Abstract: The research investigates the effects of super plasticizer and molarity of sodium hydroxide alkaline solution on the workability, microstructure and compressive strength of self compacting geopolymer concrete (SCGC). SCGC is an improved way of concreting execution that does not require compaction and is made by complete elimination of ordinary Portland cement content. The parameters studied were superplasticizer (SP) dosage and molarity of NaOH solution. SCGC were synthesized from low calcium fly ash, activated by combinations of sodium hydroxide and sodium silicate solutions, and by incorporation of superplasticizer for self compactability. The workability properties such as filling ability, passing ability and resistance to segregation were assessed using slump flow, T-50, V-funnel, L-Box and J-ring test methods. It was found that the essential workability requirements for self compactability according to EFNARC were satisfied. Results showed that the workability and compressive strength improved with the increase in superplasticizer dosage. An increase in strength and a decrease in workability of these concrete samples were observed with the increase in molarity of NaOH solution from 8M to 14M. Improvement of interfacial transition zone (ITZ) and micro structure with the increase of SP and increase of concentration from 8M to 12M were also identified.
Abstract: Many companies have switched their processes to project-oriented in the last years. This brings new possibilities and effectiveness not only in the field of external processes connected with the product delivery but also the internal processes as well. However centralized project organization which is based on the role of project manager in the team has proved insufficient in some cases. Agile methods of project organization are trying to solve this problem by bringing new view on the project organization, roles, processes and competences. Scrum is one of these methods which builds on the principles of knowledge management to drive the project to effectiveness from all view angles. Using this method to organize internal and delivery projects helps the organization to create and share knowledge throughout the company. It also supports forming unique competences of individuals and project teams and drives innovations in the company.
Abstract: School homework has been synonymous with students- life in Chinese national type primary schools in Malaysia. Although many reports in the press claimed that students were burdened with too much of it, homework continues to be a common practice in national type schools that is believed to contribute to academic achievement. This study is conducted to identify the relationship between the burden of school homework and academic achievement among pupils in Chinese National Type Primary School in the state of Perak, Malaysia. A total of 284 students (142 from urban and 142 from rural) respectively were chosen as participants in this study. Variables of gender and location (urban/rural areas) has shown significant difference in student academic achievement. Female Chinese student from rural areas showed a higher mean score than males from urban area. Therefore, the Chinese language teachers should give appropriate and relevant homework to primary school students to achieve good academic performance.
Abstract: In this article, a high vacuum system for the evaporation of organic semiconductors is introduced and a mathematical model is given. Based on the exact input output linearization a deposition rate controller is designed and tested with different evaporation materials.
Abstract: Shrunken patterning for integrated device
manufacturing requires surface cleanliness and surface smoothness in
wet chemical processing [1]. It is necessary to control all process
parameters perfectly especially for the common cleaning technique
RCA clean (SC-1 and SC-2) [2]. In this paper the characteristic and
effect of surface preparation parameters are discussed. The properties
of RCA wet chemical processing in silicon technology is based on
processing time, temperature, concentration and megasonic power of
SC-1 and QDR. An improvement of wafer surface preparation by
the enhanced variables of the wet cleaning chemical process is
proposed.
Abstract: A device analysis of the photoconductive
semiconductor switch is carried out to investigate distribution of
electric field and carrier concentrations as well as the current density
distribution. The operation of this device was then investigated as a
switch operating in X band. It is shown that despite the presence of
symmetry geometry, switch current density of the on-state steady
state mode is distributed asymmetrically throughout the device.
Abstract: The optical properties of InGaN/GaN laser diode based on quaternary alloys stopper and superlattice layers are numerically studied using ISE TCAD (Integrated System Engineering) simulation program. Improvements in laser optical performance have been achieved using quaternary alloy as superlattice layers in InGaN/GaN laser diodes. Lower threshold current of 18 mA and higher output power and slope efficiency of 22 mW and 1.6 W/A, respectively, at room temperature have been obtained. The laser structure with InAlGaN quaternary alloys as an electron blocking layer was found to provide better laser performance compared with the ternary AlxGa1-xN blocking layer.
Abstract: Explosion occurs due to sudden release of energy.
Common examples of explosion include chemical, atomic, heat, and
pressure tank (due to ignition) explosions. Petroleum, gas, and
petrochemical industries operations are threatened by natural risks
and processes. Fires and explosions are the greatest process risks
which cause financial damages.
This study aims at designing a single-floor structure for the control
room of a petroleum refinery to be resistant against gas explosion
loads, and the information related to the structure specifications have
been provided regarding the fact that the structure is made on the
ground's surface. In this research, the lateral stiffness of single pile is
calculated by SPPLN.FOR computer program, and its value for
13624 KN/m single pile has been assessed. The analysis used due to
the loading conditions, is dynamic nonlinear analysis with direct
integration method.
