Auswahl der wissenschaftlichen Literatur zum Thema „Aluminium (CZA)“

In all patients with chronic kidney disease (CKD) stages 3–5, regular monitoring of serum markers of CKD-mineral and bone disorder, including calcium (Ca), phosphorus (P), parathyroid hormone (PTH), 25-hydroxyvitamin D, and alkaline phosphatase, is recommended. Target ranges for these markers are endorsed by guidelines. The principles of therapy for secondary hyperparathyroidism include control of hyperphosphataemia, correction of hypocalcaemia, use of vitamin D sterols, use of calcimimetics, and parathyroidectomy. of hyperphosphataemia is crucial and may be achieved by means of dietary P restriction, use of P binders, and P removal by dialysis. Dietary P restriction requires caution, as it may be associated with protein malnutrition. Aluminium salts are effective P binders, but they are not recommended for long-term use, as Aluminium toxicity (though from contaminated dialysis water rather than oral intake) may cause cognitive impairment, osteomalacia, refractory microcytic anaemia, and myopathy. Ca-based P binders are also quite effective, but should be avoided in patients with hypercalcaemia, vascular calcifications, or persistently low PTH levels. Non-aluminium, non-Ca binders, like sevelamer and lanthanum carbonate, may be more adequate for such patients; however, they are expensive and may have several side effects. Furthermore, comparative trials have failed so far to provide conclusive evidence on the superiority of these newer P binders over Ca-based binders in terms of preventing vascular calcifications, bone abnormalities, and mortality. P removal is about 1800–2700 mg per week with conventional thrice-weekly haemodialysis, but may be increased by using haemodiafiltration or intensified regimens, such as short daily, extended daily or three times weekly nocturnal haemodialysis. Several vitamin D derivatives are currently used for the treatment of secondary hyperparathyroidism. In comparison with the natural form calcitriol, the vitamin D analogue paricalcitol seems to be more fast-acting and less prone to induce hypercalcaemia and hyperphosphataemia, but whether these advantages translate into better clinical outcomes is unknown. Calcimimetics such as cinacalcet can significantly reduce PTH, Ca, and P levels, but they have failed to definitively prove any benefits in terms of mortality and cardiovascular events in dialysis patients. Parathyroidectomy is often indicated in CKD patients with severe persistent hyperparathyroidism, refractory to aggressive medical treatment with vitamin D analogues and/or calcimimetics. This procedure usually leads to rapid improvements in biochemical markers (i.e. significant lowering of serum Ca, P, and PTH) and clinical manifestations (such as pruritus and bone pain); however, the long-term benefits are still unclear.

AbstractIn order to realize sustainable development, new types of cements were paid more attention. Calcium sulfoaluminate (CSA) cement is a kind of eco-friendly cement that has the characteristics of low carbon emission, low energy consumption, fast setting and hardening, and so on. But the main hydration product ettringite (AFt) is quite sensitive to curing conditions that makes CSA cement-based materials sensitive to temperature and ageing. Polymer plays a key role in improving the properties of CSA cement mortar. Our researches showed that styrene-butadiene copolymer (SB) could result in a big reduction of zeta potential and conductivity of the CSA cement paste, retard the very initial hydration of CSA cement but not after 3 h, and lead to the generation of more AFt and aluminium hydroxide (AH3). With SB addition increasing, the yield stress, viscosity, thixotropy, fluidity and thus workability of CSA cement mortar were significantly improved. The mechanical strength of CSA cement mortar showed a reduction after a certain age, but when SB was added there was no reduction anymore under various curing conditions. SEM observation of the morphology accounts well for the changes in mechanical properties. The shrinkage, water capillary adsorption, and durability such as resistance to freezing and thawing cycle, carbonization and sulfate attack were also investigated. This paper reviewed the role of polymer in CSA cement-based materials taking SB as an example based on recent research work of our group.

