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  • ItemOpen Access
    DESIGN AND SIMULATION OF A LINE FED MICROSTRIP TRIANGULAR PATCH ANTENNA FOR BLUETOOTH APPLICATION AT 2.45GHz
    (Department of Physics, Nasarawa State University, Keffi., 2017-12-23) MUHAMMAD, YUSUF ABUBAKAR
    In this research work, a line fed Microstrip Triangular Patch Antenna (MTPA) was designed and implemented using four different substrates with a conducting radiating patch on the substrates and a ground plane on the bottom side of substrates. The calculated dimensions of the proposed antennas were optimized when simulating on CST 2014 software in order to improve the antenna bandwidth, reduce antenna size and maintain the resonant frequency at 2.45GHz. The performance characteristics of the different substrates were compared in terms of return loss, bandwidth, directivity, gain, Voltage Standing Wave Ratio (VSWR), vis-à-vis dimension and size. From comparison of simulated results, it was deduced that Rogers 6010 with a patch length of 35.0 mm showed the smallest effective length compared with other chosen substrates, hence it is the best in terms of size, but has the least directivity of 4.47dBi, gain of 3.52dB with a VSWR of 1.02 and bandwidth of 33MHz. Rogers RT showed the best directivity of 6.29dBi, gain of 5.55dB with a VSWR of 1.08 and bandwidth of 42MHz. However, these advantages are at the expense of enlarged patch length of 55.0 mm. It can therefore be concluded that the proposed line fed MTPA gave better performance with Rogers RT whose permittivity is 2.2. The MTPA resonated at 2.45GHz with small dimensions and sufficient bandwidth as compared to conventional patch antenna. This makes it suitable for use in S band (2400-2485MHz) for Bluetooth application.
  • ItemOpen Access
    ANALYSIS OF SHIELDING EFFECT AND AREA SURVEY FOR X – RAY DIAGNOSIS IMAGING FACILITIES ACROSS ABUJA, NIGERIA.
    (Department of Physics, Nasarawa State University, Keffi., 2017-09-21) ISMAIL, WASIU OLANIYI
    Radiation protection source is of great concern for national and international bodies because of the potential hazard associated with ever increasing number of radiodiagnostic facilities. However, humans are exposed to ionizing radiation and there is a risk of damage to our cells and our offspring. Ten diagnostic centres/hospitals (3 private and 7 government hospitals) were assessed. The objectives are to assess the integrity (standard) of the shielding used in those centers using an inspector alert to measure the recordable dose while taking into consideration the three points of interest; controlled area, supervised area and behind the wall as well as the design of the X-ray room as a means of reducing radiation. Results show that no recordable radiation was observed at all the points of interest confirming the efficiency of the shielding and the room design as barriers against ionizing radiation. The annual effective dose rates for both occupational and public were calculated and found below annual dose limit except for centre G whose annual effective dose rate for public exposure (0.95mSv/yr,) proved higher than the other centres thought, this does not calls for any alarm as the dose still fall below the annual dose limit of 1mSv/yr for public exposure as evidenced in table 4.2.7, 40% of the centres used lead lined wall and 40% had lined doors and 20% used concrete for their diagnostic rooms design. This result further strengthens the Area survey report. Generally, there was a good compliance to the minimum standard requirement in those X-ray diagnosis imaging facilities.
