Dynamic estimation of bank-propeller interaction effect on ship maneuvering using CFD method coupled to 6DOF algorithm

This paper presents a numerical investigation of ship maneuvering under the combined effect of the bank and propeller. The incompressible turbulent flow with free surface around the self-propelled hull form is simulated using a commercial CFD software (Fluent). In order to estimate the dynamic effect of bank and propeller, the CFD model with the dynamic mesh setting is coupled to the 6DOF module to compute the ship motion due to hydrodynamic forces. The numerical simulations are carried using the equivalent experiment conditions. The validation of the CFD model is performed by comparing the numerical results to the experimental data

Expected Sensitivity to Galactic/Solar Axions and Bosonic Super-WIMPs based on the Axio-electric Effect in Liquid Xenon Dark Matter Detectors

We present systematic case studies to investigate the sensitivity of axion searches by liquid xenon detectors, using the axio-electric effect (analogue of the photoelectric effect) on xenon atoms. Liquid xenon is widely considered to be one of the best target media for detection of WIMPs (Weakly Interacting Massive Particles which may form the galactic dark matter) using nuclear recoils. Since these detectors also provide an extremely low radioactivity environment for electron recoils, very weakly-interacting low-mass particles (< 100 keV/c^2), such as the hypothetical axion, could be detected as well - in this case using the axio-electric effect. Future ton-scale liquid Xe detectors will be limited in sensitivity only by irreducible neutrino background (pp-chain solar neutrino and the double beta decay of 136Xe) in the mass range between 1 and 100 keV/c^2. Assuming one ton-year of exposure, galactic axions (as non-relativistic dark matter) could be detected if the axio-electric coupling g_Ae is greater than 10^-14 at 1 keV/c^2 (or $10^-13 at 100 keV/c^2). Below a few keV/c^2, and independent of the mass, a solar axion search would be sensitive to a coupling g_Ae ~ 10^-12. This limit will set a stringent upper bound on axion mass for the DFSV and KSVZ models for the mass ranges m_A < 0.1 eV/c^2 and < 10 eV/c^2, respectively. Vector-boson dark matter could also be detected for a coupling constant alpha'/alpha > 10^-33 (for mass 1 keV/c^2) or > 10^-27 (for mass 100 keV/c^2).Comment: 17 pages, 10 figure

The efficient computation of transition state resonances and reaction rates from a quantum normal form

A quantum version of a recent formulation of transition state theory in {\em phase space} is presented. The theory developed provides an algorithm to compute quantum reaction rates and the associated Gamov-Siegert resonances with very high accuracy. The algorithm is especially efficient for multi-degree-of-freedom systems where other approaches are no longer feasible.Comment: 4 pages, 3 figures, revtex

Development of an integrated web-based indoor parking system with sensors

Growing number of vehicles in recent years has an impact to road capacity and parking spaces. Even with support of an efficient public transport, some users prefer to use their personal vehicles. Hence, it resulted in lack of parking space in public areas. Looking for parking spaces is time, money and fuel consuming and causes unnecessary stress to drivers. This work will design and develop the sensing infrastructure which will be used as a part of an integrated smart parking system that integrates the sensing capability with wireless transmission to the central web portal. Then, the central web portal will provide a platform for vehicle parking reservation system made online through a computer. This system also permits drivers to make a reservation on available parking slots utilizing ID code keyed in for authentication and several indicators to denote availability, non-availability and reservation status at the parking slot. The communication technologies used has to upload and download information to and from the web. This work has shown that the development was successful for a single floor parking system and can be upgraded to multi-storey parking complex