AbstractCarbon fiber reinforced thermoplastic/aluminum alloy (CFRTP/AL) composite laminates have the advantages of low density, high specific strength, and good fatigue resistance, which is a new type of engineering composite material to realize lightweight vehicle body. Heterogeneous interface delamination failure occurs in the forming process of the fiber metal laminates (FMLs). It is necessary to establish an effective finite element simulation strategy to accurately predict the delamination failure behavior of FMLs. In this work, thermoplastic PA6 continuous carbon fiber/AL FMLs were taken as the research object, and the double cantilever beam (DCB) and the end-notched flexure (ENF) experiments were carried out to determine the basic mechanical parameters between the interlayer interfaces of CFRTP/AL. Furthermore, a numerical simulation model based on ABAQUS software was developed to describe the progressive damage failure behavior of the CRFTP/AL in the forming process by using the equivalent modeling strategy of discontinuous micro-shear, which realized the effective prediction of ply directional damage failure of FMLs on the basis of the S-beam model. The results show that the established damage constitutive model and numerical method coupled with cohesive zone model (CZM) can effectively predict the ply directional damage failure behavior of CFRTP/AL composites during the large deformation forming.

Adhesive bonding technology have been widespread in several industrial sectors owing to relevant benefits in comparison to conventional mechanical fastening methods like bolting or riveting. Bonded joints, in their varied formats, have been utilized in many industries as is the case of aeronautical, automotive, naval, wind energy, among others. Tubular adhesive joints (TAJ), although being rarely studied, have found their space and applicability in the construction, motor sports or pipeline industries. In this work it was performed a numerically study, involving cohesive zone modelling (CZM), aiming to assess the influence of geometrical changes on the performance of aluminium TAJ connected with Araldite® 2015 adhesive. The numerical axisymmetric CZM models used in this work were previous validated with experimental results. The geometrical variations for TAJ considered in this work were an outer chamfer, an inner chamfer (both in the adherends), and adding an adhesive fillet at the overlap ends. The geometrical variations analysed in this work have shown significant stress reductions although they are not reflected in an elevated increase in terms of the joint maximum strength, this is mainly due to plasticization of the aluminium adherends.

It is well known that the sample preparation, experimental measurement, and technique have played a vital role in empirical research work. In this chapter, the detailed discussions on the doping and various post-treatments on the PANI thin films have been made. The in-depth studies on gold, silver, aluminum, lithium, HCl, and camphor sulfonic acid (CSA) doped PANI nanocomposites and thin films have been undertaken in this chapter, followed by discussing the effect of post-annealing treatment and ion reaction medium. The impact of different doping and post-treatment on the properties of PANI films viz. microstructural, optical-electrical, thermal, etc., have been analyzed herein. The structural and optoelectrical properties of PANI films and its nanocomposites have also been discussed in which metal-nanoparticles inserted PANI films achieve particular consideration due to its relatively thought-provoking non-linear optical properties.

Digital soil mapping (DSM) is a valuable tool for natural resource conservation and management studies. It requires soil knowledge, compilation of environmental data (climate, geology, vegetation, and relief), followed by data and image analysis and interpretation. This study aimed to collect data from the experimental area of the Center for Agricultural Sciences (CCA-UFSCar, Araras-SP campus) and transform them into images to show the spatial distribution of geomorphological features and physical and chemical attributes of the surface horizon. To this end, we used the geostatistical methodology for DSM, using Kriging with the exponential semivariogram model. We could map the distribution of areas (blocks), relief, soil classes, as well as sand, clay, pH, organic matter (OM), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), aluminum (Al), potential acidity (H+Al), sum of bases (SB), cation exchange capacity (CEC), and base percentage (V%) of the Ap horizon. The methodology used allowed the spatial visualization of this information, which had been heavily used in research by the extinct IAA-Planalsucar from 1973 to 1990 and, since 1991, by UFSCar. This information is an auxiliary tool in the analysis and interpretation of scientific studies conducted at this experimental station.

Chemical vapor deposition (CVD) is an old coating technology, but it was not successfully utilized to aluminize gas turbine hardware until recently (1989). In CVD aluminizing, the use of multiple, independently controlled, low temperature, external, metal halide generators combined with computer control of all process variables gives flexibility and consistent quality that is not possible with any other aluminizing process. It has been shown that harmful coating impurities (such as sulfur and boron etc.) can be transported to a coating from a high temperature aluminum source in the coating chamber during aluminizing. Representative processes include: pack cementation, above the pack, SNECMA, and high activity CVD. In contrast, it has also been demonstrated that CVD low activity aluminizing removes harmful impurities (S, P, B & W etc.) from the coating during deposition. Furthermore, clean, low activity coatings (simple aluminide MDC-210 or platinum modified MDC-150L) have been shown to exhibit superior oxidation resistance compared to similar coatings made by other aluminizing processes. A second significant source of impurities in platinum modified aluminide diffusion coatings is electroplating, that is, plating bath components (S, P, CI, K, Ca etc.) are codeposited with the platinum, and these impurities can have either a beneficial (K&Ca) or a detrimental (S,P&Cl) influence upon the oxidation resistance of the product coating. The results of investigations on the transport of impurities during aluminizing and electroplating, plus the influence of these impurities on oxidation resistance of the product coatings will be presented and discussed.