  • ItemOpen Access
    HYDROGEOPHYSICAL INVESTIGATION OF ANGWAN ZAKARA, KEFFI SHEET 208N.E OF NORTH CENTRAL NIGERIA
    (DEPARTMENT OF PHYSICS FACULTY OF NATURAL AND APPLIED SCIENCES NASARAWA STATE UNIVERSITY, KEFFI, 2019-07-15) Sandra, Chinete Okeke
    The hydrogeological assessment of the geologic and groundwater prospect in Angwan Zakara and its environs, Karu Local Government, Nasarawa State, North-Central, Nigeria has been carried out in this study. The study area covers 25km2.The area is underlain by the Basement Complex of the North-Central Nigeria. Forty Nine (49) Vertical Electrical Sounding were carried out in the study area using Omega Resistivity Terrameter, GPS12 Garmix with a maximum cable spread of AB/2=100m and MN/2=5m. The results obtained from the field data were interpreted using IXID Software for quantitative analysis. True resistivity map, piezometric map, basement resistivity map and depth to basement map were prepared and interpreted using computer software (SURFER 8). From the IXID interpreted results, five (5) curve types were obtained from the acquired data namely A, H, KH, AH, and HK curve type is the dominant. The study area showed depth to basement ranges from 20-90m. That revealed good groundwater potential. The study area revealed 4-7lithologic sequences consisting of top soil, laterite, clay, weathered/ fractured basement, however the host rocks in the study area are biotite graninte, quartzite and schistose-gneiss. The results obtained shows that the direction of water flows revealed five ridges R1-R5 and four depressions D1-D4 with receptacles trends of the ridges are R1 and R2:NW-SE; R3 N-S, R4 : NE-SW and R5; E-W. The geoelectric sections were produced and correlated with the existing geology of the study area and it was found to be in conformity with the existing geology. Based on this, the study area is zoned into good, moderate and poor groundwater potential zones.
  • ItemOpen Access
    CONSTRUCTION OF 240V AC POWER OVERLOAD MONITOR WITH FIRE AND SMOKE ALARM SYSTEM
    (DEPARTMENT OF PHYSICS FACULTY OF NATURAL AND APPLIED SCIENCES NASARAWA STATE UNIVERSITY, KEFFI, 2019-03-10) Babangida, Babaji Abdullahi
    An AC overload monitor is a device connected between an AC power source and an AC load to detect and prevent overloading the output from the power source. An overload or short circuit causes fire in any electrical installation. So, it should be avoided. Addition to a circuit breaker, an overload monitor protects a system’s electrical installation in the event of circuit breaker failure. A current transformer is used as the current sensing unit. An Arduino based AVR microcontroller is used to process the input signal from the current transformer and give digital signal output to activate or deactivate a relay connecting the load to the source through the current transformer. In addition the overload monitor, there is a fire and smoke sensor which senses smoke. When an overload or smoke is detected, the load is automatically disconnected from the source.
  • ItemOpen Access
    MEASUREMENT OF ABDOMINAL AND PELVIC ORGANS DOSES OF CONVENTIONAL X-RAY FOR LOCALLY DEVELOPED PHANTOM IN SOME HOSPITALS IN JOS, NIGERIA
    (DEPARTMENT OF PHYSICS FACULTY OF NATURAL AND APPLIED SCIENCES NASARAWA STATE UNIVERSITY, KEFFI, 2019-01-02) Dauda, Barnabas
    The increasing use of X-ray procedure in the field of human medicine has made dosimetric evaluation and optimization of these procedures an important consideration. There is an ongoing effort to minimize dose to patient without compromising diagnostic information from such a procedure. A dose of a radiation is not only dependent on the type of radiation, imaging modality and distance from the source, but also the radiosensitivity of the organ or cell. The study aimed to measure the absorbed dose to selected organs of the abdominal and pelvic cavity. The materials that were used in the study include body phantom, thermoluminescent dosimeter (TLD-40), glycerine and water. In the study, absorbed doses to the ovary uterus, prostrate, liver, and kidney where measured by the used of the TLD chips. The chips were placed inside the phantom probe holes (inserts). These inserts contained a water-glycerine solution having density equivalent to each organ considered for dose measurement. Exposed TLDs were read by a manual TLD reader. Results shows the mean dose to the ovary at hospital H.1, H.2, H.3 and H.4 are 0.35mGy, 0.42mGy, 0.39mGy, and 0.44mGy respectively. For the uterus the result obtained were 0.36mGy, 0.68mGy, 0.40mGy, and 0.29mGy across hospital H.1, H.2, H.3 and H.4. Mean organ dose to the prostrate are: 0.45mGy, 0.41mGy, 0.39mGy, and 0.44mGy. The liver has 0.41mGy, 0.37mGy, 0.33mGy, and 0.33mGy. Lastly organ dose to the kidney was measured and the following results were obtained: 0.42mGy, 0.68mGy, 0.45mGy, 0.49mGy across hospital H.1-H.4 respectively. These results were compared with reference levels established by local and international organizations and seen to have exceeded the established benchmark. Even though in this study, the mean dose to the abdominopelvic organs is much lower than established reference levels, there appear to be wide discrepancy in the organs absorbed dose. Thus, I will recommend more of such study be carried out particularly in north central Nigeria as results such a study can be used in establishing of local, regional or even national reference level.
