Ultrasonic NDE of solid-state bonds: Inertia and friction welds

This paper discusses a number of special ultrasonic NDE problems of particular interest to inertia and friction welds, but most of the results can be readily applied to other similar or dissimilar solid-state bonds as well. One of the major problems associated with dissimilar bonds is the blinding effect of the strong interface reflection caused by the inherent elastic discontinuity at the otherwise flawless boundary. A novel signal-processing technique based on the symmetric part of the boundary reflections from the two opposite sides of the interface is introduced and shown to yield a quantitative measure of boundary imperfection even for very good, apparently flawless bonds. The second problem addressed in this paper is the so-called cold-weld effect. As a combined result of heat softening and external pressure, intimate mechanical contact can be achieved without real fusion. Frequency analysis of the reflected ultrasonic signal from such cold-welded areas is shown to be capable of measuring the degree of plastic deformation at the contacting surfaces and, indirectly, to assess interface pressure and temperature. The third problem considered in this paper is the ultrasonic evaluation of the characteristic layered distribution of the grain structure in flawless inertia and friction welds. As an example, the thickness of the heat-affected zone (HAZ) was determined by ultrasonic spectroscopy, and the results were found to be in good agreement with independent optical profile measurements. Furthermore, the HAZ thickness is shown to be strongly correlated to welding pressure, therefore it offers a sensitive indicator for bond quality assessment as well.     

Secret key rate proof of multicarrier continuous‐variable quantum key distribution

We prove the secret key rate formulas and derive security threshold parameters of multicarrier continuous‐variable quantum key distribution CVQKD. In a multicarrier CVQKD scenario, the Gaussian input quantum states of the legal parties are granulated into Gaussian subcarrier continuous variables (CVs). The multicarrier communication formulates Gaussian subchannels from the physical quantum channel, each dedicated to the transmission of a subcarrier CV. The Gaussian subcarriers are decoded by a unitary CV operation, which results in the recovered single‐carrier Gaussian CVs. We derive the formulas through the adaptive multicarrier quadrature division (AMQD) scheme, the singular value decomposition (SVD)–assisted AMQD, and the multiuser AMQD multiuser quadrature allocation (MQA). We prove that the multicarrier CVQKD leads to improved secret key rates and higher tolerable excess noise in comparison with single‐carrier CVQKD. We derive the private classical capacity of a Gaussian subchannel and the security parameters of an optimal Gaussian collective attack in the multicarrier setting. We reveal the secret key rate formulas for one‐way and two‐way multicarrier CVQKD protocols, assuming homodyne and heterodyne measurements and direct and reverse reconciliation. The results reveal the physical boundaries of physically allowed Gaussian attacks in a multicarrier CVQKD scenario and confirm that the improved transmission rates lead to enhanced secret key rates and security thresholds.     

Next Generation University Library Information Systems Based on Cooperative Learning

An integrated library information system is a resource planning system for a library, used to track resources owned, bills paid, orders made, and patrons who have borrowed. In our research, we focused on university library information systems (ULISs). We identified an important research question regarding their main limitation in offering intelligent help to the students in their documentation/learning. We identified the importance of the endowment of ULISs with artificial intelligence. In this article, we analyzed different aspects related to the presence of computational intelligence in ULISs and intelligence of ULISs. Finally, we proposed a complex next generation ULIS based on a hybrid cooperative learning, being able to offer an intelligent help for personalized learning of students. We defined some novel paradigms in the context of a novel kind of cooperative hybrid personalized learning, such as learning role and sub-role; and learning intelligence level.     

Lanthanide “Chameleon” Multistage Anti‐Counterfeit Materials

Hybrid materials displaying multistage security behavior, where a single material shows both wavelength‐ and temperature‐dependent luminescence properties, are reported. The materials consist of mixed‐lanthanide β‐diketonate complexes grafted into the pores of a nanosized 2,2′‐bipyridine‐5,5′‐dicarboxylate‐acid MOF. A very specific choice of lanthanides and their ratios, as well as β‐diketonate ligand, is crucial for obtaining the desired properties. The wavelength‐dependent luminescence properties of the materials are very well matched with the excitation wavelengths of a standard UV lamp, and a clearly visible change in luminescence is observed in a narrow temperature range (slightly below and above room temperature), proving them to be excellent materials for use in anti‐counterfeit technologies, which would be almost impossible to mimic.     

