PECVD coatings for functionalization of point-of-care biosensor surfaces

In early stage disease diagnosis, an accurate and reliable measurement of low concentrations of specific biomarkers is a key need. The detection technique requires the reaction of an antibody, which is generally covalently bound to the biosensor platform, with its antigen. The application of Zeonor^®, a cyclo olefin copolymer (COP) with very low autofluorescence, good optical properties and high precision molding characteristics, as a biosensor platform has been demonstrated recently. Highly reproducible, industrial scale surface chemical modification of the COP plastic for covalent attachment of the biomolecules for specific recognition of the target, together with low non-specific binding of other proteins that may be present in the sample is a key challenge. In this work, the applicability of plasma enhanced chemical vapor deposition (PECVD) process has been demonstrated by depositing varying surface functionalities including amines, carboxylic, mercapto, epoxy and polyethylene glycol functionalities. The plasma functionalized coatings thus created possess both reactive and repellent sites on the biosensor chip, allowing the chip to be configured either for fluorescence or light scattering-based detection or for label-free surface plasmon resonance detection techniques. The versatility of the gas phase deposition process for building sequential chemistries on low cost and disposable plastic chips is presented in detail.     

A two-phase procedure for the study of computer network reliability in automated manufacturing systems

This paper presents a mathematical model for analyzing computer networks in production systems. The manufacturing facility, which is considered to be the main part of a production system is controlled by a computer network. Every station within a production system is assumed to have a computer and a network interface unit (NIU) as part of the overall computer network. For the system to remain operational, the computer network along with the manufacturing facilities should be extremely reliable. In this paper, we studied the reliability of the former, the computer network. The manufacturing facility is assumed to be reliable. Since every station must be operational for the whole system to function, failure in any network unit (computer of NIU) will halt the system production. For such systems the topology is logically equivalent to that of a system whose stations are connected in series. Hence, series reliability formulae is appropriate for these systems. In other systems, back-up (or stand-by) units are added to the computer and/or to the NIU to enhance the reliability. We consider our model to be a generic one because the reliability analysis it uses is independent of the network topology. It assumes constant failure rates for network components and uses a two-pass procedure in determining the effect of network reliability on the total system cost. A case study is presented to illustrate the importance of reliability considerations during the network design phase. Our analysis of the network reliability reveals that, in most cases, the incremental cost due to network failures will justify the additional units.     

An Investigation into the UV-Photo-Oxidative Degradation of LDPE by Using Cobalt Naphthenate as Photosensitizer

The effect of cobalt naphthenate on photo degradation of low density polyethylene was studied. The carbonyl index, tensile strength, elongation at break, density and relative crystallinity of the samples were measured. The samples were made of different concentrations of LDPE and cobalt naphthenate. Parts of uniform thickness were cut for testing before and after UV-irradiation at every 30-days interval for 90 days. From the results of FTIR, and other measurements, it was observed that the UV-irradiation affects on the LDPE films and the rate of degradation increased with increasing both the concentration of the photosensitizer and time of irradiation.     

Version and Configuration Model for Structural Design Objects: Design and Implementation

This paper presents the design and implementation of a version and configuration model (VCM) for structural design objects. The VCM is developed to capture the incremental, evolutionary, multipath and iterative nature of the structural design process. Specifically, this model: (1) defines representational frameworks for representing the versions and configurations of design objects; (2) suggests sets of manipulation operations for creating and tracking the versions and configurations of design objects across the different representational frameworks; and (3) presents a prototype implementation scheme of a version manager, that is based on the representational frameworks and the manipulation operations of the proposed VCM. A case study of reinforced concrete T-beam is presented together with its prototype implementation using Object Pascal as a proof of concept. This is to describe the elements of the model, validate its effectiveness and demonstrate its viability. It is concluded that the VCM and its implementation is a valuable and necessary ingredient for developing a truly integrated structural engineering design system.     

