High-end Range Research Articles

Sediment accumulation rates and carbonate fluxes of deep-sea sediments in the southern Gulf of Mexico

Here we present the mass and carbonate annual fluxes, collected by two sediment traps at 1000 m depth, located on the western and southern deep-water region of the Gulf of Mexico (GM), and compare them with the total mass and carbonate accumulation rates (CAR) from 46 sediment cores retrieved from continental slopes and the abyssal plain of the southern Gulf of Mexico (sGM). CaCO3 fluxes in the sediment traps located close to 1000 m water depth, range between 15.1 and 22.4 g m−2 yr−1, these values fall on the high-end range of the mean fluxes reported for the global ocean (9–22 g m−2 yr−1). The carbonate fluxes from the water column are remarkably close to the CAR in the lower slope and abyssal sediments of the southern GM, implying that dissolution processes of biogenic carbonate in the sediments below 1000 m are negligible in the sGM. The spatial patterns of CARs in the sediments are mainly linked with surface productivity of calcareous organisms and export to depth over the continental slope and abyssal plain regions, with mean values of 15.7 ± 5.7 g m−2 yr−1 (0.15 ± 0.06 mol m−2 yr−1). However, there are some large areas over the abyssal plain to the north of the Campeche escarpment showing enhanced CAR values most likely as a result from two processes, lateral input from the Yucatan carbonate shelf region and massive collapse events originating at the Campeche escarpment and deposited to the north of the Yucatan Platform. These processes can account for an additional increase in carbonate mass accumulation by approximately 8 g m−2 yr−1 in this area, showing a decreasing gradient towards the N of the escarpment. Lateral transport by turbidity currents of carbonate platform sediments along submarine canyons and probably episodic gravity flows further aid to explain the localized higher carbonate mass accumulation (> 20 g m−2 yr−1) observed at the foot of the continental slopes to the west and south of the southern GM. We estimate total carbonate accumulation estimates for the entire Gulf of Mexico, from the upper slope to the abyssal plain (1000–3750 m), considering the northern deep-water region reported by Giering et al., 2018, of 0.09 to 0.12 Tmol/yr accounts for 0.8 to 1.8% of all carbonate sedimentation in the ocean below 1000 m. Taking into considerations its small areal extent of <0.3% of the global ocean the GM carbonate accumulation accounts for a factor of 3 to 6 its areal importance, implying that changes in the production and export of carbonate in the GM due to surface ocean warming and acidification processes in this inland sea will have a sensible effect in the global carbon cycle.

The high-end range of biliary reconstruction in living donor liver transplant.

To summarize recent evidence in literature regarding incidence and risk factors for biliary complications in living donor liver transplantation (LDLT), and current concepts in evaluation of donor biliary anatomy and surgical techniques of biliary reconstruction, to reduce the incidence of biliary complications. Advances in biliary imaging in the donor, both before surgery, and during donor hepatectomy, as well as safe hepatic duct isolation in the donor, have played a significant role in reducing biliary complications in both the donor and recipient. Duct-to-duct biliary anastomoses (DDA) is the preferred mode of biliary reconstruction currently, especially when there is a single bile duct orifice in the donor. The debate on stenting the anastomoses, especially a DDA, continues. Stenting a Roux en Y hepaticojejunostomy in children with small ductal orifices in the donor is preferred. With growing experience, and use of meticulous surgical technique and necessary modifications, the incidence of biliary complications in multiple donor bile ducts, and more than one biliary anastomoses can be reduced. Biliary anastomosis continues to be the Achilles heel of LDLT. Apart from surgical technique, which includes correct choice of type of reconstruction technique and appropriate use of stents across ductal anastomoses, better imaging of the biliary tree, and safe isolation of the graft hepatic duct, could help reduce biliary complications in the recipient, and make donor hepatectomy safe .

Creating innovative products with reference system elements - a case study on approaches in practice

As any other human being development engineers preferably act based on experience. Hence it is comprehensible that even for a product that initially appears revolutionary usually one or more references can be found. This enhances, for example, the comparability or the availability of a products subsystems so that they are more easily to deal with. Especially during the development of a new product, which means the start of a new product line, the use of reference system elements helps to reduce development efforts. Reference system elements are, for example, physical products whose functions or components are relevant for one’s own product. By scanning the system of objectives for smaller subsystems one may find those functions or components just mentioned. For this scientific work a development process of a technology rollout was examined. The objective pursued was to gain insights on possibilities and challenges of deriving knowledge from such reference system elements in this specific case. A suitable research environment was offered by a medium sized machine manufacturer. A new technology to process foam particles using radio frequency is being developed there. The established process using steam is already in the high-end range, which is why only a small development potential is left. From the findings in this case study in synthesis with the state of the art on innovation management and knowledge management a descriptive process model is derived. The focus of the process model is to support the search for relevant reference system elements. For the examined machine, for example, the common microwave was used as a reference element. The elements found can be evaluated for their suitability using previously elaborated validation criteria. This facilitates the adoption of existing solutions or the development of new solutions based on reference system elements.

