808 research outputs found
Development of dual-axis solar tracking using arduino
Renewable energy sections are fast-spreading, as they can be considered new growth areas for many countries. Contains many economic and environmental possibilities. As solar energy is considered to have a major and effective role for the acquisition of energy, in the face of the identification of rural areas that are difficult to access electric power. The traditional solar power system used is produces weak energy by assumption that the sun is moving all the day, therefore requires the purchase of more solar panels refer to the high cost .The project aims to develop the traditional solar system to solar tracking system using Arduino, two servo motor and light dependent resistor (LDR) to obtain high efficiency in electric power generation. Where, the main goal agreed is to track the sunlight at its maximum intensity until the panel move towards the sun, and the project is divided into two main parts, the development of software and hardware. In hardware development will be used four LDR installed on plastic base on solar panel, connected wires to transfer the measurements from sensors to Arduino with resistances and Multi-meter to measure the required energy coming from the pane
HCN1 Immunoreactivity of α-motoneurons Following Peripheral Nerve Injury
Peripheral axotomy causes significant alterations in intrinsic motoneuron activity and excitability. Despite successful reinnervation of peripheral targets after injury, the recovery of motor function is incomplete. Following axotomy in the adult cat, there is an increase in the afterhyperpolarization (AHP) of the action potential in specific motoneuron types. AHP duration can be inversely correlated with the amount of Ih or sag current and further shaped through SK (Small conductance calcium-activated potassium) channel currents (Gustafsson and Pinter, 1985; Kuno, Miyata, and Muñoz-Martinez, 1974a). Hyperpolarizing-cyclic nucleotide gated (HCN) channels underlie sag currents and are critical to neuronal function by their unique property of a reverse voltage-dependence that leads to activation upon hyperpolarization. There are four isoforms of HCN channels, one of which, HCN1, is expressed in motoneurons. Because there is an increase in AHP after injury, we hypothesize that there will be a decrease in expression of HCN1 immunoreactivity (IR) in the medial and lateral gastrocnemius (MG/LG) α-motoneurons following tibial nerve axotomy. To test this hypothesis, we used immunohistochemical approaches in two in vivo injury models, namely the tibial nerve crush model, that permits peripheral reinnervation of the peripheral targets and the tibial nerve ligation model, that prevents peripheral reinnervation from occurring, thus allowing us to distinguish between mechanisms and their dependency on proper reinnervation of peripheral targets. Lumbar spinal cord tissue was analyzed using immunohistochemical techniques to identify retrogradely labeled, injured MG/LG α-motoneurons and HCN1- IR. These data suggest that following injury there is a decrease in HCN1-IR followed by a peripheral reinnervation-dependent recovery
Phytochemical, antioxidant, and antimicrobial effects of methanolic leaf extract of Rhazya stricta decne
Background: In this research, we investigated the antioxidant phytochemicals, antimicrobial and antibiofilm properties of methanolic leaf extract from Rhazya stricta.Methods: The main components of R. stricta were confirmed through HPLC techniques. The antioxidant activity of methanolic leaf extract was examined by DPPD, ABTS, SOD and Glutathione peroxidase assays.Results: The results showed that the methanolic extract of R. stricta showed better free radical scavenging properties with the IC50 value 74.2 mg/ml by DPPH assay. And the tested extract showed high SOD and peroxidase activities. The HPLC analysis of leaf extract reveal the presence of rutin. Antibacterial results revealed that methanolic leaf extract of R. stricta had higher anti-bacterial activity against multi drug resistant microbes namely, Bacillus subtilis (3.51 mm), Staphylococcus aureus (1.29 mm), Escherichia coli (3.39 mm), Klebsiella pneumoniae (2.03 mm), Pseudomonas aeruginosa (5.73 mm). In addition, the leaf extract showed strong antibiofilm potential against Pseudomonas aeruginosa at 100 µg/ml.Conclusions: Overall, the methanolic leaf extract of R. stricta showed significant antioxidant capacity and highly inhibit the bacterial pathogens
Direct control of D-STATCOM based on 23-level cascaded multilevel inverter using harmonics elimination pulse width modulation
