4,933 research outputs found
Hygrothermal performance of building envelopes in the tropics under operative conditions : condensation and mould growth risk appraisal
Poor indoor hygrothermal performance increases the risk of indoor moisture problems and
deterioration due to mould growth, corrosion and damage to archival materials. Hence,
proper control of indoor thermohygric intensity abates indoor moisture and its associated
problems. This paper presents the results of envelopes hygrothermal performance
assessments in a hot and humid climate building with varying operational profile between
adjacent spaces. The case-studied building runs on 24hrs cooling mode in one part against
natural and/or mechanical supply-exhaust fan means on the other. In-situ experiments were
combined with hygrothermal analytical methods to assess the envelope thermal quality
together with the operative conditions against condensation and mould growth risks. The
results show that the building is overcooled leading to poor envelope hygrothermal
performance with associated condensation and mould growth problems on non-airconditioned sides of the envelopes
An Electronically Reconfigurable Patch Antenna Design for Polarization Diversity with Fixed Resonant Frequency
In this paper, an electronically polarization reconfigurable circular patch antenna with fixed resonant frequency operating at Wireless Local Area Network (WLAN) frequency band (2.4-2.48 GHz) is presented. The structure of the proposed design consists of a circular patch as a radiating element fed by coaxial probe, cooperated with four equal-length slits etched on the edge along x-axis and y-axis. A total of four switches was used and embedded across the slits at specific locations, thus controlled the length of the slits. By activating and deactivating the switches (ON and OFF) across the slits, the current on the patch is changed, thus modifying the electric field and polarization of the antenna. Consequently, the polarization excited by the proposed antenna can be switched into three types, either linear polarization, left-hand circular polarization or right-hand circular polarization. This paper proposes a simple approach that able to switch the polarizations and excited at the same operating frequency. Simulated and measured results of ideal case (using copper strip switches) and real case (using PIN diode switches) are compared and presented to demonstrate the performance of the antenna
Management of Cabbage Aphid, Brevicoryne brassicae L. on Canola Crop Using Neonicotinoids Seed Treatment and Salicylic Acid
Cabbage aphid, Brevicoryne brassicae L. is one of the most important pests on canola worldwide and in Egypt. Field experiments were conducted in the Faculty of Agriculture Farm, Suez Canal University, Ismailia Governorate during 2012/13 and 2013/14 seasons. The efficacy of neonicotinoids seed treatment and spraying salicylic acid (SA) alone or in combination against B. brassicae and their impact on canola yield were investigated. Results showed that canola seeds treated with Gaucho 70% WS, Cruiser70% WS and Actara 25% WG were not effective for managing of B. brassicae in the late of growing season from 15th week to 21st week. However, SA application showed significant difference in reduction of infestation compared to control. Data revealed that seed treatment with neonicotinoid insecticides followed by foliar application with SA was associated with enhanced resistance against B. brassicae. Moreover, results showed relatively increase in seed yield/plant (g) and yield/fed. (kg) in this treatment than neonicotinoid insecticides seed treatment alone, or SA alone and control.
Biochemical characterization and DNA repair pathway interactions of Mag1-mediated base excision repair in Schizosaccharomyces pombe
The Schizosaccharomyces pombe mag1 gene encodes a DNA repair enzyme with sequence similarity to the AlkA family of DNA glycosylases, which are essential for the removal of cytotoxic alkylation products, the premutagenic deamination product hypoxanthine and certain cyclic ethenoadducts such as ethenoadenine. In this paper, we have purified the Mag1 protein and characterized its substrate specificity. It appears that the substrate range of Mag1 is limited to the major alkylation products, such as 3-mA, 3-mG and 7-mG, whereas no significant activity was found towards deamination products, ethenoadducts or oxidation products. The efficiency of 3-mA and 3-mG removal was 5–10 times slower for Mag1 than for Escherichia coli AlkA whereas the rate of 7-mG removal was similar to the two enzymes. The relatively low efficiency for the removal of cytotoxic 3-methylpurines is consistent with the moderate sensitivity of the mag1 mutant to methylating agents. Furthermore, we studied the initial steps of Mag1-dependent base excision repair (BER) and genetic interactions with other repair pathways by mutant analysis. The double mutants mag1 nth1, mag1 apn2 and mag1 rad2 displayed increased resistance to methyl methanesulfonate (MMS) compared with the single mutants nth1, apn2 and rad2, respectively, indicating that Mag1 initiates both short-patch (Nth1-dependent) and long-patch (Rad2-dependent) BER of MMS-induced damage. Spontaneous intrachromosomal recombination frequencies increased 3-fold in the mag1 mutant suggesting that Mag1 and recombinational repair (RR) are both involved in repair of alkylated bases. Finally, we show that the deletion of mag1 in the background of rad16, nth1 and rad2 single mutants reduced the total recombination frequencies of all three double mutants, indicating that abasic sites formed as a result of Mag1 removal of spontaneous base lesions are substrates for nucleotide excision repair, long- and short-patch BER and RR
Decision making in uncertain times: what can cognitive and decision sciences say about or learn from economic crises?
