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A natural magnetic material, black sand, was used as cores to prepare a magnetic photocatalyst, which can be recovered using an external magnetic field. A surfactant-involved scheme was proposed to deposit a rough silica layer on the surface of black sand, which otherwise could not be coated with silica through a conventional scheme involving Stober process. Titanium dioxide (TiO 2 ) was deposited on the surface of the silica–black sand (Si/BS) through an impregnation process and a direct deposition process. The catalytic property of the resultant photocatalyst (Ti/Si/BS) was evaluated using the oxidation of aqueous phenol and exhibited less reactivity than Degussa P25 TiO 2 . The phenol removal efficiency showed a pH dependence, which was ascribed to pH effect on (a) the formation of * OH and (b) the electrostatic interaction between the photocatalyst and the substrate. The prepared photocatalyst is reusable despite slight deactivation caused by the mechanical loss of TiO 2 .

Arterial calcification is well recognized as being associated with an increased risk of adverse cardiovascular events. Numerous methods for its quantification have been published, with no consensus on the technique used. In order to assess the reproducibility of a novel technique for quantifying aortic calcification, we measured the interobserver variability between two observers analysing the abdominal aortas of 34 volunteer patients. Using non-contrast abdominal CT images together with commercial imaging software, the quantity of calcium in a pre-determined section of aorta was calculated for each patient, and the difference in values obtained between the two observers compared using a Bland-Altman plot. Minimal interobserver variability was observed, with a significant difference in results occurring for only two patients. This protocol therefore represents a reliable technique that may be applied as a future standard in order to facilitate comparison between studies.

Clay pillared with Fe-Al was synthesized as a catalyst for Fenton oxidation of phenol by hydrogen peroxide (H2O2). The pillaring process altered the basal space of clay, which is related to the amounts of aluminium and iron in the pillaring solution. The catalytic activity of the pillared clay was attributed to the accessible iron species, whose amount is regulated not only by the introduced iron species but also by the basal space that subsequently depends on the introduced aluminium species. The heterogeneous Fenton reaction exhibited an induction period followed by an apparent first order oxidation of phenol by H2O2. The induction period was proposed as an activation process of the surface iron species, which is thus enabled to complex with the reactants. The induction time (tI) depended on temperature (T) and pH condition but irrelevant to the concentrations of phenol and H2O2 and the amount of catalyst. The rate of the oxidation process was evaluated with respect to the concentrations of phenol and H2O2, the amount of catalyst, pH and temperatures. During the catalytic reaction the trend of iron leaching showed an ascending period and a descending period, which was related to the presence of ferrous ions and ferric ions. The Fe-Al pillared was recovered through two procedures, dry powder and slurry, which have different effect on the induction period.

A TiO2 photocatalyst was prepared by depositing silica and titanium dioxide on the surface of black sand that made the photocatalyst recoverable using a magnetic field. The magnetic photocatalyst was used to remove six aqueous dyes from water and the removal was attributed to both adsorption and photocatalytic oxidation. Removal by adsorption was more noticeable with the cationic dyes than with the anionic dyes. The difference was related to the electrostatic interaction between the charged dye molecular and the silica-occupied surface of the photocatalyst. Removal by photocatalytic oxidation occurred with anionic dyes, while it was not appreciable with cationic dyes. It was postulated that photocatalytic oxidation might have happened with cationic dyes as well, but the strong adsorption made the photocatalytic oxidation undetectable.

The global distribution and high stability of some haloacetic acids (HAAs) has prompted concern that they will tend to accumulate in surface waters and pose threats to humans and the ecosystem. It is important to study the degradation pathways of HAAs in aqueous systems to understand their ecotoxicological effects. Previous studies involving thermal degradation reactions show relatively long lifetimes for HAAs in the natural environment. Photolysis and photocatalytic dissociation are potentially efficient routes for the degradation of HAAs such as trichloroacetic acid to hydrochloric acid, carbon dioxide and chloroform, although such processes are poorly understood in surface waters. In our present study, we have used light to degrade the HAAs in the presence of titanium dioxide suspensions. All chloro and bromo HAAs degrade in photocatalysis experiments and the rate of degradation is directly proportional to the number of halogen atoms in the acid molecule. The half-lives of the HAAs from the photodegradation at 15 degrees C in the presence of suspended titanium dioxide photocatalyst are 8, 14, 83 days for the tri-, di- and mono-bromoacetic acids. Tri-, di- and mono-chloroacectic acids have half-lives of 6, 10 and 42 days respectively. The mixed bromochloro and chlorodifluoroacetic acids degrade with half-lives of 18 and 42 days respectively. Our results therefore suggest that the photocatalytic process can provide an additional degradation pathway for the HAAs in natural waters.

