Assessment of nuclear energy sustainability index using fuzzy logic

Nuclear energy is increasingly perceived as an attractive mature energy generation technology that can deliver an answer to the worldwide increasing energy demand while respecting environmental concerns as well as contributing to a reduced dependence on fossil fuel. Advancing nuclear energy deployment demands an assessment of nuclear energy with respect to all sustainability dimensions.In this paper, the nuclear energy, whose sustainability will be assessed, is governed by the dynamics of three subsystems: environmental, economic, and sociopolitical. The overall sustainability is then a non-linear function of the individual sustainabilities. Each subsystem is evaluated by means of many components (pressure, status, and response). The combination of each group of indicators by means of fuzzy logic provides a measurement of sustainability for each subsystem.     

Technique to Measure 3D Work-of-Fracture of Concrete in Compression

A high-resolution 3D scanning technique called X-ray microtomography was applied to measure internal damage and crack growth in small mortar cylinders loaded in compression. Synchrotron-based microtomography allows us to resolve internal features that are only a few microns in size. Multiple tomographic scans were made of the same specimen at different levels of deformation using a custom-built loading frame. 3D image analysis was used to measure internal crack growth during each deformation increment. Measured load-deformation curves were used to calculate the nonrecoverable work of the external load on the specimen. Nonrecoverable work of load was related to measured incremental change in crack surface area to estimate work-of-fracture in three dimensions. Initial results indicate a nearly constant work-of-fracture for the early stages of crack growth. These results show that basic fracture mechanics principles may be applied to concrete in compression; however, we must think in terms of 3D multiple crack systems rather than traditional 2D single crack systems.     

Heat-treatment of isomorphously substituted ZSM-5 (MFI) zeolites An ESR and Mössbauer spectroscopy and kinetic study

Fe-ZSM-5 zeolites comprise of three types (I, II and III) of iron (Fe³⁺) sites in both as synthesized (AS) and heat-treated states. Previous evidence could be confirmed by the assignment of ESR lines, registered in the X-band, stating: (i) type I framework Fe³⁺ sites (in T_h oxygen coordination), where charge compensation occurs mainly by Na⁺ ions and the crystal field (cf) approximates cubic symmetry, produce resonances at near to g = 2.00; (ii) type II and probably type III binuclear Fe...Fe dioxo- and oxo-bridges manifest themselves in producing slightly distorted surroundings of axial symmetry, and the relevant powder-averaged subspectrum is superimposed on the previous one in the g  2.45–1.98 interval. As the temperature of the heat-treatment (HT) is raised, type II and III sites will be annihilated with preference, under concomitant production of amorphous Fe₂O₃ possessing molecular dispersity. (iii) The weak ESR signal (2–4%) at g  4.27 is attributed to T_h coordinated framework sites in the surface layers (≈ 1 u.c. thick) under the influence of solid surface tension, giving rise to fully rhombic cf symmetry.

The size of the ejected Fe₂O₃ particles, as estimated from Mössbauer spectra (no hyperfine structure at 77 K) is less than 2.9 nm. The extremely large electron affinity of Fe³⁺ ions manifests itself in decreased ionicity (and unexpectedly dominant cubic symmetry), activity in biomimetic oxidations, autoreduction and spontaneous reoxidation etc.

In the liquid phase oxidation by hydrogen peroxide of n-hexane and cyclohexane the heat-treated Ti-ZSM-5 samples exhibited both activity- and selectivity dependence on HT. On the basis of experiences drawn from the heat-treatments proposal is made for the structures of the defect site (producing the 960 cm⁻¹ IR signal) and the active centre of selective oxidation. The proposal seems to be in accord with the experimental observations (isotopic exchange, MAS-NMR behaviour etc.) published so far.     

An approximate model for three-dimensional alternating current potential drop analyses using a commercial finite element code

Alternating current potential drop (ACPD) is an established technique for non-destructive testing and materials characterisation. Finite element (FE) simulation is a very useful tool for the optimisation of probes and the prediction of test results, but three-dimensional models of ACPD problems are computationally intensive. This paper presents a new, simple model in which frequency-related effects are taken into account by appropriately modifying the geometry of the modelled structure: a DC analysis can then be performed on a smaller domain, thus reducing the computational power required. The results of experimental tests for the validation of the model are also presented and discussed.     

