De-tert-butylation of 2-tert-butylphenol was carried out over thermally-treated and acid-treated Jordanian bentonite clay samples. This reaction was found to follow first-order kinetics for all clay samples with different pretreatment procedures. The apparent rate constant, k, was also determined, and found to depend on the pretreatment. Thermal pretreatment at temperatures up to 250°C has an enhancing effect on surface acid sites. The total surface acidity (Ho <4.8) and the concentration of strong acid sites peaked at 250°C. Also, as a result, the maximum catalyst activity was obtained with samples treated at this temperature. Acid pretreatment with 0.10 M HCl, 1.0 M H2SO4 or 1.0 M H3PO4, followed by thermal treatment at 250°C produced the best enhancement effect on the surface acidity and catalytic activity.

Although low density polyethylene (LDPE) has long been widely used in packaging applications, some limitations in its use still exist and are due to its relatively poor gas barrier properties and low mechanical strength which can restrict its extensive use for more advanced applications, such as electronic and pharmaceutical packaging. The purpose of this study was to investigate the possibility of using montmorillonite (MMT) nanoclay as a means to enhance the thermal, mechanical, and barrier properties of LDPE prepared via melt extrusion. The level of exfoliated dispersion of the MMT nanoclay in the prepared LDPE-MMT composite was confirmed using transmission electron microscopy (TEM). The relationship between the resulting morphology and the thermal, mechanical, and barrier properties as a function of the MMT content was evaluated. The results showed that incorporating >3 wt.% of MMT nanoclay produced significant changes in the morphology of the LDPE-MMT nanoclay composite in that the segregated matrix adopted an oriented arrangement of exfoliated clay platelets. Thermogravimetric analysis (TGA) showed that the thermal stability of LDPE improved significantly as a result of MMT nanoclay incorporation. Furthermore, differential scanning calorimetry (DSC) analysis indicated that increasing clay content above 3 wt.% effectively reduces the crystallinity of LDPE-MMT composites through the suppression effect. The tensile strength of LDPE increased gradually with an increased content of MMT nanoclay and the maximum value of 16.89 N/mm2 was obtained at 10 wt.% MMT content. This value represents a 40.87% increase relative to the tensile strength of the pristine LDPE. Barrier properties of LDPE and LDPE-MMT nanoclay composites were assessed by examining the permeability with respect to oxygen and water vapor. As the content of MMT nanoclay was increased to 10 wt.%, the permeability of the nanocomposite films to oxygen and water vapor notably decreased to 42.8% and 26.2%, respectively.

Precision farming advances are providing opportunities in both production agriculture and agricultural research. For growers and agronomists, the benefits of identifying where crops are stressed, the location of weeds and estimating yields on a large scale are clear. Researchers, who have different needs, can benefit from a detailed focus on a specific characteristic, such as one disease (e.g. yellow rust). This paper will review how recent advances in technology are beginning to allow the development of specialised tools within research and agriculture and how current precision agriculture tools can be effective at measuring desirable traits.

Thermal weed control methods have been incorporated into weed control programs in organic and conventional production systems. Flaming is commonly used, but steaming has been proposed to increase efficiency of heat transfer to weeds and reduce the risk of fire. The objective of this research was to measure injury to leaves of plant species that differ in leaf morphology and to measure injury to plants at different stages of plant development. The study was conducted in a glasshouse and plants were exposed to steaming at 400 C for 0.36 s—equivalent to a steaming speed of 2 km/h. Overall, leaf thickness was the best morphological characteristic to predict injury ( = 0.51), with greater thickness resulting in less injury. For broadleaf species only, species with wider leaves were injured more than species with narrower leaves ( = 0.64). Injury was greatest when plants had fewer than six true leaves and when their shoots were less than 10 cm long. There was a wide range of injury across species, and the grass species bermudagrass and perennial ryegrass were injured (68 to 81%) more than other species such as common purslane and English daisy (23 to 34%). Biomass of all species tested was reduced by approximately 40%, indicating that leaf injury was not the sole effect of steaming on plant growth. These results indicated that considering both visual estimates of injury and morphological characteristics is important to properly assess thermal weed control effectiveness.

