators have to manage a large number of maintenance tasks, they often lose the sense of what is more important and end up focusing their time on lower-priority issues. As a result, operators may react slowly to critical tasks, increasing network downtime and maintenance costs. We propose a system that estimates the relative importance of different maintenance tasks. According to this estimation, network operators can prioritize their reaction, for example, by spending more time on avoiding disruption caused by high-impact tasks. In particular, we focus on configuration tasks related to BGP sessions. BGP sessions are frequently modified for maintenance operations, such as policy changes, router upgrades, and the addition of peers. These maintenance operations cause route changes, often leading to a huge amount of data loss. The proposed system estimates this amount of data loss by simulating the behavior of BGP. We implement the proposed system and estimate the impact of 372 sessions in a nationwide ISP network. We observe sessions with a wide range of impact, from those with nearly zero impact, to those that can result in 1000 GB of data loss if not properly protected. We also observe that these measures change over time, often in unpredictable ways (e.g., from 50 GB to 0 over a month period). According to this observation, we suggest that network operators perform periodic audits with the proposed system and classify sessions by highlighting those with a large impact. Operators can then prioritize the level of responses to the classified sessions accordingly and significantly reduce maintenance costs (i.e., by giving priority to the advanced protection of sessions with a large impact).     

Understanding the effect of polymer crystallinity on the electrical conductivity of exfoliated graphite nanoplatelet/polylactic acid composite films

Electrically conductive exfoliated graphite nanoplatelet (GNP) / polylactic acid (PLA) nanocomposite films were fabricated using a two-step, scalable melt compounding process. The effect of the polymer’s physical properties, such as crystallinity, on the mechanical and electrical properties of the composites were determined. The crystallization characteristics of PLA were altered significantly by altering the cooling rate during compression molding of the films. The crystallinity and crystal structure were investigated using differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), and polarized optical microscopy (POM). The mechanical and electrical properties were also examined as a function of PLA’s crystallinity dictated by the cooling rate during compression molding. The electrical conductivity was examined using impedance spectroscopy. For the same GNP content, the crystallinity increases by ~40 % and electrical conductivity increases by ~3 orders of magnitude with decreased cooling rate indicating a strong correlation between polymer physical properties and electrical conductivity of the polymer composites. This mechanism can be utilized to tailor the electrical conductivity of a given filler/polymer system by tuning the physical properties of the polymer, without altering the fillers’ characteristics or the processing method, which is the common approach used.     

Synthesis and characterization of hetarylazo disperse dyes derived from substituted N‐β‐acetoxyethylanilines—Application on cellulose acetate

The heterocyclic amines 2‐amino‐6‐methoxy‐ and 2‐amino‐6‐nitrobenzothiazole, 3‐amino‐5‐nitro‐[2,1]‐benzisothiazole, and 2‐amino‐3,5‐dinitrothiophene were diazotized and coupled to substituted N‐β‐acetoxyethylanilines to give dyes which colored cellulose acetate in red to deep blue hues. The color of the dyes is discussed with respect to the nature of the heterocyclic ring and to the substituents in the diazo and coupling component. Dyeing and fastness properties of the dyes on cellulose acetate are also reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3479–3483, 2004     

Antioxidant and aldose reductase inhibition activity of Ligustrum japonicum and Olea europaea L. leaf extracts

Ligustrum japonicum and Olea europaea leaf extracts prepared via domestic techniques were studied for antioxidant and aldose reductase inhibitory activity (ARI) in relation to individual phenol/flavonoid composition (HPLC‐various detection means) and content. On the same extract weight basis L. japonicum leaf extracts, poorer in total polar phenol (TPP) content and in most cases in flavonoids, were less efficient than olive leaf extracts in radical scavenging and in retarding lipid oxidation. On the same TPP content basis, the former were of comparable efficiency in radical scavenging but exhibited lower activity than the latter in bulk oils or liposomes. L. japonicum extracts were characterized by the presence of verbascoside and apigenin derivatives, whereas O. europaea extracts by that of oleuropein. Superiority of L. japonicum infusion versus O. europaea infusion was evidenced using the ARI activity assay either on the same extract weight or on TPP content basis. The former was also superior in comparison to oleuropein, tyrosol, and hydroxytyrosol activity. These findings suggest the presence of other active compounds besides the so far identified phenolics and enhance our view on the importance of Oleaceae plants as sources of bioactive compounds beyond O. europaea. Practical applications : Oleaceae plants are a unique source for the secoiridoid oleuropein or verbascoside that confer well documented biological properties. On continuation of our effort to valorize plants of this family as sources for functional constituents we examined, in parallel, leaf extracts of the less investigated species Ligustrum japonicum versus those of Olea europaea L. The data presented for the extracts obtained via domestic preparations techniques (infusions, decoctions, tinctures) are expected to attract the interest of those involved in herbal teas and dietary supplements sector.     

