Aluminum Absorption Research Articles

Human Health Effects of Dietary Aluminum

<p>Aluminum is abundant in the environment and can also be found in most foods. To date, no convincing data has been found regarding the possible risk of ingesting aluminum through food, water and pharmaceuticals. This paper sought to review current literature to find evidence of the health effects of aluminum absorption in the diet in humans.</p><p>The review found that the evidence is contradictory and as such, there is no established causation between dietary aluminum and adverse health effects. Many studies suggest a relationship between aluminum consumption and Alzheimer’s disease, but here again, the results are inconsistent. More research is needed to establish the risk of daily ingestion of aluminum through the diet, drinking water and the use of pharmaceuticals. Further research should be conducted on subpopulation groups, such as children, chronic pharmaceutical drug users and other vulnerable groups.</p>

Selection of Best Materials and Parametric Optimization of Solar Parabolic Collector Using Fuzzy Logic

This paper focused on selection of best materials for absorber tube and reflective surfaces of Solar Parabolic Collector (SPC) using fuzzy logic, after analysing the material data. The glass mirror and Aluminium absorber have been identified as best materials. These selected materials are replaced in existing experimental setup. An experimental design is prepared based on the considered parabolic collector parameters: Absorptivity, Reflectivity and Period of Sun Incidence. During experiments, outlet temperature of water and discharge is recorded for each experimental run. These data are analyzed using fuzzy Logic integrated with the Taguchi method and optimal parameter combination has been found.

Flat Plate Collector for Process Heat with Full Surface Aluminium Absorber, Vacuum Super Insulation and Front Foil

A new flat plate collector is under development for economic process heat of temperatures between 80° and 150°C. A vacuum super insulation (VSI) with micro-porous powders (perlite or fumed silica) in an evacuated (0.1 mbar) stainless steel envelope has been developed for the rear side of the collector which replaces the mineral wool insulation of standard collectors. CFD simulations of the equivalent thermal conductivity of the VSI including losses via the powder and edge losses have been performed depending on geometry. Applying a 100μm thin VA foil as VSI cover, the collector losses can be reduced by about 0.6W/m2K. Between glass cover and absorber the collector will be equipped with a transparent ETFE foil reducing the loss coefficient further by about 1.2W/m2K. Additionally, a full surface aluminium absorber with a very high collector efficiency factor F’ of 0.97 is used, reaching maximum collector efficiencies of about 0.9. Up to a temperature difference of 110K, the new collector is estimated to have higher efficiencies than standard flat plate and vacuum tube collectors. In the temperature range of 80° and 150°C the efficiency is expected to lie between 65% and 35%. Four different and successively improved prototypes are under test and construction, respectively. The first prototype showed the principal feasibility of the concept and was the first VSI collector operated under outdoor conditions at temperatures up to 120K over ambient.

Estimation of aluminium pollution in oak stands on the Krotoszyn Plateau

Estimation of the degree of aluminium absorption by oak stands on the Krotoszyn Plateau and on reference areas is reported in this paper. Soil pH, the content of exchangeable aluminium in soil and the content of aluminium in the xylem and roots of <em>Quercus robur</em> L. were determined. The performed studies show a very strong acidification of soils from the investigated areas of the Krotoszyn Plateau; pH vs. 1 M KCI did not exceed 4.0, whereas the content of exchangeable Al in some places was 50 mg/100 g. The results also showed an elevated content of aluminium in the wood and roots of oaks growing on the Krotoszyn Plateau as compared to oaks in Zawiercie (near a Steel Mill), where the reaction of soil is neutral. The content of Al in the xylem of oaks from the Krotoszyn Plateau was over the range 3.8-9.9 µg/g, in the roots 198-499 µg/g, that in the xylem and roots of oaks in Zawiercie was 1.5 µg/g and 56 µg/g, respectively

Effect of Diffrent Absorbing Materials on Th Performance of Basin Solar Still Under Libyan Climate Conditions

This experimental study deals with a single-basin solar still using various absorbing materials with and without black painting. Different types of absorbing materials with and without black painting were used to enhance the solar still productivity throughimprovement in absorptivity. Those materials are steel and aluminum with and without black painting and rubber. Two identical solar stills were manufactured using locally available materials. All the results were compared together to reach the best absorbing materials with and without painting that can be used for solar still. It was found that the rubber absorber has the highest water collection during the daytime, followed by the black painted steel absorber, then by black-painted aluminum absorber and steel without painting absorber. The average enhancement in the daily productivity was about 50% for the rubber absorber comparedwith the black painted aluminum absorber and about 43% for the rubber absorber compared with the black painted steel absorber.