PROX reaction of CO in H2/H2O/CO2 Water–Gas Shift (WGS) feedstocks over Cu–Mn/Al2O3 and Cu–Ni/Al2O3 catalysts for fuel cell applications

Abstract Catalytic conversion performance of the γ-Al2O3-supported Cu-, Mn- and Ni-based materials for the selective preferential oxidation of CO was investigated. The influence of CO2 and H2O in the reactor feed gas on activity and selectivity was lastly investigated for copper bimetallic catalysts containing manganese and nickel. Cu/Al2O3 proved to be optimal among the monometallic examined. It was observed that even in the absence of H2, CO was effectively converted. Upon H2 presence, a fraction of oxygen is utilized for the latter, which results in the decrease of CO turnover. Cu–Mn/Al2O3 surpassed other single and mixed metal oxide catalysts which could be due to a combination of surface desorption capacity and redox properties. The oxygen storage capacities (OSC) were in the order of Cu–Mn/Al2O3 > Cu–Ni/Al2O3 > Cu/Al2O3 > Mn/Al2O3 > Ni/Al2O3, in an agreement with reactivity. The efficiency at low process temperatures was enhanced by adding H2O vapors, nonetheless, decreased at high-end range due to the reverse water–gas shift (RWGS). Also, the rate of CO conversion was high utilizing Cu–Mn/Al2O3; furthermore, even upon applying H2O and CO2. CO2 notably affected CO conversion, and ultimately, decreased the activity, which, conversely, remained stable upon time-on-stream.

Proton tracking in a high-granularity Digital Tracking Calorimeter for proton CT purposes

Radiation therapy with protons as of today utilizes information from x-ray CT in order to estimate the proton stopping power of the traversed tissue in a patient. The conversion from x-ray attenuation to proton stopping power in tissue introduces range uncertainties of the order of 2–3% of the range, uncertainties that are contributing to an increase of the necessary planning margins added to the target volume in a patient. Imaging methods and modalities, such as Dual Energy CT and proton CT, have come into consideration in the pursuit of obtaining an as good as possible estimate of the proton stopping power. In this study, a Digital Tracking Calorimeter is benchmarked for proof-of-concept for proton CT purposes. The Digital Tracking Calorimeter was originally designed for the reconstruction of high-energy electromagnetic showers for the ALICE-FoCal project. The presented prototype forms the basis for a proton CT system using a single technology for tracking and calorimetry. This advantage simplifies the setup and reduces the cost of a proton CT system assembly, and it is a unique feature of the Digital Tracking Calorimeter concept. Data from the AGORFIRM beamline at KVI-CART in Groningen in the Netherlands and Monte Carlo simulation results are used to in order to develop a tracking algorithm for the estimation of the residual ranges of a high number of concurrent proton tracks. High energy protons traversing the detector leave a track through the sensor layers. These tracks are spread out through charge diffusion processes. A charge diffusion model is applied for acquisition of estimates of the deposited energy of the protons in each sensor layer by using the size of the charge diffused area. A model fit of the Bragg Curve is applied to each reconstructed track and through this, estimating the residual range of each proton. The range of the individual protons can at present be estimated with a resolution of 4%. The readout system for this prototype is able to handle an effective proton frequency of 1MHz by using 500 concurrent proton tracks in each readout frame, which is at the high end range of present similar prototypes. A future further optimized prototype will enable a high-speed and more accurate determination of the ranges of individual protons in a therapeutic beam.

Food mechanical properties, feeding ecology, and the mandibular morphology of wild orangutans

