Abstract: Gold nanoparticles (AuNPs) have gained increasing
interest in recent times. This is greatly due to their special features,
which include unusual optical and electronic properties, high stability
and biological compatibility, controllable morphology and size
dispersion, and easy surface functionalization. In typical synthesis,
AuNPs were produced by reduction of gold salt AuCl4 in an
appropriate solvent. A stabilizing agent was added to prevent the
particles from aggregating. The antibacterial activity of different
sizes of gold nanoparticles was investigated against Staphylococcus
aureus, Salmonella typhi and Pseudomonas pneumonia using the disk
diffusion method in a Müeller–Hinton Agar. The Au-NPs were
effective against all bacteria tested. That the Au-NPs were
successfully synthesized in suspension and were used to study the
antibacterial activity of the two medicinal plants against some
bacterial pathogens suggests that Au-NPs can be employed as an
effective bacteria inhibitor and may be an effective tool in medical
field. The study clearly showed that the Au-NPs exhibiting inhibition
towards the tested pathogenic bacteria in vitro could have the same
effects in vivo and thus may be useful in the medical field if well
researched into.
Abstract: 2024 Aluminum alloy was squeezed cast by the Gas Induced Semi Solid (GISS) process. Effect of artificial aging on microstructure and mechanical properties of this alloy was studied in the present work. The solutionized specimens were aged hardened at temperatures of 175°C, 200°C, and 225°C under various time durations. The highest hardness of about 77.7 HRE was attained from specimen aged at the temperature of 175°C for 36h. Upon investigation the microstructure by using transmission electron microscopy (TEM), the S’ phase was mainly attributed to the strengthening effect in the aged alloy. The apparent activation energy for precipitation hardening of the alloy was calculated as 133,805 J/mol.
Abstract: The paper represents the dependence of ammonia concentration on microclimate parameters and photocopying shop circulation. The concentration of ammonia was determined during 8-hours working time over five days including three sampling points of a photocopying shop in Novi Sad, Serbia. The obtained results pointed out that the room temperature possesses the highest impact on ammonia release. The obtained ammonia concentration was in the range of 1.53 to 0.42ppm and decreased with the temperature decreasing from 24.6 to 20.7oC. As the detected concentrations were within the permissible levels of The Occupational Safety and Health Administration, The National Institute for Occupational Safety and The Health and Official Gazette of Republic of Serbia, in the range of 35 to 200ppm, there was no danger to the employee’s health in the photocopying shop.
Abstract: In Singapore, there are about 1 million baby boomers, defined as those born between 1947 and 1964. They constitute a sizeable proportion (about 30 per cent) of the resident population comprising Singapore citizens and permanent residents. The first batches of these baby boomers have already 65 years old by 2012. Thereafter, baby boomers will swell the ranks of the elderly population in Singapore until 2030. The baby boomers in this study are divided into broad groups, namely, the early baby boomers (born 1947-54) and late baby boomers (1955-64). Continuing decline in fertility and mortality rates in the past three decades as well as improvements in health care facilities and services have changed the demography of Singapore from a “pyramid-shape” young, post war baby boomers population to a rapidly ageing population. With the ageing of the baby boom generation, the population of Singapore is about to grey rapidly over the next three decades. As such, there is a need for Singapore to understand the profile, perceptions and aspirations of this group, and devise strategies to address the needs and concerns as well as opportunities that arise with the ageing of baby boomers are discussed and presented in this work.
Abstract: Palm kernel shell is an important bioenergy resource
in Thailand. However, due to elevated alkali content in biomass ash,
this oil palm residue shows high tendency to bed agglomeration in a
fluidized-bed combustion system using conventional bed material
(silica sand). In this study, palm kernel shell was burned in the
conical fluidized-bed combustor (FBC) using alumina and dolomite
as alternative bed materials to prevent bed agglomeration. For each
bed material, the combustion tests were performed at 45kg/h fuel feed
rate with excess air within 20–80%. Experimental results revealed
rather weak effects of the bed material type but substantial influence
of excess air on the behavior of temperature, O2, CO, CxHy, and NO
inside the reactor, as well as on the combustion efficiency and major
gaseous emissions of the conical FBC. The optimal level of excess air
ensuring high combustion efficiency (about 98.5%) and acceptable
level of the emissions was found to be about 40% when using
alumina and 60% with dolomite. By using these alternative bed
materials, bed agglomeration can be prevented when burning the
shell in the proposed conical FBC. However, both bed materials
exhibited significant changes in their morphological, physical and
chemical properties in the course of the time.
