Preparation of high surface area activated carbon from waste-biomass of sunflower piths: Kinetics and equilibrium studies on the dye removal

Sunflower pith (SP), a vast agricultural waste is herein used as a precursor material for highly porous low density activated carbon production. Porosity and flake-like microstructure of the SP in its natural form are shown by micro-computed tomography (Micro-CT). Carbonization process turns the SP into thin, separated carbon flakes of 200 nm thickness. Two types of alkaline based chemical activation with KOH and NaOH are performed to yield SP based activated carbon (AC), K-SPAC and N-SPAC, respectively. Microstructural changes upon carbonization and activation process are elaborated by RAMAN, FTIR and SEM analyses. BET Surface area of the NaOH-activated N-SPAC was calculated as 2690 m2/g and was higher than KOH-activated K-SPAC with 2090 m2/g. Maximum adsorption capacity of N-SPAC was calculated as 965 mg/g whereas it was 580 mg/g for K-SPAC. Adsorption kinetic studies for N-SPAC revealed that at a low initial concentration of dye (500 mg/L), the pseudo first-order kinetic model was predictive. On the other hand, at high initial MB concentration (1000 mg/L), the results indicate that the adsorption kinetics follow the Elovich model with intraparticle diffusion as one of the rate-determining steps. In conclusion, overall results suggest that thanks to its highly porous microstructure, the SP is an alternative renewable AC precursor choice for dye removal applications

A micro-accelerometer MDO benchmark problem

Many optimization and coordination methods for multidisciplinary design optimization (MDO) have been proposed in the last three decades. Suitable MDO benchmark problems for testing and comparing these methods are few however. This article presents a new MDO benchmark problem based on the design optimization of an ADXL150 type lateral capacitive micro-accelerometer. The behavioral models describe structural and dynamic effects, as well as electrostatic and amplification circuit contributions. Models for important performance indicators such as sensitivity, range, noise, and footprint area are presented. Geometric and functional constraints are included in these models to enforce proper functioning of the device. The developed models are analytical, and therefore highly suitable for benchmark and educational purposes. Four different problem decompositions are suggested for four design cases, each of which can be used for testing MDO coordination algorithms. As a reference, results for an all-in-one implementation, and a number of augmented Lagrangian coordination algorithms are given. © 2009 The Author(s)

Post-buckling of composite I-sections. Part 1: Theory

A theoretical investigation of initial local buckling and post-buckling behavior of composite I-sections is presented. The equilibrium equation for initial buckling is solved both exactly and with an approximate method, namely, Galerkin's method. In Galerkin's method, the out-of-plane deflection of each plate element is approximated by a weighted sum of polynomial functions. The post-buckling response is studied as an extension of the approximate analysis with Galerkin's method where now both equilibrium and compatibility equations must be solved. The bending deflection in the post-buckling regime is assumed to be a magnification of the deflection function used in initial buckling analysis. No mode-shape change is thus allowed in the post-buckling region. A polynomial type of function is also adopted for stress distribution in order to take into account the deviation from uniform in-plane load distribution in the plate elements following the onset of local buckling. The paper provides an efficient and accurate method for predicting the post-buckling behavior of composite structural sections composed of plate elements. Galerkin's method was previously applied to isotropic flat plates only. The present approach is tested against a commercial code, STAGS, with a very good agreement in results and a very large saving in computer time for post-buckling analysis of an I-section

Catalytic synthesis of boron nitride nanotubes at low temperatures

KFeO2 is demonstrated for efficiency catalysing the formation of BN nanotubes (BNNT) by thermal chemical vapor deposition (TCVD). This alkali-based catalyst enables the formation of crystalline and high aspect ratio, multi-walled BNNTs at temperatures as low as 750°C, significantly lower than those typical of production by TCVD

Serum Thymidine Kinase 1 Activity in Solid Tumor (Breast and Colorectal Cancer) Patients Treated With Adjuvant Chemotherapy