Analysis of Absorption Coefficient for Eco-Friendly Acoustical Absorbers

Primarily used for domestic buildings as a sound absorber are glass wool, rock wool, etc. These absorbers as well as waste absorber created by recycling wastes, PP+PET fiber absorber made from polypropylene and polyester, wood wool board bonded with finely sliced roots of trees and foamed aluminum absorber are recyclable eco-friendly absorbers that are constantly being developed. In this study, we compared the sound absorption performance of currently used absorbers and eco-friendly building absorbers. As a result, the NRC (Noise Reduction Coefficient) was found to be 0.85 for glass wool, 0.95 for rock wool, and 0.70 for polyester, 0.65 for waste absorber, 0.75 for PET+ PP fiber absorber, 0.40 for wood wool board, and 0.75 for foamed aluminum absorber. Based on the results of these absorption coefficients, we expect the usability of the absorbers continues to increase as future eco-friendly building absorbers.

Comparative Study of Leaching of Aluminium from Aluminium, Clay, Stainless Steel, and Steel Cooking Pots

Analyses on the absorption of aluminium by rice boiled in distilled water in a variety of containers, such as old and new aluminium pots, clay receptacles, stainless steel pots, and steel pots, were carried out. 10 g of rice was taken as a representative sample. Colorimetric analysis of classical methods was used to determine the concentration of aluminium. The control for aluminium was 350 ± 130 μg/g. The new aluminium pots had a concentration of 126 ± 64 μg/g, old aluminium pots had 314 ± 128 μg/g, new clay pots had 132 ± 68 μg/g, old clay pots had 195 ± 137 μg/g, new steel pots had 241.00 ± 200 μg/g, old steel utensils had 186.83 ± 75.18 μg/g, new stainless steel utensils had 294.83 ± 163 μg/g, and old stainless steel utensils had 289.00 ± 75.155 μg/g. Aluminium leaching was detected in all forms of new and old cooking utensils, and leaching was below and within the control concentration range. Old aluminium pots had the highest concentration of leaching while new steel pots had the least leaching of aluminium. However, the aluminium contamination of the foods tested was insufficient to constitute a hazard to health.

Calculation of half-value thickness for aluminum absorbers by means of fractional calculus

Half-value thickness of aluminum absorbers has been investigated experimentally and theoretically. Cs-137, Tl-204 and Sr-90/Y-90 radio-isotopes were used as beta sources. Inconsistency between experimental measurements and standard theoretical calculations has been removed with the help of fractional calculus. The experimental and theoretical half-thickness values have been found equivalent for fractional derivative order ≈0.3.

Experimental study on spiral flow passive solar water heater

This study presents the experimental analysis of spiral flow flat plate collector passive solar water heater. A solar water heater was fabricated with spiral shaped copper water tube fixed on the flat plate aluminium absorber plate. The experiments were conducted at Kovilpatti (9°10′ N, 77°52′ E), India, during summer. Variations in exit water temperature and efficiency of the system were studied for different mass flow rates. Around 2 pm, the system reached the maximum efficiency point. The maximum efficiency of the system was 65.98% at 0.015 kg/s mass flow with exit water temperature of 95°C when the ambient temperature was 36°C.