Enzymatic glycerolysis and transesterification of vegetable oil for enhanced production of feruloylated glycerols

Novel functional groups can be introduced into vegetable oils using enzymes, resulting in value-added products. The transesterification kinetics of ethyl ferulate with MAG, DAG, and TAG were examined. Transesterification was catalyzed by immobilized Candida antarctica lipase B in solventless batch and packed-bed reactors. Initial reaction rates with TAG were slightly sensitive to water activity, whereas rates with MAG and DAG were water activity independent. Transesterification was also three-to sixfold faster with MAG and DAG. These observations indicate that the reaction is rate limited by the acyl acceptor, and that oils with free hydroxyl groups are preferred acyl acceptors in comparison with TAG, which must undergo partial hydrolysis before becoming reactive.     

Humic substances-clay complexes in Hungarian coals

BY mechano-chemical activation, 20–62% of a natural lignite dust and four brown coals can be peptized. The peptizable and non-peptizable parts (concentrated coals) are humic substances of medium and high coalification that are bonded in complexes with clay minerals and amorphous aluminium hydrosilicates. For coals of equal degree of coalification there is no significant difference between the elemental analyses (C, H, O) of the organic parts of the peptized and concentrated fractions. The tested concentrated coals do not contain uncomplexed organic parts (i.e. material with ash yield <2%). The applied mechano-chemical process induces intense hydration, and presumably this will be of importance in the formation of humus. Heat-stability investigations indicate that the aluminium hydrosilicate—humus material complexes will have higher stability and probably a longer lifetime in the soil than the calcium humates present in a peat sample. It appears that disaggregated complexes derived from lignites and brown coals will prove the cheapest organic materials for amelioration of sandy soil. It is shown that the solubility of the clay minerals in water increases markedly if they are bound in complexes with humic substances. A new hypothesis is advanced for the genesis of the Nógrád coal basin.     

The transmission of vibration through gloves: effects of push force, vibration magnitude and inter-subject variability

The extent to which a glove modifies the risks from hand-transmitted vibration is quantified in ISO 10819:1996 by a measure of glove transmissibility determined with one vibration magnitude, one contact force with a handle and only three subjects. This study was designed to investigate systematically the vibration transmissibility of four 'anti-vibration' gloves over the frequency range 16-1600 Hz with 12 subjects, at six magnitudes of vibration (0.25-8.0 ms(-2) r.m.s.) and with six push forces (5 N to 80 N). The four gloves showed different transmissibility characteristics that were not greatly affected by vibration magnitude but highly dependent on push force. In all conditions, the variability in transmissibility between subjects was as great as the variability between gloves. It is concluded that a standardised test of glove dynamic performance should include a wide range of hands and a range of forces representative of those occurring in work with vibratory tools. STATEMENT OF RELEVANCE: The transmission of vibration through anti-vibration gloves is highly dependent on the push force between the hand and a handle and also highly dependent on the hand that is inside the glove. The influence of neither factor is well reflected in ISO 10819:1996, the current standard for anti-vibration gloves.     

Automated signal pattern evaluation of a bladder cancer specific multiprobe-fish assay applying a user-trainable workstation

OBJECTIVE: Signal pattern enumeration of Urovysion Fluorescence in Situ Hybridization test is tedious and requires great experience. Our aim was to eliminate human interaction by automating the process, using an adoptable, automated image acquisition, and analysis system. METHODS: For extensive analytical analysis control, cell populations were used, while preliminary clinical study was performed on 21 patients with clinical suspicion for bladder cancer. All investigations were carried out using an automated user‐trainable workstation (Metafer4‐Metacyte). RESULTS: The system identified nuclei with a specificity and sensitivity of 92.7 and 96.6%, respectively, while signal detection accuracy was 81.1% on average. Both analytical and diagnostic accuracy of automated analysis was comparable to manual approach (94.8 and 71% vs. 97.9 and 76%, respectively), but classification accuracy increased with degree of polysomy, thus diagnostic sensitivity in low grade, low stage cases was poor. CONCLUSION: It is possible to automate signal enumeration of Urovysion using a user‐trainable system, and achieve efficiency comparable to manual analysis. Previously introduced automated immunophenotypic targeting should further increase diagnostic sensitivity, while resulting in a comprehensively automated method. However, the problem of reduced detection accuracy in cases featured with low polysomy is likely to remain a great challenge of automated signal enumeration. Microsc. Res. Tech. 75:814–820, 2012. © 2011 Wiley Periodicals, Inc.     

On radiant energy in high-temperature research

The mechanism of heating solids with radiant energy is reviewed and the need for measuring radiative properties is pointed out. Image furnaces are suitable for such measurement at high temperatures. The limitations of image furnace operations are discussed and methods as well as equipment offered to overcome the limitations. The importance of artificial black bodies in high-flux measurements is described and a new shape for such cavities is proposed. Data comparing this shape with hitherto used shapes are tabulated. Design for a fast-action on-off shutter for image furnaces is presented. In its retracted position the shutter does not cast any shadow on the mirror and it does not require artificial cooling even when exposed to radiation.