Studies on miscibility in homopolymer/ random copolymer blends by equation of state theory

The miscibility of poly(methyl methacrylate) (PMMA) and styrene-acrylonitrile random copolymers (SAN) blends was investigated on the basis of the Flory—Orwoll—Vrij equation of state theory. To obtain the equation of state parameters (P*, V*_sp, T*: characteristic parameters), the pressure—volume—temperature (PVT) behaviour was measured for PMMA and a series of SANs with various acrylonitrile contents. The exchange energy parameter X_ij was also calculated by fitting the theory to some phase diagrams of PMMA/SAN blends. The Flory—Huggins interaction parameter χ was separated into two contributions based on the equation of state theory for mixtures: the exchange energy term χ_inter and the free volume term χ_free. Both the temperature and copolymer composition dependences of χ_inter and χ_free were estimated by calculations using the equation of state parameters. There exists a region in which χ_inter is negative, leading to a miscibility window in PMMA/SAN blends. However, the immiscibility at high temperatures in the blends cannot be explained only by χ_inter; it is caused by the free volume contribution, χ_free. The miscibility window behaviour in PMMA/SAN blends may be explained within the framework of the equation of state theory.     

Chemical interactions between soil N and alkaline-hydrolysing N fertilizers

Chemical interactions between soil N and alkaline-hydrolysing N fertilizers labelled with¹⁵N were studied in the laboratory using twelve-irradiated soils. Fertilizer was recovered in the soil organic N fraction via the process of NH₃ fixation. NH₃ fixation at day 7 varied from 1.8 to 4.6% of the N added as aqua ammonia at 1000 mg kg^–1 soil. The amount of NH₃ fixed increased with increasing rates of application of NH_3(aq) and urea. The rate of NH₃ fixation decreased with time, with more than 55% of the total NH₃ fixation in 28 days occurring in the first week following application of 2000 mg urea-N kg^–1 soil. Soil pH and NH₃ fixation varied in response to N source, and increased in the order of di-ammonium phosphate 3 fixation, resulting in the release of unlabelled ammonium (deamination) and a real added nitrogen interaction in all but two of the soils studied. The release of NH ₄ ⁺ initially increased up to a pH of 7.5, was inhibited between pH 8.5 and 9.0, but increased thereafter. The balance (N_bal) between NH₃ fixation and deamination was either positive or negative, depending on the pH of the fertilized soil, which was directly related to N source and concentration for a given soil.     

Exploring the Interactions of Storylines from Informative News Events

Today＇s news readers can be easily overwhelmed by the numerous news articles online. To cope with information overload, online news media publishes timelines for continuously developing news topics. However, the timeline summary does not show the relationship of storylines, and is not intuitive for readers to comprehend the development of a complex news topic. In this paper, we study a novel problem of exploring the interactions of storylines in a news topic. An interaction of two storylines is signified by informative news events that play a key role in both storylines. Storyline interactions can indicate key phases of a news topic, and reveal the latent connections among various aspects of the story. We address the coherence between news articles which is not considered in traditional similarity-based methods, and discover salient storyline interactions to form a clear, global picture of the news topic. User preference can be naturally integrated into our method to generate query-specific results. Comprehensive experiments on ten news topics show the effectiveness of our method over alternative approaches.     

基于VB6.0的红外甲烷检测仪串行通信的实现

针对煤矿安全生产中存在的瓦斯爆炸问题,该文以MSP430系列单片机为核心,设计了红外甲烷检测仪.其中着重介绍了检测仪的串行通信,编写了串行通信程序,使检测仪能实现与PC机的数据通信功能,并使用VB6.0编写了人机交互界面,以方便用户及时观察和处理数据,实现对检测仪的校准、复位和阈值设置等操作功能.实验结果表明,编写的串行通信程序能实现检测仪与PC的数据通信功能,检测仪能快速、准确地检测出甲烷气体的浓度,具有较高的实用价值.     

Reaction pathway of benzonitrile formation during toluene ammoxidation on vanadium phosphate catalysts

The reaction pathway of the ammoxidation of toluene on (VO)₂P₂O₇ used as catalyst and the interaction of potential intermediates with the pyrophosphate were studied by spectroscopic techniques (FTIR, EPR), temperature-programmed chemisorptions/ reactions (TPD, TPRS) and transient studies such as the temporal analysis of products (TAP) technique. NH₃ is chemisorbed on the catalyst surface, forming three different species, i.e., NH ₄ ⁺ ions located on BrØnsted sites, coordinatively bound NH₃ on Lewis sites and NH ₂ ^– groups, presumably P-NH₂. Toluene that is probably adsorbed on Lewis sites reacts in a first step to a benzyl radical. A subsequent partial oxidation by interaction of V^IV=O groups generates a V...O=CH-C₆H₅ surface structure. This benzaldehyde-like surface species reacts with adsorbed NH₃ according to a Langmuir-Hinshelwood mechanism. TAP experiments on ammonium-containing vanadium phosphates revealed that NH ₄ ⁺ ions could act as potential N-insertion species. No formation of benzylamine as well as the generation of V=NH surface groups as possible intermediates or N-insertion sites were observed.     