Oxidation of sulfur dioxide (SO2) in gelatine gels has been used as a model for the process in leather and other collagen artifacts. Oxidation rate constants for 5–30% w/w gelatine gels at 25 °C had a mean first order rate constant of 3.25 × 10–6 s–1 (i.e. t 1 2 = 60 h). The water content of the gelatine has no effect on the observed rate of SO2 oxidation. Copper can act as a catalyst, but is often rendered ineffective because it is bound to the gel. Significant rate increases only emerge at low gel concentrations and high free copper concentrations. Three copper ions bind to a single gel unit and it is all bound when the protein material (% w/w)/free copper (mol kg–1) value exceeds 100,000. The availability of free copper to promote catalysis is dramatically reduced as the gelatine concentration approaches 30% w/w. Concentrations of likely catalysts together with total sulfur were determined in 11 samples of historical parchment and leather using inductively coupled plasma (ICP) emission analysis: iron 0.058–1.513; copper 0.002–0.065; manganese 0.002–0.091; sulfur 1.962–28.273 (g kg–1 dry leather). Although sulfuric acid (5% w/w) causes degradation of gelatine, the presence of metals did not alter the rate of this process. Gelatine appeared to be a useful good surrogate for leather in this study.

Petri nets augmented with time are interesting models which can be used for the modelling and analysis of a wide range of concurrent discrete-event systems. In this paper, the nature of the semantics of different approaches to incorporating time in Petri nets is illustrated by examples. The paper considers the critical roles of conflict, confusion and concurrence in the formulation of execution policies. Several different methods for the analysis of timed Petri net models are also discussed. The paper then introduces a timed Petri net structure which incorporates all the other structures described.

Henry's law constants K′H (mol kg-1 atm-1) have been measured between 278.15 K and 308.15 K for the following organic acids: CH2FCOOH (ln(K′H[298.15 K]) = 11.3 ± 0.2), CH2ClCOOH (11.59 ± 0.14), CH2BrCOOH (11.94 ± 0.21), CHF2COOH (10.32 ± 0.10), CHCl2COOH (11.69 ± 0.11), CHBr2COOH (12.33 ± 0.29), CBr3COOH (12.61 ± 0.21), and CClF2COOH (10.11 ± 0.12). The variation of K′H with temperature was determined for all acids except CH2FCOOH and CBr3COOH, with Δr H° for the dissolution reaction ranging from −85.2 ± 2.6 to −57.1 ± 2.5 kJ mol-1, meaning that their solubility is generally more sensitive to temperature than is the case for the simple carboxylic acids. The Henry's law constants show consistent trends with halogen substitution and, together with their high solubility compared to the parent (acetic) acid (ln(K′H[298.15 K]) = 8.61), present a severe test of current predictive models based upon molecular structure. The solubility of haloacetic acids and strong dissociation at normal pH mean that they will partition almost entirely into cloud and fog in the atmosphere (0.05–1.0 g H2O m-3), but can reside in both phases for the liquid water contents typical of aerosols (10-5-10-4 g H2O m-3).

The Henry's law constant of trichloroacetic acid [K′H (mol kg-1 atm-1) for the equilibrium CCl3COOH(g) ⇌ CCl3COOH(aq)] has been determined from measured partial pressures over aqueous solutions at 298.15 K and 308.15 K. Its value is given by: ln(K′H) = (11.21 ± 0.5) – 8.66 × 103 (l/Tr – l/T) where T (K) is temperature and Tr is equal to 298.15 K, for an aqueous phase dissociation constant (Ka) of 0.55 mol kg-1 determined from literature osmotic coefficient and electromotive force data. Accuracy is estimated to be 4–30% in the product K′HKa. Trichloroacetic acid is highly soluble and will partition strongly into aqueous atmospheric aerosols, and completely into fog and cloud water. Its occurrence and transport in the environment are therefore to be associated primarily with liquid phases.

