Numerical Study of Negative-Refractive Index Ferrite Waveguide

Consider a magnetized ferrite-wire waveguide structure situated between two half free spaces. Ferrites to provide negative permeability and wire array to provide negative permittivity. The structure form left - handed material (LHM) with negative refractive index. The transmission of electromagnetic waves through the structure is investigated theoretically. Maxwell's equations are used to determine the electric and magnetic fields of the incident waves at each layer. Snell's law is applied and the boundary conditions are imposed at each layer interface to calculate the reflected and transmitted powers of the structure. Numerical results are illustrated to show the effect of frequency, applied magnetic fields, angle of incidence and LHM thickness on the mentioned powers. The analyzed results show that the transmission is very good when the permeability and permittivity of the structure are both simultaneously negative. The frequency band corresponding to this transmission can be tuned by changing the applied magnetic fields. The obtained results are in agreement with the law of conservation of energy. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2489

Maximum and Minimum Transmittance of a Structure Containing N-Identical Pairs of Left- and Right-Handed Materials

The optical transmission properties of a structure consisting of N identical pairs of left- and right-materials are investigated theoretically and numerically. Maxwell's equations are used to determine the electric and magnetic fields of the incident waves at each layer. Snell's law is applied and the boundary conditions are imposed at each layer interface to calculate Fresnel coefficients. Expressions for reflectance and transmittance of the structure are given in terms of these coefficients. In the numerical results the transmittance of the structure is computed and illustrated as a function of frequency under different values of N. Minimum transmittance is achieved by using high and low opposite refractive indices of left and right materials of each pair of the structure. The frequency band of this transmittance is reduced by decreasing N. Maximum transmittance is demonstrated by using two slabs of the same width and opposite refractive indices placed between two dielectric media of the same kind. The effect of frequency and angle of incidence is very weak in these structures as compared to their all-dielectric counterparts. Moreover the obtained results are in agreement with the law of conservation of energy. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3026

Numerical study of a structure containing left-handed material waveguide

In this paper a waveguide structure consisting of a pair of left-handed material (LHM) and dielectric slabs inserted in vacuum is investigated theoretically. Maxwell’s equations are used to determine the electric and magnetic fields of the incident waves at each layer. Snell’s law is applied and the boundary conditions are imposed at each layer interface to calculate the reflected and transmitted powers of the structure. Numerical results are illustrated to show the effects of frequency, angle of incidence and LHM thickness on the transmitted power when the refractive index of the dielectric layer changes. The same procedure is repeated to show the variation of the transmitted power with the change in the mentioned parameters under different values of dissipation factor of the lossy LHM. Consequently, two cases of the LHM are considered, loss-less case and loss case. The results obtained, are in agreement with

Effect of negative permittivity and permeability on the transmission of electromagnetic waves through a structure containing left-handed material

We investigate the characteristics of electromagnetic wave reflection and transmission by multilayered structures consisting of a pair of left-handed material (LHM) and dielectric slabs inserted between two semi-infinite dielectric media. The theoretical aspect is based on Maxwell's equations and matching the boundary conditions for the electric and magnetic fields of the incident waves at each layer interface. We calculate the reflected and transmitted powers of the multilayered structure taking into account the widths of the slabs and the frequency dependence of permittivity and permeability of the LHM. The obtained results satisfy the law of conservation of energy. We show that if the semi-infinite dielectric media have the same refractive index and the slabs have the same width, then the reflected (and transmitted) powers can be minimized (and maximized) and the powers-frequency curves show no ripple. On the other hand if the semi-infinite dielectric media have different values of refractive indices and the slabs have different widths, then under certain conditions the situation of minimum and maximum values of the mentioned powers will be reversed

Pattern of Anorectal malformations in Gzira National Center for Pediatric Surgery (GNCPS)

Background: Anorectal malformations (ARM) are one of the common clinically and socially demanding problems in the world especially in the poorly resourced countries. Patients and Methods: It is a cross-sectional descriptive hospital based study, in the period from June 2009 to December 2011 of 80 patients of ARM in Gezira National Center for Pediatric Surgery (GNCPS). History and examination in addition to invertogram and distal loopogram were the tools of assessment. Results: Eighty children with ARM were studied, 64 males and 16 females. Sixty six patients have delayed presentation. More than 61% presented from rural areas. Twenty-one (26%) patients had one or more associated congenital anomalies, with cardiac and limb anomalies being the most common associated malformation. High anomaly was found in 48.75% of patients, intermediate type was found in 5%, while 43.75% of patients had low anomaly. Conclusion: Delayed presentation entails suboptimal training of midwives and resident doctors in obstetric hospitals and nurseries to evaluate congenital defects in the newborn