Abstract: Affordable housing delivery for low and lower middle income families is a prominent problem in many developing countries; governments alone are unable to address this challenge due to diverse financial and regulatory constraints, and the private sector's contribution is rare and assists only middle-income households even when institutional and legal reforms are conducted to persuade it to go down market. Also, the market-enabling policy measures advocated by the World Bank since the early nineties have been strongly criticized and proven to be inappropriate to developing country contexts, where it is highly unlikely that the formal private sector can reach low income population. In addition to governments and private developers, affordable housing delivery systems involve an intricate network of relationships between a diverse range of actors. Collaboration between them was proven to be vital, and hence, an approach towards partnership schemes for affordable housing delivery has emerged. The basic premise of this paper is that addressing housing affordability challenges in Egypt demands direct public support, as markets and market actors alone would never succeed in delivering decent affordable housing to low and lower middle income groups. It argues that this support would ideally be through local level partnership schemes, with a leading decentralized local government role, and partners being identified according to specific local conditions. It attempts to identify major attributes that would ensure the fulfillment of the goals of such schemes in the Egyptian context. This is based upon evidence from diversified worldwide experiences, in addition to the main outcomes of a questionnaire that was conducted to specialists and chief actors in the field.
Abstract: With the objective of characterizing the profile and performance of energy use by slaughterhouses, surveys and audits were performed in two different facilities located in the northeastern region of Portugal. Energy consumption from multiple energy sources was assessed monthly, along with production and costs, for the same reference year. Gathered data was analyzed to identify and quantify the main consuming processes and to estimate energy efficiency indicators for benchmarking purposes. Main results show differences between the two slaughterhouses concerning energy sources, consumption by source and sector, and global energy efficiency. Electricity is the most used source in both slaughterhouses with a contribution of around 50%, being essentially used for meat processing and refrigeration. Natural gas, in slaughterhouse A, and pellets, in slaughterhouse B, used for heating water take the second place, with a mean contribution of about 45%. On average, a 62 kgoe/t specific energy consumption (SEC) was found, although with differences between slaughterhouses. A prominent negative correlation between SEC and carcass production was found specially in slaughterhouse A. Estimated Specific Energy Cost and Greenhouse Gases Intensity (GHGI) show mean values of about 50 €/t and 1.8 tCO2e/toe, respectively. Main results show that there is a significant margin for improving energy efficiency and therefore lowering costs in this type of non-energy intensive industries.
Abstract: This article presents a current and future energy situation in Libya. The electric power efficiency and operating hours in power plants are evaluated from 2005 to 2010. Carbon dioxide emissions in most of power plants are estimated. In 2005, the efficiency of steam power plants achieved a range of 20% to 28%. While, the gas turbine power plants efficiency ranged between 9% and 25%, this can be considered as low efficiency. However, the efficiency improvement has clearly observed in some power plants from 2008 to 2010, especially in the power plant of North Benghazi and west Tripoli. In fact, these power plants have modified to combine cycle. The efficiency of North Benghazi power plant has increased from 25% to 46.6%, while in Tripoli it is increased from 22% to 34%. On the other hand, the efficiency improvement is not observed in the gas turbine power plants. When compared to the quantity of fuel used, the carbon dioxide emissions resulting from electricity generation plants were very high. Finally, an estimation of the energy demand has been done to the maximum load and the annual load factor (i.e., the ratio between the output power and installed power).
Abstract: Medical image analysis is one of the great effects of computer image processing. There are several processes to analysis the medical images which the segmentation process is one of the challenging and most important step. In this paper the segmentation method proposed in order to segment the dental radiograph images. Thresholding method has been applied to simplify the images and to morphologically open binary image technique performed to eliminate the unnecessary regions on images. Furthermore, horizontal and vertical integral projection techniques used to extract the each individual tooth from radiograph images. Segmentation process has been done by applying the level set method on each extracted images. Nevertheless, the experiments results by 90% accuracy demonstrate that proposed method achieves high accuracy and promising result.