The distribution static synchronous compensator (D-STATCOM) is primarily used for solving power quality problems. Normally, the phase-shifted pulse width modulation (PS-PWM) switching is employed in conjunction with the direct control of the D-STATCOM. However, the PS-PWM exhibits high switching losses. To alleviate this problem, a direct control scheme for D-STATCOM based on the harmonic elimination PWM (HEPWM) switching is developed. Due to the difficulty in solving the equations for the HEPWM angles, no work is reported on the direct control for a multilevel voltage source inverter (MVSI) D-STATCOM with more than 15-levels. Thus, the main contribution of the work is the application of HEPWM for 23-level cascaded MVSI using a wide modulation index (MI) range (i.e. 5.40 – 8.15 p.u). The main motivation to utilize the high number of level is to allow for the output voltage of the D-STATCOM to be sufficiently high, thus avoiding the use of step-up transformer. Furthermore, the achieved MI keeps the total harmonic distortion of the MVSI output voltage below the IEEE 519 Standard (5%) over the entire operating range. The eleven HEPWM switching angles were computed using an optimization technique, known as the differential evolution. Since the angles were computed offline, they were retrieved from a look-up table whenever the output voltage of the MVSI was to be constructed. The HEPWM-based direct control was benchmarked against the popular PS-PWM using ± 6.5MVAr/11kV D-STATCOM modelled in MATLAB-Simulink and PLECS software. For the same switching frequency, the proposed HEPWM switching exhibited superior harmonic spectra, hence had lower losses. Furthermore, the size of the series coupling inductor can be reduced to at least half. Dynamically, the steady state value of the reactive current was reached in less than one mains cycle when a transition from the full inductive to full capacitive modes was imposed. In addition, the proposed D-STATCOM controller mitigated the swell and sag problems in less than one cycle
Affordable interactive virtual reality system for the Dynamic Hip Screw surgery training in vitro
Interactive virtual reality systems provide safe and cost-effective training environment to improve the technical skills and competence of surgeons. The trainees can have as many practice sessions, without need to the trainer all the time, before even start carrying out the procedure on any real patient. In this paper, we present an affordable interactive virtual reality system for the Dynamic Hip Screw (DHS) surgery training in vitro, through 3D tracking. The system facilitates a safe (in vitro / off patient) training to improve the cognitive coordination of trainees and junior surgeons, in particular the Hands, Eyes and Brain coordination. The system is based on very cheap commercial off-the-shelf (COT) components, which are very affordable, and needs minimum setup effort and knowledge. It also provides a range of visual and quantitative feedback information and measures, such as position, orientation, insertion point, and depth of drilling. It is envisaged that improving this level of coordination, through the training system, will contribute to reducing the failure rate of the DHS procedure. This means better treatment for patients and less costs for the Health services systems (e.g. UK's NHS system)
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Utility computing: Certification model, costing model, and related architecture development
The purpose of the thesis was to propose one set of solutions to some of the challenges that are delaying the adoption of utility computing on a wider scale. These components enable effective deployment of utility computing, efficient look-up, and comparison of service offerings of different utility computing resource centers connected to the utility computing network
Epidemiological Study of Road Traffic Accidents, Casualties and Fatalities in the United Arab Emirates
In the United Arab Emirates (UAE), with its rapid expansion of road construction and increase in the number of vehicle, road traffic accidents are becoming a serious public health problem. It was aimed to study road traffic accidents (RTA) in view of the fact that cause a substantial waste of national resources which could be used fruitfully for the improvement of health schemes and other aspects of life in UAE. It was observed that there has been a dramatic increase in the number of registered vehicles during this period. During the ten years period 1983 to 1992, the population of UAE increased at the rate of7.2% per year and the number of registered vehicles increased at the rate of 5.4% per year. Despite the enormous increase in the population there is a decline in the vehicle per capita, the total number of cars went on decreasing till 1991, but in 1992 there has been substantially an increasing trend in the number of registered vehicles. Road traffic accidents rates per 100 vehicles sharply decreased from 184.3 in 1983 to 91.9 in 1992. Also, casualty rates doubled from 27.5 in 1983 to 51.7 in 1992. Then, motor vehicle accident fatalities have gone up from 539 in 1984 to 770 in 1992 during the decade showing an average annual growth of 4.8%. UAE showing lower accident rate but higher casualty and fatality rates. In addition, the population, number of registered cars, accidents, casualties and fatalities in the seven Emirates were reviewed. Overall, results showed a decrease in accidents at the Abu Dhabi and Dubai Emirates. But there were increase in injuries and fatalities at the Sharjah, Ajman, Umm Al-Quwain, Ras AI Khaimah and Fujairah Emirates. It was observed that 1.4% of the accidents, 16.2% of the casualties and 14.8% of the fatalities were pedestrians their age less than 11 years of age. The findings of this study into the road safety in the UAE and other Gulf countries indicate that fatality rates (per 100 accident and per licensed vehicle) are high in comparison with those in developed countries.