  • ItemOpen Access
    SIMULATION AND CONSTRUCTION OF A 180-200 VDC MOTOR CONTROLER
    (Physics Department, Nasarawa State University, Keffi, 2018-09-04) Abdullahi, Jibrin
    With the advancement in drive technology,electric motors have experienceed an expansion in their touring region (from 20% to about 80%) . The direct consequence of this, is the need for ―soft‖ control of motors, especially dc motors.A laboratory dc motor controller has been designed and constructed in this study. The scope covers the simulation and construction of a microcontroller-based variable speed laboratory dc motor controller with LCD visual indication. The methodology adopted employs the use of traditional calculations to develop models, selection of various component parameters and final fabrication.The heart of the design is the Arduino Microcontroller; ARTMEGA 328P (UNO board). It is configured into proteus is schematic capture and simulation. Tests carried out indicate a fair level of conformity with industry standards. It is recommended that additional circuitry be implemented to enable remote sensing and status monitoring in conjunction with Supervisory Control and Data Acquisition.
  • ItemOpen Access
    ASSESSMENT OF THE SYNERGISTIC EFFECT OR PLASMA ACTIVATED WATER AND SOME SELECTED ANTIBIOTICS ON BACTERIA
    (FACULTY OF NATURAL AND APPLIED SCIENCE DEPARTMENT OF PHYSICS, 2019-12-03) Agana, Daniel Timothy
  • ItemOpen Access
    RIEMANNIAN QUANTUM ENERGY OF A PARTICLE IN A FINITE-POTENTIAL WELL
    (DEPARTMENT OF PHYSICS FACULTY OF NATURAL AND APPLIED SCIENCES NASARAWA STATE UNIVERSITY, KEFFI, 2018-10-16) Ewa, Ibrahim Inusa
    In this research work, the golden Riemannian Laplacian operator was constructed using the golden metric tensor in spherical polar coordinate and was applied to the Schrodinger wave equation in order to obtain the golden Riemannian Schrodinger equation for a particle in a finite-potential well. The golden Riemannian Schrodinger equation was solved analytically to obtain the particle energy. The solution resulted to two expressions for the energy of a particle in a finite-potential well. One of the expressions is for the odd energy levels while the other is for the even energy levels. The results are that the golden Riemannian Laplacian operator and golden Riemannian Schrodinger equations were augmented with additional terms which are not found in the existing equations; and this can be applied to a finite-potential well problem so as to obtain the corresponding expression for the energy values.
