Topology Optimization of Carbon Nanotube Reinforced Polymer Damping Structures

Topology optimization has been successfully used for improving vibration damping in constrained layer damping structures. Reinforcing carbon nanotubes in a polymer matrix greatly influence the mechanical properties of the polymer. Such nanotube-reinforced polymers (NRP) can be used to further enhance the damping properties of the constrained layer structures. In this work, topology optimization is performed on constrained damping layer structures using NRP in order to maximize the loss factor for the first resonance frequency of the base beam. In addition to the material fractions of the NRP and elastic material, the volume fraction of the nanotubes in the polymer is also a design variable in the optimization process. The modal strain energy method is used for the loss factor calculation. A commercially available finite element code ABAQUS is used for the finite element analysis. The structure is discretized using 2-dimensional 8-noded quadratic elements. Optimization is performed with a gradient based optimization code which uses a sequential quadratic programming algorithm. To make the optimization process more efficient, an analytical method to calculate the gradients is derived to replace the previously used finite difference method. The resulting structures show a remarkable increase in damping performance. To show the robustness of the optimization process, material fraction and base beam thickness parameter studies are also performed

INDDoS+: secure DDoS detection mechanism in programmable switches

Volumetric distributed Denial-of-Service (DDoS) attack is a key issue in modern telecommunication networks since it can exhaust the resources of legitimate users and cripple network services. Recently, with the emergence of high-throughput and low-latency programmable switches, DDoS detection mechanisms have been designed and implemented in an in-network manner, that is, DDoS detection executed directly within programmable switches. State-of-the-art works use advanced data structures to monitor the number of connections targeting destination hosts: if there is sudden increase of connections and the number exceeds a given threshold, the destination host is most likely under DDoS attack. However, while this approach is efficient in DDoS victims identification, it has inherent vulnerabilities in the detection mechanism that may lead to security issues. In this paper, we study two possible vulnerabilities in DDoS detection data structures, showing the possibilities to break DDoS detection mechanisms in programmable switches. To mitigate the constructed attacks, we propose a solution called INDDoS+. The results show that INDDoS+ is robust to attacks and can accurately detect DDoS attempts when limited hardware resources are assigned

Tracking Normalized Network Traffic Entropy to Detect DDoS Attacks in P4

Distributed Denial-of-Service (DDoS) attacks represent a persistent threat to modern telecommunications networks: detecting and counteracting them is still a crucial unresolved challenge for network operators. DDoS attack detection is usually carried out in one or more central nodes that collect significant amounts of monitoring data from networking devices, potentially creating issues related to network overload or delay in detection. The dawn of programmable data planes in Software-Defined Networks can help mitigate this issue, opening the door to the detection of DDoS attacks directly in the data plane of the switches. However, the most widely-adopted data plane programming language, namely P4, lacks supporting many arithmetic operations, therefore, some of the advanced network monitoring functionalities needed for DDoS detection cannot be straightforwardly implemented in P4. This work overcomes such a limitation and presents two novel strategies for flow cardinality and for normalized network traffic entropy estimation that only use P4-supported operations and guarantee a low relative error. Additionally, based on these contributions, we propose a DDoS detection strategy relying on variations of the normalized network traffic entropy. Results show that it has comparable or higher detection accuracy than state-of-the-art solutions, yet being simpler and entirely executed in the data plane.Comment: Accepted by TDSC on 24/09/202

Safety evaluation of seabuckthorn (Hippophae rhamnoides) leaves in Japanese quail

Aim: The present study was designed to evaluate the safety of seabuckthorn (Hippophae rhamnoides L. Elaeagnaceae) leaves added in the diet of Japanese quail. Materials and Methods: A total of ninety quail chicks were randomly divided into 2 groups and fed a standard quail chick mash added with or without 2% SBT leaf powder (Group SX), and a standard quail chick mash (Group CX, control) for 21 days. Six animals from each group were randomly sacrificed at 7, 14 and 21 day post feeding. Blood and tissue samples were collected for biochemical and histopathological studies.Results: The inclusion of SBT in quail diet did not affect the weekly body weights, clinical signs or mortality among the birds. The serum biochemical parameters like alanine transaminase, total protein, albumin, cholesterol and uric acid values in SBT treated group were found at par with those in the control group. Gross and histopathological studies of various internal organs such as liver, kidneys, heart, spleen, proventriculus, small intestine, bursa and thymus did not reveal any significant lesions in the tissue sections. However, proliferation of lymphoid tissue was a prominent finding noted in different lymphoid organs.Conclusion: In conclusion, the addition of seabuckthorn leaf powder at 2% level in the diet of Japanese quail was found to be safe and it can be used as a feed additive