A descriptive study was carried out using available data and records of Accident Emergency Department of Al-Ain Hospital in Al-Ain, UAE. The study presents the results of a all patients with road traffic accidents (RTA) injuries that attended the Accident Emergency Department of Al-Ain Hospital, Al-Ain, UAE for the period 1 January - 31 December 1993. The AI-Ain Hospital recorded a total of 1383 road traffic accidents (RTA) casualties with 63 deaths during year 1993. The road traffic accident rate was 461 per 100,000 population and the death was 21 per 100,000. Three-fourths of all were under 35 years of age (77%). The great majority of the victims (84%) were males. UAE nationals comprised 29% while those of other Arabs 36% and Asian origin formed 35% respectively. It is noteworthy that 44% suffered from head & neck injuries. Most of the casualties occurred between 8.00am to 2.00pm The main single cause for these R TA was excessive speeding. The injuries produced a severe strain on the manpower.
Also, this study describes the magnitude of this problem and studies some aspects of road user behaviour in UAE. Road injuries, besides being a major health hazard lead to a high rate of morbidity, impact on the victims, his family, and the nation as a whole. The magnitude of the problem could be greatly reduced if appropriate measures were taken concerning road user behaviour. Some factors which influence driver behaviour are presented and discussed.
Additionally, a cross sectional study was carried out between November 1993 and June 1994 to assess the knowledge, attitudes and practices of hospitalized drivers involved in road traffic accidents regarding seat belt usage in U.A.E. During this period, a total of 1000 vehicle drivers were seen and treated in the Accident and Emergency Departments of two general hospitals (Tawam and Al-Ain Hospitals). A total of 787 (78.7%) drivers gave responded response for the study. This study demonstrated that the rate of constant seat belt usage among drivers was 9.4%, and the rate of frequent seat belt usage was 5.2%. There was statistically significant difference between seat belt usage versus non usage by age groups (p=0.007) and nationality(p=0.001). However, there was no significant statistical differences between seat belt usage versus non usage by sex, and marital status. There were statistically significant difference between user and non-users of seat belts concerning their educational level (p\u3c0.002) and occupation (p\u3c0.02). The results demonstrated a reduction in the number of injuries due to usage of seat belts. Those patients who were not wearing seat belts were at risk 5.84 times as often as drivers who were restrained by belts. There were statistically significant differences between number of persons injured wearing and not wearing seat belts for head injury [Odds ratio (OR)=1.74; Confidence Interval (CI)= 1.18-2.56 ,and p=0.003], neck injury [OR=1.73; (CI)= 0.99-3.04 ,and p=0.04], spinal injury [OR=4.64; (CI)= 2.30-9.47 and p\u3c0.0001], limbs injury [OR=2.11; (CI)= 1.45-3.08 ,and p\u3c0. 0001]. But, we did not find statistically significant differences between number of person injured in chest, abdomen and pelvis by wearing or not wearing seat belts [OR=0.62; (CI)= 0.34-1.14 ,and p\u3c0.101]. It was observed that the majority of patients stated that seat belts are the best protective measure against all injuries (66%) and severe injuries (26%) of road traffic accidents. Also, there was very strong support for the mandatory use of safety seat belts (53%). We may suggest that these data are encouraging, and would suggest general acceptance of seat belt legislation in the United Arab Emirates.