  • ItemOpen Access
    A GENERALIZATION OF NEWTON’S DYNAMICAL GRAVITATIONAL FIELD EQUATION AND ITS APPLICATIONS TO PLANETARY THEORY
    (Department of physics, Nasarawa State University Keffi, 2014-07-10) Lumbi, William Lucas
    Over the years there has been the need to generalize both Newton’s dynamical theory of gravitation and Einstein’s geometrical theory of gravitation in order to provide better agreement to all physical theories. In this research work, the Riemann’s Laplacian operator was used to generalize Newton’s dynamical gravitational field equation to construct a generalized dynamical gravitational field equation. The generalized dynamical gravitational field equation was applied to static homogeneous spherical massive bodies to obtain generalized exterior and interior gravitational scalar potentials. The generalized dynamical gravitational scalar potential exterior to the body was substituted into the well-known Newton’s dynamical equations of motion, General dynamical equations of motion and Einstein’s geometrical equations of motion to obtain generalizations of Newton’s dynamical equations of motions, General dynamical equations of motion and Einstein’s geometrical equations of motion. The generalized equations of motion (Newton’s dynamical equations of motions, General dynamical equations of motion and Einstein’s geometrical equations of motion) are applied to the motion of the planets in the solar system to obtain generalized planetary equations of motion and hence the planetary parameters such as the orbital eccentricity, amplitude, the angular frequency, period, angular momentum per unit rest mass and the perihelion and aphelion distances. The results are that the generalized dynamical gravitational field equation, dynamical gravitational scalar potentials exterior and interior, Newtonian acceleration vector, Newtonian equations of motion, General dynamical equations of motion, Einstein’s geometrical equations of motion, Newtonian dynamical planetary equations of motion, General dynamical planetary equations of motion and Einstein’s
  • ItemOpen Access
    CONSTRUCTION AND IMPLEMENTATION OF A CHARGE CONTROLLER CIRCUIT WITH MAXIMUM POWER POINT TRA+CKER (MPPT) FOR PHOTOVOLTAIC SYSTEM
    (DEPARTMENT OF PHYSICS FACULTY OF NATURAL AND APPLIED SCIENCES NASARAWA STATE UNIVERSITY, KEFFI, 2018-11-12) Egwa, Omaku Samuel
    The limited availability of resources to meet day-to-day increase in power demand due to the limitations of conventional energy resources have become the concern of every nation. worst is the case of Nigeria was where the power supply depends solidly on hydro, leading to inefficient power generation and distribution In this research , a charge controller with Maximum Power Point Tracker (MPPT) for photovoltaic system was implemented using a micro controller PIC 16F8768 and a prototype was constructed with an out of 24 volts for optimum energy transfer throughout a clear day .Proteus 8.0 software as in appendix A and was constructed with output of 24V and implemented for optimal energy transfer throughout a clear day. The average of each term (voltage, current and power) outputs we are taking and there efficiencies for both dry season and rain season. The MPPT is responsible for extracting the maximum possible output from the photovoltaic and feed into the load via the boost converter which step up the voltage to the required. The performance characteristics of the charge controller with MPPT and without MPPT of the different output voltages were measured. Both output voltage and current with the MPPT and without MPPT were compared in terms of time (dry season and raining season ) and total power were evaluated. By using Proteus 8.0 software, the charge controller with MPPT was also stimulated. Result shows that the efficiency of power without MPPT was 58.7% where as with MPPT was 60.33%. The charge controller with MPPT gives 5.632 W maximum power at 3:05 pm .The charge controller with MPPT has better performance even though this advantages is at the expenses of additional components that makes up the tracking unit of the charge controller system . Therefore it can be recommended were the availability of grid is very low. Another advantage of using charge.
  • ItemOpen Access
    REVIEW OF EFFICIENT COMBINATION OF DIGITAL MODULATION TECHNIQUES AND CODING SCHEMES FOR OPTIMIZED PERFORMANCE IN SATELLITE COMMUNICATION
    (DEPARTMENT OF PHYSICS FACULTY OF NATURAL AND APPLIED SCIENCES NASARAWA STATE UNIVERSITY, KEFFI, 2017-08-25) Musa, Abdullahi Usman
    Satellite system was traditionally believed to be power – limited on its downlink channels. However, today‟s increase in bandwidth – demanding application have also makes satellite system to be bandwidth – limited (spectrum). The fundamental strive for efficiency faced by design engineers is further reinforced by the challenge of striking balance between power and bandwidth which are the two critical communication resources of meeting the system performance requirements without severe financial implications. This paper expresses methodologies for making the most efficient combination of coding scheme and digital modulation technique under bandwidth – limited is and power – limited conditions in satellite link capacity. One of the method adopted in proving this solution is to poise a trade –off of the probability of error (PE) and the ratio of bit energy to noise-power spectral density (Eb/NO). Matlab was used to solve the huge mathematical complexities therein. The implementation of this mechanism in satellite industry will yield great financial saving whose second order effects are keeping satellite services providers in business, meet customers‟ demand and optimize satellite systems operations.