Background: Government reports have persistently indicated the intent of terrorists and hostile nations to acquire and “weaponize” nuclear materials for deliberate attack on a major US metropolitan city.

Methods: A modeling analysis of the effects of 20- and 550-kiloton nuclear detonations on the 2 major metropolitan centers of Los Angeles and Houston is presented with a focus on thermal casualties. Brode’s work as modified by Binninger was used to calculate thermal fluence, using thermal fractions. The EM-1 and WE programs were used to calculate blast effects. Fallout radiation was calculated using the Defense Threat Reduction Agency’s Hazard Prediction and Assessment Capability V404SP4 with “urban effects” turned on. The ESRI ArcView program calculated affected populations from 2000 US Census block-level data for areas affected by thermal effects.

Results: The population affected by a 550-kiloton nuclear weapon detonated in Los Angeles and Houston is staggering: surviving thermal casualties are estimated at 185,000 and 59,000, respectively. Even the 20-kiloton detonations in Los Angeles and Houston are significant: the numbers of surviving thermal casualties requiring care exceed 28,000 and 10,000, respectively.

Conclusions: The surviving health care community postdetonation would be faced with an unprecedented burden of care for thermal casualties. A great expansion of personnel involved in emergency burn care response is critical. Bold, new approaches such as regionalization and predetermined medical air transport need to be considered. (Disaster Med Public Health Preparedness. 2007;1:80–89)

Tilting-Pad Journal Bearings (TPJB) are commonly used on high-performance turbomachinerydue to their excellent stability properties at high speed when compared to other designsfor oil film bearings. Hence, efforts have been made to improve the accuracy for theavailable models for these mechanical devices, achieving nowadays anelasto-thermo-hydrodynamic formulation. On the other hand, the basic design of theTilting-Pad Journal Bearing has been modified in order to transform it into a smartmachine element. One approach to do so is to inject pressurized oil directly into thebearing clearance through holes drilled across the bearing pads. By adjusting theinjection pressure, it is possible to modify the dynamic characteristics of the bearing. Acontrollable lubrication regime is obtained, allowing to expand the operational boundariesof the original design. This work focuses on presenting an elasto-thermo-hydrodynamicmodel (ETHD) for the Tilting-Pad Journal Bearing, including the effect ofthe controllable lubrication system. The basic model is validated by comparing its resultsagainst theoretical and experimental results available in the literature. Then, thevalidated code is used to show the benefits of applying a controllable lubrication regime,by means of the modification of the thermal and dynamic behaviour of the bearing.

An observational study is presented of the spectral evolution of gamma-ray burst (GRB) prompt emissions with the Suzaku Wide-band All-sky Monitor (WAM). We selected 6 bright GRBs exhibiting 7 well-separated fast-rise-exponential-decay (FRED) shaped light curves to investigate spectral changes by evaluating exponential decay time constants of the energy-resolved light curves. In addition, we carried out time-resolved spectroscopy of two of them which were located with accuracy sufficient to evaluate the time-resolved spectra with precise energy response matrices. The two imply different emission mechanisms; the one is well reproduced with a cooling blackbody radiation model with a power-law component, while the other prefers non-thermal emission model with a decaying turn over energy.

All events that result in disasters are unique, and it is impossible to become fully prepared. However, through thorough planning and preparedness, it is possible to gain a better understanding of the typical injury patterns and problems that arise from a variety of hazards. Such events have the potential to claim many lives and overwhelm local medical resources. Burn disasters vary in scope of injury and procedures required, and are much more labor and resource intensive than non-burn disasters.

This review of the literature should help determine whether, despite each event having its own unique features, there still are common problems disaster responders face in the prehospital and hospital phases, what recommendations were made from these disasters, and whether these recommendations have been implemented into practice and the current disaster planning processes.