Aluminum Involvement in the Progression of Alzheimer's Disease

The neuroanatomic specificity with which Alzheimer's disease (AD) progresses could provide clues to AD etiopathology. Magnetic resonance imaging studies of AD clinical progression have confirmed general conclusions from earlier studies of AD neuropathological progression wherein neurofibrillary tangle pathology was observed to spread along a well-defined sequence of corticocortical and corticosubcortical connections, preferentially affecting certain cell types, while sparing others. Identical and non-identical twin studies have consistently shown AD has mixed (environmental and genetic) etiopathogenesis. The decades-long prodromal phase over which AD develops suggests slow but progressive accumulation of a toxic or infective agent over time. Major environmental candidates are reviewed to assess which best fits the profile of an agent that slowly accrues in susceptible cell types of AD-vulnerable brain regions to toxic levels by old age, giving rise to AD neuropathology without rapid neuronal lysis. Chronic aluminum neurotoxicity best matches this profile. Many humans routinely ingest aluminum salts as additives contained in processed foods and alum-treated drinking water. The physical properties of aluminum and ferric iron ions are similar, allowing aluminum to use mechanisms evolved for iron to enter vulnerable neurons involved in AD progression, accumulate in those neurons, and cause neurofibrillary damage. The genetic component of AD etiopathogenesis apparently involves a susceptibility gene, yet to be identified, that increases aluminum absorption because AD and Down syndrome patients have higher than normal plasma, and brain, aluminum levels. This review describes evidence for aluminum involvement in AD neuropathology and the clinical progression of sporadic AD.

Adsorption and absorption of boron, nitrogen, aluminum, and phosphorus on silicene: Stability and electronic and phonon properties

Ab initio calculations within the density-functional theory formalism are performed to investigate the chemical functionalization of a graphene-like monolayer of silicon - silicene - with B, N, Al or P atoms. The structural, electronic, magnetic and vibrational properties are reported. The most preferable adsorption sites are found to be valley, bridge, valley and hill site for B, N, Al and P adatoms, respectively. All the relaxed systems with adsorbed/substituted atoms exhibit metallic behaviour with strongly bonded B, N, Al, and P atoms accompanied by an appreciable electron transfer from silicene to the B, N and P adatom/substituent. The Al atoms exhibit opposite charge transfer, with n-type doping of silicene and weaker bonding. The adatoms/substituents induce characteristic branches in the phonon spectrum of silicene, which can be probed by Raman measurements. Using molecular dynamics we found that the systems under study are stable up to at least T = 500 K. Our results demonstrate that silicene has a very reactive and functionalizable surface.