BackgroundThe aim of this study was to evaluate the changing of TK1 (where TK is thymidine kinase) activity before and after adjuvant chemotherapy in patients with breast and colorectal cancer. MethodsThe study included 16 breast cancer, 25 colorectal cancer, and 38 healthy volunteers as the control group. Blood samples were taken twice from each patient; first at the beginning of the chemotherapy and second after six cycles of chemotherapy. TK1 activity was measured enzyme immunoassay method. ResultsThe mean TK1 activity in the breast and colorectal cancer was significantly higher than the controls. TK1 activity in the colorectal cancer was higher than the breast cancer but this difference was not significant. TK1 activity after six doses of chemotherapy was lower than baseline TK1 activity before the start of chemotherapy in breast and colorectal cancer. TK1 activity was positively correlated with CA15-3, before and after chemotherapy in patients with breast cancer. TK1 activity in the colorectal cancer was also positively correlated with CA19-9, before and after chemotherapy. The values for the cutoff point, sensitivity, specificity, and the area under curve were determined for TK1 as >44.36 Du/L, 68.29%, 100% and 0.819, respectively in all subjects. ConclusionOur results showed that serum TK1 activity in patients with breast and colorectal cancer was significantly higher than that of the healthy controls. Moreover, after the completion of chemotherapy the values were lower than baseline. Pretreatment TK1 activity should be considered as a useful marker for assessment tumor cell proliferation in breast and colorectal cancer. Further work is needed to understand TK1 activity better in large populations of patients with solid tumor. (C) 2013 Wiley Periodicals, Inc.WOS:0003298115000092-s2.0-84878022307PubMed: 2368677

Experimental Investigation of Strength of Curved Beam by Thin Ply Non-Crimp Fabric Laminates

Resistance against delamination failure and through the thickness tensile properties of curved carbon fiber reinforced plastics composites are investigated experimentally by conducting the curved beam strength tests. Effect of novel material thin ply non crimp fabric (NCF) architecture on delamination resistance of carbon fiber reinforced composites are investigated and compare with that of standard UD layups. In order to determine through the thickness tensile properties of curved carbon fiber composites, standard test method is carried out, namely four-point bending tests. The dynamic delamination propagation and failure sequences under curved beam bending is captured using Photron© Fastcam SA5 ultra high speed system. For the non-crimp fabric configuration an increase in the curved beam strength is observed in comparison with [0] and [0/45/-45/0] laminates by unidirectional (UD) tape material. For the UD tape, the initial defects caused by the out-of-autoclave manufacturing process is found to be the potential failure sites. The test results and observations suggest that thin-ply NCF is much less vulnerable to the existence of manufacturing voids in contrast to standard thickness UD tape. Finally, TPNCF is shown to have superior properties in regard to delamination resistance and curved-beam strength

Post-buckling of composite I-sections. Part 2: Experimental validation

An experimental investigation was conducted in order to verify the theoretical model described in Part 1 as well as to obtain experimental insight and to generate a database for the post-buckling behavior of composite I-sections. The experiments were performed using a combination of the shadow moire technique, strain gages, LVDTs (linear variable differential transformer), and dial gages. A total of twenty carbon-fiber/epoxy I-section columns were manufactured and tested with seven specimens from woven fabric and thirteen from unidirectional (UD) tape. The initial buckling load, lateral deflection of the web and flange as well as the crippling load were measured. The experimental results were compared with those of the theoretical model described in Part 1. A good agreement was observed

Use of free composite graft for a large defect in the anterior skull base

Until recently, most skull base turners, particularly those extending into the orbit or anterior or middle cranial fossa base, were excised incompletely because of the technical difficulty in performing en bloc resections. However, improved craniofacial surgical techniques, recent developments in technology and equipment improved imaging techniques, interdisciplinary collaboration, and improved anesthetic techniques have enabled a wide range of attempts resulting in successful clinical outcome, We present a case of recurrent meningioma with intracranial and extracranial extension in which three previous operations left a large craniectomy defect in the frontal area as well as a frontal lobe defect. After removal of the tumor, we reconstructed the large defect using composite graft (free bone and fascia lata)