An ultrastructural study of age-related changes in mouse olfactory epithelium

Transmission and scanning electron microscopic examinations were undertaken to detail changes in the olfactory epithelium (OE) resulting from the ageing process. Samples were prepared from 3% glutaraldehyde/1% formaldehyde perfused mice aged 6 months and 29-30 months. Compared to OE from young adults, a number of striking changes were apparent in tissue from older animals. The most obvious of these were extensive local accumulations of large inclusion bodies, totally disrupting the normal morphology of such affected areas of olfactory epithelium. Even in areas where these deposits were absent, other significant signs of ageing were noted in the seemingly unaffected OE of all older mice studied. Quantitative analysis of semi-thin resin sections revealed that the OE of aged mice was significantly reduced in thickness, and with significantly fewer olfactory sensory neurons, irrespective of whether or not inclusions were present. In addition, pale cells, which have been suggested to be a form of degenerating cells, were more abundant in aged OE. The straight, sharp boundary between respiratory and olfactory epithelia which is seen in young adults became irregular and disrupted with age due to an intermingling of the respiratory and olfactory cells. Such structural alterations may parallel olfactory dysfunction reputed to occur in older mammals.     

Effects of additives on oxidation characteristics of palm oil‐based trimethylolpropane ester in hydraulics applications

Hydraulic fluids represent one of the most important groups of industrial lubricants. Increasing attention to environmental issues drives the lubricant industry to choose vegetable‐based hydraulic fluids which are biodegradable as compared to mineral‐based fluids. However, the lubricating properties of vegetable oil, such as poor oxidative stability and high pour point, have hindered their use. In this study, trimethylolpropane ester, which was derived from palm‐based methyl ester, was used as the base hydraulic fluid. The purpose of the study was to determine the optimum formulation for palm oil‐based synthetic lubricants by using suitable additives that can improve the oxidative stability and viscosity in accordance with the standard regulations for hydraulic fluid applications. The oxidative stability of the oil was evaluated by total acid number (TAN) and viscosity tests. In general, base oil without additive began to degrade after 200 h. The formulated oil, on the other hand, was quite stable even after 800 h of operation. The best formulation was obtained using 1.0% of either additive A or additive B. Both TAN and viscosity values were found to increase with increasing heating temperature. Meanwhile, the results have also shown that additive A performs better than additive B. After 800 h of exposure, the final TAN value for the formulated oil was only at 0.32 as compared to 4.88 mg KOH/g for the oil without additive. However, the kinematic viscosity of the oil at 40 and 100 °C was almost unchanged as compared to the oil without additive.     

Synthesis of polymer/MWCNT nanocomposite catalyst supporting materials for high-temperature PEM fuel cells

In this study, the polymer/MWCNT nanocomposites were synthesized from the pristine MWCNT and polymer binders using functionalization with solution processing methods. The synthesized polymer/MWCNT nanocomposites exhibited high specific surface areas than the pristine MWCNT. The MWCNT/Nafion nanocomposite attributed to the maximum peak current at 5.795 × 10^?5 (A) while the peak current of MWCNT/PBI was obtained at 3.662 × 10^?5 (A). Moreover, polymer/MWCNT based electrocatalysts performed better electrochemical activity because of polymers binders can assist electrochemical interaction using the high surface areas of the catalyst supporting material. Also, the MEAs fabricated using the hot pressing method, while the acid doped PBI membrane sandwiched between the electrodes. The fabricated MEAs were successfully demonstrated in a single cell and found capable of measuring a maximum power density of 112.10 mW/cm² under 150 °C temperature. In conclusion, the synthesized catalyst-supporting materials enhanced the electrochemical activity and catalyst stability which fulfilling the main objective of this study.     

The effect of combustion parameters on the nitric oxide emission in direct injection type diesel engine

This paper presents the investigation of influence factors on the output performance and the reduction of exhaust emission in the direct injection type diesel engine. In this work, the analysis of combustion products and combustion characteristics are investigated by numerical method and experiment under the various engine operating conditions. The combusion performance and exhaust emissions are analyzed in terms of the heat release, cylinder pressure and major exhaust emissions of engine. The accuracy of the prediction versus experimental data and the capability of the heat release, cylinder pressure and all the major exhaust emissions are demonstrated. The results of this study show that the combustion parameters have influence on the combustion processes and the nitric oxide emission in the direct injection type diesel engine. The nitric oxide concentration decreases with the increase of engine speed and the advance of injection timing.     