Performance Evaluation of a Double-Glazed Box-Type Solar Oven with Reflector

This research paper describes the performance evaluation of a double-glazed box-type solar oven with reflector fabricated using locally available materials, compressed sawdust with binder; size of the box is 700&#x2009;mm&#x2009;&#xd7;&#x2009; 700&#x2009;mm &#xd7; 400&#x2009;mm and 10&#x2009;mm thickness. The experimental solar cooker consists of an aluminium absorber plate (1&#x2009;mm) painted matt black and a double-glazed lid. The bottom and sides are lagged with fibreglass wool insulator, thickness = 50&#x2009;mm, <svg style="vertical-align:-0.1638pt;width:64.612503px;" id="M1" height="12.4375" version="1.1" viewBox="0 0 64.612503 12.4375" width="64.612503" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,12.162)"><path id="x1D458" d="M480 416q0 -21 -18 -41q-9 -11 -17 -7q-20 9 -42 9q-62 0 -140 -78q23 -69 88 -192q17 -31 27 -42t20 -11q16 0 62 46l17 -20q-64 -92 -119 -92q-35 0 -70 66q-41 73 -84 187q-36 -30 -62 -61q-27 -115 -35 -172q-41 -8 -78 -20l-6 6l140 612q7 28 0.5 34t-37.5 7l-34 1&#xA;l5 26q38 4 74 13.5t57 17t25 7.5q12 0 4 -32l-104 -443h2q35 38 97 93q39 35 65.5 56t62 41.5t58.5 20.5q19 0 30.5 -10t11.5 -22z" /></g><g transform="matrix(.017,-0,0,-.017,13.322,12.162)"><path id="x3D" d="M535 323h-483v50h483v-50zM535 138h-483v50h483v-50z" /></g><g transform="matrix(.017,-0,0,-.017,28.025,12.162)"><path id="x30" d="M241 635q53 0 94 -28.5t63.5 -76t33.5 -102.5t11 -116q0 -58 -11 -112.5t-34 -103.5t-63.5 -78.5t-94.5 -29.5t-95 28t-64.5 75t-34.5 102.5t-11 118.5q0 58 11.5 112.5t34.5 103t64.5 78t95.5 29.5zM238 602q-32 0 -55.5 -25t-35.5 -68t-17.5 -91t-5.5 -105&#xA;q0 -76 10 -138.5t37 -107.5t69 -45q32 0 55.5 25t35.5 68.5t17.5 91.5t5.5 105t-5.5 105.5t-18 92t-36 68t-56.5 24.5z" /></g><g transform="matrix(.017,-0,0,-.017,36.185,12.162)"><path id="x2E" d="M113 -12q-24 0 -39.5 16t-15.5 42q0 24 16 40.5t40 16.5t40 -16.5t16 -40.5q0 -26 -16 -42t-41 -16z" /></g><g transform="matrix(.017,-0,0,-.017,40.061,12.162)"><use xlink:href="#x30"/></g><g transform="matrix(.017,-0,0,-.017,48.22,12.162)"><path id="x35" d="M153 550l-26 -186q79 31 111 31q90 0 141.5 -51t51.5 -119q0 -93 -89 -166q-85 -69 -173 -71q-32 0 -61.5 11.5t-41.5 23.5q-18 17 -17 34q2 16 22 33q14 9 26 -1q61 -50 124 -50q60 0 93 43.5t33 104.5q0 69 -41.5 110t-121.5 41q-53 0 -102 -20l38 305h286l6 -8&#xA;l-26 -65h-233z" /></g><g transform="matrix(.017,-0,0,-.017,56.379,12.162)"><path id="x32" d="M412 140l28 -9q0 -2 -35 -131h-373v23q112 112 161 170q59 70 92 127t33 115q0 63 -31 98t-86 35q-75 0 -137 -93l-22 20l57 81q55 59 135 59q69 0 118.5 -46.5t49.5 -122.5q0 -62 -29.5 -114t-102.5 -130l-141 -149h186q42 0 58.5 10.5t38.5 56.5z" /></g> </svg>&#x2009;W/m&#xb0;C. The reflector consists of a wooden-framed commercially available specular plane mirror which is sized to form a cover for the box when not being in use. Its thermal performance was tested according to the ASAE International Test procedure and Bureau of Indian Standards (BIS) for testing the thermal performance of box-type solar cooker. Thermal performance experiments were conducted in order to determine the first figure of merit (<i>F</i>₁), the second figure of merit (<i>F</i>₂) and standard cooking power (<i>P</i>_<i>s</i>). The obtained test results were employed to calculate the two figures of merit (<i >F</i>₁, and <i>F</i>₂) and the standard cooking power (<i>P</i>₅₀) to be 0.11&#x2009;Km<sup >2</sup>w<sup >&#x2212;1</sup>, 0.31, and 23.95&#x2009;W, respectively. Finally, the results illustrated that the cooker has a good reliability for cooking food and boiling water.

Regular consumption of a silicic acid-rich water prevents aluminium-induced alterations of nitrergic neurons in mouse brain: histochemical and immunohistochemical studies.

Silicon is not generally considered an essential nutrient for mammals and, to date, whether it has a biological role or beneficial effects in humans is not known. The results of a number of studies suggest that dietary silicon supplementation might have a protective effect both for limiting aluminium absorption across the gut and for the removal of systemic aluminium via the urine, hence, preventing potential accumulation of aluminium in the brain. Since our previous studies demonstrated that aluminium exposure reduces the number of nitrergic neurons, the aim of the present study was to compare the distribution and the morphology of NO-containing neurons in brain cortex of mice exposed to aluminium sulphate dissolved in silicic acid-rich or poor drinking water to assess the potential protective role of silicon against aluminium toxicity in the brain. NADPH-d histochemistry and nNOS immunohistochemistry showed that high concentrations of silicon in drinking water were able to minimize the impairment of the function of nitrergic neurons induced by aluminium administration. We found that silicon protected against aluminium-induced damage to the nitrergic system: in particular, we demonstrated that silicon maintains the number of nitrergic neurons and their expression of nitrergic enzymes at physiological levels, even after a 12 and 15 month exposure to aluminium.

