Review on vinyl acetic acid-based polymer microgels for biomedical and other applications

Vinyl acetic acid comonomers-based microgels exhibit exceptional behavior and morphological properties as compared to other comonomer polymerized microgels. High hydrophobic character of vinyl acetic acid induces core-shell type structure in poly(N-isopropylacrylamide-vinyl acetic acid) microgels. This review article describes the preparation methodologies and various properties of poly(N-isopropylacrylamide-vinyl acetic acid)-based microgels. Applications of poly(N-isopropylacrylamide-vinyl acetic acid) microgels in the field of nanotechnology, drug loading and delivery vehicle, morphology-tuned applications, optical etalon formation and catalysts have been discussed in detail. Future aspects of these specific types of polymer microgels have also been elaborated in detail.     

Stabilization of Expansive Soil Using Tire Rubber Powder and Cement Kiln Dust

Soil Mechanics and Foundation Engineering - There are different techniques to stabilize and improve the properties of soils with low shear strength, bearing capacity and other swelling parameters....     

Magnetic phase transition and magneto-dielectric analysis of spinel chromites: MCr2O4 (M = Fe,Co and Ni)

In this work, we present magnetic phase transition temperatures and magneto-dielectric coupling in MCr₂O₄ (M = Fe, Co and Ni) ceramics, synthesized using sol–gel auto-combustion route. In order to develop their respective crystalline textures, all these chromites were calcined at 650?°C for 2?h. X-ray diffraction patterns confirmed that FeCr₂O₄ had a rhombohedral structure while NiCr₂O₄ and CoCr₂O₄ exhibited a spinel-type cubic structure. The presence of relevant elements in the specific stoichiometric ratios was confirmed using energy dispersive X-ray spectroscopy. The shapes and sizes of the grains for all the samples were determined using the images obtained from a field emission scanning electron microscope. Temperature dependent magnetic analysis have shown that FeCr₂O₄, CoCr₂O₄ and NiCr₂O₄ are ferromagnetic at 5?K and their magnetic phase transition temperatures were measured as 80, 83 and 90?K, respectively. Spin-orbit interference was also studied through magneto-dielectric coupling for these chromites using a modified impedance analyzer set-up.     

Acetone sensing and modeling through functionalized Ag-catalysts and CNTs via low cost metal-organic framework-derived ZnO nanostructures

Cost-effective synthesis, portability, quick response and fascinating features of semiconducting metal oxide sensors have drawn much accredited to be utilized in wide variety of potential sensing applications. Herein, flexible acetone sensor was fabricated through spray coating method using different conductive inks of carbon nanotubes (CNTs), zinc oxide (ZnO) and silver (Ag) nanoparticles solutions on cellulose paper. Morphological analysis revealed the fiber like morphology of cellulose over which CNTs, ZnO and Ag nanoparticles are uniformly distributed. The energy dispersive X-ray spectroscopic analysis was performed to observe the elemental composition in the as-prepared samples. The recovery time toward acetone was greater for CNTs/Ag acetone sensor at 95% as compared to CNTs/ZnO/Ag sensor. Additionally, sensing time of the samples towards acetone was measured and the observed response time was greater for CNTs/ZnO/Ag (0.52 s) acetone sensor as compared to CNTs/Ag sensor (0.41 s). Hence, CNTs/ZnO/Ag can be easily employed for sensing applications due to quick response.     

Deactivation in Continuous Deoxygenation of C18-Fatty Feedstock over Pd/Sibunit

Catalytic continuous deoxygenation of stearic acid, ethyl stearate and tristearin without any solvents was investigated using Pd/Sibunit as a catalyst in a trickle bed reactor at 300 °C. The main emphasis was to investigate the effect of gas atmosphere and catalyst deactivation. In addition to liquid-phase analysis made offline by GC, also online gas-phase analysis with IR were performed. The main liquid-phase product coming from all reactants was n-heptadecane. In addition to deoxygenation, which was observed for all substrates, also C₁₈ and C₁₆ alkanes were formed from tristearin. The relative ratios between stearic acid, ethyl stearate and tristearin conversions to alkanes after 3 days time-on-stream were 2.8/2.3/1.0, respectively using 5 % H₂/Ar as a gas atmosphere, whereas rapid catalyst deactivation occurred with all substrates under H₂-lacking atmosphere. The spent catalyst’s specific surface area profile along the downward reactor was maximum in the middle of the catalyst beds with the highest pore shrinking in the beginning and at the end of the reactor catalyst segments in the case of stearic acid and tristearin deoxygenation whereas that decreased consecutively as ethyl stearate passed through the reactor.     

Obesity and eating habits among college students in Saudi Arabia: a cross sectional study

Background  

During the last few decades, the Kingdom of Saudi Arabia (KSA) experienced rapid socio-cultural changes caused by the accelerating economy in the Arabian Gulf region. That was associated with major changes in the food choices and eating habits which, progressively, became more and more "Westernized". Such "a nutritional transition" has been claimed for the rising rates of overweight and obesity which were recently observed among Saudi population. Therefore, the objectives of the current work were to 1) determine the prevalence of overweight and obesity in a sample of male college students in KSA and 2) determine the relationship between the students' body weight status and composition and their eating habits.     

An efficient Sm and Ge co-doped ceria nanocomposite electrolyte for low temperature solid oxide fuel cells

In this study we present a new nanocomposite electrolyte based on samarium (Sm) and germanium (Ge) co-doped ceria Ce_0.7Sm_0.15Ge_0.15O_2-δ (SGeDC). The nanocomposite electrolyte was prepared using co-precipitation method. The crystal structure and surface morphology were determined using x-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Four probe dc conductivity indicated the value of 0.074 S/cm at 650 °C. The Fuel cell performance was carried out using hydrogen as fuel. The maximum OCV observed was 0.95 V while the peak power density came out to be 600 mW/cm² at 600 °C. It is suggested that adding Ge, the conductivity as well as performance of this new nanocomposite electrolyte is comparatively enhanced and it can find potential applications in low temperature solid oxide Fuel cells (LTSOFCs).     

Robust regression for face recognition

In this paper we address the problem of robust face recognition by formulating the pattern recognition task as a problem of robust estimation. Using a fundamental concept that in general, patterns from a single object class lie on a linear subspace (Barsi and Jacobs, 2003 [1]), we develop a linear model representing a probe image as a linear combination of class specific galleries. In the presence of noise, the well-conditioned inverse problem is solved using the robust Huber estimation and the decision is ruled in favor of the class with the minimum reconstruction error. The proposed Robust Linear Regression Classification (RLRC) algorithm is extensively evaluated for two important cases of robustness i.e. illumination variations and random pixel corruption. Illumination invariant face recognition is demonstrated on three standard databases under exemplary evaluation protocols reported in the literature. Comprehensive comparative analysis with the state-of-art illumination tolerant approaches indicates a comparable performance index for the proposed RLRC algorithm. The efficiency of the proposed approach in the presence of severe random noise is validated under several exemplary noise models such as dead-pixel problem, salt and pepper noise, speckle noise and Additive White Gaussian Noise (AWGN). The RLRC algorithm is found to be favorable compared with the benchmark generative approaches.