Abstract: Silver nanoparticles were prepared by chemical reduction method. Silver nitrate was taken as the metal precursor and hydrazine hydrate as a reducing agent. The formation of the silver nanoparticles was monitored using UV-Vis absorption spectroscopy. The UV-Vis spectroscopy revealed the formation of silver nanopart├¡cles by exhibing the typical surface plasmon absorption maxima at 418-420 nm from the UV–Vis spectrum. Comparison of theoretical (Mie light scattering theory) and experimental results showed that diameter of silver nanoparticles in colloidal solution is about 60 nm. We have used energy-dispersive spectroscopy (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and, UV–Vis spectroscopy to characterize the nanoparticles obtained. The energy-dispersive spectroscopy (EDX) of the nanoparticles dispersion confirmed the presence of elemental silver signal no peaks of other impurity were detected. The average size and morphology of silver nanoparticles were determined by transmission electron microscopy (TEM). TEM photographs indicate that the nanopowders consist of well dispersed agglomerates of grains with a narrow size distribution (40 and 60 nm), whereas the radius of the individual particles are between 10 and 20 nm. The synthesized nanoparticles have been structurally characterized by X-ray diffraction and transmission high-energy electron diffraction (HEED). The peaks in the XRD pattern are in good agreement with the standard values of the face-centered-cubic form of metallic silver (ICCD-JCPDS card no. 4-0787) and no peaks of other impurity crystalline phases were detected. Additionally, the antibacterial activity of the nanopart├¡culas dispersion was measured by Kirby-Bauer method. The nanoparticles of silver showed high antimicrobial and bactericidal activity against gram positive bacteria such as Escherichia Coli, Pseudimonas aureginosa and staphylococcus aureus which is a highly methicillin resistant strain.
Abstract: In present work are considered the scheme of
evaluation the transition probability in quantum system. It is based on
path integral representation of transition probability amplitude and its
evaluation by means of a saddle point method, applied to the part of
integration variables. The whole integration process is reduced to
initial value problem solutions of Hamilton equations with a random
initial phase point. The scheme is related to the semiclassical initial
value representation approaches using great number of trajectories. In
contrast to them from total set of generated phase paths only one path
for each initial coordinate value is selected in Monte Karlo process.
Abstract: This paper presents an architecture of current filesystem
implementations as well as our new filesystem SpadFS and operating
system Spad with rewritten VFS layer targeted at high performance
I/O applications. The paper presents microbenchmarks and real-world
benchmarks of different filesystems on the same kernel as well as
benchmarks of the same filesystem on different kernels – enabling
the reader to make conclusion how much is the performance of
various tasks affected by operating system and how much by physical
layout of data on disk. The paper describes our novel features–most
notably continuous allocation of directories and cross-file readahead
– and shows their impact on performance.
Abstract: The growing importance of sustainability in corporate
policies represents a great opportunity for workers to gain more
consideration, with great benefits to their well being. Sustainable
work is believed to be one which improves the organization-s
performance and fosters professional development as well as
workers- health. In a multiple case study based on document
research, information was sought about work activities and their
sustainability or corporate social responsibility (CSR) policies, as
disseminated by corporations. All the companies devoted attention to
work activities and delivered a good amount of information about
them. Nevertheless, the information presented was generic; all the
actions developed were top-down and there was no information about
the impact of changes aimed at sustainability on the workers-
activities. It was found that the companies seemed to be at an early
stage. In the future, they need to show more commitment through
concrete goals: they must be aware that workers contribute directly to
the corporations- sustainability. This would allow room for
Ergonomics and Work Psychodynamics to be incorporated and to be
useful for both companies and society, so as to promote and ensure
work sustainability.
Abstract: Software maintenance, which involves making enhancements, modifications and corrections to existing software systems, consumes more than half of developer time. Specification comprehensibility plays an important role in software maintenance as it permits the understanding of the system properties more easily and quickly. The use of formal notation such as B increases a specification-s precision and consistency. However, the notation is regarded as being difficult to comprehend. Semi-formal notation such as the Unified Modelling Language (UML) is perceived as more accessible but it lacks formality. Perhaps by combining both notations could produce a specification that is not only accurate and consistent but also accessible to users. This paper presents an experiment conducted on a model that integrates the use of both UML and B notations, namely UML-B, versus a B model alone. The objective of the experiment was to evaluate the comprehensibility of a UML-B model compared to a traditional B model. The measurement used in the experiment focused on the efficiency in performing the comprehension tasks. The experiment employed a cross-over design and was conducted on forty-one subjects, including undergraduate and masters students. The results show that the notation used in the UML-B model is more comprehensible than the B model.
Abstract: Ciprofloxacin (CIP) and Carbamazepine (CBZ), nonbiodegradable pharmaceutical residues, were become emerging pollutants in several aquatic environments. The objectives of this research were to study the possibility to recover these pharmaceuticals residues from pharmaceutical wastewater by increasing the selective adsorption on synthesized functionalized porous silicate, comparing with powdered activated carbon (PAC). Hexagonal mesoporous silicate (HMS), functionalized HMSs (3- aminopropyltriethoxy, 3- mercaptopropyltrimethoxy and noctyldimethyl) were synthesized and characterized physico-chemical characteristics. Obtained adsorption kinetics and isotherms showed that 3-mercaptopropyltrimethoxy functional groups grafted on HMS provided highest CIP and CBZ adsorption capacities; however, it was still lower than that of PAC. The kinetic results were compatible with pseudo-second order. The hydrophobicity and hydrogen bonding might play a key role on the adsorption. Furthermore, the capacities were affected by varying pH values due to the strength of hydrogen bonding between targeted compounds and adsorbents. Electrostatic interaction might not affect the adsorption capacities.