Irregular repetition code hybrid ARQ in wireless system

Error control consists of error detection and error correction in the communication system. The purpose of this research work is to reduce error in the wireless communication system by using the advantages of both error correction techniques which are forward error correction (FEC) and automatic repeat request (ARQ). Thus, error can be corrected without retransmission and also via retransmission(s) when needed. Combination of FEC and ARQ is known as Hybrid ARQ. In this paper, Hybrid ARQ system is designed using three components which are the irregular repetition code (IRC) as a simple code, bit-interleaved coded modulation with iterative decoding (BICM-ID) as a simple Turbo processing and ARQ. The HARQ system is enhanced by the extended mapping (EM) adopted in the mapping system. The performance of the systems is evaluated in the additive white Gaussian noise (AWGN). The results show the Hybrid ARQ with extended mapping (Hybrid ARQ-EM) outperforms Hybrid ARQ with standard mapping (Hybrid ARQ-SM). Hybrid ARQ-EM achieves low bit error rate BER (10-5) at low signal-to-noise ratio SNR which only 3.03dB close to the theoretical limit. The proposed system Hybrid ARQ-EM achieves 52 percent gain enhancement of SNR gap from the theoretical limit compared to Hybrid ARQ-SM. Hybrid ARQ-EM gives better performance although in worse channel condition

Study of seasonal sexual activity variations in Algerian rams: Sexual behaviour, testosterone concentration control and environmental factors

This study focuses on the determination of seasonal effect on two main andrological sexual activity parameters within young and adults rams of Rembi breed from Algeria for a period of one year. The experiment involved a weekly evaluation of males’ sexual behaviour and a monthly measurement of serum testosterone concentration in order to know the main testicular endocrine activity. The purpose of this experiment was to assess better the characteristics of the reproductive activity between two categories of rams age-wise and to define the variations and interactions between the two parameters during each season. Data shows no statistically significant effect of age on the testosterone concentration but showed a highly significant difference between age groups in terms of sexual behaviour. Seasonal variations of the studied parameters were statistically significant in both ram ages with higher values during spring and autumn and lower values during summer and winter.Keywords: Rembi, ram, testosterone, sexual activity, season, age.African Journal of Biotechnology Vol. 12(41), pp. 6042-604

Seasonal variation of plasma testosterone levels in Algerian male Arabia goats

The aim of the present work was to evaluate the general monthly averages of the testosterone hormone and the influence of  season and photoperiod on plasma testosterone levels in Arabia bucks of Algeria. Testosterone concentrations were determined throughout one year in blood samples collected every fortnight of the month from nine males of Arabia goat breeds, fed a constant diet, maintained without interactions with female goat. Plasma testosterone level was measured by radioimmunoassay. Analyses performed show that the monthly averages of the testosterone hormone vary during the year; higher levels were recorded during August (T=8.57±6.72, P=0.00***) however, bucks displayed the same change tendency during the same period (P=0.79). Plasma testosterone concentrations vary significantly between seasons (P=0.00***) being higher during autumn (6.15±3.81ng/ml) compared with spring (0.90 ± 1.27ng/ml) when hormone synthesis reaches its lowest levels. In conclusion, Arabia bucks of Algeria displayed a clear seasonality of plasma testosterone concentration with very low levels in winter and spring (from January to May) and high levels in summer and autumn (from July to November).Keywords: Arabia bucks, testosterone, season, photoperiod

EVALUATION OF SEMEN QUALITY IN RABBIT OF LOCAL ALGERIAN POPULATION AND SYNTHETIC LINE IN THE SUMMER SEASON: A COMPARATIVE STUDY

The aim of our study was to compare the libido and semen characteristics in 24 rabbits of local and synthetic line during summer season. Results showed that both breeds had similar (p ˃0.05) libido (13.92 vs 16.85 s). Gel free volume (0.88 vs. 0.87 mL), pH (7.51 vs. 7.65), and live sperm (56.21 vs. 55.88%) were similar. Local population had higher semen concentration (398.50 x106 /mL vs. 328.90 x106 /mL) and percentage of abnormal spermatozoa (36.54 vs 30.28%). Massal and individual motility (p=0.006 and p=0.008) were significantly increased in local population. Kinetic traits for Local population were significantly greater (P<0.05), except for VCL, ALH and BCF. We conclude that, rabbit bucks of local population had a good ability of adaptation to produce in a hot climate