Libyan Journal of Science &Technology

Diode Amplitude Modulation and Demodulation

Arwa A. Ayad — 2025-03-01

Diode amplitude modulation and demodulation have been investigated and the modulation index and modulation percentage were calculated. Of the several amplitude modulation methods, the diode modulation has been chosen to execute the amplitude modulation process because it was the first method used and it is the simplest method. A 50 Hz sine wave is used as a modulating signal to amplitude modulate a 1 kHz sine wave used as a carrier wave. During the modulation process, the amplitude of the modulating signal was kept constant at a value of 6 V while the amplitude of the carrier wave was given values between 6 V to 12 V increasing the value in steps of 1 V. The shapes of the modulation stages and of the demodulation processes were displayed on the oscilloscope screen using the simulation programmed named NI Multisim 14.2. The experiments were also carried out practically in the advanced electronics laboratory in the Physics department/Faculty of Science/University of Benghazi using real electronic equipment and parts. The recovered audio signal in the demodulation process was the same as that used as a modulating signal.

A survey of medical plants of Cyrene (campus Apollo) Shahat-Al-Jabal Al-Akhdar, Libya.

Rania F. Ali — 2025-03-01

AL-Jabal AL-Akhdar region is very rich in diversity in plants, and studies are still few in AL-Jabal AL-Akhdar. This study was 2021/2022, conducted for four seasons. An inventory of the plants of this region was made entirely, and the medicinal plants were counted in the study area. The results indicated the presence of a total of 70 medicinal plant species belonging to 45 families and 67 genera and 68 species. Gymnosperms were represented by only 3 families, 3 genera, and 3 species, 1 sup species. Angiosperms composed the most dominant botanical group with 41 families. Dicotyledons were the most presented group of the angiosperms with 35 families, 7 genera and 58 species, and 1 sup species, whereas Monocotyledons comprised a far less diverse group of medicinal plants in the area study with only 6 families, 7 genera and 7 sup species, pteridophyta, 1 family, 1 genus,1 species. Asteraceae and Lamiaceae attained the highest number of genera recorded in the study area with 5 genera and 5 species, followed by Fabaceae with 4 genera, 5 genera and 5 species, followed by Fabaceae with 4 genera and 4 species. Our results revealed that the most represented life forms of the medicinal plants in Shahat were Therophytes (Th) (36%) 24 species, Phanerophytes (Ph) (18%) 12 species, Chamaephytes (Ch) (16%) 11 species, followed by Geophytes (G) (10%) 7 species, Heleophytes (H) and Nano-phanerophytes (7%) 5 species, as for Hemicryptophytes, Hydrophytes and Linaes the percentage of their presence was very simple (2%), It is represented by one type for each of them. Also on the list is an endemic and endangered medicinal plant. Cyclamen rohlfsianum Aschers, belonging to the family Primulaceae.

The Frequency of Ear, Nose, Throat, Head and Neck Lesions of Tuberculosis in the Eastern District of Libya.

Yosef H. Abdulkarim — 2025-03-01

Tuberculosis (TB) in the head and neck region represents a diagnostic challenge as it can mimic many conditions, such as malignancy and chronic granulomatous diseases. Therefore, the clinician must have a high index of suspicion for head and neck TB increasing the awareness of health workers in Libya of how TB affects the head and neck areas and its common presenting features may prevent unnecessary delays in the diagnosis and treatment of these cases and improve their outcomes. Objective: Assess the frequency of ENT manifestations of tuberculosis. A cross-sectional observational study was conducted, and the cases were subjected to a detailed history and a head and neck examination. The data were analyzed to assess any association existing between the study variables and the prevalence of ENT, head, and neck manifestations of tuberculosis. The results of this study showed that, out of 168 cases of TB included in the study, 49 were positive for ENT, head, and neck tuberculosis. Tuberculous lymphadenitis was the most common TB manifestation in the head and neck region, accounting for 87.8% of positive cases. Laryngeal TB and TB abscesses of the deep neck spaces account for 4.1% and 4.1% of positive cases, respectively. TB otitis and nasal TB account for 2% and 2% of positive cases, respectively. Conclusion: TB in the head and neck region represents a diagnostic challenge, and a high index of suspicion is needed. All suspected cases should be investigated appropriately. Close cooperation between TB-related medical specialists is needed.

Using Markov Chains to Predicate Pandemic Trend: A Case Study in Libya for COVID–19.

Elmabrok H. Abdelrahim — 2025-03-01

Many predictive models have been developed by various academic institutions to support health systems in strategic decision-making, planning, and policies that help in the challenge against COVID-19. These models are useful in determining, the expected number of cases and deaths due to COVID–19, as well as the required resources such as hospital beds for isolation period and ICU, and necessary supplies such as protective equipment. In this article, the stationary Markov Chain is applied to the Libyan population to predict the status of the pandemic in Libya after more than four years of its spread. The data used was collected by WHO, and the results showed that the chain had converged due to the large sample size taken, resulting in the limiting probability being very close to the initial distribution. Additionally, the probability of staying in a good situation is 70.9% and to become worse is 29.1%. Finally, due to the convergence of the chain, these results will remain the same regardless of the initial state of the chain.

A study on the prevalence of the malaria parasite in the city of Sebha among expatriate workers from neighboring countries.