Characterization of TiAlSiN/TiAlSiON/SiO2 optical stack designed by modelling calculations for solar selective applications

Preparation and characterization of TiAlSiN/TiAlSiON/SiO2 solar selective absorber is reported in this contribution. All layers were deposited in a continuous mode using an industrial equipment. The nitride and oxynitride were prepared by reactive magnetron sputtering and the SiO2 layer by Plasma Enhanced Chemical Vapour Deposition. The optical constants of individual layers were calculated by modelling of spectral transmittance and reflectance of the individual layers. The three layered stack absorber was then designed using those optical properties. The thickness of the individual layers was optimised until a solar absorptance of 96% was obtained resulting in a total thickness of about 200nm, deposited in copper and extruded aluminium absorbers. An emissivity of 5% for an absorber temperature of 100°C was obtained by analyzing the measured data from a FTIR spectrometer with integrating sphere. After the test duration of 600h, the samples subjected to a thermal annealing at 278°C in air showed a performance criterion (PC) below 4%, while the samples in the humidity tests showed a PC below 2%.

Electrochemical and Metal-Phase Processes Accompanying Hydrogen Absorption in Aluminum During Aqueous Corrosion

not Available.

SU-E-T-178: Optically Stimulated Luminescence (OSL) Dosimetry: A Study of A-Al2O3:C Assessed by PENELOPE Monte Carlo Simulation.

To use the Monte Carlo code PENELOPE to study attenuation and tissue equivalence properties of a-Al2O3:C for OSL dosimetry. Mass attenuation coefficients of α-Al2O3 and α-Al2O3:C with carbon percent weight concentrations from 1% to 150% were simulated with PENELOPE Monte Carlo code and compared to mass attenuation coefficients from soft tissue for photon beams ranging from 50kV to 10MV. Also, the attenuation of primary photon beams of 6MV and 10MV and the generation of secondary electrons by α-Al2O3 :C dosimeters positioned on the entrance surface of a water phantom were studied. A difference of up to 90% was found in the mass attenuation coefficient between the pure \agr;-A12O3 and the material with 150% weight concentration of dopant at 1.5 keV, corresponding to the K-edge photoelectric absorption of aluminum. However for energies above 80 keV the concentration of carbon does not affect the mass attenuation coefficient and the material presents tissue equivalence for the beams studied. The ratio between the mass attenuation coefficients for \agr-A12O3:C and for soft tissue are less than unit due to the higher density of the \agr-A12O3 (2.12 g/cms ) and its tissue equivalence diminishes to lower concentrations of carbon and for lower energies due to the relation of the radiation interaction effects with atomic number. The larger attenuation of the primary photon beams by the dosimeter was 16% at 250 keV and the maximum increase in secondary electrons fluence to the entrance surface of the phantom was found as 91% at 2MeV. The use of the OSL dosimeters in radiation therapy can be optimized by use of PENELOPE Monte Carlo simulation to provide a study of the attenuation and response characteristics of the material.

Experimental Investigation of Polymeric Foam and Grooves Effects on Crashworthiness Characteristics of Thin-Walled Conical Tubes

In this article, an experimental study is presented to investigate the crushing behavior and energy absorption of empty and polyurethane foam-filled thin-walled aluminum grooved conical tubes under axial compression. In this innovative design model, the plastic hinges occur at predetermined intervals along the tube, by creating the circumferential grooves from the outer and inner surface of conical. The energy absorption ability of empty and foam-filled grooved conical tubes due to plastic deformation in a crushing process is evaluated. The results show that the load–displacement curve and energy absorbed by the axial crushing of tubes can be controlled by filling them with appropriate lightweight materials and grooves number. Therefore, the results from this study will assist automotive industry to design crashworthy components based on the grooved conical tubes.

Efficient absorption of H2S by aluminum doped zinc oxide nanoparticles

In this study, hydrogen sulfide absorption of aluminum doped zinc oxide nanoparticles with different aluminum concentrations (ZnxAl1−xO) has been investigated. The gas absorption rate and the samples' structural evolutions have been also investigated by X-ray fluorescence and X-ray diffraction measurements. The morphologies and particles size distribution of samples have been determined by scanning electron microscope. The results showed that the Al doped samples have higher absorption rate in respect to the pure zinc oxide. The maximum absorption rate was obtained for the sample with x=0.01. The average size of nanoparticles in this sample was 44nm, which was also the lowest value among the other samples.