  • ItemOpen Access
    GOLDEN RIEMANNIAN DYNAMICAL GRAVITO ELECTRIC FIELD EQUATION MODEL FOR A STATIC HOMOGENEOUS SPHERICAL CHARGEDMASSIVE BODY
    (DEPARTMENT OF PHYSICS FACULTY OF NATURAL AND APPLIED SCIENCES NASARAWA STATE UNIVERSITY, KEFFI, 2017-12-13) Yusuf, Ephraim
    The coupling of electromagnetism and gravitation approximately showed that both fields can be converted into each other. We find that every electromagnetic field is associated with a gravitomagnetic field, but gravitomagnetic fields can exist without electromagnetic ones in the case of neutral matter. In this research work the golden Riemannian Laplacian operator was used to construct a generalized Maxwell electric field equation for a static homogeneous spherical charged massive body. This field equation also known as the golden Riemannian dynamical gravito electric field equation was applied to a static homogeneous spherical charged of a massive body to obtain a golden Riemannian dynamical gravito electric scalar potential exterior and interior to the body. The golden Riemannian dynamical gravito electric scalar potential exterior to the body was substituted into the generalized Maxwell electric potential energy and also Maxwell generalized instantaneous Mechanical energy to obtain the golden Riemannian dynamical gravito electric potential energy as well as the mechanical energy respectively. Results shows that the generalized Maxwell‟s field equation, generalized electric scalar potential exterior and interior, generalized electric potential energy and generalized electric mechanical energy were augmented with additional correction terms which are not found in the well known Maxwellian field equation, electric scalar potential, electric potential energy and mechanical energy.
  • ItemOpen Access
    PERFORMANCE ANALYSIS OF DENSE WAVELENGTH DIVISION MULTIPLEXING (DWDM) USING DIFFERENT OPTICAL AMPLIFIERS IN OPTICAL FIBER TECHNIQUES
    (Department of Physics, Nasrawa State University, Keffi., 2017-11-11) Husseini, Umar Arafat
    In this research work, we analyzed the performance of Dense Wavelength Division Multiplexing (DWDM) using different optical amplifiers. DWDM systems consist of 120 channels having 0.25 nm channel spacing using RAMAN amplifier, Erbium Doped Fiber Amplifier (EDFA). The length of the RAMAN, EDFA amplifier are varying from 14.5 m to 20.5 m. Due to our observation, we conclude that the Gain increases as the length of amplifier increases in the EDFA, it gives better results as compare to the RAMAN. The gain flatness is more in RAMAN amplifier as compare to EDFA amplifiers.