Tensile modulus of carbon nanotube/polypropylene composites – A computational study based on experimental characterization

Micromechanical and computational models significantly over-predict the tensile modulus of composites, as they ignore many experimentally observed factors. Computational models that capture the effect of polymer-filler contact, the presence of carbon nanotube (CNT) agglomerates and the alignment of CNTs with respect to the applied load on the tensile modulus of CNT-reinforced polypropylene (PP) are proposed and discussed in detail in this study. The CNT/PP composites are made by melt mixing and injection molding. The CNT/PP contact area is characterized in terms of width and modulus using Atomic Force Microscope (AFM). The presence, including the size and distribution of CNT agglomerates, is characterized using Scanning Electron Microscope (SEM). The tensile modulus of CNT/PP composites, measured as a function of CNT content according to ASTM D638, is compared to predictions made using numerical methods based on Finite Element Analysis (FEA) within the composite’s elastic regime. The model over-predicts the modulus of the CNT/PP composites by 85% for 5 wt.% CNT/PP composites assuming perfect filler–polymer interfacial contact. When imperfect CNT/PP contact, CNT agglomerates and alignment are accounted for in the model the effective composite modulus predicted is in good agreement with the experimental data. The computational design tools proposed in this study by systematically incorporating experimentally observed characteristics, in combination with the manufacturing method used to make the CNT/PP composites, can lead to composites with engineered properties made by a scalable and cost effective method.     

Alternative storage options for solar thermal systems

The efficient implementation of solar systems in buildings depends on the storage of energy yielded, as it can both increase the solar system's autonomy and make it a feasible solution for zero energy buildings, and make storage vessels more compact, reducing precious space requirements. This is of particular important in places with reduced time of sunshine, where solar systems are less effective, because of the deviation between solar radiation and the demand. The traditional storage options use water, which is practical, safe and low‐cost, especially when the storage requirements are small. However, when larger storage is needed, limits concerning the use of water exist, mainly due to the need for larger installation space and the increased thermal losses. The use of phase change materials (PCM) for thermal energy storage seems an upcoming technology. The main idea is the substitution of water with PCM, which feature larger specific energy storage capacity compared to other conventional materials. In the context of the specific paper, a combined solar thermal system used for the preparation of domestic hot water (DHW) and space heating (Solar Combi System) with two different types of storage is studied, for two Greek cities. The aim is to find out which is the most efficient way of storing energy with respect to the autonomy of the system, for a solar combi system. This is being achieved by determining the comparative autonomy of PCM and water storage system for various climates. It was proven that using PCM is advantageous, as it can extend the autonomy duration of the solar system for 2 to 8 hours, depending on the season and the climatic conditions. However, it was also seen that in solar combi systems used throughout the whole year, PCM are inefficient during summer period.     

阿卡迪亚Ⅲ山羊与人

本项目结合当代语境,对“阿卡迪亚”(希腊南部地区,在诗歌和小说中常用来指代世外桃源)进行重新解读.阿卡迪亚曾经代表了人与自然的理想关系,没有文化因素的介入,常被人们用来表达浪漫主义的乌托邦想象.而本项目将畜牧业工作流程视为人与自然关系中的主要行为,剥去了原有的浪漫主义与田园想象的色彩. 人类文化的发展以及与之相伴的技术进步影响着畜牧业.不同时代的畜牧业状况都反映了当时的社会经济架构.如今的社会状况也蕴含着畜牧业的现代化及其为适应兴起中的增强生态而进行的流程改造.费利克斯·加塔利将思想、社会和环境的生态三角定义为生态智慧,而这正是让人类、动物与技术和谐共生的新型畜牧模式的动力所在.     

Comparative Anti-Inflammatory Effects of Salix Cortex Extracts and Acetylsalicylic Acid in SARS-CoV-2 Peptide and LPS-Activated Human In Vitro Systems

The usefulness of anti-inflammatory drugs as an adjunct therapy to improve outcomes in COVID-19 patients is intensely discussed in this paper. Willow bark (Salix cortex) has been used for centuries to relieve pain, inflammation, and fever. Its main active ingredient, salicin, is metabolized in the human body into salicylic acid, the precursor of the commonly used pain drug acetylsalicylic acid (ASA). Here, we report on the in vitro anti-inflammatory efficacy of two methanolic Salix extracts, standardized to phenolic compounds, in comparison to ASA in the context of a SARS-CoV-2 peptide challenge. Using SARS-CoV-2 peptide/IL-1β- or LPS-activated human PBMCs and an inflammatory intestinal Caco-2/HT29-MTX co-culture, Salix extracts, and ASA concentration-dependently suppressed prostaglandin E2 (PGE₂), a principal mediator of inflammation. The inhibition of COX-2 enzyme activity, but not protein expression was observed for ASA and one Salix extract. In activated PBMCs, the suppression of relevant cytokines (i.e., IL-6, IL-1β, and IL-10) was seen for both Salix extracts. The anti-inflammatory capacity of Salix extracts was still retained after transepithelial passage and liver cell metabolism in an advanced co-culture model system consisting of intestinal Caco-2/HT29-MTX cells and differentiated hepatocyte-like HepaRG cells. Taken together, our in vitro data suggest that Salix extracts might present an additional anti-inflammatory treatment option in the context of SARS-CoV-2 peptides challenge; however, more confirmatory data are needed.     

Provenance and Technology Investigation of Agia Sophia Bricks, Istanbul, Turkey

Bricks from the Agia Sophia in Istanbul, Turkey, were investigated to better formulate a plan for restoration. According to an ancient text, these bricks are extremely light and were manufactured on the island of Rhodes. Results of neutron activation analysis, grouped by multivariate statistics, show that the brick samples do not correlate with clays thought to be local and used in contemporary churches in Istanbul. The bricks are similar to those used in the Great Basilica of Rhodes. However, the Agia Sophia bricks are lighter (45% porosity) than the bricks from the other churches (35% porosity). The Agia Sophia bricks are made of a noncalcareous, fine paste with quartz temper, fired at low temperature (∼750°C). The exceptional characteristic is their homogeneity and small pore-size distribution (0.3–0.8 μm). The tensile strength of the dome bricks is unexpectedly high (up to 1.3 MPa), even though the bricks have high porosity.