Effect of the talc filler content on the mechanical properties of polypropylene composites

This research examines the effect of a microsize/nanosize talc filler on the physicochemical and mechanical properties of filled polypropylene (108MF10 and 33MBTU from Saudi Basic Industries Corp. and HE125MO grade from Borealis) composite matrices. A range of mechanical properties were measured [tensile properties, bending properties, fracture toughness, notched impact strength (at the ambient temperature and ?20°C), strain at break, and impact strength] along with microhardness testing and thermal stability testing from 40 to 600°C as measured by differential thermal analysis and thermogravimetric analysis. Increasing filler content lead to an increase in the mechanical strength of the composite material with a simultaneous decrease in the fracture toughness. The observed increase in tensile strength ranged from 15 to 25% (the maximum tensile strength at break was found to be 22 MPa). The increase in mechanical strength simultaneously led to a higher brittleness, which was reflected in a decrease in the mean impact strength from the initial 18 kJ/m² (for the virgin polypropylene sample) to 14 kJ/m², that is, a 23% decrease. A similar dependency was also obtained for the samples conditioned at ?20°C (a decrease of 12.5%). With increasing degree of filling of the talc–polypropylene composite matrix, the thermooxidative stability increased; the highest magnitude was obtained for the 20 wt % sample (decomposition temperature = 482°C, cf. 392°C for the virgin polymer). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Review of Toward a psychology of persons.

Reviews the book, Toward a psychology of persons by W. E. Smythe (see record 1998-04017-000). One of the gems of the grand theoretical movement in contemporary psychology is the group known as the Western Canadian Theoretical Psychologists, founded in 1989. Their first book, Positivism in Psychology, edited by Charles Tolman, was published in 1992. This review is of the group's second volume, a result of their more recent discussions and debates concerning depersonalization in psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Properties and in vitro characterization of polyhydroxybutyrate–chitosan scaffolds prepared by modified precipitation method

Porous polyhydroxybutyrate (PHB)–chitosan biopolymer scaffolds were prepared by co-precipitation from biopolymer solutions with propylene carbonate and acetic acid as solvents. A change of the fibrous character of chitosan precipitates to globular shaped forms with a polyhydroxybutyrate addition was found in suspensions. Scaffolds differ by porosity and morphology of polymers in microstructures, while chitosan represented more compact plate-like fibers and PHB characterized mainly fine fibrous globular agglomerates. Two structurally dissimilar phase regions were verified in blended scaffolds. A rise in the number of smaller pores, and fine structured polymer forms with PHB content were observed in the scaffolds. A significant reduction in the average molecular weight of biopolymers was found in pure chitosan scaffold, this after precipitation of the chitosan in the presence of propylene carbonate and in blends after mutual biopolymer mixing. Interactions between shortened chitosan chains, PHB and chitosan biopolymers in the blends were observed. An excellent fibroblast proliferation was found in scaffolds prepared from biopolymer blends.     

The new research agenda for a cultural psychology.

Qualitative methods are the investigative tools of choice for the field of cultural psychology, in which the study of meaning is central. The process of cultural psychological research calls for an approach that emphasizes the quality of the relationship between researchers and participants. We argue for the importance of this relationship in the development of the validity and usefulness of such work. Methods within this framework often include dialectic communication, respect, participatory partnership, inductive reasoning, and the taking of extra time as necessary. In this paper, research projects with urban Canadian street youth, Inuit prison inmates, and Inuit community members experiencing a youth suicide epidemic are provided as case studies that highlight the relational motif in qualitative research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

8位网络微控制器

利用8位微控制器实现网络连接似乎是一件难以想象的事情,事实上,随着越来越多的嵌入式器件需要与网络连接,设计人员开始考虑采用8位微控制器。并非所有应用都需要通过台式机接入Internet,例如,网络温度调节器并不需要在32位微控制器上运行Linux,只需在温度下降时通知用户启动加热系统即可,因此,选择8位微控制器将更加合理。许多开发人员可能会对用8位处理器连接网络的方案持怀疑态度,但是,随着功能强大的C编译器的出现,如Keil 8051编译器,这些编译器可以提供完备的IDE和固化的基础库文件。Keil通过提供仿真器和用于调试目标硬件的调试监…     

Sustainable Maintenance of Rural Roads in Slovakia

Systematic approach to the maintenance of rural road network is a very important issue from the viewpoint of public costs. Most countries developed custom PMS （pavement management systems） based on deterministic or probabilistic approach. The main goal is to ensure safety and continuity of road traffic on road network with low intensity and lower technical requirements. Article presents PMS used for Slovakia rural road network based on road construction diagnostics, traffic volume, climate factors and evaluation of maintenance works economics effectives by using of software tools like HDM-4 developed by World Bank. Local road administrators of rural road networks often lack the software equipment, most PMS, however effective, are often cumbersome, demanding in regard to energy, know-how and software equipment. The majority of local road administrators of rural road networks thus resort to non-effective reactive maintenance strategies. This article describes an easy to use method, based on predetermined maintenance repair and rehabilitation standards. A simple method, based on road user cost, is introduced that administrator can use to prepare a list of road section eligible for repair according to their repair priority.     