Determination of kinetic parameters for thermal decomposition of bamboo leaf to extract bio-silica

Bio-silica has many applications due to its high reactivity and pozzolanic properties. The extraction of silica from biomass such as bamboo leaf is usually accomplished by thermal decomposition. Currently, the thermal decomposition requires external heat energy input. In this work, the possibility to reuse the heat released during thermal decomposition to make the process self-sustained is explored. The kinetic parameters of the combustion were determined by fitting thermogravimetric analysis (TGA) data to the Flynn–Wall–Ozawa model, where the corresponding activation energy and frequency factor are 211.7 ± 3.8 kJ mol^?1 and 4.5 × 10¹⁵ s^?1, respectively. The lower heating value of bamboo leaf determined is 8.709 kJ g^?1, which is comparable to common wood fuels. Hence, the heat released in the combustion of bamboo leaf can be reused to make the process self-sustainable.     

Phase formation of REBa2Cu3O7−δ (RE: Y0.5Gd0.5, Y0.5Nd0.5, Nd0.5Gd0.5) superconductors from nanopowders synthesised via co-precipitation

Phase formation of REBa₂Cu₃O_7−δ (RE: Y_0.5Gd_0.5, Y_0.5Nd_0.5, Nd_0.5Gd_0.5) superconductors synthesised via co-precipitation (COP) method were investigated by thermogravimetric analysis (TGA), differential thermal analysis (DTA) and X-ray diffraction (XRD) analysis. All samples showed identical thermal decomposition behaviour from the thermogram in which 5 major weight losses were observed. However, XRD of the samples at different heat treatment temperatures showed different diffraction patterns indicating different thermolytic processes. Meanwhile, transmission electron microscopy and surface area analysis revealed that the powders obtained from COP have particle sizes ranging from 7 to 12 nm with relatively large surface area. Molar ratios of prepared samples obtained were near to the theoretical values as confirmed by elemental analyses using X-ray fluorescence (XRF). The T_C(R=0) for sintered YGd, YNd and NdGd were 87 K, 86 K and 90 K, respectively. Surface morphological study via scanning electron microscope showed the structures of samples were dense and non porous.     

Rational mutagenesis of cyclodextrin glucanotransferase at the calcium binding regions for enhancement of thermostability

Studies related to the engineering of calcium binding sites of CGTase are limited. The calcium binding regions that are known for thermostability function were subjected to site-directed mutagenesis in this study. The starting gene-protein is a variant of CGTase Bacillus sp. G1, reported earlier and denoted as "parent CGTase" herein. Four CGTase variants (S182G, S182E, N132R and N28R) were constructed. The two variants with a mutation at residue 182, located adjacent to the Ca-I site and the active site cleft, possessed an enhanced thermostability characteristic. The activity half-life of variant S182G at 60 °C was increased to 94 min, while the parent CGTase was only 22 min. This improvement may be attributed to the formation of a shorter α-helix and the alleviation of unfavorable steric strains by glycine at the corresponding region. For the variant S182E, an extra ionic interaction at the A/B domain interface increased the half-life to 31 min, yet it reduced CGTase activity. The introduction of an ionic interaction at the Ca-I site via the mutation N132R disrupted CGTase catalytic activity. Conversely, the variant N28R, which has an additional ionic interaction at the Ca-II site, displayed increased cyclization activity. However, thermostability was not affected.     

Influence of Process Variables on the Reactivity of Low Formaldehyde Emission Urea-Formaldehyde Resin

One of the important characteristics of the thermosetting resins such as urea-formaldehyde resin is the cure property. This is an invaluable characteristic for determining the processing capabilities of the resin. Differential scanning calorimetry (DSC) measurements are ideally suited to achieve this end. This paper presents the results of the effect of process variables on the enthalpy of cure of a low formaldehyde emission UF resin prepared by a four-stage process as described in the text. Response surface methodology (RSM) was used to design and the analyze the experiments. Urea (U) was added to the reaction mixture according to a pre-determined program of varying the number of additions and the duration between the additions during the second stage of the process. A mathematical relationship between the process variables and enthalpy of cure was established. The urea-formaldehyde (UF) resin was prepared under optimum conditions. Experiments were performed with the resin so prepared to determine the energy of activation of the curing reaction catalyzed by ammonium chloride.     

Multiband frequency reconfigurable substrate integrated waveguide antenna using copper strip for cognitive radio applicable to internet of things application

In this paper, a Multiband Frequency Reconfigurable Substrate Integrated Waveguide (FR-SIW) cavity backed slot antenna for Cognitive Radio appropriate to Internet of Things (IoT) technology is presented. The proposed antenna is developed to address the specific design challenges posed by the IoT based Cognitive Radio (CR) networks. Reconfiguration of frequency bands is achieved using copper strips. The antenna resonates during the selected five switching states of the copper strips at 2.9 GHz, 2.6 GHz, 2.824 GHz, 2.792 GHz, 2.872 GHz, 4.488 GHz, 4.724 GHz, 4.712 GHz, 5.476 GHz, 5.336 GHz, 5.448 GHz, 5.392 GHz, and 5.42 GHz. The multiple frequency bands are controlled by altering the electrical length of designed slots. Overall, the simulated and measured results showed good agreement and the designed antenna is a potential candidate for cognitive radio applications, especially to IoT applications.