  • ItemOpen Access
    INVESTIGATION OF HEAVY METALS AND ASSOCIATED HEALTH RISKS IN SOME SWAMPY AGRICULTURAL SOILS OF NASARAWA WEST, NIGERIA
    (Department of Physics, Nasrawa State University, Keffi., 2019-08-17) Abbas, Abdullahi Auta
    Soil plays a central role in food safety as it determines the possible composition of food and feed at the root of food chain. The study investigated heavy metals with specific emphasis on the health risk assessment in some swampy agricultural soils in Nasarawa West, Nigeria. Fifty soil samples were collected from five Local Government Areas. Karu, Keffi, Kokona, Nasarawa and Toto. Indicating ten soil samples from each Local Government Areas. The samples were collected at thirty centimeter depth from the top soil and the coordinate points were recorded using Global Positioning System. They soils were dried under ambient temperature. Agate Pestle and Mortar was used to pulverize the soils into fine particles and allowed to pass through 2.0mm sieve, and subjected to X-Ray Florescence Spectroscopy Analysis at Center for Energy Research and Development. Obafemi Awololowo University, Ile Ife. The results revealed the following heavy metals As, Cd, Cr, Cu, Ni, Pb and Zn. Ingestion, inhalation and dermal contact of food grown from heavy metal contaminated soils pose potential human health risk. The hazard index (HI) for all the pathways for adult was equal to 26.61. A value much greater than one (>1) due to dermal pathway and for children was 0.04. A value less than one due to inhalation pathway. This makes non-carcinogenic effects significant to the adult population. The total excess life cancer risk for Karu and Keffi (1.3x108, 1.1x109) was found to be higher than acceptable values of United State (1.0x10-4 to 1.0x10-6 ) and South Africa (5.0x10-6). However, Kokona, Nasarawa and Toto (2.1x10-3, 3.0x10-3 and 6.4x10-3) respectively were found to be below the reference value. This implies that there is a probability that one adult in 10,000 may be affected in Karu and Toto. Remediation measures and techniques should be employ by the appropriate authority (Government) at all levels so as to formulate polices and to reduce significant heavy metal concentration levels in soils for agricultural production.
  • ItemOpen Access
    CONSTRUCTION OF A 12V DC AUTOMOBILE ELECTRONIC CAR JACK
    (Department of Physics, Nasrawa State University, Keffi., 2018-09-22) SIMON, NWAFORCHA LUGARD
    Side road emergency like tire puncher, is a problem most common in cars. Conventional car jacks uses mechanical advantage to allow a human to lift a vehicle manually. This project describes the modification of the current automobile electronic jack by incorporating an electric DC motor, 555 timer using a dual pair 1N4148 diode and potentiometer, pickup circuit to detect noise in the circuit, a transistor driver pre-amplifier circuit to drive the electronic circuit, screw in other to make load lifting easier for emergency purpose using a power car battery (12volts). Belt is used to increase the lifting speed. Construction of electric jack was done by incorporating a belt to regulate the speed and also an on and off power button to turn off and on of the electronic car jack. Result shows that fabrication work was done using welding machine. The developed car jack was tested on loads ranging from 500-1000kg due to inefficiency in lifting the car which was as a result of much speed. The significance and purpose of this work is to modify the existing car jack in order to make the operation easier, safer and more reliable in order to reduce stress, health risk and energy in doing work which might lead to back ache when squatting for a long period of time. Speed controller should be used in future work to solve the problem and making car lifting at a great rate. The electronic car jack should be introduced to automobile industries so as to enable the development and ease in automobiles. Further research, design and construction should be done to achieve up to 90% efficiency in automobile jacks.
  • ItemOpen Access
    ASSESSMENT OF RADIATION EXPOSURE LEVEL FROM SOME SCRAP METAL DUMP SITES IN NASARAWA STATE, NIGERIA.