Determination of acrylamide in roasted chestnuts and chestnut-based foods by isotope dilution HPLC-MS/MS

A collaboratively trial tested isotope dilution liquid chromatographic method with positive electrospray ionisation tandem mass spectrometry for the analysis of acrylamide in bakery ware and potato products has been extended to the determination of acrylamide in roasted chestnuts and chestnut-based foods. As chestnuts have a similar composition to potatoes, considerable amounts of acrylamide can be expected, especially in roasted chestnut products. This paper presents the concentrations of acrylamide in 31 different chestnut samples (fresh, roasted, flour, cooked, glazed) that were collected in nine European countries during 2005/2006. The influence of the roasting time on the acrylamide content was also experimentally investigated. A test portion was extracted after homogenisation with water and isotopically labelled acrylamide was added. The extract was centrifuged and the supernatant was cleaned-up in two consecutive solid phase extraction steps. The final extract was analysed by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). An HPLC column based on graphitised carbon was applied for chromatographic separation. Acrylamide concentrations in purchased roasted chestnuts were in the range of <8–1278 μg/kg whereas only low amounts (<4–159 μg/kg) were found in chestnut products. However, the median acrylamide content of the commercial roasted chestnut samples was 90 μg/kg. The influence of the roasting time on the acrylamide content in roasted chestnuts was evaluated too. As with roasted and fried potato products, the roasting time has a significant influence on the acrylamide formation. Therefore, the consumers might be exposed to significant amounts of acrylamide by eating roasted chestnuts, especially when a batch remains in the roasting vessel for too long time.     

Demystifying Disclosure Controls: Understanding Them to Effectively Leverage Toward Objectives

Abstract

All organizations are subject to some degree of disclosure requirements, which are also commonly called external reporting requirements. They can be as simple as filing tax returns or as complex as meeting applicable rules and regulations of a governmental regulator, such as the U.S. Securities and Exchange Commission (SEC). No matter the extent, organizations are well advised to have robust disclosure controls in place to help ensure that external disclosures are prepared and delivered in accordance with the applicable external reporting requirements. While the article tackles disclosure controls mostly from SEC's definition, it also has ideas for entities not subject to SEC rules and regulations since this is a topic that applies to all types of organizations. It is essential to complete disclosures in an accurate, timely and complete manner to protect against adverse legal actions and to preserve the organization's reputation. The interests of stakeholder groups such as governments, creditors and regulators are essential to the success of any business and ignoring or under-resourcing their requirements is a recipe for disaster that can be averted through appropriate disclosure controls.     

Cognitive and academic problems associated with childhood cancers and sickle cell disease.

Childhood cancers and sickle cell disease represent some of the most complex medical conditions of childhood, impacting development in all domains. The influence of these conditions on cognitive functioning and academic achievement has particular relevance for the school psychologist, who is poised to promote the positive adaptation of children with these chronic illnesses in the school setting. This article provides a review of the research related to cognitive aspects of pediatric cancer and sickle cell disease. Based on that literature, science-based practice recommendations of relevance to the school psychologist are offered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Proficiency test on the determination of mineral oil in sunflower oil

Following the discovery of mineral oil contamination of Ukrainian sunflower oil in April 2008, the Institute for Reference Materials and Measurements (IRMM) of the European Commission's Joint Research Centre (JRC) was requested by the Directorate General Health and Consumers (DG SANCO) to organise a proficiency test on the determination of mineral oil in sunflower oil. The aim of this test was to evaluate the comparability of analysis results gained by laboratories in the EU and the Ukraine. The organisation of the study and the evaluation of the results were done in accordance with “The International Harmonised Protocol for the Proficiency Testing of Analytical Chemistry Laboratories” and ISO Guide 43. Altogether 62 laboratories from 19 EU member states, Switzerland and the Ukraine subscribed for participation in the study. Four test samples at concentration levels between about 100 and 350 mg/kg, comprising contaminated crude sunflower oil, contaminated refined sunflower oil, and spiked sunflower oil, and a solution of mineral oil in n‐heptane were dispatched to the participants. The participants were asked to determine the mineral oil content of the test samples by application of their in‐house analysis methods. In total, 55 sets of results were reported to the organisers of the study. The performance of laboratories was expressed by z‐scores for the oil samples and by relative bias for the mineral oil solution in n‐heptane. The percentage of successful laboratories in the determination of the mineral oil content of sunflower oil was for all sunflower oil test materials about 80%.