Polyurea/vinylester hybrid thermoset resins with in situ produced silicate filler: Preparation and static mechanical properties

Proprietary polyurea‐based thermosets were produced from polyisocyanate and water glass (WG) using a phosphate‐type phase transfer catalyst. WG was dispersed in the polyisocyanate resulting in water‐in‐oil (W/O) type emulsion. The polyurea matrix, formed after crosslinking, contained the WG derived silicate in coarse particles showing a broad particle size distribution. The mean particle size of the silicate was markedly reduced and its distribution narrowed when the polyisocyanate was hybridized with a peroxide crosslinkable vinylester resin (VE) when the amount of the latter was <75%. This resin hybridization strongly improved the mechanical (flexural) properties of the related thermosets, however, at cost of the fracture mechanical characteristics (fracture toughness and energy under mode I condition). This was mostly attributed to the formation of a conetwork or interpenetrated network between the polyurea and VE. The static flexural and fracture mechanical properties were determined as function of the resin hybridization ratio. It was found that the mechanical properties change according to the additivity rule as a function of the resin hybridization in the first approximation. The silicate dispersion and the failure behavior in the polyurea/VE hybrids were studied by scanning electron microscopy (SEM) and discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 853–859, 2007     

Structural origin of coiling in coiled carbon nanotubes

The statistical distribution of a large number of helically coiled carbon nanotubes was analyzed in a cross-correlated way in their geometrical configuration space defined by diameter and pitch. Stability islands were identified, in which the number of coils exceeds about 15-10 times the value corresponding to a uniform distribution. When comparing our data with data from literature, a good agreement is found. The statistical findings are interpreted as indirect evidence that the geometric configuration of coiled carbon nanotubes is rather decided by the atomic structure of carbon layers building up the coils than by the external parameters which on the other hand may induce the particular conditions under which coiling occurs. The possible effect of impurities like N and S on the incorporation of non-hexagonal rings and tubular growth is pointed out.     

Modifications of and special operating tricks in the classical technique of surgery against strabismus

Even nowadays the idea of most of the operations against strabismus is based on myectomy and reposition of the rectus muscles. At the Department of Ophthalmology of the University Medical School of Debrecen we use mainly these two methods of operation. At our Department we performed 1605 operations against strabismus during the last 10 years. 1269 of our patients had convergent, 336 had divergent strabismus. The majority of the operations were performed on patients less than 6 years of age, under general anesthesia. The outcome of the operation is successful if it results in a situation, in which torque affecting the eyeball stabilizes it in the normal position. The advantage of the combined surgical procedure is that the former muscular balance remains intact, and by relatively small intervention good results can be achieved. In the rectus muscles of squint patients anatomical and histopathological changes could be found, especially if they did not receive pleoptic treatment preoperatively. Depending on the direction of the strabismus one of the muscles is thicker, while the other is thinner, due to hyper- and hypofunction. Our surgical experience of many years showed that by modifying the classical technique of the operations with some fine technical tricks it was possible to increase the success rate. In our film we presented the right way of incising and handling the subconjunctival connective tissue (Tenon capsule) thus making it possible to lay it back to its original place at the end of the operation. This way the chance of postoperative scarring is reduced. We demonstrated how to test the contractility of the muscles by using muscle-hooks, that replaces the forceps test. In case of myectomy we demonstrated the tricks of how to handle the easiest and the finest way. In case of retroposition we can achieve perfect reconstruction and wound healing by using the shown simple technique. We also take much care of suturing the conjunctiva during operations performed on infants that is important because of their undisciplined behavior.     

Reservoir engineering assessment of low-temperature geothermal resources in the Skierniewice municipality (Poland)

Low temperature geothermal resources and their production potential in the Skierniewice area of Poland were evaluated assuming conventional well doublet arrays. The reservoir engineering assessment was carried out, within the framework of a World Bank project, to study the feasibility of providing heat to the local district heating system, using data from two existing wells and from geophysical surveys, and by evaluating results of production, injection and interference well tests. Two options were simulated mathematically, using both semianalytical and numerical codes, considering a simplified reservoir model: one based on the two existing wells, the other considering four wells, two to be drilled. The injection of spent brines into a different reservoir was also studied.