Enterprise security pattern: A model-driven architecture instance

To secure their information assets, organizations should seek support from enterprise security architectures. Security patterns are a good way to build and test new security mechanisms, but they have some limitations related to their usability. In previous work, we defined a new type of security pattern called Enterprise Security Pattern. The main objective of these patterns is to provide an instance of model-driven architecture, which offers a solution to recurring problems that have to do with information systems security. In recent years, the hiring of Software as a Service (SaaS) from cloud providers has become very popular. There seem to be many advantages of using these services, but organizations need to be aware of a variety of threats, as well as being prepared to handle them. In another work undertaken previously, we defined an enterprise security pattern called Secure Software as a Service (Secure SaaS), which the organizations could apply to protect their information assets when using SaaS. In this paper, we present different instances of the solution models of the enterprise security pattern Secure SaaS, aiming to verify the risks that an organization would assume if each of the instances were deployed. With this approach, we intend to show how the design decisions adopted when performing the transformations between the solution models can have a direct impact on the security provided by the pattern.     

新型载体树脂在色母粒中的应用研究

对不同熔体质量流动速率（MFR）的同种聚乙烯树脂在色母粒应用方面进行了比较。结果表明：载体树脂MFR的差别对色母粒的质量、加工性能和应用影响较大；高MFR树脂制备的色母粒，加工性能较好，颜料在色母粒中的分散程度较高，但对其他树脂进行着色的效果不理想。因此，应该从色母粒中颜料的分散和色母粒与着色树脂的相容性两个方面进行新型色母粒用载体树脂的开发。     

双单体接枝聚丙烯的制备及性能研究

研究了以苯乙烯（St）为共聚单体，聚丙烯（PP）熔融接枝丙烯酸（AA）的反应工艺。探讨了AA、共聚单体及引发剂用量等因素对接枝反应的影响。通过FTIR分析证实，AA和St接枝到PP链上形成PP-g-AASt接枝物，并且随着引发剂DCP用量的增大，接枝率呈现先升后降的趋势。通过TGA、WAXD及DSC等方法表征了接枝物的热性能和结晶性能。结果表明，随着接枝产物的接枝率的提高，其分解温度及最大失重率温度先上升，维持一段后再下降。而AA和St主要接枝在PP表面上，未破坏原来的晶型，少量的AA有利于结晶成核，提高结晶度。     

POE-g-GMA对聚丙烯／聚磷酸铵复合材料玻璃化转变活化能的影响

以熔融反应挤出得到的POE-g-GMA作为增容剂，制备了增韧PP／APP复合材料。采用动态力学的方法，计算得到不同POE-g-GMA含量的PP／APP复合材料的玻璃化转变活化能。结果表明，在相同的测试频率下，接枝物POE-g-GMA的加入会导致PP／APP复合材料的内耗峰的峰温降低，而内耗峰的强度增加；降低复合材料的玻璃化转变活化能。这说明在PP／APP复合体系中加入POE-g-GMA可以改善PP和无机填料APP之间的相容性，使复合材料中的PP分子链段在进行玻璃化转变时更加容易。只需要较低的活化能就可以了。从中可以判断出接枝物POE-g-GMA对于PP／APP共混体系来说是很好的相容剂。     

In situ generation of hydrogen peroxide from reaction of O2 with hydroxylamine from hydroxylammonium salt in neutral aqueous or non-aqueous medium using reusable Pd/Al2O3 catalyst

In situ generation of H₂O₂ with high yield can be accomplished by reacting O₂ with NH₂OH from hydroxylammonium salt [NH₂OH · HCl or (NH₂OH)₂ · H₂SO₄] in a neutral aqueous medium using a reusable heterogeneous Pd (1.0 wt%)/Al₂O₃ catalyst, even at low temperature (10 °C), with the formation of harmless by-products (viz. N₂ and water). The presence of KCl or KBr in the medium has beneficial effect. The H₂O₂ generation is strongly influenced by the pH of medium, reaction period and temperature; best results are obtained at the optimum pH and reaction medium.     

