Effects of elevated water temperatures on interfacial delaminations,failure modes and shear strength in externally-bonded CFRP-concrete beams using infrared thermography,gray-scale images and direct shear test

This paper reports the results of a durability study of the effects of exposing externally-bonded CFRP-concrete beams to three elevated water temperatures (25 °C, 40 °C and 60 °C). The effects of the heated water environments on the adhesive bonding layer between the CFRP and concrete beams were evaluated by quantifying: (1) the changes of delaminations within the adhesive bonding layer, (2) the changes in resistance to direct shear force and (3) the changes of failure mode distribution. Before the exposure, the condition of the adhesive bonding layer was inspected by infrared thermography (IRT). After exposure, the deterioration of the same bonding layer and failure mode distributions were measured by analyzing the visual photos on the failed CFRP strips. The failure modes were found to be affected largely by the combined effect of elevated temperature and moisture ingress, in which three types were identified: failure at concrete beams, at adhesive bonding layer and interface between CFRP strip and concrete. With these methods, results of 54 specimens show that the adhesive bonding layers of all the specimens had gradually deteriorated in the 40 °C and 60 °C water baths. This deterioration was due to the weakening of the adhesive bonding layers when the glass transition temperature (T_g) or the heat distortion temperature (HDT) was approached or even exceeded, and gradual development of delaminations at adhesive bonding layer.     

Development of a re-configurable ambisonic decoder for irregular loudspeaker configuration

This study reports a heuristic genetic algorithm to determine the decoding parameters in a first-order ambisonic system for reconstructing a three-dimensional sound field with an arbitrary quad speaker configuration. On this basis, a hardware prototype has been developed using a field programmable gate array (FPGA) to decode ambisonic signals that are encoded in the standard B-format. To allow direct coupling with digital audio sources, the input and output channels of the decoder are implemented with the I2S interface. Evaluations reveal that the decoding parameters derived by this method are superior to existing approaches in terms of flexibility in loudspeaker configuration and optimisation of some of the essential factors in surround sound reconstruction.     

Improvement of borrowing channel assignment for patterned traffic load by online cellular probabilistic self-organizing map

This paper describes an improvement of borrowing channel assignment (BCA) for patterned traffic load by using the short-term traffic prediction ability of cellular probabilistic self-organizing map (CPSOM). The fast growing cellular mobile systems demand more efficient and faster channel allocation techniques today. In case of patterned traffic load, the traditional BCA methods are not efficient to further enhance the performance because heavy-traffic cells cannot borrow channels from their neighboring cells with light or medium traffic that may have unused nominal channels. The performance can be increased if the short-term traffic load can be predicted. The predicted results can then be used for channel re-assignment. Therefore, the unused nominal channels of the light-or-medium-traffic cells can be transferred to the heavy-traffic cells that need more nominal channels. In this paper, CPSOM is used online for traffic prediction. In this sense, the proposed CPSOM-based BCA method is able to enhance the performance for patterned traffic load compared with the traditional BCA methods. Simulation results corroborate that the proposed method enables the system to work with better performance for patterned traffic load than the traditional BCA methods.     

Multimedia-MAC protocol: its performance analysis and applications for WDM networks

The design of the medium-access control (MAC) protocol is the most crucial aspect for high-speed and high-performance local and metropolitan area networks, since the decisions made at this level determine the major functional characteristics of these networks. Most of the MAC protocols proposed in the literature are not suitable for multimedia applications, since they have been designed with one generic traffic type in mind. As a result, they perform quite well for the traffic types they have been designed for, but poorly for other traffic streams with different characteristics. In this paper, we propose an integrated MAC protocol called the Multimedia-MAC (M-MAC), which integrates different MAC protocols into a hybrid protocol in a shared-medium network to efficiently accommodate various types of multimedia traffic streams with different characteristics and quality-of-service demands, namely, a constant-bit-rate traffic, bursty traffic (say, variable-bit-rate traffic), and emergency messages (say, control messages). We have developed a mathematical framework for the analysis and performance evaluation of our M-MAC protocol, which involves a queueing system with vacation. We have applied our M-MAC design approach to a wavelength-division multiplexing network, and evaluated its performance under various traffic conditions.     

Do routine antibiotics after loop diathermy excision reduce morbidity?

AIMS: To determine functional results after unilateral and bilateral cataract surgery in children with different aphakic optical correction. METHODS: In this retrospective study, we evaluated visual acuity and binocular vision in 107 children who underwent cataract surgery during the 10 year period from 1985 to 1995. Aphakia was corrected by an intracapsular intraocular lens (IOL), spectacles or contact lenses. RESULTS: Mean visual acuity was > 20/40 (< 0.3 log MAR) with normal binocular vision in 58 children over 7 months of age operated on for bilateral cataracts. Pseudophakic eyes regained visual acuity > 20/63 (< 0.5 log MAR) more often (90%) than aphakic eyes (46%) (p < 0.001). Binocular vision was also achieved more often after IOL implantation (p < 0.001). Visual outcome of early bilateral cataracts was less satisfactory in children with abnormal foveolar function. For 49 children who had surgery for unilateral cataracts, prognosis was poor when surgery was performed before the age of 7 months. For cataract surgery in older children (> or = 7 months) mean visual acuities were better with IOL implantation (p < 0.05). CONCLUSION: Cataract surgery with unilateral and bilateral IOL implantation can provide a beneficial effect on final visual outcome in children who are operated on before abnormal foveolar function develops.     

Successful innominate thromboembolectomy of a paradoxic embolus

A 54 year-old man had symptoms of acute right hemispheric cerebral ischemia. He was initially considered for participation in a trial of early thrombolysis in stroke, but an innominate artery embolus was found with no apparent arterial source. The embolus was removed by means of a combined brachial and carotid bifurcation approach to protect the cerebral vasculature from embolic fragmentation during extraction. Further investigation revealed deep venous thrombosis, evidence of pulmonary emboli, and a patent foramen ovale, supporting a diagnosis of paradoxic embolus. Additional treatment included anticoagulation and placement of an inferior vena caval filter. The unusual condition of paradoxic embolus is reviewed, and the management of this patient is discussed.     

Extraction, quantification, and biological availability of fumonisin B1 incorporated into the Oregon test diet and fed to rainbow trout

The purpose of this study was (i) to determine whether pure fumonisin B1 could be incorporated into, recovered, and detected by high-pressure liquid chromatographic analysis from the semipurified Oregon test diet (OTD) used in rainbow trout feeding studies, and (ii) to determine if the incorporated fumonisin B1 was biologically available using the change in free sphingoid bases in liver, kidney, and serum as a mechanism-based biomarker. The results indicate that fumonisin is not easily quantified in the OTD. Recoveries ranged from 12 to 81% of the calculated concentrations based on the fumonisin B1 added to the OTD. However, the fumonisin B1 in the OTD was readily absorbed and biologically active as evidenced by marked increases in free sphinganine in liver, kidney, and serum. The magnitude of the increase in free sphinganine at 100 ppm in the OTD was comparable to that known to be associated with liver toxicity in rats, pigs, and ponies.