Investigation on the feasibility of eliminating harmonic excitation signal en-route to performing experimental modal analysis (EMA) under operational condition

This study focuses on introducing a criteria for conducting harmonic excitation signal elimination as well as investigating its effectiveness towards achieving complete isolation of harmonic disturbance in performing EMA under operational condition. By modulating the ratio between harmonic excitation and impact knocking frequencies, it was revealed that the harmonic signal was efficiently attenuated with sufficient number of averaging blocks. The results highlighted close agreement between simulation and experimental approaches with maximum deviation of 2 %, under specific design criteria. It was determined that a non-periodic triggering frequency significantly affect the elimination performance in terms of trend and amplitude reduction. This work underlines the importance of controlling the triggering frequency to yield the desired design criteria for achieving rapid and highly efficient elimination of harmonic excitation signal. The results have proven that the proposed technique can be further adapted to isolate the harmonic in conventional EMA conducted under operational condition.     

Coffee mixtures—Spectrophotometric method for the determination of coffee content

The method described in this paper gives results which are good approximations of the actual coffee contents of roasted coffee/roasted chicory and roasted coffee/roasted fig mixtures.It has also been applied to coffee and chicory essence, cereal products and instant coffee/chicory, instant coffee/cereal/chicory mixtures.     

IKONOS image fusion process using steepest descent method with bi-linear interpolation

There are many image fusion processes to produce a high-resolution multispectral (MS) image from low-resolution MS and high-resolution panchromatic (PAN) images. But the most significant problems are colour distortion and fusion quality. Previously, we reported a fusion process that produced a1 m resolution IKONOS fused image with minimal spectral distortion. However, block distortion appeared at the edge of the curved sections of the fused image, which was reduced by performing the wavelet transformation as a post-process. Here, we propose an image fusion process using the steepest descent method with bi-linear interpolation, which can remove block distortion without using wavelet transformation. Bi-linear interpolation provides the proper initial values of the fused image, and then the steepest descent method produces the optimum results of the fusion process. These results achieve improvement on the spectral as well as spatial quality of a1 m resolution fused image when compared with other existing methods and remove block distortion completely.     

Evaluation of toxic elements in baby foods commercially available in Pakistan

In present work, the concentrations of toxic elements, aluminium (Al), cadmium (Cd), nickel (Ni) and lead (Pb) were measured in different solid baby foods (BFs), primarily to evaluate whether the intakes comply within permissible levels of these toxic elements (TEs). The BFs were evaluated for total contents of TEs, using a simple and fast ultrasound-assisted extraction (UAE) method. The accuracy of the proposed UAE method was ensured by using certified reference materials and results obtained by conventional wet acid digestion method on same CRM, at 95% confidence level. The range of the investigated TEs in different BFs were 4770–35,200, 25.6–88.3, 124–332 and 52.5–90.6 μg/kg for Al, Cd, Ni and Pb, respectively. The results indicated that BFs including rice cereals have high level of all four TEs. The daily intakes of TEs for children through BFs have also been estimated, and are well below the recommended tolerable levels.     

Clinical reasoning gains in medical PBL: an UMLS based tutoring system

Problem based learning is becoming widely popular as an effective teaching method in medical education. Paying individual attention to a small group of students in medical problem-based learning (PBL) can place burden on the workload of medical faculty whose time is very costly. Intelligent tutoring systems offer a cost effective alternative in helping to train the students, but they are typically prone to brittleness and the knowledge acquisition bottleneck. Existing tutoring systems accept a small set of approved solutions for each problem scenario stored into the system. Plausible student solutions that lie outside the scope of the explicitly encoded ones receive little acknowledgment from the system. Tutoring hints are also confined to the knowledge space of the approved solutions, leading to brittleness in the tutoring approach. We report the clinical reasoning gains off a tutoring system for medical PBL that employs and represents the widely available medical knowledge source UMLS as the domain ontology. We exploit the structure of the concept hierarchy to expand the plausible solution space and generate hints based on the problem solving context. Evaluation of student learning outcomes led to highly significant learning gains (Mann-Whitney, p < 0.001).     

