Cochannel interference suppression with successive cancellation innarrow-band systems

Successive cancellation of cochannel signals is described in the context of TDMA mobile radio systems employing coherent receivers. Both symbol aligned and mis-aligned cochannel signals are studied. Signal separability, a major problem in successive cancellation of cochannel signals, is obtained using the relative timing delay between cochannel signals. Both hard and soft subtractions are examined. Soft subtraction, along with initial signal separation, leads to significant C/I gains     

Adsorption behavior of Congo red from an aqueous solution on 4‐vinyl pyridine grafted poly(ethylene terephthalate) fibers

In this study, a reactive fibrous adsorbent was prepared through the grafting of 4‐vinyl pyridine monomer onto poly(ethylene terephthalate) (PET) fibers for the removal of Congo red (CR) dye from an aqueous solution with the batch adsorption method. Effects of various parameters such as the grafting yield, pH, treatment time, and initial dye concentration on the amount of adsorption of the dye onto the reactive fibers were investigated. The effective pH was 4.0 for adsorption on grafted PET fibers. The sufficient time to attain equilibrium was 150 min. The maximum adsorption capacity of the reactive fibers for CR was 17.3 mg/g of fiber. The rates of adsorption conformed to pseudo‐second‐order kinetics with good correlation. The adsorption isotherm of CR fit a Langmuir‐type isotherm. The reactive fibers were stable and regenerable by acid and base without loss of activity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Constraining Effects of Lead-Free Solder Joints During Stress Relaxation

Reliability and quality control of microelectronics depend on a detailed understanding of the complex thermomechanical properties of miniaturized lead-free solder joints. With the continuous reduction in size of modern electronic devices, including also the size of the solder joints themselves, mechanical constraint effects may become of importance for the reliability of the joints. In the present study stress relaxation tests in tensile mode were performed on model solder joints consisting of eutectic Sn-3.5Ag solder between Cu substrates. The gap size of the joints was varied between 750 μm and 150 μm in order to investigate the variation of the mechanical properties as a function of the gap size. As it turned out, stress relaxation was dramatically reduced when the solder gaps became smaller due to constraint effects already well known from earlier measurements of the tensile strength. By employing a traditional creep model, the stress exponents and the activation energies were derived and compared with available data in the literature. The consequences of these constraint effects for the case of thermomechanical fatigue are discussed.     

The false positive effect of residue of sulphur sources on dithiocarbamate analysis based on CS2 measurement

Turkey plays an important role in the international trade of apricots as it has the largest production rate in the world. Since the sulphurisation process is allowed to be used for different products, the effect of residual sulphur and its compounds (which can be found in products as pesticide residues or additive residues) on the positive detection of carbon disulphide (CS₂) still creates a big challenge in international trade. Therefore, the main objective of the present study was to investigate the effects of residues of sulphur or sulphur compounds on dithiocarbamate analysis methods based on CS₂ measurement. In this study, apricots were chosen since they contain sulphur residues as a result of the sulphurisation process. Sulphur dioxide and dithiocarbamate analyses were conducted on dried apricots prepared with the sulphurisation process (SA) and without the sulphurisation process (NSA); analysis was by two different accredited laboratories. No of pesticide was applied to either SA or NSA samples. Although some of the NSA samples had <LOQ values, approximately 70 ± 32 mg/kg SO₂ and 0.061 ± 0.021 mg/kg dithiocarbamate were detected for NSA samples. On the other hand, for the SA sample group, 927–2915 mg/kg of SO₂ and 0.265–0.825 mg/kg of dithiocarbamate were detected. Furthermore, a strong correlation between residual sulphur and dithiocarbamate values was observed. This study showed that the analysis method based on CS₂ measurement may lead to false positive results for dithiocarbamates when residues of sulphur or sulphur compounds are found in products as pesticide or additive residues. Therefore, residual sulphur compounds as a result of the sulphurisation process (which is not considered during the evaluation of products) must be taken into account during the evaluation of products for dithiocarbamates.     

Improving heat-retaining property of cotton fabrics through surface coatings

Regulating thermal conductivity of fabrics through surface coating is of practical importance. This work shows that a thin layer of polymer containing thermal insulating fillers can considerably increase the thermal insulating property of the fabric. Three commonly used thermal insulating materials, aluminum oxide (Al₂O₃), zirconium oxide (ZrO₂), and fumed silica, were used as filler. When they were dispersed separately in a polymer solution and applied to cotton fabric, the fabric showed decrease in thermal conductivity by 19.1–44.5% (based on pure cotton fabric). Marsh cooling method was used for the measurement of thermal insulation feature. The heating/cooling behavior of the fabrics was characterized by infrared thermography. The effects of the coatings on air permeability, surface wettability, color appearance, and flexural rigidity were also studied. The highest reduction in air permeability was 87.4% for the fumed silica-containing coating. Aluminum oxide coating increased the hydrophilicity of the cotton fabric while fumed silica coatings made the fabric surface hydrophobic. All coatings diluted the color of the fabric and changed it to paler one. Flexural rigidity of the fabric was increased in the order of ZrO₂ > Al₂O₃ > fumed silica.     