Ruolo e limiti del contratto negli assetti familiari in funzione successoria

The Article 457 c.c. expressly excludes the contract by the sources of the succession. Moreover, the article 458 c.c., apart from the initial brief aside dedicated to the institute of the family pact, agrees nullity of the agreements with whom someone decides its own succession as well as those with which the future successor could decide about his rights or renounce to them about a succession not yet open. However, for a long time, the Italian doctrine wonders about the role of the contract within the succession law. It feels, in fact, the need to expand the private autonomy within the inheritance that is excessively sacrificed by the prohibition of succession agreements and by the norms for the protection of legitimate heirs. The reasons which led the legal science to these conclusions are based on different events, both social and economic, that push the interpreter to a modernization of dogmatic categories with which he can represent the succession mortis causa. In addiction, it is necessary to underline the crisis of the agreements mortis causa due to this economical and social events: as a matter of fact, the will, as the only way to give the assets post mortem, revealed itself incomplete and extremely severe compared to the new social needs. In fact, increasingly the way to give the assets happens out of the inheritance and despite to the institutions designed by the law. For these reasons, in order to adapt the system of succession to modern economic and social needs, the doctrine has identified, within the system, institutions of a contractual nature in order to better achieve the interests of private, obviating the limits assigned to the shop last will. And recently, in this context, our legislator has introduced the institution of the family pact (art. 768 bis et seq. c.c.), that is the agreement through “the entrepreneur transfers, in whole or in part , the company, and the holder of equity investments transfers, in whole or in part, its shares, to one or more descendants". While, however, part of the doctrine encourages the provision of tools that enable a person to have in advance of his succession, on the other hand there are those who promote the centrality of the will within our legal system and calls for the revitalization in respect of its vast potential is not always adequately exploited. This research aims to verify whether the contract can find importance within the phenomenon of succession for the inter vivos transfer of family assets and if the same has the characteristics to be considered a working alternative to the will. In the present work will be analyzed, in addition, some of the institutions that the doctrine has considered alternatives to the will and particularly the institution of the family pact. The survey will also be directed to the limits that the private autonomy and the legislator met in the use of the contractual instrument, limits that are mostly originated by the rules and principles of the law of succession

Low Power Arithmetic Units using Pass Logic

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In-Network Volumetric DDoS Victim Identification Using Programmable Commodity Switches

Volumetric distributed Denial-of-Service (DDoS) attacks have become one of the most significant threats to modern telecommunication networks. However, most existing defense systems require that detection software operates from a centralized monitoring collector, leading to increased traffic load and delayed response. The recent advent of Data Plane Programmability (DPP) enables an alternative solution: threshold-based volumetric DDoS detection can be performed directly in programmable switches to skim only potentially hazardous traffic, to be analyzed in depth at the controller. In this paper, we first introduce the BACON data structure based on sketches, to estimate per-destination flow cardinality, and theoretically analyze it. Then we employ it in a simple in-network DDoS victim identification strategy, INDDoS, to detect the destination IPs for which the number of incoming connections exceeds a pre-defined threshold. We describe its hardware implementation on a Tofino-based programmable switch using the domain-specific P4 language, proving that some limitations imposed by real hardware to safeguard processing speed can be overcome to implement relatively complex packet manipulations. Finally, we present some experimental performance measurements, showing that our programmable switch is able to keep processing packets at line-rate while performing volumetric DDoS detection, and also achieves a high F1 score on DDoS victim identification.Comment: Accepted by IEEE Transactions on Network and Service Management Special issue on Latest Developments for Security Management of Networks and Service

Molecular Interaction Studies of Trimethoxy Flavone with Human Serum Albumin

Background: Human serum albumin (HSA) is the most abundant protein in blood plasma, having high affinity binding sites for several endogenous and exogenous compounds. Trimethoxy flavone (TMF) is a naturally occurring flavone isolated from Andrographis viscosula and used in the treatment of dyspepsia, influenza, malaria, respiratory functions and as an astringent and antidote for poisonous stings of some insects. Methodology/Principal Findings: The main aim of the experiment was to examine the interaction between TMF and HSA at physiological conditions. Upon addition of TMF to HSA, the fluorescence emission was quenched and the binding constant of TMF with HSA was found to be KTMF = 1.060.01610 3 M 21, which corresponds to 25.4 kcal M 21 of free energy. Micro-TOF Q mass spectrometry results showed a mass increase of from 66,513 Da (free HSA) to 66,823 Da (HAS +Drug), indicating the strong binding of TMF with HSA resulting in decrease of fluorescence. The HSA conformation was altered upon binding of TMF to HSA with decrease in a-helix and an increase in b-sheets and random coils suggesting partial unfolding of protein secondary structure. Molecular docking experiments found that TMF binds strongly with HSA at IIIA domain of hydrophobic pocket with hydrogen bond and hydrophobic interactions. Among which two hydrogen bonds are formed between O (19

Improved Process for the Synthesis of 3-(3-Trifluoromethylphenyl)propanal for More Sustainable Production of Cinacalcet HCl

Cinacalcet (I), sold as hydrochloride salt, is a calcimimetic drug which has been approved for the treatment of secondary hyperparathyroidism in patients with chronic renal disease and for the treatment of hypercalcemia in patients with parathyroid carcinoma. Here, an improved method for the synthesis of 3-(3-trifluoromethylphenyl)propanal (II), a key intermediate for the preparation of I, is described. The protocol required a Mizoroki–Heck cross-coupling reaction between 1-bromo- 3-(trifluoromethyl)benzene and acroleine diethyl acetal, catalyzed by Pd(OAc)2 in the presence of nBu4NOAc (tetrabutylammonium acetate), followed by the hydrogenation reaction of the crude mixture of products in a cascade process. Palladium species, at the end of the reaction, were efficiently recovered as Pd/Al2O3. The procedure was developed under conventional heating conditions as well as under microwave-assisted conditions. The obtained mixture of 1-(3,3-diethoxypropyl)-3- (trifluoromethyl)benzene (III), impure for ethyl 3-(3-trifluoromethylphenyl) propanoate (IV), was finally treated, under mild conditions, with potassium diisobutyl-tert-butoxyaluminum hydride (PDBBA) to obtain after hydrolysis 3-(3-trifluoromethylphenyl)propanal (II), in an excellent overall yield and very high purity. Microwave conditions permitted a reduction in reaction times without affecting selectivity and yield. The final API was obtained through reductive amination of (II) with (R)-(+)-1-(1-naphthyl)ethylamine (V) using a catalyst prepared by us with a very low content of precious metal