Mechanical and dynamic mechanical properties of jute fibers–Novolac–epoxy composite laminates

A study was done of jute composite using a polymer matrix of epoxidized Novolac resin (ENR), diglycidyl ether of bisphenol A (DGEBA)–based epoxy, and their blends with different weight percentages of the resins. It was found that on blending ENR with DGEBA, the storage modulii at room temperature are enhanced by about 100% or more in the case of 30 and 40% ENR‐containing matrices, whereas the enhancement in the case of 20 and 12% ENR‐containing matrices is only 50% that of the pure matrix. It was also observed that the tan δ peak heights of the composites containing 30 and 40% ENR are closer to that of 20% ENR‐containing composite. The probable explanation drawn on the basis of experimental findings of DMA and mechanical analysis is that by blending ENR with DGEBA epoxy it is possible to manufacture jute composites with increased stiffness without sacrificing their ductility. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2800–2807, 2002     

Molar volume and ultrasonic studies of europium soaps in mixed organic solvents

The ultrasonic velocity and density measurements of europium soaps in a mixture of benzene and methanol (3:2, vol/vol) were used to evaluate various acoustic parameters and molar volume and to determine the critical micelle concentration. The results showed that the ultrasonic velocity, specific acoustic impedance, molar sound velocity, and molar compressibility increase, and intermolecular free length, adiabatic Compressibility, and relative association decrease with increasing concentration and chainlength of the soap. The results were interpreted in terms of soap-solvent interaction.     

The comparative effect of a mixed urea,ammonium nitrate,ammonium sulphate granular formulation on the efficiency of N recovery by perennial ryegrass

The¹⁵N isotope was used to study the mode of action of individual nitrogen sources in a 30% urea:30% ammonium nitrate: 10% ammonium sulphate:30% filler (w/w) granular fertilizer for perennial ryegrass in a greenhouse pot experiment. The fertilizer consisted of two types of granules, one containing 80% urea and 20% filler and the second containing 48% ammonium nitrate (AN), 16% ammonium sulphate (AS) and 36% filler. In addition the effect of dolomite compared with silica as the filler was investigated on nitrogen recovery from the 30:30:10:30 formulation.Dolomite adversely affected the recovery of nitrate N from the system and evidence suggested that MgCO₃ was the active component. Granules containing dolomite resulted in a lower dry-matter yield than those containing silica, however the difference was not significant as nitrate contributed only 20% of the N in the formulation. AN gave the greatest DM yield and urea the lowest with AS being intermediate. The¹⁵N budget in shoots, roots and soil indicated that only 65% of the N from urea was recovered at the end of the experiment compared with 86% for AN and 91% for AS. The dry-matter yield of the 30:30:10:30 formulation using silica as the filler was intermediate between urea and AN; however, the apparent N recovery was significantly higher than expected from the sum of the individual components. The use of¹⁵N labelling indicated that using separate granules for ammonium N and urea the recovery of urea was improved by 11% in the triple N mixture when both AN and AS were present in the second granule compared to the recovery on its own. The enhanced recovery of urea appeared to be a function of AN and AS acting together as neither source in double combination with urea had any effect on urea N recovery.Urea enhanced the recovery of nitrate N by 10% but decreased the recovery of AS by 6% (in the 30:30:10:30 formulation) in comparison with the single sources on their own. The results indicate that interactions can occur between N sources even when they are physically separated by being in different granules.     

Study on interaction-induced symptoms with respect to virtual grasping and manipulation

Owing to the popularity of various hand tracking interfaces, there have been numerous applications developed to provide intuitive hand interaction with the virtual world. As users start with great anticipation, they end up with dissatisfaction due to difficulties of manipulation or physical tiredness coming very short. Although the task itself is rather trivial in a real life situation, it requires much effort in the virtual environment. We address this awkwardness as ‘VR interaction-induced fatigue symptom’ and hypothesize its causes based on our observations. We argue that the source of the fatigue comes from the restricted sensory information of the VR interfaces, and that users try to accommodate the missing sensory feedback by excessive motion leading to wrong posture or bad timing. We demonstrate our hypothesis by conducting experiments of two types of virtual interaction scenarios: object transport and 3D selection. Furthermore, by analyzing the behaviors of users' action collected from our experiment, we derive essential factors to be considered in designing VR applications, and propose a conceptual interaction model for orchestrating virtual grasping.     

How social distance shapes human–robot interaction

This paper investigates how social distance can serve as a lens through which we can understand human–robot relationships and develop guidelines for robot design. In two studies, we examine the effects of distance based on physical proximity (proxemic distance), organizational status (power distance), and task structure (task distance) on people׳s experiences with and perceptions of a humanlike robot. In Study 1, participants (n=32) played a card-matching game with a humanlike robot. We manipulated the power distance (supervisor vs. subordinate) and proxemic distance (close vs. distant) between participants and the robot. Participants who interacted with the supervisor robot reported a more positive user experience when the robot was close than when the robot was distant, while interactions with the subordinate robot resulted in a more positive experience when the robot was distant than when the robot was close. In Study 2, participants (n=32) played the game in two different task distances (cooperation vs. competition) and proxemic distances (close vs. distant). Participants who cooperated with the robot reported a more positive experience when the robot was distant than when it was close. In contrast, competing with the robot resulted in a more positive experience when it was close than when the robot was distant. The findings from the two studies highlight the importance of consistency between the status and proxemic behaviors of the robot and of task interdependency in fostering cooperation between the robot and its users. This work also demonstrates how social distance may guide efforts toward a better understanding of human–robot interaction and the development of effective design guidelines.