Sorption,Desorption, Remediation and Fertility Characteristics of a Clay Soil

This study is conducted to investigate sorption and desorption characteristics of a clay soil of Medicine Hat, Alberta, Canada. Also, the soil fertility after the desorption tests was investigated. Sorption of copper by a clay soil was examined using copper solutions with concentrations from 1,000 mg/L to 5 mg/L. The influence of copper concentration and pH on desorption was also studied. Electrokinetic remediation was carried on soil specimen spiked with copper. Soil fertility parameters for specimens acidized by electrolysis reactions and nitric, hydrochloric, and citric acids were compared. From the results, the adsorption of copper by the soil is proportional to the concentration in the solution and Langmuir isotherm represents the data. Desorption of copper was found to increase with the increase of initial copper in the soil and the decrease ofpH. At pH of 5.75 -4- 0.25, the maximum desorption was 16.5% of initial copper and the minimum was 4.2%. In tests with similar copper concentrations, the maximum desorption was 76.6% in the test with pH of 2. Electrokinetics reduced the pH of soil near the anode to 2.1 and removed 86% of copper. Soil specimen acidized by electrolysis reactions preserved favourable fertility parameters compared with specimens acidized by acids.     

Preliminary Results of Cone Z-Pinch Device with 5 kJ

The Cone Z-Pinch Experiment with 5 kJ is designed, constructed and operated. The electric discharge takes place between an upper ring electrode and a lower pin electrode creating plasma sheath in shape of cone. The preliminary experimental results using Helium gas in discharge show that the discharge period is 35 μs, the total system inductance is 287 nH, and the total system resistance is 15 mΩ. The breakdown curve shows a minimum breakdown value at 0.2 torr pressure. The cone plasma is confined by electromagnetic force and plasma inductance has its maximum value at the pinch. The plasma current has a maximum value of 53 kA at the axis of the discharge tube. The experimental results showed that a time of 2.1 μs at least is required for the pinch to occur and that both the pinch time and the duration time decrease with increasing the charging voltage.     

Monitoring the strength properties of electrokinetically treated soil by bender elements to determine the treatment period

Bender elements have been used as a non-destructive soil investigation technique by many researchers and have proven to be effective in predicting the shear strength of various soils. In this paper, electrokinetic treatment tests were performed with embedded bender elements to monitor the increase in the shear strength of a soft sandy clay during the treatment. The bender element system, designed and assembled for this study, was integrated into the electrokinetic treatment process in order to quell a common uncertainty associated with this form of soil improvement technique, namely: when is the treatment completed? The cross-correlation and first-peak arrival times were used to measure the shear wave velocity of a clayey soil under the treatment of electrokinetics using bender elements. To determine shear wave velocity before and during treatment, a variety of shear wave tests were performed every hour of treatment using frequencies ranging from 100 Hz to 2500 Hz via the use of bender element. The results show that monitoring the soil improvement during the treatment by bender elements can shorten the treatment time by 43% and reduce the energy consumption, which is a major expenditure in an electrokinetic treatment process, by 33% while consistently improving the shear strength and the load capacity by approximately 200% and 300%, respectively.     

Study of selected trace elements in cancerous and non-cancerous human breast tissues from Sudanese subjects using instrumental neutron activation analysis

This study was performed to investigate the influence of cancer on selected trace elements among Sudanese patients with confirmed breast cancer. Instrumental neutron activation analysis was used to estimate contents of Se, Zn, Fe, Cr, Rb, Cs, Co and Sc in 40 subjects. Wilcoxon signed ranks test was used to examine if there was any difference in the concentrations of elements from normal and malignant tissues. It was found that Se, Zn and Cr elements from the malignant tissues are significantly elevated (P < 0.05) compared to the normal tissue. The results obtained have shown consistency with results obtained by some previous studies.     

On the reliability of links in a ring network

This paper analyzes the reliability of links in a computer network which is configured in a ring topology. It will be shown that the expression for reliability of elements connected in series is not adequate for computing the reliability of links in a ring network. Consequently, new expressions for computing such reliability for rings with and without back-up links are proposed. Furthermore, an optimal back-up links assignment which guarantees optimal links reliability is formulated.