Effect of Gaseous Ozone on Papaya Anthracnose

Anthracnose caused by the fungus Colletotrichum gloeosporioides is considered as one of the most devastating postharvest disease of papaya. The aim of this study was to evaluate the effectiveness of gaseous ozone as a potential antifungal preservation technique to overcome anthracnose disease of papaya during cold storage. Different concentrations of ozone (0 (control), 0.04, 1.6, and 4 ppm) were applied for various exposure durations (48, 96, and 144 h). Radial mycelia growth and conidial germination were evaluated in vitro after fungal exposure to the different levels and durations of ozone. Significant inhibition in radial mycelia growth of C. gloeosporioides was observed (p?<?0.05) in all ozone treatments as compared to the control during 8 days of incubation at room temperature (25?±?3 °C). Ozone treatment of papaya fruit with 1.6-ppm ozone for 96 h delayed and simultaneously decreased the disease incidence to 40 % whereas disease severity was rated at 1.7, following 28 days of storage at 12?±?1 °C and 80 % relative humidity. The scanning electron microscopy showed that 4-ppm ozone caused disintegration of spore structure and did not affect the cuticular surface of fruit. Thus, ozone fumigation can reduce postharvest losses of papaya caused by anthracnose.     

Dry sliding wear in case-hardened niobium microalloyed steels

Low-carbon steel samples containing a small addition of niobium singly or in combination with nitrogen have been carburized in a natural Titas gas atmosphere at 950 °C and 15 psi gas pressure for different time periods. At the end of the predetermined time period, the specimens were pre-cooled to 860 °C in the furnace and quenched in 10% brine. One set of the quenched specimens was tempered at a low temperature of 160 °C and the other set was sub-zero treated at −195 °C in liquid nitrogen, followed by tempering at the same tempering temperature. Surface hardness was measured by Rockwell hardness testing machine and optical microscopy was performed on etched samples. Using a pin-on-disc type apparatus, wear test was carried out under dry sliding condition to assess the beneficial effect of niobium and niobium with nitrogen on the wear properties of the carburized and hardened low-carbon steels in relation to the resulted surface hardness and microstructures.

It has been found that niobium with or without nitrogen improves the wear resistance under both the heat treatment conditions. Niobium with nitrogen is more effective than niobium in improving the wear resistance. Whatever was the heat treatment condition, the wear rate of the specimens increases for all the steels as the carburizing time increases. It has also been found that samples with sub-zero treatment always have higher wear resistance than that of samples without sub-zero treatment. Niobium singly or in combination with nitrogen has been found as a modifier of the wear mechanism.     

Effect of aspirin on prostaglandin E2 and leukotriene B4 production in human colonic mucosa from cancer patients

Elderly persons typically show diminished immune responsiveness to influenza vaccination. Chiron Vaccines has developed a novel oil-in-water adjuvant emulsion, MF59, to enhance vaccine immunogenicity without compromising safety and tolerability. MF59 was shown to augment influenza vaccine immunogenicity in senescent mice. Subsequently, eight similarly designed, randomized, controlled clinical trials of a subunit influenza vaccine combined with MF59 were conducted between 1992 and 1995 in 1807 elderly volunteers (> or = 65 years old). Mild, transient, injection-site reactions were increased with MF59, but systemic reactions generally were not. For two of the three vaccine antigens (B and A/H3N2), postimmunization haemagglutinin inhibition geometric mean titres were statistically significantly higher with MF59. During influenza season, fewer deaths occurred among MF59 recipients. This development programme demonstrates how an adjuvant that stimulates effectors associated with immunosenescence can improve the performance of an existing vaccine in elderly persons.     

Preparation,characterization, viscosity,and thermal conductivity of nitrogen-doped graphene aqueous nanofluids

Nanofluids perform a crucial role in the development of newer technologies ideal for industrial purposes. In this study, Nitrogen-doped graphene (NDG) nanofluids, with varying concentrations of nanoparticles (0.01, 0.02, 0.04, and 0.06 wt%) were prepared using the two-step method in a 0.025 wt% Triton X-100 (as a surfactant) aqueous solution as a base. Stability, zeta potential, thermal conductivity, viscosity, specific heat, and electrical conductivity of nanofluids containing NDG particles were studied. The stability of the nanofluids was investigated by UV–vis over a time span of 6 months and concentrations remain relatively constant while the maximum relative concentration reduction was 20 %. The thermal conductivity of nanofluids was increased with the particle concentration and temperature, while the maximum enhancement was about 36.78 % for a nanoparticle loading of 0.06 wt%. These experimental results compared with some theoretical models including Maxwell and Nan’s models and observed a good agreement between Nan’s model and the experimental results. Study of the rheological properties of NDG nanofluids reveals that it followed the Newtonian behaviors, where viscosity decreased linearly with the rise of temperature. It has been observed that the specific heat of NDG nanofluid reduced gradually with the increase of concentration of nanoparticles and temperature. The electrical conductivity of the NDG nanofluids enhanced significantly due to the dispersion of NDG in the base fluid. This novel type of fluids demonstrates an outstanding potential for use as innovative heat transfer fluids in medium-temperature systems such as solar collectors.