Effect of rock properties on the Los Angeles abrasion and impact test characteristics of the aggregates

Aggregate is the most fundamental and widely used component of construction. It is used as an unbound material which constitutes about 100% of the volume of base courses, 95 to 93% of the volume of asphalt and about 85 to 75% of the volume of Portland cement concrete. Aggregate is exposed to a number of physical and chemically degrading forces during processing, transporting, and construction. As the main load carrying component of unbound and bituminous and Portland cement concretes, the aggregate must be clean, hard, sound, durable, resistant to abrasion, uniform in quality and free of any detrimental quantities of soft, friable, thin, elongated or laminated pieces, disintegrated material, alkali or other deleterious substance. For assesing the abrasion resistance of aggregates, the most common method is the Los Angeles abrasion and impact test (LAAI) which determines the relative competence or resistance to abrasion of the aggregates.In this study, four limestones, four travertines, three crystalline marbles and one andesite were tested to evaluate the correlations between the LAAI values and the physical properties covering bulk density, Schmidt hardness, shore hardness, P-wave velocity and mechanical properties such as uniaxial compressive strength, point load index, and indirect tensile strength of rocks. Since these properties are of great importance as a source of aggregates, tests on the rock can give an indication of the strength of the aggregates.The above rock properties were determined through standard testing methods in order to investigate the correlation between LAAI and each rock property by using regression analysis. A simple equation predicting the LAAI value based on each rock property was suggested. From the statistical tests, rock properties were found to be significant in estimating the LAAI values of rocks.     

Ion imprinted beads embedded cryogels for in vitro removal of iron from β-thalassemic human plasma

Molecular recognition based Fe³⁺ imprinted poly(GMA-MAC) (MIP) beads embedded PHEMA composite cryogel was prepared for selective removal of Fe³⁺ ions from β-thalassemia patient plasma. The precomplexation was achieved by the coordination of Fe³⁺ ions with N-methacryloyl-(L )-cysteine methyl ester (MAC-Fe³⁺). MIP beads were prepared by dispersion polymerization in the presence of MAC-Fe³⁺ complex and glycidyl methacrylate (GMA) monomer. Then the MIP beads were embedded into poly(hydroxyethyl methacrylate) (PHEMA) cryogel. The specific surface area and the swelling degree of the PHEMA-MIP composite cryogel were found to be 76.8 m²/g and 7.7 g H₂O/g cryogel, respectively. The maximum adsorption amount of Fe³⁺ ions was 2.23 mg/g. The relative selectivity of PHEMA-MIP composite cryogel towards the Fe³⁺ ions was 135.0, 61.4, and 57.0 times greater than that of the PHEMA-NIP cryogel as compared with the Ni²⁺, Zn²⁺, and Fe²⁺ ions, respectively. PHEMA-MIP composite cryogel was recovered and reused many times without any significant decrease in its adsorption capacity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Design and analysis of a polymeric photo-thermal microactuator

This paper presents the modeling, simulation and characterization of a photo-thermally actuated bent-beam microactuator. The microactuator consists of a single polymeric layer (SU-8) fabricated with conventional photolithography techniques. The principle of operation is based on the thermal expansion of the bent-beams that absorb the required heat by laser illumination. This provides an effective non-contact actuation mechanism by laser beam focusing. A theoretical model of the microactuator is derived and verified by finite element simulations and experiments. The experiments show that a bent-beam actuator with 800 m long, 40 m wide, 100 m thick and 6° bent arms achieves a tip displacement of 16 m with an incident laser beam of 50 mW power while keeping the maximum temperature less than 125 °C. This study merges the advantages of photo-thermal actuation with practicality of polymeric materials. To verify the effectiveness of the proposed microactuator mechanism, a microgripper with bent-beam actuator was fabricated and characterized. It has been demonstrated that the opening of the gripping fingers can be increased from 20 to 50 m for a microgripper with 1000 m long fingers with an incident laser power of 50 mW. This polymeric microgripper with photo-thermal actuation provides a way of gentle grasping with electrical isolation, high repeatability and low temperature operation that is particularly crucial for biomanipulation applications. The polymeric photo-thermal actuator described in this study expands the practical applications of microactuators/microgrippers which are critical tools in bioMEMS devices.     

A dynamic neural network model for accelerating preliminary parameterization of 3D triangular mesh surfaces

Neural Computing and Applications - This study proposes an effective and fast preliminary mapping algorithm for 3D triangular mesh surfaces. The proposed method exploits barycentric mapping theory...     

The effects of inulin as a prebiotic supplement and the synbiotic interactions of probiotics to improve oxalate degrading activity

This paper examines the impact of inulin, Lactobacillus spp. (candidate probiotics), and synbiotic (inulin + Lactobacillus spp.) preparation on oxalate degrading activity and viability of Escherichia coli. In this study, the lowest viability of E. coli was recorded for the synbiotic treatments of Lactobacillus fermentum BP5 (59%) and IP5 (60%). The oxalate degrading activity of L. fermentum IP5 was 38.18 and 29.60% higher than the other strains after growth in 10 mM and 20 mM MRS-ox plus 5% inulin media, respectively. The mixture of three strains demonstrated higher oxalate degrading capacity than the individual strains and showed the same good growth rates (9.43 CFU mL⁻¹) as individuals. The study concludes that the addition of prebiotics has a significant effect on probiotics; therefore, a combination of L. fermentum IP5 with inulin could be a viable probiotic-based functional food approach in administering oxalate metabolism and also treatment of E. coli-related infections.     