The aluminum alloy 6061-T6 is a material used for some part of experimental reactor for its interesting physical and mechanical proprieties. To respect the European rules on pressure equipments, a material must present some minimal characteristics for toughness and ductility. In particular, a preventive analysis against abrupt break can be performed in order to ensure the integrity of the structure. In this frame, some characterizations of the toughness were undertaken. Some tests present singular propagation at the beginning of the crack propagation. These singular crack propagation brings some difficulties in the interpretation of the testing and in the J0,2BL/JIC determination. It is the reason why a benchmark on the determination of this value for such material was organized between three different laboratories: the LISN of the French atomic commission (CEA), the LC2M of the CEA and the CESMAN of the DCNS industry. All participants receive a piece of the same material and realize some toughness testing according to its own usage. The benchmark allows comparing the different experimental methodology (machining specimen, pre-crack, testing conditions, equipments …) and the interpretation methodology (ASTM 1820 and ISO 12135 application). This leads to propose a list of recommendations on the realization of the toughness testing and more specifically some necessary adaptation of the ASTM 1820 and ISO 12135 standard for such material.

Capsule-type micro actuator driven by the volume change of hydrogen storage alloys (HSA-CMA) was proposed to be applied as an actuator mounted on the joints of the super multilink manipulator to capture space debris. This actuator consists of a hollow sphere frame made of aluminum, a membrane of hydrogen storage alloys and a valve, and is compact and lightweight. The aim of this study was to evaluate the availability of HSA-CMA. Finite element analyses were performed to investigate the actuator displacement and the generating force as the static performance, and the obtained static performances were compared with that of other smart actuators. The analysis on the actuator displacement led to the design map of HSA-CMA. The comparison result suggests that HSA-CMA has the actuator displacement and the generating force as well or better than other smart actuators and that it is suitable for use in space.

Chemical Vapor Aluminizing (CVA) is used for more than 20 years to protect blades and vanes in the hot section of aero- and land based turbines against oxidation and hot corrosion [1]. Modern CVA is an advanced process capable of controlled alloying the coating with additional elements using metal chlorides and tight control of the coating composition. CVA processes offer a number of advantages over conventional pack and above-the-pack cementation. This paper deals with the industrial CVA technology to produce multi-component coatings using different metal chloride generating devices. Specific examples illustrate the influence of the coating parameters and base materials on the NiAl-based coatings microstructure and composition. Advanced co-deposition CVA processes with addition of different metal elements to the aluminide coatings are presented. Modified coating properties and structures of multiple metal coatings with elements like Al, Cr, Si, Co, Y and others will be discussed.

<p>Aluminium as a structural material is known for its lightweight, which facilitates easy transportation and installation, and reduces foundation requirements. However, this lightweight characteristic makes it sensitive to excitations from vehicular traffic leading to dominating dynamic design over the static one. The dynamic design of highway bridges by the Canadian Highway Bridge Design Code (CSA S6-19) is based on the concept of equivalent dynamic amplification factors (DAF), which were derived largely based on the observations from bridges constructed with traditional materials such as concrete, wood and steel. It is prudent to evaluate whether these factors are applicable to lightweight bridges made with extruded aluminium decks. In addition, since road roughness plays an important role in the dynamic behaviour of a bridge, it is important to consider the influence of roughness on the bridge vibration response. The objective of this research is to investigate the dynamic behaviour of aluminium deck-on-steel girder bridges under vehicular loads considering the effect of road roughness, and consequently evaluate the applicability of the current design DAFs for such structures. For this purpose, numerical models have been developed in Abaqus for a range of selected bridge configurations and loading parameters and subsequently the key observations and conclusions from the numerical analysis have been presented in this paper.</p>