In the UAE, as in other GCC countries, RTA poses a major health problem. It is the second major cause mortality, after coronary heart disease in the UAE. Information concerning RIA is therefore valuable in taking appropriate measures to reduce their incidence and also to plan health services in the area. The result of this study would provide vital results and essential statistical information for health education, safety education, planning programming managing and evaluating anti-motor vehicle accidents activities aiming at significantly reducing the road traffic accidents and hazards
Robust Intrusion Detection for Resilience Enhancement of Industrial Control Systems: An Extended State Observer Approach
We address the problem of attack signal estimation in industrial control systems that are subjected to actuator false data injection attack (FDIA) and where the sensor measurements are corrupted by non-negligible high-frequency measurement noise. The actuator FDIA signal is categorized as disturbance to be estimated and subsequently compensated, based on the concept of extended state observer (ESO). We investigate the efficacy of two alternatives to conventional ESO namely, cascade ESO (CESO) and low-power higher-order ESO (LHESO), that guarantee improved estimation performance in case of noisy measurement data as well as time-varying attack signals. Simu-lation and experimental results under different types of FDIAs demonstrate the advantages of designed schemes in comparison to conventional linear and nonlinear ESOs, using network motion control system as an illustrative example. The results highlight the limitations of conventional ESO under noisy measurement data, particularly nonlinear ESO which is based on fal(·) function and commonly used in control literature
High-Rate Space-Time Coded Large MIMO Systems: Low-Complexity Detection and Channel Estimation
In this paper, we present a low-complexity algorithm for detection in
high-rate, non-orthogonal space-time block coded (STBC) large-MIMO systems that
achieve high spectral efficiencies of the order of tens of bps/Hz. We also
present a training-based iterative detection/channel estimation scheme for such
large STBC MIMO systems. Our simulation results show that excellent bit error
rate and nearness-to-capacity performance are achieved by the proposed
multistage likelihood ascent search (M-LAS) detector in conjunction with the
proposed iterative detection/channel estimation scheme at low complexities. The
fact that we could show such good results for large STBCs like 16x16 and 32x32
STBCs from Cyclic Division Algebras (CDA) operating at spectral efficiencies in
excess of 20 bps/Hz (even after accounting for the overheads meant for pilot
based training for channel estimation and turbo coding) establishes the
effectiveness of the proposed detector and channel estimator. We decode perfect
codes of large dimensions using the proposed detector. With the feasibility of
such a low-complexity detection/channel estimation scheme, large-MIMO systems
with tens of antennas operating at several tens of bps/Hz spectral efficiencies
can become practical, enabling interesting high data rate wireless
applications.Comment: v3: Performance/complexity comparison of the proposed scheme with
other large-MIMO architectures/detectors has been added (Sec. IV-D). The
paper has been accepted for publication in IEEE Journal of Selected Topics in
Signal Processing (JSTSP): Spl. Iss. on Managing Complexity in Multiuser MIMO
Systems. v2: Section V on Channel Estimation is update
Design of Tunable Beamforming Networks Using Metallic Ridge Gap Waveguide Technology
Wireless communication is a leap of development in the history of humanity. For the past 100 years, a considerable effort has been spent to develop better standards, and technologies for a higher speed wireless communication with high system capacity for different applications. This requires the design of a high-frequency, point-to-multipoint antenna array system to achieve the mentioned goals. In addition, the reconfigurability of this antenna system is essential to change the system characteristics to achieve acceptable performance in different situations.
The main goal of this thesis is to design a reconfigurable beamforming network to work on the Ka-band for waveguide applications. Among different beamforming networks in the literature, the Butler matrix is chosen due to its higher efficiency and the smaller number of components required than other beamforming networks. The Butler matrix is designed using a dual-plane topology to avoid using crossovers. Ridge gap waveguide technology is chosen among different transmission lines to implement the Butler matrix for several reasons: It does not need dielectrics to operate, so its power handling capacity is defined by the gap height, and it has no dielectric losses. Its zero-field region represents the operating principle for some tunable devices introduced here and its contactless nature, which eases the assembly of waveguide parts at the millimeter-wave frequencies. The reconfigurability of the Butler matrix is implemented such that beamwidth, maximum gain, and beam direction may be all tuned for optimum system performance.
To that end, several components are designed to achieve the required target, and strict requirements are placed on several components to achieve an acceptable cascaded-system performance. These components include a ridge gap waveguide 90o-hybrid working over a more than 30% bandwidth, which can provide several coupling levels ranging from 3 dB to 33 dB and a return loss and isolation better than 30 dB. Another component is a wideband reconfigurable power splitter that has a 40% bandwidth, a return loss better than 20 dB in the worst case and the ability to achieve all power splitting ratios including switching between the two guides. In addition, a wideband reconfigurable phase shifter is designed to have 33% bandwidth and phase shift tuning range from 0o to 200o. Two coaxial-to-ridge gap waveguide transitions are designed to work over a more than 100% bandwidth to facilitate testing different ridge gap waveguide components. Analysis of the asymmetric double ridge waveguide is introduced where its impedance is deduced and may be used to design a single to double ridge waveguide transition useful for the dual-plane Butler matrix introduced here. In addition, this concept is used to develop a wideband unequal power divider in the single ridge waveguide technology.
At the end, the whole system is assembled to show its performance in different tuning states. The ability of the system to produce radiation patterns of different characteristics is demonstrated. The presented Butler matrix design is a promising beamforming network for several applications like radar, base stations for mobile communications, and satellite applications
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