A series of lateritized footslope benches are observed on the isolated hill masses which rise to 500 m above the interior plain of Sierra Leone. Field observations and chemical analyses of samples indicate that each bench has a characteristic geochemistry controlled by its own topography, hydrological environment and leaching history. The benches are related, each inheriting material from above and providing material for the bench below. The material is transported both mechanically and in solution. As a result, the parent material of each bench is not only the bedrock (metamorphosed volcanic and sedimentary rocks of Proterozoic age in the case of the Kasewe Hills), but also material which has undergone various degrees of lateritization. This cratonic region has been subjected to denudational processes since Mesozoic times at least. Denudational processes, especially etchplanation, are long continued, yet weathering, the development of breakaway slopes and subterranean flushing are patently continuing processes: these palaeosurfaces and palaeosoils may, therefore, be ancient in origin but they cannot be considered as being fossilized.

Development of any interactive system simulation is greatly assisted by end-user evaluation, particularly so at a concept demonstration stage. Evaluation of any individual aspect of the man-machine interface can sometimes be difficult, however, if the remaining features of the interface are underdeveloped or crude such that the general environment portrayed by the simulation differs significantly from that of the real system. The use of an additional, intermediary interface, taking the form of an experienced simulation operator, can help alleviate these difficulties; having the ability to make some of the operating procedures automatic can also be quite powerful. This paper discusses how such evaluation procedures were used in the development of the F-111C Pave Tack Simulation (FPTS) which is a large, event-stepping, interactive simulation of the F-111C navigation and weapon delivery system. The operator of the simulation takes the role of the F-111C navigator, flies a pre-set mission and interacts with that mission through the use of emulated Pave Tack and other cockpit controls and associated displays. The FPTS is being used in the training of F-111C navigators.

Leaching of aluminium from the weathering profile of the African surface in Malawi was deduced from the chemistry of a vadose profile. Its loss occurs where congruent kaolinite dissolution results in saprolite collapse, leaving a weakly lateritized, sandy residual mantle. This leaching is a contemporary process, as shown by the precipitation of aluminosilicate evaporites in the dambos (seasonally waterlogged bottomlands). This paper presents the results of determinations, by ICP-OES and AAS-graphite furnace, of aluminium levels in groundwaters, examining the effects of a variety of pretreatments. Filtration (0.45 μm) substantially reduces the levels of total aluminium, showing it to be in particulate form. Subsequent acidification causes precipitation of < 0.45 μm forms of aluminium, further reducing the apparent levels to below ICP-OES detection limit. This is consistent with mobilization in organically bound forms which are destabilized at low pH, and accords with earlier work which showed that indigenous micro-organisms can cause dissolution of kaolinite. Organically bound mobilization provides an explanation for aluminium leaching at near-neutral pH in conjunction with the presence of silica in solution. The identification of this mechanism of kaolinite dissolution and aluminium evacuation from vadose profiles provides a realistic process for the levelling of extensive planation surfaces; the contingent collapse of the kaolinized saprolite would lower the interfluves, progressively narrowing the vadose zone until the landsurface approaches the planar form of the stable, regional water-table.

BACKGROUND: Approximately 4% of patients diagnosed with early breast cancer have occult metastases at presentation. Current national and international guidelines lack consensus on whom to image and how. METHODS: We assessed practice in baseline radiological staging against local guidelines for asymptomatic newly diagnosed breast cancer patients presenting to the Cambridge Breast Unit over a 9-year period. RESULTS: A total of 2612 patients were eligible for analysis; 91.7% were appropriately investigated. However in the subset of lymph node negative stage II patients, only 269 out of 354 (76.0%) investigations were appropriate. No patients with stage 0 or I disease had metastases; only two patients (0.3%) with stage II and < or =3 positive lymph nodes had metastases. Conversely, 2.2, 2.6 and 3.8% of these groups had false-positive results. The incidence of occult metastases increased by stage, being present in 6, 13.9 and 57% of patients with stage II (> or =4 positive lymph nodes), III and IV disease, respectively. CONCLUSION: These results prompted us to propose new local guidelines for staging asymptomatic breast cancer patients: only clinical stage III or IV patients require baseline investigation. The high specificity and convenience of computed tomography (chest, abdomen and pelvis) led us to recommend this as the investigation of choice in breast cancer patients requiring radiological staging.