Signal level performance variation of radio frequency identification tags used in cow body

Ruminant diseases are strictly connected to pH and temperature values of the rumen. Therefore, the attenuation to dynamic measurement and tracking of both pH and temperature values through animal rumen has grown rapidly for decades. Reading performance of RFID tags depends on signal quality and signal level, and this can be understood by means of wave attenuation through tissue. In this article, attenuation through cow body is investigated for improving reading performance and battery life. Number of receiving antennas will be used in the system, their location and heights are critical for this aim. Signals from different points of animals' body are measured and compared with the signals spread just out of RFID tags. Equivalent dielectric constants of tissue between RFID tag and receiving antenna is modeled by using literature data, and finally simulation and analytical results are verified by measurement results. Measured value of attenuation through the cow body is varying between 25 dB and 87 dB for RFID tags operating at 434 MHz. Within the 30 m radius, the strongest signal is obtained at 50 cm height and taken from the left side of the animal body, which is offered as optimum communication position.     

Characterization of Turkish Olive Oils by Triacylglycerol Structures and Sterol Profiles

A characterization study of Turkish monovarietal olive oils using chemical variables such as fatty acid, sn‐2 fatty acid, triacylglycerol, and sterol composition is presented. A total of 101 samples of Olea europaea L. fruits from 18 cultivars were collected for two crop years from west, south, and southeast regions of Turkey. Olives were processed to oil and olive oil samples were evaluated for their triacylglycerol structures and sterol composition. Oleic acid content ranged from 60.15 to 80.46 % of total fatty acids and represented 70.90–89.02 % of sn‐2 position triacylglycerols. Major triglycerides of oil samples were triolein, palmitodiolein, dioleolinolein, palmitooleolinolein, dipalmitoolein, and stearodiolein. Triolein values were between 24.72 and 48.64 % and compatible with the fatty acid composition. Total sterol content varied from 1,145.32 to 2,211.77 mg/kg and Edremit yagl?k stood out because of its high sterol content. A one‐way analysis of variance revealed significant differences for variables among cultivars. Principle component analysis enabled the classification of common varieties on the basis of analytical data. Sterol composition achieved more relevant discrimination than fatty acid and triglyceride composition. Classification according to geographical origin was performed by discriminant analysis.     

Influence of preparation conditions on porous structures of olive stone activated by H3PO4

An olive factory residue was used as a precursor in the preparation of granular activated carbon by chemical activation with H₃PO₄. Effects of final activation temperature, time, and H₃PO₄ concentration used in the impregnation stage on the porous development were investigated. SO₂ adsorption experiments were also performed for some of the activated carbon samples to represent their adsorption performance. Activation at low temperature represented that micropores were developed first at early stages of the temperatures. Mesoporosity developed at around 250 °C, enhanced up to 400 °C, and then started to decrease due to possibly shrinking of pores. The optimum temperature for olive stone was found to be around 400 °C on the basis of total pore volume and BET surface area. It was clearly demonstrated that H₃PO₄ concentration used in the impregnation stage was not only effective for development of surface area and pore volumes but also an effective tool for tailoring the pore structure and size distribution.     

Poly(vinylbenzylchloride) beads grafted with polymer brushes carrying hydrazine ligand for reversible enzyme immobilization

Poly(glycidylmethacrylate), p(GMA), brush grafted poly(vinylbenzyl chloride/ethyleneglycol dimethacrylate), p(VBC/EGDMA), beads were prepared by suspension polymerization and the beads were grafted with poly(glycidyl methacrylate), p(GMA), via surface‐initiated atom transfer radical polymerization aiming to construct a material surface with fibrous polymer. The epoxy groups of the fibrous polymer were reacted with hydrazine (HDZ) to create affinity binding site on the support for adsorption of protein. The influence of pH, and initial invertase concentration on the immobilization capacity of the p(VBC/EGDMA‐g‐GMA)‐HDZ beads has been investigated. Maximum invertase immobilization onto hydrazine functionalized beads was found to be 86.7 mg/g at pH 4.0. The experimental equilibrium data obtained invertase adsorption onto p(VBC/EGDMA‐g‐GMA)‐HDZ affinity beads fitted well to the Langmuir isotherm model. It was shown that the relative activity of immobilized invertase was higher than that of the free enzyme over broader pH and temperature ranges. The K_m and V_max values of the immobilized invertase were larger than those of the free enzyme. After inactivation of enzyme, p(VBC/EGDMA‐g‐GMA)‐HDZ beads can be easily regenerated and reloaded with the enzyme for repeated use. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009