Abstract: Carbon capture, transport and underground storage have become a major solution to reduce CO2 emissions from power plants and other large CO2 sources. A big part of this captured CO2 stream is transported at high pressure dense phase conditions and stored in offshore underground depleted oil and gas fields. CO2 is also transported in offshore pipelines to be used for enhanced oil and gas recovery. The captured CO2 stream with impurities may contain water that causes severe corrosion problems, flow assurance failure and might damage valves and instrumentations. Thus, free water formation should be strictly prevented. The purpose of this work is to study the solubility of water in pure CO2 and in CO2 mixtures under real pipeline pressure (90-150 bar) and temperature operation conditions (5-35°C). A set up was constructed to generate experimental data. The results show the solubility of water in CO2 mixtures increasing with the increase of the temperature or/and with the increase in pressure. A drop in water solubility in CO2 is observed in the presence of impurities. The data generated were then used to assess the capabilities of two mixture models: the GERG-2008 model and the EOS-CG model. By generating the solubility data, this study contributes to determine the maximum allowable water content in CO2 pipelines.
Abstract: Nowadays the use of Hybrid Electric Vehicles (HEV) is increasing dramatically. The HEV is mainly dependent on electricity and there is always a need for storage of charge. Fuel Cell (FC), Batteries and Ultra Capacitor are being used for the proposed HEV as an electric power source or as an energy storage unit. The aim of developing an energy management technique is to utilize the sources according to the requirement of the vehicle with help of controller. This increases the efficiency of hybrid electric vehicle to reduce the fuel consumption and unwanted emission. The Maximum Power Point Tracking (MPPT) in FC is done using (Perturb & Observe) algorithm. In this paper, the control of automobiles at variable speed is achieved effectively.
Abstract: The influence of finite ground conductivity is of great importance in calculating the induced voltages from the radiated electromagnetic fields due to lightning. In this paper, we try to give a comprehensive approach to calculate the impact of the ground on the radiated electromagnetic fields to lightning. The vertical component of lightning electric field is calculated with a reasonable approximation assuming a perfectly conducting ground in case the observation point does not exceed a few kilometers from the lightning channel. However, for distant observation points the radiated vertical component of lightning electric field is attenuated due finitely conducting ground. The attenuation is calculated using the expression elaborated for both low and high frequencies. The horizontal component of the electric field, however, is more affected by a finite conductivity of a ground. Besides, the contribution of the horizontal component of the electric field, to induced voltages on an overhead transmission line, is greater than that of the vertical component. Therefore, the calculation of the horizontal electric field is great concern for the simulation of lightning-induced voltages. For field to transmission lines coupling the ground impedance is calculated for early time behavior and for low frequency range.
Abstract: This paper studies a random fuzzy queueing system
that the interarrival times of customers arriving at the server and
the service times are independent and identically distributed random
fuzzy variables. We match the random fuzzy queueing system with
the random fuzzy alternating renewal process and we do not use from
α-pessimistic and α-optimistic values to estimate the average chance
of the event ”random fuzzy queueing system is busy at time t”, we
employ the fuzzy simulation method in practical applications. Some
theorem is proved and finally we solve a numerical example with
fuzzy simulation method.
Abstract: In this paper, a low cost duty-cycle modulation scheme is studied in depth and compared to the standard pulse width modulation technique. Using a mix of analytical reasoning and electronics simulation tools, it is shown that under the same operating conditions, most characteristics of the proposed duty-cycle modulation scheme are better than those provided by a standard pulse width modulation technique. The simulation results obtained when testing both modulation control policies on prototyping systems, indicate that the proposed duty-cycle modulation approach, appears to be a high quality control policy in a wide variety of application areas, including A/D and D/A conversion, signal transmission and switching control in power electronics.
