Flexural Strength and Porosity of NaOH-Treated Maize Stalk Cellulose-Fibers-Reinforced Geopolymer Composites

This study characterizes the flexural strength and porosity of NaOH-treated maize stalk cellulose-fibers-reinforced geopolymer composites. Flexural strength tests are conducted, and the fracture surfaces of the composite and geopolymer powder are observed using a scanning electron microscope (SEM). Moreover, porosity analysis is also performed using Image J software from SEM images. The formation of geopolymer is confirmed using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The addition of 1.5 wt% of NaOH-treated maize stalk cellulose fibers improves flexural strength by 2.4 times. The results show that the main failure mechanisms, namely fiber breakage, fiber pullout, and debonding of the fiber and matrix, can increase flexural strength and reduce failures during service life. During the analysis for fiber and particle pullout, SEM images under 25^2 pixels of pore areas are not considered, and an average porosity of 36.7% is achieved

A Novel Carbon Nanofibers Grown on Glass Microballoons Immunosensor: A Tool for Early Diagnosis of Malaria

This paper presents a novel method for direct detection of Plasmodium falciparum histidine rich protein-2 (PfHRP-2) antigen using carbon nanofiber (CNF) forests grown on glass microballoons (NMBs). Secondary antibodies specific to PfHRP-2 densely attached to the CNFs exhibit extraordinary ability for the detection of minute concentrations of Plasmodium species. A sandwich immunoassay protocol was employed, where a glass substrate was used to immobilize primary antibodies at designated capture zones. High signal amplification was obtained in both colorimetric and electrical measurements due to the CNFs through specific binding. As a result, it was possible to detect PfHRP-2 levels as low as 0.025 ng/mL concentration in phosphate buffered saline (PBS) using a visual signal within only 1 min of test duration. Lower limits of 0.01 ng/mL was obtained by measuring the electrical resistivity of the capture zone. This method is also highly selective and specific in identifying PfHRP-2 and other Plasmodium species from the same solution. In addition, the stability of the labeling mechanism eliminates the false signals generated by the use of dyes in current malaria rapid diagnostic test kits (MRDTs). Thus, the rapid, sensitive and high signal amplification capabilities of NMBs is a promising tool for early diagnosis of malaria and other infectious diseases

ETCE 2002/OT-29152 ENHANCEMENT OF COMPOSITE SUCKER RODS FOR USE IN THE OIL INDUSTRY

ABSTRACT Analysis of polymer-matrix composite sucker rod systems using finite element methods is performed. Composite sucker rods fail mainly due to fatigue loading. In majority of cases, the failure is in the region of the joint where the composite rod and the steel endfitting meet. 2D and 3D Finite Element Analysis and experimental tests are carried out in order to observe the stress distribution and to find the regions of stress concentrations inside the endfitting. The causes of fatigue failure of the composite sucker rods are identified. These are overloading of the rod causing high transverse compressive stress that results crushing of the rod, and high stress concentrations present at the grooves of the endfitting that initiate premature fatigue cracks. Based on the result of this study, enhanced design of the composite sucker rod system can be accomplished. INTRODUCTION Composite sucker rods are usually made of polymer matrix composite manufactured by pultrusion process. Polymer matrix composites offer excellent mechanical properties over other types of composites and are finding many applications in marine and oil industries. Inherent advantages of polymer matrix composite include lightweight and low cost. The main advantage of using composite sucker rods over steel rods is less weight, and thus eliminating the purchasing of large expensive pumping units. In addition, corrosion resistance is considered an important advantage. Composite sucker rod systems have steel rods at the lower portion of the rod strings to act as weighing mechanism for the whole system. Corrosion fatigue is of less concern in steel portion of the fiberglass sucker rod strings because the most highly stressed rods (in the upper portion of the rod strings) are nonmetallic. Concerning corrosion of the steel endfittings, the cross section of steel endfittings is larger than the rod bodies, so minor pitting on the endfittings or couplings does not lead to fatigue failure rapidl

Porous Maize Stalk Cellulose Fiber-Reinforced Geopolymer Composites for Heat Insulation at the Bottom Side of a Local Electric Stove

The objective of this work is to develop porous maize stalk cellulose fiber-reinforced geopolymer composites for heat insulation on the bottom side of an electric stove using the solid impregnation method. Heat loss measurement is conducted using an infrared thermometer. Moreover, the temperature effect on the composites is investigated. The maize stalk cellulose fibers are very essential to anticipate the cracking phenomenon generated by high temperatures. The degradation of the fibers causes the formation of small cavities in the matrix, and thus leads to high temperatures. The experimental result shows that it takes 22 minutes to boil water using the proposed electric stove, whereas it takes 29 minutes using the existing local electric stove. By using the proposed electric stove to boil water, 113,793,148.104 KWh of energy per year at the national level can be saved

Application of Bucky Gel in Fabrication of a Low-Voltage Rapid Microvalve for Flow Regulation

Bucky gel is a gelatinous mixture of carbon nanotubes and an ionic liquid. This mixture was employed in fabrication of a low-voltage, rapid, and dry electroactive bimorph actuator: Bucky Gel Actuator (BGA). Feasibility studies were carried out on BGA to evaluate its potential application as a new interface for flow regulation in microfluidics. Following the promising results, a flow regulator was designed and fabricated utilizing BGA as a microvalve. Flow rate measurements showed the capability of BGA microvalve in controlling the output flow rate in the range of 0.1–1 mL/min. BGA microvalve demonstrated great potential to be used for flow regulation in microfluidic devices for point-of-care devices and biomedical applications