B.M. was supported by a Visiting Scholar Award from the British Academy and Grant ME 3717/2 from the Deutsche Forschungsgemeinschaft (DFG) as part of the priority program ‘New Frameworks of Rationality’ (SPP 1516)
Linear and nonlinear arx model for intelligent pneumatic actuator systems
System modeling in describing the dynamic behavior of the system is very important and can be considered as a challenging problem in control systems engineering. This article presents the linear and nonlinear approaches using AutoRegressive with Exogenous Input (ARX) model structure for the modeling of position control of an Intelligent Pneumatic Actuator (IPA) system. The input and output data of the system were obtained from real-time experiment conducted while the linear and nonlinear mathematical models of the system were obtained using system identification (SI) technique. Best fit and Akaike’s criteria were used to validate the models. The results based on simulation reveals that nonlinear ARX (NARX) had the best performance for the modeling of position control of IPA system. The results show that nonlinear modeling is an effective way of analyzing and describing the dynamic behavior and characteristics of IPA system. This approach is also expected to be able to be applied to other systems. A future study exploring the execution of other model structures in demonstrating the position control of IPA system would be exceptionally intriguing
Effects of fuel ratio on performance and emission of diesel-compressed natural gas (CNG) dual fuel engine
Recent research breakthrough reveals that diesel-CNG dual fuel (DDF) combustion can potentially reduce exhaust emission of internal combustion engines. However, problem arises when knock phenomenon occurs producing high carbon monoxide (CO) and hydrocarbon (HC) emission due to uncontrolled blending ratio of diesel-CNG fuel on specific engine load. This study will determine the limit of dual fuel ratio before knock occurrence while analysing performance and exhaust emission of an engine operating with diesel and DDF fuel mode. A 2.5 litre 4-cylinder direct injection common-rail diesel engine was utilised as a test platform. The modelstested were 100% Diesel, 90% DDF, 80% DDF and 70% DDF, representing diesel to CNG mass ratio of 100:0, 90:10, 80:20 and 70:30 respectively. It was found that DDF engine performance was lower compared to diesel engine at 1500 rpm engine speed. At higher engine speed, the 70% DDF showed engine performance comparable to diesel engine. However, high HC emission with knock onset and a decrease of Nitrogen Oxide (NOX) emission were recorded. This study suggests the preferred limit of dual fuel ratio should not be lower than 70% DDF which will be able to operate at high engine speed without the occurrence of knock and poor exhaust emission
An Overview and Tutorials on Modeling and Simulation
The modeling and simulation are the most important challenges to the researcher to present the system reality and study the different metrics of it. This article provides the short overview to assist the new researchers toward their goals. With aid of differ scenarios related to an engineering domain the designers have an ability to answer critical questions about modeling and simulation
Geometric Quantization on the Super-Disc
In this article we discuss the geometric quantization on a certain type of
infinite dimensional super-disc. Such systems are quite natural when we analyze
coupled bosons and fermions. The large-N limit of a system like that
corresponds to a certain super-homogeneous space. First, we define an example
of a super-homogeneous manifold: a super-disc. We show that it has a natural
symplectic form, it can be used to introduce classical dynamics once a
Hamiltonian is chosen. Existence of moment maps provide a Poisson realization
of the underlying symmetry super-group. These are the natural operators to
quantize via methods of geometric quantization, and we show that this can be
done.Comment: 17 pages, Latex file. Subject: Mathematical physics, geometric
quantizatio
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