Miscible blends of poly(n-vinyl-2-pyrrolidone) with poly(3-chloropropyl methacrylate), poly(2-bromoethyl methacrylate) and poly(2-iodoethyl methacrylate)

Summary Poly(N-vinyl-2-pyrrolidone) is miscible with poly(3-chloropropyl methacrylate), poly(2-bromoethyl methacrylate) and poly(2-iodoethyl methacrylate) as shown by the optical clarity and the glass transition behaviour of the blends. The miscible blends degrade before phase separation could be induced by heating. The three T_g-composition curves can be fitted by the Gordon-Taylor equation. The implication of the Gordon-Taylor k parameters of the blends is discussed.     

Thermal inertia of newspaper sandwiched aerated lightweight concrete wall panels: Experimental study

A short term experimental investigation on the thermal inertia: time lag and decrement factor of aerated lightweight concrete (ALC) wall panels is the main purpose of this study. ALC wall panels of different density and different aerial intensity of newspaper sandwiched were produced and erected on a prototype house. All wall panels were installed facing east direction and subjected to natural environment or tested under transient condition. The inner and outer surface temperatures of the wall panels were recorded at 3 min interval, 24 h a day. Time lag and decrement factor were computed from the surface temperatures recorded. The results showed that newspaper sandwiched ALC panel has greater time lag and lower decrement factor compared to ordinary ALC panel. It is found that time lag and decrement factor were influenced by the thermal diffusivity value of the wall panel. The thermal inertia property of the panels was negatively related to its thermal diffusivity.     

Key project management practices affecting Singaporean firms’ project performance in China

Foreign (non-mainland Chinese) architectural, engineering and construction (AEC) firms may face difficulties managing construction projects in China because they are unfamiliar with this new operating environment. This study investigates project management (PM) practices adopted by Singaporean AEC firms in China. It determines the performance level of their projects in China; identifies PM practices that led to better performance; and recommends key PM practices that could be adopted by foreign AEC firms in China to achieve project success. A structured questionnaire was designed and data were collected via a self-administered postal and email survey, targeting Singaporean AEC firms that had undertaken and managed projects in China. The study finds that certain PM practices do indeed affect project performance. The most important of these are practices relating to scope management, such as controlling the quality of the contract document, quality of response to perceived variations and extent of changes to the contract. It is recommended that foreign firms adopt some of the PM practices highlighted in this study to help them achieve better project performance in China.     

Numerical Modelling of Thin-Walled Stainless Steel Structural Elements in Case of Fire

In this paper, the structural response of stainless steel thin-walled elements submitted to fire is analysed numerically by means of the geometrically and materially non-linear Finite Element program SAFIR, including imperfections. In order to make these simulations, two main changes in the program were made: (i) the code was changed in order to deal with the stainless steel 2D material constitutive law to be used with shell elements and (ii) the possibility of the program to take into account residual stresses with shell finite elements was introduced. The stainless steel stress–strain relationship at high temperatures was based on the one presented in part 1.2 of Eurocode 3. To model the strain hardening exhibited by the stainless steels, using the shell element formulation, an approximation to the Eurocode 3 constitutive law was needed. Local and global geometrical imperfections were considered in the simulations. The paper shows the influence of the residual stresses on the ultimate load-carrying capacity of thin-walled stainless steel structural elements in case of fire.     

Contrast enhancement dynamic histogram equalization for medical image processing application

Image processing requires an excellent image contrast‐enhancement technique to extract useful information invisible to the human or machine vision. Because of the histogram flattening, the widely used conventional histogram equalization image‐enhancing technique suffers from severe brightness changes, rendering it undesirable. Hence, we introduce a contrast‐enhancement dynamic histogram‐equalization algorithm method that generates better output image by preserving the input mean brightness without introducing the unfavorable side effects of checkerboard effect, artefacts, and washed‐out appearance. The first procedure of this technique is; normalizing input histogram and followed by smoothing process. Then, the break point detection process is done to divide the histogram into subhistograms before we can remap the gray level allocation. Lastly, the transformation function of each subhistogram is constructed independently. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 280‐289, 2011;     

Efficient vector outcrossing analysis of the excursion of a moored vessel

Extreme value prediction of combined first- and second-order motions of a moored floating structure has remained topical for years. Many researchers have applied the Kac–Siegert technique to derive the statistical distribution of the non-Gaussian responses. Almost exclusively, the previous studies have focused on a single-degree-of-freedom system, with the understanding that for any linear dynamical system, one may decouple a specific mode of interest from other degrees-of-freedom. The design philosophy is to assess the allowable limit of each individual motion separately. This paper presents an efficient method for predicting the extreme lateral excursion based on the vector sum of the surge and sway offsets. To this end, the vector outcrossing rate from a prescribed watch-circle is calculated. The joint probability density of the surge and sway responses is approximated using the Nataf transformation. The outcrossing rates thus estimated are found to agree well with those directly extracted from Monte Carlo simulation.     

低压电器产品紧固螺钉的计算及设计

对低压电器螺钉连接的强度进行了理论分析和探讨。得出螺钉连接的可靠性设计数据，对金属薄板件小螺纹孔翻边成形的设计提出了设计依据和数值。     

Mycoflora of hazelnut (Corylus avellana L.) and aflatoxin content in hazelnut kernels artificially infected with Aspergillus parasiticus

In this research, 30 hazelnut samples were used to determine their internal mould populations and their aflatoxin contents. The results showed that Aspergillus was the most common genus in the experimental samples (96.6% of all samples). Thirty-one% of isolates were classified as Aspergillus flavus and none of the samples contained aflatoxins. In the second part of the experiment, the kernels were inoculated with conidia of Aspergillus parasiticus and incubated at three different humidified conditions and two different temperatures for 45 days. Aflatoxin contents of the samples kept in 98% relative humidity and at 28 degrees C were higher (904.6 micrograms/kg) than that of the other samples. On the other hand, no aflatoxin was detected in the control samples that were not inoculated but kept at the same conditions.