Bornean orangutan mandibular morphology has been functionally linked to the exploitation of hard and tough foods, based on evidence that Pongo pygmaeus wurmbii spends a greater percentage of time feeding on bark, seeds and vegetation compared with Pongo abelii (Sumatran orangutans) and the assumption that these tissues are more challenging to process than fruit pulp. We measured and compared toughness (R) and Young's modulus (E) of ripe and unripe foods exploited by P. abelii and P. p. wurmbii. Additionally, we recorded and compared the percentage of time these orangutans fed on plants/plant parts of varying degrees of R and E. Compared with P. abelii, P. p. wurmbii consumed significantly tougher and more displacement limited (R/E)0.5 fruit parts, leaves and inner bark, and spent a significantly greater percentage of time feeding on immature leaves, unripe fruit and other vegetation. Modulus did not vary as expected between species, likely because we failed to capture the high-end range of modulus values for tissues consumed by P. p. wurmbii. Notably, P. p. wurmbii spent ∼40% of its feeding time on the toughest foods consumed (between 1000 and 4000 J m−2). Thus, the hypothesis that mandibular robusticity in P. p. wurmbii is functionally linked to feeding on tough foods is supported and is likely related to countering relatively larger external forces and/or repetitive loads required to process the toughest tissues. The importance of elastic modulus on morphological divergence awaits future studies capturing the full range of this material property for P. p. wurmbii. Finally, phenophase and fruit availability influence orangutan species differences in food material properties and percentage of time spent feeding on various foods, emphasizing the importance of incorporating these variables in future studies of feeding ecology and craniodental morphology in extant taxa.

Vertical Product Line Extension Strategies: An Evaluation of Brand Halo Effect according to Range Level

The brand halo effect for vertical product line extensions is analyzed using the central nucleus theory. The empirical study is based on experimentation linked to six brands in the automotive sector. This research shows that central brand associations are transferred to the vertical product line extension regardless of range level — low, middle or high-end range — and that such transference systematically reinforces linkages between such associations and the product line extensions. In contrast, the transfer of peripheral associations appears to be range-dependent, increasing or decreasing linkages between such associations and the product line extension according to the range level considered.

Validation of serum ferritin values by magnetic susceptometry in predicting iron overload in dialysis patients

Guidelines for treating anemia in dialysis patients accept, as high-end range of serum ferritin useful to optimize erythropoietin therapy, values high as 500 to 900 microg/L, on the hypothesis that ferritin might be not representative of iron overload. A superconducting quantum interference device (SQUID) was used to make direct noninvasive magnetic measurements of nonheme hepatic iron content in 40 dialysis patients treated with intravenous iron, and liver iron content was compared with biochemical markers of iron status. Only 12/40 (30%) patients showed normal hepatic iron content (SQUID <400 microg/g), while 32.5% had mild (400 to 1000 microg/g) and 37.5% severe (>1000 microg/g) iron overload, although 28/40 patients (70%) had serum ferritin below 500 microg/L. Among many parameters, hepatic iron content was only correlated with ferritin (r= 0.324, P= 0.04). The receiver operating characteristic (ROC) analysis showed the best specificity/sensitivity ratio to identify iron overload for ferritin >340 microg/L (W = 0.716). Multivariate logistic regression analysis demonstrated that an increase in serum ferritin of 100 microg/L and female gender were independent variables associated with moderate to severe hepatic iron overload: OR 1.71 (95% CI 1.10 to 2.67) and OR 10.68 (95% CI 1.81 to 63.15), respectively. Hepatic iron overload is frequent in dialysis patients with ferritin below currently proposed high-end ranges, and the diagnostic power of ferritin in indicating true iron stores is better than presumed. Safety concerns should prompt a reevaluation of acceptable iron parameters, focusing on potential gender-specific differences, to avoid potentially harmful iron overload in a majority of dialysis patients, mainly females.

Application of statistical methods (SPC) for an optimized control of the irradiation process of high-power semiconductors

Abstract High-power bipolar semiconductor devices (thyristors and diodes) in a disc-type shape are key components (semiconductor switches) for high-power electronic systems. These systems are important for the economic design of energy transmission systems, i.e. high-power drive systems, static compensation and high-voltage DC transmission lines. In their factory located in Pretzfeld, Germany, the company, eupec GmbH+Co.KG (eupec), is producing disc-type devices with ceramic encapsulation in the high-end range for the world market. These elements have to fulfil special customer requirements and therefore deliver tailor-made trade-offs between their on-state voltage and dynamic switching behaviour. This task can be achieved by applying a dedicated electron irradiation on the semiconductor pellets, which tunes this trade-off. In this paper, the requirements to the irradiation company Mediscan GmbH, from the point of view of the semiconductor manufacturer, are described. The actual strategy for controlling the irradiation results to fulfil these requirements are presented, together with the choice of relevant parameters from the viewpoint of the irradiation company. The set of process parameters monitored, using statistical process control (SPC) techniques, includes beam current and energy, conveyor speed and irradiation geometry. The results are highlighted and show the successful co-operation in this business. Watching this process vice versa, an idea is presented and discussed to develop the possibilities of a highly sensitive dose detection device by using modified diodes, which could function as accurate yet cheap and easy-to-use detectors as routine dosimeters for irradiation institutes.