Offensive Support (OS) modelling has generally not been implemented within a closed simulation in such a way that its contribution to the overall mission performance can be captured, measured and integrated. However, the issue of realistically measuring OS performance becomes more critical as new technologies are proposed to improve or compress the Kill Chain, particularly in the context of complex environments. A study is being conducted to determine and implement an explicit Kill Chain in CASTFOREM such that it can be configured to use a variety of components and its impact on performance can be measured and compared. To assess the Kill Chain, six measures have been adopted from the original research done by the Royal Australian Air Force and Air Operations Division, DSTO. These are Timeliness, Appropriateness, Precision, Discrimination, Orchestration and Survivability, referred to as TAPDOS. These performance measures will allow the study to align with accepted standards of OS usage in the Australian joint fires environment, and to facilitate the use of Subject Matter Experts to support the study and promulgate performance results. The outcome of the study will be a closed simulation capable of identifying and reporting specific Kill Chain events and measures associated with the target performance demands, system performance availability, system selection and performance delivered.

Defense organizations around the world are formulating new visions, strategies, and concepts that utilize emerging information-age technologies. Central among these is network-based operations. Measures and metrics are needed that allow analysts to link the effects of alternative network structures, operating procedures and command and control arrangements to combat outcomes. This paper reports on measures and mathematical metrics that begin to address this problem. Networks are assessed in terms of their complexity, their ability to adapt, and the collaboration opportunity they afford. The metrics measure the contributions of complexity to information flow, and the deleterious effects of information overload and disconfirming reports to overall network performance. In addition, they measure the contributions of collaboration to shared situational awareness in terms of the accuracy and precision of the information produced and the costs associated with an imbalance of the two. We posit a fixed network connecting a Naval Task Force’s various platforms, and assess the ability of this network to support the range of missions required of the task force. The emphasis is not on connectivity, but rather on information flow and how well the network is able to adapt to alternative flow requirements. We assess the impact alternative network structures, operating procedures and command arrangements have on combat outcomes by applying the metrics to a cruise missile defense scenario.

Effective battlespace awareness is essential for any defence operation; this is especially true in the increasingly complex and dynamic land component of the military environment. Because of its relatively small force size dispersed piece-wise across a large and largely vacant landmass, the Defence of Australia presents a somewhat unique challenge for the development of systems that support command decision-making. The intent of this paper is to first examine the digitisation effort under way in Australia and describe the Army Battlefield Command Support System (BCSS) being developed for use in the tactical arena. BCSS is essentially a suite of commercial-off-the-shelf and government-off-the-shelf software components provided via a standard operating environment to aid decision-making. Then, we present the development of a Tactical Land C4I Assessment Capability (TLCAC) synthetic environment which is being used to undertake controlled performance evaluations of the various elements of the BCSS suite and provide impact assessments of new technological advances. The TLCAC provides a capacity to assess in near real-time Brigade and below level command post exercise activities. That is, when deployed it provides a mechanism to automatically collect command and control and manoeuvre data, which can aid in the after action review process.

The Henry's law constant of trifluoroacetic acid [K H′ (mol kg −1 atm −1 ), for the equilibrium CF 3 COOH (g) ⇔ CF 3 000H (aq) ] has been determined from measured partial pressure over aqueous solutions at 278.15, 298.15 and 308.15 K, and is given by: ln(K H′ ) = 9.099 − 9.328 × 10 3 (1/T r − 1/T) where T (K) is temperature and T r is equal to 298.15 K. Accuracy is estimated to be ±25% in K H′ , partly limited by uncertainties in the pK a of the acid (0.47 at all temperatures, from literature data). Trifluoroacetic acid in the atmosphere will partition entirely into fog and cloud water (0.05–1.0 g H 2 O m −3 ), but can reside in both phases for the liquid water contents typical of aerosols (10 −5 − 10 −4 g H 2 O m t3 ) depending on aerosol pH and to some extent on composition.