Microstructure of the HMX‐Based PBX KS32 after Mechanical Loading

Non‐destructive X‐ray diffraction techniques were applied in order to monitor the influence of mechanical and shock‐loading on the microstructure of the plastic‐bonded high explosive KS32. The investigations uncovered damage to embedded coarse HMX crystals and to the binder system HTPB‐IPDI. Damage to the crystals occurred already during the kneading process in terms of deformation twinning. On higher loading between 400 MPa (static) and 480 MPa (dynamic) also crystal fracture was observed. The change in the binder structure was found after both static and dynamic loading, but not in the cured, differently kneaded samples. Moreover, the change in binder structure after dynamic loading was verified by dynamic mechanical analysis, and interpreted as a partial damage of the binder rubber shell around the explosive particles. The results are compared to literature data from imaging techniques.     

A geometric approach to remote eye tracking

This paper presents a principled analysis of various combinations of image features to determine their suitability for remote eye tracking. It begins by reviewing the basic theory underlying the connection between eye image and gaze direction. Then a set of approaches is proposed based on different combinations of well-known features and their behaviour is evaluated, taking into account various additional criteria such as free head movement, and minimum hardware and calibration requirements. The paper proposes a final method based on multiple glints and the pupil centre; the method is evaluated experimentally. Future trends in eye tracking technology are also discussed.     

Long-term inhalable particles and other air pollutants related to mortality in nonsmokers

Long-term ambient concentrations of inhalable particles less than 10 microm in diameter (PM10) (1973- 1992) and other air pollutants-total suspended sulfates, sulfur dioxide, ozone (O3), and nitrogen dioxide-were related to 1977-1992 mortality in a cohort of 6,338 nonsmoking California Seventh-day Adventists. In both sexes, PM10 showed a strong association with mortality for any mention of nonmalignant respiratory disease on the death certificate, adjusting for a wide range of potentially confounding factors, including occupational and indoor sources of air pollutants. The adjusted relative risk (RR) for this cause of death as associated with an interquartile range (IQR) difference of 43 d/yr when PM10 exceeded 100 microg/m3 was 1.18 (95% confidence interval [CI]: 1.02, 1.36). In males, PM10 showed a strong association with lung cancer deaths-RR for an IQR was 2.38 (95% CI: 1.42, 3.97). Ozone showed an even stronger association with lung cancer mortality for males with an RR of 4.19 (95% CI: 1.81, 9.69) for the IQR difference of 551 h/yr when O3 exceeded 100 parts per billion. Sulfur dioxide showed strong associations with lung cancer mortality for both sexes. Other pollutants showed weak or no association with mortality.     

Differential regulation of angiotensinogen and AT1A receptor mRNA within the rat subfornical organ during dehydration

The present study describes the differential rostro-caudal patterning of angiotensinogen (AoGen) and AT1A receptor mRNAs in the rat SFO using specific and validated oligodeoxynucleotide probes for in situ hybridization. Highest levels of AoGen-specific gene expression were observed in the rostral region of the SFO with gradually decreasing intensity towards the caudal region of this sensory circumventricular organ lacking blood-brain barrier function. AoGen-related hybridization signals proved to be specifically prominent above cells in lateral aspects of the SFO, surrounding septal venules. Maximal expression of the AT1A receptor-specific gene, on the other hand, could be detected in the neuron-enriched, ventro-medial core region and dorsal annulus of the SFO, with low-intensity hybridization signals in its rostral and caudal parts. Water deprivation for 48 h, leading to extracellular hypertonic hypovolemia with elevated circulating AngII concentrations within the physiological range, caused a significant increase in AoGen-specific hybridization signals in the rostral and medial SFO regions. AT1A receptor gene expression and AngII receptor binding were markedly stimulated in the medial and caudal regions of the SFO (core and annulus) as compared to euhydrated animals. These data indicate, that mild dehydration differentially up-regulates AoGen- and AT1A receptor-specific mRNA formation as well as AT1 receptor binding in distinct regions of the SFO, and supports the involvement of different cellular subgroups in the expression of two major components of the central nervous renin-angiotensin system in this sensory circumventricular organ.     

Ventral scent marking in Meriones unguiculatus may contribute to thermoregulation.

Conducted 3 experiments with adult male gerbils to demonstrate that ventral scent marking can act to transfer body heat to the object marked. Exp I, with 16 Ss, showed that surgical removal of the ventral gland pad in 8 Ss reduced the amount of heat transferred by 50%, even though intact and glandless Ss did not differ in the average frequency of scent marking. Exp II, with the same 16 Ss used in Exp I, demonstrated that the difference in heat transfer due to the presence or absence of the scent pad was not due to differential pressure applied to the substrate during marking. Exp III, with 14 Ss, showed that the pattern of ventral hair spread that occurred as an S moved over an object was different between intact and glandless Ss but that this difference did not account for the difference in heat transfer. It is suggested that heat transfer to the environment with ventral scent marking may increase thermoregulatory competence and also may function to volatilize sebum used in chemocommunication. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Designing highly toughened hybrid composites through nature-inspired hierarchical complexity

The notion of replicating the unique fracture resistance of natural composites in synthetic materials has generated much interest but has yielded few real technological advances. Here we demonstrate how using ice-templated structures, the concept of hierarchical design can be applied to conventional compounds such as alumina and poly(methyl methacrylate) (PMMA) to make bulk hybrid materials that display exceptional toughness that can be nearly 300 times higher (in energy terms) than either of their constituents. These toughnesses far surpass what can be expected from a simple “rule of mixtures”; for a ～80% Al₂O₃–PMMA material, we achieve a K_Jc fracture toughness above 30 MPa m^1/2 at a tensile strength of ～200 MPa. Indeed, in terms of specific strength and toughness, these properties for alumina-based ceramics are at best comparable to those of metallic aluminum alloys. The approach is flexible and can be readily translated to multiple material combinations.     

In vitro gas production profiles and fermentation end‐products in processed peas,lupins and faba beans

BACKGROUND: An experiment was carried out to establish whether using a pre‐compacting device (expander) changes the contribution of dry matter (DM) and degradative behaviour of peas, lupins and faba beans over the different fractions (non‐washable fraction, NWF; insoluble washable fraction, ISWF; soluble washable fraction, SWF). Samples of the entire concentrate ingredients (WHO ingredients) and their different fractions (NWF, ISWF and SWF) were subjected to three processes (Retsch milling, R; expander treatment, E; expander‐pelleting, EP) and their fermentation characteristics were evaluated using an in vitro gas production technique. RESULTS: In peas and faba beans, both the E and EP processes increased the size of the NWF (P < 0.05) and decreased the size of the SWF compared with the R process. The maximum fractional rate of gas production in the first phase of fermentation was higher in the E and EP samples than in the R samples (P < 0.05). In lupins and faba beans the E and EP processes shifted the pattern of fermentation towards a more glucogenic fermentation, as represented by a lower non‐glucogenic to glucogenic ratio (NGR). Ammonia production (NH₃‐N) in the E and EP samples was significantly (P < 0.05) lower than that in the R samples. CONCLUSION: It is concluded that the E and EP processes provide a certain level of protection against ruminal breakdown to dietary protein and shift the pattern of fermentation towards a more glucogenic fermentation. Copyright © 2008 Society of Chemical Industry