Flexible rewritable organic memory devices using nitrogen-doped CNTs/PEDOT:PSS composites

Nonvolatile rewritable organic memory devices based on poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and nitrogen doped multi-walled carbon nanotube (NCNT) nanocomposites were fabricated on glass and PET substrates.Organic memory devices with bistable resistive switching were obtained using very low NCTN concentration (∼0.002 wt%) in the polymeric matrix. The memory devices exhibited a good ON/OFF ratio of approximately three orders of magnitude, a good retention time of 10⁴ s under operating voltages ≤ |4V| and a few hundredths of write-read-erase-read cycles. The bistable resistive switching is mainly attributed to the creation of oxygen vacancies. These defects are introduced into the thin native Al oxide (AlOx) layer on the bottom electrode during the first voltage sweep. The well-dispersed NCNTs immersed in PEDOT:PSS play a key role as conductive channels for the electronic transport, hindering the electron trapping at the AlOx-polymer interface and inducing a soft dielectric breakdown of the AlOx layer. These PEDOT:PSS + NCNTs memory devices are to easy to apply in flexible low-cost technology and provide the possibility of large-scale integration.     

Synthesis and photovoltaic properties of D-A copolymers based on alkylthio-thiophene or alkylthio-selenophene-BDT donor unit and DPP acceptor unit

Two new 2D-conjugated D-A copolymers, PBDTT-S-DPP and PBDTSe-S-DPP, based on benzodithiophene (BDT) donor unit with alkylthio-thiophene or alkylthio-selenophene conjugated side chains and 2,5-bis(2-butyloctyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione) (DPP) acceptor unit, were synthesized for the application as donor materials in polymer solar cells (PSCs). The two polymers were characterized by absorption spectroscopy, cyclic voltammetry, thermogravimetric analysis, theoretical calculation with density functional theory, X-ray diffraction and photovoltaic measurements. The results show that the alkylthio-thiophene/selenophene side groups on BDT unit and intramolecular hydrogen bonding interaction in DPP acceptor unit play important roles in affecting the absorption, HOMO energy levels, molecular planarity and the crystallinity of the polymers. The PSCs based on PBDTT-S-DPP or PBDTSe-S-DPP as donor and PC₇₁BM as acceptor demonstrate power conversion efficiency (PCE) of 5.62% and 5.01%, with relatively higher V_oc of 0.79 V and 0.76 V, respectively.     

A game-theoretic approach to the financial benefits of infrastructure-as-a-service

Financial benefits are an important factor when cloud infrastructure is considered to meet processing demand. The dynamics of on-demand pricing and service usage are investigated in a two-stage game model for a monopoly Infrastructure-as-a-Service (IaaS) market. The possibility of hybrid clouds (public clouds plus own infrastructure) turns out to be essential in order that not only the provider but also the clients have significant benefits from on-demand services. Even if the client meets all demand in the public cloud, the threat of building a hybrid cloud keeps the instance price low. This is not the case when reserved instances are offered as well. Parameters like load profiles and economies of scale have a huge effect on likely future pricing and on a cost-optimal split-up of client demand between either a client’s own data center and a public cloud service or between reserved and on-demand cloud instances.     

Effect of N and C on stress corrosion cracking susceptibility of austenitic Fe18Cr10Mn-based stainless steels

Stress corrosion cracking (SCC) susceptibility of austenitic Fe18Cr10Mn alloys with 0.3N, 0.6N and 0.3N0.3C was investigated in aqueous chloride environment using a slow strain rate test method. The SCC susceptibility of Fe18Cr10Mn alloys in 2 M NaCl solution at 50 °C under constant anodic potential condition decreased with increase in N content from 0.3 to 0.6 wt%, and with addition of 0.3 wt% C to the Fe18Cr10Mn0.3N alloys. The present study strongly suggested that the beneficial effects of N and C on the SCC behavior of Fe18Cr10Mn alloys would be associated with the resistance to pitting corrosion initiation and the repassivation kinetics.     

Exploring the potential of fur farming wastes and byproducts as substrates to anaerobic digestion process

Mink farming is a well-established economic activity with a significant environmental footprint. In this work mink farming derived organic waste was assessed, for the first time, as substrate to anaerobic digestion plants. The substrates assessed were; (a)fresh mink manures, (b)weathered mink manures, (c)waste feed and (d)mink derived meat and bone meal. Substrates with in inoculum to substrate ratio of 2 offered specific methane productions ranging between 368 and 591 mLCH₄/gVS_added corresponding to 67.4 and 91.1% of their theoretical methane potential. In the second phase of the experiments three organic loading rates and three inoculum to substrate ratios were assessed. Substrate/inoculum ratios, in batch mode, lower than 1 seem to affect negatively the process, due to slow hydrolysis and acetogenesis of the macromolecules. In addition, initial organic loading rates of up to 50 gVS/L can be applied in batch systems when manure is utilized as substrate. In contrast to this, when mink derived byproducts are used the same loading rate will result into an irreversible process inhibition due to the accumulation of intermediate products.