The objective of this review was to assess: (1) prehospital and hospital responses used during past burn disasters; (2) problems faced during those disaster responses; (3) recommendations made following those disasters; (4) whether these recommendations were integrated into practice; and (5) the key characteristics of burn disasters and how they differ from other disasters. This review is important to determine why, despite having disaster plans, things still go wrong.

This paper describes a novel tactile sensor array designed to provide information about the material constitution and shape of objects held by a robot manipulator. The sensor is modeled on the thermal touch sense which enables humans to distinguish between different materials based on how warm or cold they feel. Some results are presented and methods of analysing the sensor data are discussed.

Une analyse numérique du processus d'évolution de l'écoulement dans le plan axial d'un cylindre d'un moteur à deux soupapes et quatre temps pendant la course d'admission est effectuée en utilisant une méthode d'éléments-finis pour un problème à frontières mobiles. Le domaine de calcul, à géométrie variable, inclut simultanément le conduit d'admission, la région de la soupape et la chambre de combustion. Le mouvement des interfaces entre le fluide, le piston et la soupape a été considéré. La méthode Lagrangienne Eulérienne Arbitraire (ALE) a été utilisée pour décrire les champs aérodynamique et thermique. Deux modèles d'interpolation des vitesses de maillage ont été adoptés : l'un est rattaché au mouvement du piston et l'autre à celui de la soupape. Le processus d'évolution et d'établissement des diverses structures tourbillonnaires et du champ thermique dans le plan axial du cylindre, caractérisé par une chambre hémisphérique et des soupapes latérales, est présenté. Cette étude a montré que la modélisation adoptée conduit à une simulation numérique avec une précision raisonnable en comparaison avec les résultats expérimentaux publiés récemment.

The hygrothermal-mechanical behavior of a quad flat non-lead (QFN) package without a chip inside is investigated experimentally and numerically. The present study is focused on understanding the effect of the inherent hygrothermal behaviors of epoxy molding compound (EMC) on the deformations of QFN package. Prior to studying the package, the coefficient of moisture expansion for the EMC is measured experimentally. Full-field moiré and Twyman-Green interferometries are used for measuring the real-time in-plane and out-of-plane deformations of the specimen, respectively, under thermal and moisture loading. In addition, the finite element and theoretical analyses are adopted for validating the experimental observations and further understanding the hygrothermal mechanics of the specimen. The coefficient of moisture expansion of the EMC was experimentally obtained to be about 0.2. The experimental results of the full-field deformations of the specimen, due to temperature, moisture and a combination of both, are presented. The experimental observations are validated by the finite element and theoretical analyses. It was observed that the maximum moisture-induced deformation (strain) can be up to as large as 50% of the thermal deformation (strain) caused by ΔT = 50°C for the specimen. As a result, neglecting moisture-induced deformations (strains) would cause the significant amount of error in thermal deformation (strain) measurement of plastic packages. Furthermore, the present study has laid down the fundamental mechanics and approaches for the QFN packaging structural design and analysis in terms of hygrothermal effects.

La technique d'évaporation présentée dans ce travail consiste à faire ruisseler un liquide à évaporer à la surface d'ailettes enroulées en spirale autour d'un tube vertical, chauffé intérieurement par un fluide caloporteur. Le tube et les ailettes sont usinés dans un monobloc massif en graphite imprégné. Compte tenu de la grande complexité de la géométrie de cet échangeur et de l'écoulement sur ses ailettes, la détermination du coefficient de transfert thermique par convection externe est difficile à obtenir par un calcul direct. Il est déterminé ici par voie indirecte en suivant la méthode de Wilson basée sur deux étapes : une expérimentale et l'autre théorique. On détermine dans cet article la quantité de chaleur échangée et la conductance globale au transfert thermique de cet échangeur/évaporateur lors de l'échauffement. On détermine également les différentes résistances partielles ainsi que le coefficient de convection entre la paroi externe de l'ailette et le film de la solution à chauffer. La démarche proposée dans cet article a permis de valider la méthode indirecte.