Abstract: Constructivism, the latest teaching and learning theory in western countries which is based on the premise that cognition (learning) is the result of "mental construction", lays emphasis on the learner's active learning. Guided by constructivism, this thesis discusses the teaching plan and its application in extensive reading course. In extensive reading classroom, emphasis should be laid on the activation of students' prior knowledge, grasping the skills of fast reading and the combination of reading and writing to check extracurricular reading. With three factors supplementing each other, students' English reading ability can be improved effectively.
Abstract: Demanding structural safety under various loading conditions, has focused attention on their variation and structural elements behavior due to these variations. Jacket structures are designed for a specific water level (LAT). One of the important issues about these kinds of structures is the water level rise. For example, the level of water in the Caspian Sea has risen by 2.5m in the last fifteen years and is continuing to rise. In this paper, the structural behavior of one typical shallow or medium water jacket platform (a four-leg steel jacket platform in 55m water depth) under water level rise has been studied. The time history of Von Mises stress and nodal displacement has chosen for evaluating structural behavior. The results show that dependent on previous water depth and structural elements position; different structural elements have different behavior due to water level rise.
Abstract: This paper proposes and analyzes an SIRS epidemic model incorporating the effects of the awareness programs driven by the media. Media and media driven awareness programs play a promising role in disseminating the information about outbreak of any disease across the globe. This motivates people to take precautionary measures and guides the infected individuals to get hospitalized. Timely hospitalization helps to reduce diagnostic delays and hence results in fast recovery of infected individuals. The aim of this study is to investigate the impact of the media on the spread and control of infectious diseases. This model is analyzed using stability theory of differential equations. The sensitivity of parameters has been discussed and it has been found that the awareness programs driven by the media have positive impact in reducing the infection prevalence of the infective population in the region under consideration.
Abstract: The present study aimed to investigate the effect of two type of soil (clay and sandy soils) in the potential allelopathic effects of Artemisia herba-alba, Oudneya africana crude powder (0, 1, 3 and 6%) on some growth parameters of two weeds (Bromus tectorum and Melilotus indica) under laboratory conditions (pot experiment).
The experimental findings have reported that the donor species crude powder concentrations were suppressing to shoot length (SL), root length (RL) and the leaf number (LN)) in both soil types and caused a gradual reduction particularly when they are high. However, the reduction degree was varied and species, concentration dependent. The suppressive effect of the two donors on the two weedy species was in the following order Melilotus indica > Bromus tectorum. Generally, the growth parameters of two recipient species were significantly decreased with the increase of each of the donor species crude powder concentration levels. Concerning the type of soil stoical analyses indicated that significant difference between clay and sandy soils.
Abstract: Coverage and capacity performance in a cellular network determines the system potentials. If the coverage radius is limited, end users suffer poor service quality, if the system capacity reduces, fewer subscribers will be accommodated. This paper investigated the performance effects of the noise rise caused by the spurious emission from a co-located jammer involving downlink frequency of CDMA2000 and uplink frequency of WCDMA operating at 1.9GHz. Measurements were carried out to evaluate the impact on the coverage radius and the system capacity.
Abstract: This paper presents a study on use of alkali activated bottom ash (BA) and ground granulated blast furnace slag (GGBS) blend in paver blocks. A preliminary effort on alkali-activated bottom ash, blast furnace slag based geopolymer (BA-GGBS-GP) mortar with river sand was carried out to identify the suitable mix for paver block. Several mixes were proposed based on the combination of BA-GGBS. The percentage ratio of BA: GGBS was selected as 100:0, 75:25, 50:50, 25:75 and 0:100 for the source material. Sodium based alkaline activators were used for activation. The molarity of NaOH was considered as 8M. The molar ratio of SiO2 to Na2O was varied from 1 to 4. Two curing mode such as ambient and steam curing 60°C for 24 hours were selected. The properties of paver block such as compressive strength split tensile strength, flexural strength and water absorption were evaluated as per IS15658:2006. Based on the preliminary study on BA-GGBS-GP mortar, the combinations of 25% BA with 75% GGBS mix for M30 and 75% BA with 25% GGBS mix for M35 grade were identified for paver block. Test results shows that the combination of BA-GGBS geopolymer paver blocks attained remarkable compressive strength under steam curing as well as in ambient mode at 3 days. It is noteworthy to know BA-GGBS-GP has promising future in the construction industry.