Abstract: We present a general comparison of punctual kriging based image restoration for different neighbourhood sizes. The formulation of the technique under consideration is based on punctual kriging and fuzzy concepts for image restoration in spatial domain. Three different neighbourhood windows are considered to estimate the semivariance at different lags for studying its effect in reduction of negative weights resulted in punctual kriging, consequently restoration of degraded images. Our results show that effect of neighbourhood size higher than 5x5 on reduction in negative weights is insignificant. In addition, image quality measures, such as structure similarity indices, peak signal to noise ratios and the new variogram based quality measures; show that 3x3 window size gives better performance as compared with larger window sizes.
Abstract: In this paper, we introduce a novel platform
encryption method, which modify its keys and random number
generators step by step during encryption algorithms. According to
complexity of the proposed algorithm, it was safer than any other
method.
Abstract: Polyurethanes (PURs) are very versatile polymeric
materials with a wide range of physical and chemical properties.
PURs have desirable properties such as high abrasion resistance, tear
strength, shock absorption, flexibility and elasticity. Although they
have relatively poor thermal stability, this can be improved by using
treated clay. Polyurethane/clay nanocomposites have been
synthesized from renewable sources. A polyol for the production of
polyurethane by reaction with an isocyanate was obtained by the
synthesis of palm oil-based oleic acid with glycerol. Dodecylbenzene
sulfonic acid (DBSA) was used as catalyst and emulsifier. The
unmodified clay (kunipia-F) was treated with cetyltrimethyl
ammonium bromide (CTAB-mont) and octadodecylamine (ODAmont).
The d-spacing in CTAB-mont and ODA-mont were 1.571 nm
and 1.798 nm respectively and larger than that of the pure-mont
(1.142 nm). The organoclay was completely intercalated in the
polyurethane, as confirmed by a wide angle x-ray diffraction
(WAXD) pattern.
The results showed that adding clay demonstrated better thermal
stability in comparison with the virgin polyurethane. Onset
degradation of pure PU is at 200oC, and is lower than that of the
CTAB-mont PU and ODA-mont PU which takes place at about
318oC and 330oC, respectively. The mechanical properties (including
the dynamic mechanical properties) of pure polyurethane (PU) and
PU/clay nanocomposites, were measured. The modified organoclay
had a remarkably beneficial effect on the strength and elongation at
break of the nanocomposites, which both increased with increasing
clay content with the increase of the tensile strength of more than
214% and 267% by the addition of only 5 wt% of the
montmorillonite CTAB-mont PU and ODA-mont PU, respectively.
Abstract: The paper presents the case study of hazard
identification and sensitivity of potential resource of emergency
water supply as part of the application of methodology classifying
the resources of drinking water for emergency supply of population.
The case study has been carried out on a selected resource of
emergency water supply in one region of the Czech Republic. The
hazard identification and sensitivity of potential resource of
emergency water supply is based on a unique procedure and
developed general registers of selected types of hazards and
sensitivities. The registers have been developed with the help of the
“Fault Tree Analysis” method in combination with the “What if
method”. The identified hazards for the assessed resource include
hailstorms and torrential rains, drought, soil erosion, accidents of
farm machinery, and agricultural production. The developed registers
of hazards and vulnerabilities and a semi-quantitative assessment of
hazards for individual parts of hydrological structure and
technological elements of presented drilled wells are the basis for a
semi-quantitative risk assessment of potential resource of emergency
supply of population and the subsequent classification of such
resource within the system of crisis planning.
Abstract: Sensors have been used in various kinds of academic
fields and applications. In this article, we propose the idea of
modularized sensors that combine multiple sensor modules into a
unique sensor. We divide a sensor into several units according to
functionalities. Each unit has different sensor modules, which share
the same type of connectors and can be serially and arbitrarily
connected each other. A user can combine different sensor modules
into a sensor platform according to requirements. Compared with
current modularized sensors, the proposed sensor platform is highly
flexible and reusable. We have implemented the prototype of the
proposed sensor platform, and the experimental results show the
proposed platform can work correctly.
Abstract: The use of e-business in small and medium-sized
enterprises (SMEs) has been recently received an enormous attention
in information systems research by both academic and practitioners.
With the adoption of new and efficient technologies to enhance
businesses, Thai SMEs should be able to compete worldwide.
Unfortunately, most of the owners are not used to new technologies.
It is clear that most Thai SMEs prefer to work manually rather than
electronically. This paper aims to provide a fundamental conceptual
framework for E-business adoption by Thai SMEs. Rooted in
Knowledge transfer model, several factors are identified, which drive
and enable e-business adoption. By overlooking the benefits
associated with implementing new technologies, it is difficult for
Thai SMEs to perform well enough to compete globally. The paper
also helps Thai SMEs to understand factors related to E-business
adoption.