<p>Aluminium as a structural material is known for its lightweight, which facilitates easy transportation and installation, and reduces foundation requirements. However, this lightweight characteristic makes it sensitive to excitations from vehicular traffic leading to dominating dynamic design over the static one. The dynamic design of highway bridges by the Canadian Highway Bridge Design Code (CSA S6-19) is based on the concept of equivalent dynamic amplification factors (DAF), which were derived largely based on the observations from bridges constructed with traditional materials such as concrete, wood and steel. It is prudent to evaluate whether these factors are applicable to lightweight bridges made with extruded aluminium decks. In addition, since road roughness plays an important role in the dynamic behaviour of a bridge, it is important to consider the influence of roughness on the bridge vibration response. The objective of this research is to investigate the dynamic behaviour of aluminium deck-on-steel girder bridges under vehicular loads considering the effect of road roughness, and consequently evaluate the applicability of the current design DAFs for such structures. For this purpose, numerical models have been developed in Abaqus for a range of selected bridge configurations and loading parameters and subsequently the key observations and conclusions from the numerical analysis have been presented in this paper.</p>

Abstract Polymeric substrates have to be severely cooled during the plasma spraying process to limit detrimental effect due to the high heating flow from the plasma jet. The « Atmosphere and Temperature Controlled process » (ATC, patented by CEA) was used to maintain the substrates near room temperature. However, the PET substrates might undergo some superficial modifications which could result from the plasma jet heating and particle heating at the impact. This paper deals with a study of chemical modifications in PET as a function of surrounding atmospheres during plasma processing. Aluminum coating adhesion was determined using tensile tests.