The rotating elastic-plastic hollow shaft conveying a hot medium

Based on Tresca’s yield criterion and the flow rule associated with it, the distribution of stress and strain in a linearly strain hardening elastic-plastic hollow shaft subject to monotonously increasing angular speed and a negative radial temperature gradient—corresponding to the flow of a hot medium—is investigated. Presupposing circular symmetry and plane strain conditions, the problem is amenable to an analytical treatment. It is found that—depending on the temperature difference between the outer and the inner surface—several qualitatively different types of solutions may occur, and a comprehensive discussion of the admissible maximum angular speeds for elastic behaviour as well as of the elastic-plastic states is performed. Moreover, the residual stresses at stand-still are studied.     

牛奶蛋白纤维的染色与后整理（第Ⅲ部分）

牛奶蛋白纤维均匀度好、杂质少,蓬松、易包装,且可纺性优异,但也存在着纤维间摩擦系数小、抱合力弱、质量比电阻大等问题,所以为了获得优质的纱线,必须进行预处理,同时必须选择合适的运行湿度,并添加抗静电剂。牛奶蛋白纤维应用广泛,可用于针织、机织产品,具有很强的市场竞争力。     

A Chemometric Approach to Assess the Frying Stability of Cottonseed Oil Blends During Deep-Frying Process: Fatty Acid Composition and Tocopherol Analyses

The aim of the present study was to determine impacts of different additives on fatty acid composition and total tocopherol content of cottonseed oil during deep-frying process using a chemometric approach. A quarter-fractional factorial design with two levels and five factors was used for preparing the frying cottonseed oil blends. In the experimental design, additives were such as ascorbic palmitate, mixed tocopherols, dimethylpolysiloxane, lecithin, and sesame oil were used as factors. The effect of additives on fatty acid composition and tocopherol content were evaluated with normal distribution (ND) graphs during ten hours frying at 170 ± 5°C. The data were statistically assessed by one-way analysis of variance at a significance level of p < 0.05. The analysis of variance test results were in good agreement with ND graphs and data indicated that the interaction between ascorbic palmitate and dimethylpolysiloxane (A × C factor) showed a significant and protective effect on fatty acids. Meanwhile, the sesame oil (E factor) and A × C factor were showed a significant effect on level of tocopherols. The results of study indicated that present approach could be used to assess and improve the frying stability of any oil with respect to fatty acid composition and tocopherols.     

What determines farmers’ adaptive capacity? Empirical evidence from Malawi

This paper assesses farmers’ incentives and conditioning factors that hinder or promote adaptation strategies and evaluates their impact on crop productivity by using data from nationally representative sample households in Malawi. We employed multivariate probit (MVP) and multinomial treatment effect (MTE) techniques to model adoption decisions and their yield impact. Exposure to delayed onset of rainfall and greater climate variability was positively associated with the choice of risk-reducing agricultural practices such as tree planting, legume intercropping, and soil and water conservation (SWC) but reduced the use of inputs (such as inorganic fertilizer) whose risk reduction benefits are uncertain. Concerning household adaptive capacity, wealthier households were more likely to adopt both modern and sustainable land management (SLM) inputs and were more likely to adopt SLM inputs on plots that were under greater security of tenure. In terms of system-level adaptive capacity, rural institutions, social capital and supply-side constraints were key in governing selection decisions for all practices considered, but particularly for tree planting and both organic and inorganic fertilizer applications. A combination of practices gave rise to higher yields suggesting that this might be a course of action that would sustain growth of yield in Malawi in the future.     

Temperature dependence of the optical band gap and refractive index of poly(ethylene terepthalate) oligomer–DDQ complex thin film

The temperature dependence of the optical band gap and refractive index dispersion of thin film of poly(ethylene terepthalate) oligomer–DDQ charge transfer complex has been investigated. The absorption edge shifts to the lower energy as consequence of the thermal annealing on film and the fundamental absorption edge corresponds to a direct energy gap. The temperature coefficient of the optical band gap for the film was found as dE_g/dT = − 3.15 × 10⁻³ eV/K. The temperature dependence of the refractive index has also been investigated and it is observed that the refractive index changes by annealing temperatures.