In vitro study of percutaneous absorption of aluminum from antiperspirants through human skin in the Franz™ diffusion cell

Aluminum salts such as aluminum chlorohydrate (ACH) are known for use as an active antiperspirant agent that blocks the secretion of sweat. A local case report of hyperaluminemia in a woman using an aluminum-containing antiperspirant for 4years raises the problem of transdermal absorption of aluminum (Al). Only a very limited number of studies have shown that the skin is an effective barrier to transdermal uptake of Al. In accordance with our analytical procedure, the aim of this study with an in vitro Franz™ diffusion cell was to measure aluminum uptake from three cosmetic formulations of antiperspirant: the base for an “aerosol” (38.5% of ACH), a “roll-on” emulsion (14.5% ACH), and a “stick” (21.2%), by samples of intact and stripped human skin (5 donors). The Al assays were performed by Zeeman Electrothermal Atomic Absorption Spectrophotometry (ZEAAS). Following contacts lasting 6, 12 and 24h, the Al assays showed only insignificant transdermal absorption of Al (≤0.07% of the quantity of Al deposited) and particularly low cutaneous quantities that varied according to the formulations (1.8μg/cm² for “aerosol base” and “stick” — 0.5μg/cm² for the “roll-on”). On stripped skin, for which only the “stick” formulation was tested, the measured uptake was significantly higher (11.50μg/cm² versus 1.81μg/cm² for normal skin). These results offer reassurance as regards to the use of antiperspirants for topical application of ACH-containing cosmetic formulations on healthy skin over a limited time span (24h). On the other hand, high transdermal Al uptake on stripped skin should compel antiperspirant manufacturers to proceed with the utmost caution.

The Effects of Glutamate and Citrate on Absorption and Distribution of Aluminum in Rats

The objective of this study was to evaluate the effect of glutamate (Glu) and citrate (Cit) on the absorption and distribution of aluminum in rats. In the in vitro experiment, 18 adult male Sprague-Dawley rats (average weight of 250 ± 15 g) were randomly divided into three groups. The entire intestine was rapidly removed and cultured in prediction samples of 20 mmol AlCl(3), 20 mmol AlCl(3)+20 mmol Cit, and 20 mmol AlCl(3)+20 mmol Glu, respectively. Liquid in different intestines and the intestines were obtained for Al determination. In the in vivo chronic study, 24 adult male Sprague-Dawley rats (average weight of 127 ± 10 g) were divided into four groups fed with the following diets: no Al and Glu added (control), AlCl(3) (1.2 mmol), AlCl(3) (1.2 mmol) + Cit (1.2 mmol), and AlCl(3) (1.2 mmol) + Glu (1.2 mmol) daily for 50 days, respectively. After rat sacrifice, blood samples were obtained for biochemical analyses, and organ samples like the brain, kidney, liver, and bone were rapidly taken for Al determination. The results showed that the absorption rate of Al with the following order: duodenum > jejunum > ileum in the in vitro study and the administration of AlCl(3)+Cit or AlCl(3)+Glu resulted in significant increases in Al absorption in the three parts of the gut (duodenum, jejunum, and ileum) compared to the AlCl(3) alone group based on wet weight (P < 0.05). There were no differences between the AlCl(3)+Cit and AlCl(3)+Glu groups. In the in vivo chronic study, supplementing either AlCl(3) alone or AlCl(3)+Glu decreased food consumption significantly (P < 0.05) compared with the control group. Compared with the control group, animals fed with the AlCl(3) diet monitored for red blood cell, kidney, and liver showed a higher level (P < 0.05), but did not significantly increase Al retention in the brain and bone (P > 0.05); animals fed with AlCl(3)+Cit diets were monitored for higher Al retention in the brain, kidney, bone, and liver (P < 0.05), while animals fed with AlCl(3)+Glu diets were monitored for red blood cell, brain, and kidney (P < 0.05). Compared with the AlCl(3) group, simultaneous administration of AlCl(3) and Glu led to a significant increase in Al retention in red blood cell, brain, and kidney (P < 0.01) while AlCl(3) and Cit in the kidney and bone (P < 0.01). Simultaneous administration of AlCl(3) and Cit significantly increases plasma malondialdehyde level (P < 0.05); both simultaneous administration of AlCl(3) and Glu or AlCl(3) and Cit led to significant decreases in superoxide dismutase level in the plasma (P < 0.05), while AlCl3 alone did not. The results indicated that both Cit and Glu enhanced Al absorption in the intestine in vitro, and Glu increased Al deposition in red blood cell, brain, and kidney in vivo.