Beneficial use of reclaimed wastewater (RW) and biosolids (BS) in soils is accompanied by large input of sewage-originated P. Prolonged application may result in P accumulation up to levelsBeneficial use of reclaimed wastewater (RW) and biosolids (BS) in soils is accompanied by large input of sewage-originated P. Prolonged application may result in P accumulation up to levels that impair plant nutrition, increase P loss, and promote eutrophication in downstream waters. This study aims to shed light on the RW- and BS-P forms in soils and to follow the processes that determine P reactivity, solubility, availability, and loss in RW and BS treated soils. The Technion group used sequential P extraction combined with measuring stable oxygen isotopic composition in phosphate (δ18OP) and with 31P-NMR studies to probe P speciation and transformations in soils irrigated with RW or fresh water (FW). The application of the δ18OP method to probe inorganic P (Pi) speciation and transformations in soils was developed through collaboration between the Technion and the UCSC groups. The method was used to trace Pi in water-, NaHCO3-, NaOH-, and HCl- P fractions in a calcareous clay soil (Acre, Israel) irrigated with RW or FW. The δ18OP signature changes during a month of incubation indicated biogeochemical processes. The water soluble Pi (WSPi) was affected by enzymatic activity yielding isotopic equilibrium with the water molecules in the soil solution. Further it interacted rapidly with the NaHCO3-Pi. The more stable Pi pools also exhibited isotopic alterations in the first two weeks after P application, likely related to microbial activity. Isotopic depletion which could result from organic P (PO) mineralization was followed by enrichment which may result from biologic discrimination in the uptake. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with RW. Specific P compounds were identified by the Technion group, using solution-state 31P-NMR in wastewater and in soil P extracts from Acre soils irrigated by RW and FW. Few identified PO compounds (e.g., D-glucose-6-phosphate) indicated coupled transformations of P and C in the wastewater. The RW soil retained higher P content, mainly in the labile fractions, but lower labile PO, than the FW soil; this and the fact that P species in the various soil extracts of the RW soil appear independent of P species in the RW are attributed to enhanced biological activity and P recycling in the RW soil. Consistent with that, both soils retained very similar P species in the soil pools. The HUJ group tested P stabilization to maximize the environmental safe application rates and the agronomic beneficial use of BS. Sequential P extraction indicated that the most reactive BS-P forms: WSP, membrane-P, and NaHCO3-P, were effectively stabilized by ferrous sulfate (FeSul), calcium oxide (CaO), or aluminum sulfate (alum). After applying the stabilized BS, or fresh BS (FBS), FBS compost (BSC), or P fertilizer (KH2PO4) to an alluvial soil, P availability was probed during 100 days of incubation. A plant-based bioassay indicated that P availability followed the order KH2PO4 >> alum-BS > BSC ≥ FBS > CaO-BS >> FeSul-BS. The WSPi concentration in soil increased following FBS or BSC application, and P mineralization further increased it during incubation. In contrast, the chemically stabilized BS reduced WSPi concentrations relative to the untreated soil. It was concluded that the chemically stabilized BS effectively controlled WSPi in the soil while still supplying P to support plant growth. Using the sequential extraction procedure the persistence of P availability in BS treated soils was shown to be of a long-term nature. 15 years after the last BS application to MN soils that were annually amended for 20 years by heavy rates of BS, about 25% of the added BS-P was found in the labile fractions. The UMN group further probed soil-P speciation in these soils by bulk and micro X-ray absorption near edge structure (XANES). This newly developed method was shown to be a powerful tool for P speciation in soils. In a control soil (no BS added), 54% of the total P was PO and it was mostly identified as phytic acid; 15% was identified as brushite and 26% as strengite. A corn crop BS amended soil included mostly P-Fe-peat complex, variscite and Al-P-peat complex but no Ca-P while in a BS-grass soil octacalcium phosphate was identified and o-phosphorylethanolamine or phytic acid was shown to dominate the PO fraction that impair plant nutrition, increase P loss, and promote eutrophication in downstream waters. This study aims to shed light on the RW- and BS-P forms in soils and to follow the processes that determine P reactivity, solubility, availability, and loss in RW and BS treated soils. The Technion group used sequential P extraction combined with measuring stable oxygen isotopic composition in phosphate (δ18OP) and with 31P-NMR studies to probe P speciation and transformations in soils irrigated with RW or fresh water (FW). The application of the δ18OP method to probe inorganic P (Pi) speciation and transformations in soils was developed through collaboration between the Technion and the UCSC groups. The method was used to trace Pi in water-, NaHCO3-, NaOH-, and HCl- P fractions in a calcareous clay soil (Acre, Israel) irrigated with RW or FW. The δ18OP signature changes during a month of incubation indicated biogeochemical processes. The water soluble Pi (WSPi) was affected by enzymatic activity yielding isotopic equilibrium with the water molecules in the soil solution. Further it interacted rapidly with the NaHCO3-Pi. The more stable Pi pools also exhibited isotopic alterations in the first two weeks after P application, likely related to microbial activity. Isotopic depletion which could result from organic P (PO) mineralization was followed by enrichment which may result from biologic discrimination in the uptake. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with RW. Specific P compounds were identified by the Technion group, using solution-state 31P-NMR in wastewater and in soil P extracts from Acre soils irrigated by RW and FW. Few identified PO compounds (e.g., D-glucose-6-phosphate) indicated coupled transformations of P and C in the wastewater. The RW soil retained higher P content, mainly in the labile fractions, but lower labile PO, than the FW soil; this and the fact that P species in the various soil extracts of the RW soil appear independent of P species in the RW are attributed to enhanced biological activity and P recycling in the RW soil. Consistent with that, both soils retained very similar P species in the soil pools. The HUJ group tested P stabilization to maximize the environmental safe application rates and the agronomic beneficial use of BS. Sequential P extraction indicated that the most reactive BS-P forms: WSP, membrane-P, and NaHCO3-P, were effectively stabilized by ferrous sulfate (FeSul), calcium oxide (CaO), or aluminum sulfate (alum). After applying the stabilized BS, or fresh BS (FBS), FBS compost (BSC), or P fertilizer (KH2PO4) to an alluvial soil, P availability was probed during 100 days of incubation. A plant-based bioassay indicated that P availability followed the order KH2PO4 >> alum-BS > BSC ≥ FBS > CaO-BS >> FeSul-BS. The WSPi concentration in soil increased following FBS or BSC application, and P mineralization further increased it during incubation. In contrast, the chemically stabilized BS reduced WSPi concentrations relative to the untreated soil. It was concluded that the chemically stabilized BS effectively controlled WSPi in the soil while still supplying P to support plant growth. Using the sequential extraction procedure the persistence of P availability in BS treated soils was shown to be of a long-term nature. 15 years after the last BS application to MN soils that were annually amended for 20 years by heavy rates of BS, about 25% of the added BS-P was found in the labile fractions. The UMN group further probed soil-P speciation in these soils by bulk and micro X-ray absorption near edge structure (XANES). This newly developed method was shown to be a powerful tool for P speciation in soils. In a control soil (no BS added), 54% of the total P was PO and it was mostly identified as phytic acid; 15% was identified as brushite and 26% as strengite. A corn crop BS amended soil included mostly P-Fe-peat complex, variscite and Al-P-peat complex but no Ca-P while in a BS-grass soil octacalcium phosphate was identified and o-phosphorylethanolamine or phytic acid was shown to dominate the PO fraction.