Naima I. Al-Haddad — 2025-03-01

Libya eliminated malaria in 1973. The majority of malaria cases reported in Libya are imported cases, that travelled abroad, especially to neighboring countries where malaria is endemic. Rapid diagnostic test (RDTs) was conducted to determine the possible risk of malaria among expatriates residing in different areas in Sebha City. The results of this study showed that out of 363 expatriates,141 had an infection with malaria (38.8%). Infection of Plasmodium falciparum and Plasmodium vivax was reported among one hundred one (27.8%) and forty expatriates (11.01%) respectively. The infection rate was higher in males than females, reaching 39.2% and 31.2%, respectively. Infection of malaria was higher among expatriates who came from Chad (55.55%) and Niger (41.35 %). The correlation between the infection rate of malaria and the educational attainment of expatriates was substantially statistically significant (χ²=9.571; P=0.002). This study confirms that the prevalence of malaria among expatriates is relatively high which may impose a high risk of re-introducing malaria to the southern regions of the country.

Evaluation of microbial risk factors in prepared homemade food in Al-Zawia City, Libya.

Amina K. Elzawi — 2025-03-01

Foodborne infections remain a public health issue, emphasizing the need to understand microbiological dangers in home food preparation. This study analyzes foodborne pathogen parameters to assess home cooking microbiological risks. A questionnaire-based cross-sectional study examined microbial 1 in home food preparation. The questionnaire gathers data providing a comprehensive understanding of microbiological risk factors. Using IBM SPSS Statistics, statistical analysis will reveal variable linkages. The study reveals profound links in home food preparation. Participants with lower levels of education have a notable correlation with increased presence of pathogens history (p=0.00638*). Significantly, 22.85% of individuals indicate a previous occurrence of foodborne infections, with Salmonella spp. (12.85%), E. coli (7.15%), and Campylobacter spp. (2.85%) being the most commonly observed. There are strong associations between hygienic practices: hand washing (p = 0.00014*), surface cleaning (p = 0.00066*), and thermometer use (p=0.00008*). Preservation behaviors exhibit notable correlations: checking expiry dates (p=0.000235*), promptly refrigerating (p<0.00001*), and defrosting techniques (p=0.04882*). There is a significant correlation between education (p=0.00638*) and awareness (p=0.00129*) concerning pathogen history. Diverse sources of information indicate a non-significant association (p=0.8878). This study emphasizes the need for focused food safety measures including education and awareness to improve home food safety. Understanding these linkages allows people to adopt safer cooking practices, improving health and safety. The public health effects require awareness of home food preparation procedures to prevent microbiological risks.

Invited review: A Review on Field Emission Microscopy, Principles, Theory, and Applications.

Khalil I. Hashim — 2025-03-01

The purpose of this paper is to shed light on a very important field of electronic physics which should be known to those who are interested in physics and in electronic physics. The study describes a simple field emission microscope which was designed to permit measurement of electron emission from the whole area of the emitter's surface and a probe hole field emission microscope which was designed to permit measurement of electron emission from individual planes of the emitter's surface. Selection of the planes can be achieved by mechanical, magnetic, or electrostatic deflection of the image onto the probe-hole, which is located in the centre of the screen, and the transmitted current is collected by an electrode sited behind a hole in the centre of the screen. Changes in work function which result from the adsorption of metal atoms on the whole tip and individual planes of the emitter surfaces have been measured by many authors by noting the changes in the slope of Fowler-Nordheim plots. In addition, surface diffusion and desorption of metal atoms from the emitter surface have been investigated and the activation energies for these processes evaluated.

Shell model calculations for 18O and 18Ne nuclei.

Souad S. Almanqoush — 2025-03-01

A simple shell model was used to calculate the low-lying energy spectra, reduced electric quadrupole transition probabilities B(E2), and electric quadrupole moments for the oxygen nucleus (¹⁸O) and neon nucleus (¹⁸Ne). The calculations were performed using computer codes written in the FORTRAN language. Only two identical particles outside a doubly magic core have been considered to occupy the valence single-particle states. The single particle energies were taken from the experimental spectra of ¹⁷O and ¹⁷F nuclei. The modified surface delta interaction (MSDI) was employed as an effective interaction to calculate the two body matrix elements. The results of previous studies using empirical interactions are also included along with the experimental data to facilitate the comparison. It is found that the results of this work qualitatively compare well with the experimental data, but quantitatively, they are not as good as the previous theoretical works on the same nuclei.

Modeling Time-Independent Schrödinger Equation for an Infinite Potential Well Using Numerov and Matrix Methods

Dalal Y. Saad — 2025-03-01

The objective of this study is to numerically solve and apply two approximate methods to investigate the Time Independent Schrödinger Equation (TISE) in one dimension for an infinite potential square well. These two numerical methods are the Numerov Method (NM) and Matrix Method (MM). As a simulation tool, MATLAB, a high-level programming language and an efficient simulation tool, is used for modeling and solving TISE in one dimension. Exact analytical solutions for these potential functions are obtained and compared with numerical solutions and computational techniques. The energy eigenvalues and Eigen functions of a particle (such as an electron) restricted to move inside this potential are discussed as an illustration. The numerically calculated energies of several states with increasing numbers of points were obtained from both methods and compared with the simulation results of the exact solution. As an exemplary case, the first five wave functions are accurately determined numerically where the discreteness is found since the wave function vanishes at the boundary. The obtained results show very good agreement and the similarity is clearly confirmed between the three cases. This agreement confirms that this approach was highly accurate and efficient. The accuracy and the convergence of the numerical obtained results were easily checked. The stability of these methods is due to the fact that there are no restrictions on the time steps to be taken. The merits of these numerical methods are to avoid a huge expense in time when solving Schrödinger equation.