We have studied experimentally the effect of ambient temperature on performance of the surface-passivated Al0.2Ga0.8N/GaN heterostructure field-effect transistors in the temperature range from 25°C to 250°C. The measured data have been compared with physics-based modeling of the GaN transistor characteristics under different ambient temperatures. The experimental data, showing about 33% degradation in the saturation current with a temperature increase from 25°C to 250°C, agrees well with the results of simulations performed using ISE DESSIS software. Obtained results and analytical extrapolations can be used for predicting device performance in changing environments, as well as for optimization of the device structure.

The aspartic proteinase, chymosin (EC 3.4.23.4) is the principal milk clotting enzyme used in cheese production and is one of the principal proteolytic agents involved in cheese ripening. Varietal differences in chymosin activity, due to factors such as cheese cooking temperature, fundamentally influence cheese characteristics. Furthermore, much chymosin is lost in whey, and further processing of this by-product may require efficient inactivation of this enzyme, with minimal effects on whey proteins. In the first part of this study, the thermal inactivation kinetics of Maxiren 15 (a recombinant chymosin preparation) were studied in skim milk ultrafiltration permeate, whole milk whey and skim milk whey. Inactivation of chymosin in these systems (at pH 6.64) followed first order kinetics with a D45.5 value of 100±21 min and a z-value of 5.9±0.3 °C. D-Values increased linearly with decreasing pH from 6.64 to 6.2, while z-values decreased as pH decreased from 6.64 to 6.4, but were similar at pH 6.4 and 6.2. Subsequent determination of chymosin activity during manufacture of Cheddar and Swiss-type cheese showed good correlations between predicted and experimental values for thermal inactivation of chymosin in whey. However, both types of cheese curd exhibited relatively constant residual chymosin activity throughout manufacture, despite the higher cooking temperature applied in the manufacture of Swiss cheese. Electrophoretic analysis of slurries made from Cheddar and Swiss cheese indicated decreased proteolysis due to chymosin activity during storage of the Swiss cheese slurry, but hydrolysis of sodium caseinate by coagulant extracted from both cheese types indicated similar levels of residual chymosin activity. This may suggest that some form of conformational change other than irreversible thermal denaturation of chymisin takes place in cheese curd during cooking, or that some other physico-chemical difference between Swiss and Cheddar cheese controls the activity of chymosin during ripening.

We investigated the structural evolution of the Ni/Au contact on GaN(000l) during annealing in N2, using in-situ x-ray diffraction, anomalous x-ray scattering, and high resolution electron microscopy. GaN decomposition occurred mostly along GaN dislocations at temperature higher than 500°C. The decomposed Ga diffused into Au and Ni substitutional positions, and the decomposed nitrogen reacted with Ni, forming Ni4N. Interestingly, Ni4N was grown epitaxially. The epitaxial relationship of the Ni4N, Au, and Ni was identified as M(111)//GaN(0002) and M[1 −1 0]//GaN[1 1 −2 0] (M= Ni4N, Au, and Ni). At dislocation free regions, however, the atomically smooth interface remained intact up to 700 °C. Remarkable improvement of device reliability is expected in the contact on dislocation free regions compared with the contact on dislocations.

Lateral epitaxial overgrowth (LEO) on Si(111) substrates using an AlN buffer layer is demonstrated and characterized using scanning electron microscopy, atomic force microscopy, transmission electron microscopy, x-ray diffraction, photoluminescence spectroscopy, and cathodoluminescence imaging. The <100>-oriented LEO GaN stripes grown on silicon substrates are shown to have similar structural properties as LEO GaN grown on GaN/Al2O3 substrates: the surface topography is characterized by continuous crystallographic steps rather than by steps terminated by screw-component threading dislocations; the density of threading dislocations is <106 cm−2; the LEO regions exhibit crystallographic tilt (0.7-4.7°) relative to the seed region. The AlN buffer thickness affects the stripe morphology and, in turn, the microstructure of the LEO GaN. The issues of chemical compability and thermal expansion mismatch are discussed.