    (Department of Physics, Nasrawa State University, Keffi., 2019-03-11) KERINJA, SERIOUS SILAS
    Scrap yards, steel works and nonferrous metal smelters and refiners are increasingly detecting radioactive substances in incoming scrap metal as the result of losses, accidents or inadvertent disposal of radioactive material. In this study, the radiation exposure rate emanating from scrap metals dump site was assessed and the radionuclides responsible for the emission identified using an Interceptor – Spectroscopic personal radiation detector (SPRD). Sixteen (16) scrap metal dumpsites were selected at random across four Local Government Areas (Nasarawa, Lafia, Akwanga, and Keffi) of Nasarawa State, Nigeria and the gamma activity level in μrem/hr on three (3) randomly selected points on each of the scrap metal dumpsite was determined. A reading was taken on point 100m away from each of the scrap metal dump site. Results shows that, the highest annual effective dose equivalent was observed in Akwanga (AKW4) scrap metal dumpsite with annual effective dose equivalent of 0.2167mSv/yr, followed by Keffi (KEF1) with annual effective dose equivalent of 0.1758mSv/yr. The scrap metal dumpsite with the lowest annual effective dose equivalent were observed in Lafia(LAF3) and (LAF4) with annual effective dose equivalent of 0.0613mSv/yr. The excess lifetime cancer risk of 0.7585 × 10-3 was the highest value recorded in AKW4, while the lowest value was found to be 0.2146 × 10-3 in LAF3 and LAF4. The radionuclides identified are Med Pd-103, Ind Nb-95, Med Lu-176, Ind Xe-135, Ind Te-132,Ind La-140, Nat U-233, Med Se-75, Ind Cr-51, Ind Lu-176, Nat Th-177, Med Tc-99m, Ind La-140 and Med I-125 with thrust level ranging from 42- 83%. These values were below the ICRP dose limit of 1mSv/yr indicating that, the environment around these scrap metal dumpsites is safe. The excess lifetime cancer risk value (ELCR) obtained in some locations are higher than the world average value of 0.29 × 10-3. Therefore, we recommend that scavengers, workers and the public around the scrap dumpsites are to minimise the period of their stay within the dumpsites, so as to minimise the risk of developing cancer in future.
  • ItemOpen Access
    TIME DELAY ESTIMATION OF SIGNALS USING WIGNER-VILLE DISTRIBUTION
    (DEPARTMENT OF PHYSICS FACULTY OF NATURAL AND APPLIED SCIENCES NASARAWA STATE UNIVERSITY, KEFFI, 2018-05-13) Zubairu, Abdulmumini Loko
    The conventional representation of signals in the time domain or frequency domain are inadequate for analysis of signals, the obvious solution was to seek an alternative way to represent the signal as a two-variable function whose domain was two-dimensional space. An effective method based on correlation was proposed in this research work for the estimation time-delay of a signal which is corrupted by the non-stationary random noise. The time delay estimation was converted into parameter estimation. The research shows that the concept of reducing cross-terms with the help of using appropriate parameter values, which are unfortunate mathematical artifacts in determination of Wigner-Ville Distribution (WVD) of a multi-component chirp signal. The research was carried out using Linear Frequency Modulated (LFM) (chirp) signal based on quadratic time-frequency domain. From the derivation as well as simulation result of WVD of a multi-component chirp signal, it was clearly shown that cross-term appears in the middle of the signals. Quadratic TFD (QTFD) is able to provide high time and frequency resolutions but suffer heavily from the cross-terms which cause inaccurate signal interpretation. If the signal characteristics are known, a kernel can be designed that can suppress the cross-terms while preserving the auto-terms which is very important in generating accurate TFD. However, this is not practical in a non-cooperative environment where the exact signal characteristics are unknown. Thus, a new adaptive directional ambiguity function Wigner-Ville distribution (ADAF-WVD) was developed that adaptively estimate the kernel parameters in the ambiguity domain based on the signal characteristics. Accurate TFRs are produced for all signals with IF estimation performance verified using Monte Carlo simulation meeting the requirements of the Cramer-Rao Lower Bound (CRLB) at SNR > 8dB. A time delay estimation of chirp signal based on correlation method is presented which is converted to parameter estimation with less computational complexity and is suitable for chirp signal analysis. The statistical analysis in terms of signal-to-noise-ratio (SNR) and the estimation accuracy was also studied. The proposed method based on correlation, approximates the Cramer-Rao Lower Bound (CRLB) in terms of the inverse mean square errors (MSEs) for different signal-to-noise ratios (SNRs). The method was tested by simulations to show the efficacy which yield result of variance which is theoretically equated to Cramer-Rao Lower Bound (CRLB). The result of the estimation was obtained with the help of construction of appropriate MATLAB code and valid when compared with other simulation results and related theory.
  • ItemOpen Access
    ASSESSMENT OF HEAVY METAL CONCENTRATIONS IN LIPSTICKS
    (Department of Physics, Nasrawa State University, Keffi., 2018-09-07) ESOMNOFU, VICTOR ANUGO
  • ItemOpen Access
    MATHEMATICAL MODELLING OF THE DYNAMIC OF HEPATITIS B VIRUS TRANSMISSION AND CONTROLIN PRESENCE OF VACCINATION
    (FACULTY OF NATURAL AND APPLIED SCIENCES NASARAWA STATE UNIVERSITY, KEFFI NIGERIA, 2017-08-19) Idoko, Yahqub Aroon
    In this dissertation,we formulate and systematically study the global dynamics of a simple model of hepatitis B virus in termsof ordinary differential equations. This model has two important and novel features compared to the well-knownbasic virus model in the literature. Specifically, the infectious class incorporates those with one covalently closed circular DNA (cccDNA), and those with multiple cccDNA.cccDNA is the cell that restrict the treatment of Hepatitis B. As a result of this the infection reproductionnumber is no longer dependent on the patient liver size (number of initial healthy liver cells). For this model,the existence and the stability analysis of the Disease Free State is explicitly determined using the determinant and trace of the Jacobian Matrix approach. We deduce from stability analysis that the Hepatitis B virus is asymptotical stable if the < 1(Basic infection reproduction number which shows that the disease can be control using effective treatment on the infectious class and with the aid of vaccination the spread of the disease will be less compare to when vaccine is not administered.
  • ItemOpen Access
    HEALTH RISK ASSESSMENT OF SOME FACIAL COSMETICS SOLD IN KEFFI MARKETS, NASARAWA STATE, NIGERIA.
    (DEPARTMENT OF PHYSICS FACULTY OF NATURAL AND APPLIED SCIENCES NASARAWA STATE UNIVERSITY, KEFFI NIGERIA, 2018-07-11) Dahiru, Musa Maryam
    The demand for cosmetic products from around the world has increased rapidly due to the growing awareness of the need to beautify the human body. This study assess the health risk due to exposure to heavy metals in various brands of cosmetics sold in Keffi Markets, Nasarawa State using the x- ray fluorescence spectroscopy Analyzer. Eight heavy metal contents were measured in 32 different cosmetics commonly sold in local markets and super markets in Keffi, Nasarawa State which include Talcum powder, pressed powder, Dental powder, eye shadow, eye lines, and hair dye. The concentration of heavy metals such as Cd, Pd, Cr, Zn, Mn, Fe, Cu, Ni was determined. The hazard quotients, systemic exposure dose and margin of safety were determined. Results shows that, the range of mean concentrations of metals in these facial cosmetics are Cd (0.216 -1.46 mg/kg), Pd (53.628- 267.962 mg/kg), Cr (18.571- 30.631 mg/kg), Zn (10.443 -315.746 mg/kg), Mn (77.693 - 256.319 mg/kg), Fe (123.081 - 632.828 mg/kg), Cu (9.285 - 36.126 mg/kg), and Ni (8.603 – 48.887 g/kg). The hazard quotients were found to be greater than 1 which indicates risk of carcinogenesis. The systemic exposure dosage (SED) values for these metals acquired from the personal care products were below the WHO limit of 100. The margin of safety values obtained were greater than 100, indicating that the concentrations of metals investigated in these facial cosmetic exert no risk associated with their occurrence in these products. The maximum value of oral cancer risk was detected in Hair dye and the minimum value in eye Liner. Conclusively heavy metal content within the studied cosmetic were ordered as Fe > Pb > Mn > Zn > Cr > Ni > Cu > Cd at all cosmetics brand. Eye liner has the highest MOS values which indicate that there is little risk associated with the concentration of metals in eyeliner have the value was lower than one (1) indicated that the overall risks in both exposure pathways are within safe level. Hi value were lower than one (1).