Prolonged trismus post tetanus in a Nigerian boy: The role of oral baclofen- A case report and literature review

Background: Tetanus is characterized by increased muscle tone and spasms caused by the neurotoxin, tetanospasmin. Management principles include wound debridement, antibiotic therapy, neutralize circulating toxins, spasm control, supportive care and initiation of active immunization.Aim: To highlight the use of oral baclofen in tetanus treatment.Method: The management of a peculiar case of tetanus was highlighted. Medscape and Pubmed were also searched for some related literatures.Case Presentation: A nine year old boy with antecedent history of dirty wound presented with trismus and generalized spasms of one week duration. Though fully conscious, he could neither talk nor eat. He was from a poor socio-economic background. He had wound debridement, I.V metronidazole for seven days, a cocktail of diazepam infusion 5mg/kg/day, I.V chlorpromazine 25mg 12hourly and I.M phenobarbitone for 14 days. Five days into treatment the spasms stopped but trismus persisted up to the third week.By this time the maximal interincisors distance was 0.5cm. Baclofen syrup was commenced at 10mg daily. Five days later the maximal inter-incisors’ distance was 1.0cm, and a week later it was 2.5cm. By the second week of oral baclofen there was complete resolution of trismus and recovery of speech.Conclusion: This report suggests the need for further studies on the use of enteral baclofen during tetanus. Although intratheccal baclofen is in use, during recovery from tetanus, treatment with oral baclofen may reduce morbidity

The Nigerian girls education project: giving the girl child a voice

The three-year Girls’ Education Project (GEP) aims to improve the quality of life of girls by seeking to increase their enrolment, retention and completion of primary school education. The project is being implemented in six states of Northern Nigeria, under a bilateral agreement between the Federal Government of Nigeria and United Nations Children’s Fund (UNICEF) with funding support from the Department for International Development (DFID). It uses an inter-sectoral approach to provide amongst other things, WASH facilities in the targeted schools. Results in three states include construction of 323 boreholes and 688 blocks of VIP latrines; establishment of WASH school clubs; enhanced partnerships between collaborating ministries, the three tiers of government, public and private sector, communities and schools. Other outcomes include increased enrolment and retention of girls as well as improved self esteem. This paper seeks to share the human impact of the GEP project in three states of Nigeria

Ameliorative Effect of Vitamin C on Alterations in Thyroid Hormones Concentrations Induced by Subchronic Coadministration of Chlorpyrifos and Lead in Wistar Rats

The present study evaluated the ameliorative effect of vitamin C on alteration in thyroid hormones induced by low-dose subchronic coadministration of chlorpyrifos (CPF) and lead (Pb). Forty Wistar rats were divided into 4 groups of 10 animals each. Groups I and II were administered soya oil (2 mL/kg) and vitamin C (100 mg/kg), respectively. Group III was coadministered CPF (4.25 mg/kg ~1/20th LD50) and Pb (250 mg/kg ~1/20th LD50), respectively. Group IV was pretreated with vitamin C (100 mg/kg) and then coadministered with CPF (4.25 mg/kg) and Pb (250 mg/kg), 30 min later. The regimens were administered by gavage for a period of 9 weeks. The marginal decrease in serum triiodothyronine and thyroxine and the significant increase in the concentrations of thyroid stimulating hormone and malonaldehyde in the group coadministered with CPF and Pb were ameliorated by vitamin C partly due to its antioxidant properties

Effect of Processing on Fatty Acid and Phospholipid Compositions of Harms (Brachystegia eurycoma) Seed Grown in Nigeria

A comprehensive study on the effect of processing on fatty acid and phospholipid compositions of Brachystegia eurycoma seed flour was conducted. Processing methods (boiling, fermentation and roasting) were adopted using standard analytical techniques. The most concentrated fatty acids (%) were linoleic acid (47.95 – 50.91) > oleic acid (26.51 – 30.91) > palmitic acid (11.51 – 14.16) > stearic acid (3.06 – 5.54). Lenoceric, erucic, and arachidic acids were present with none of them recording up to 1% while caprylic, capric and margaric acids were not at the detection limit of GC. All the processing methods increased the contents of palmitic, palmitoleic, linoleic and linolenic acids. The oleic acid content was reduced in boiled, fermented and roasted samples by 60.93, 59.97 and 63.77%, respectively. The phospholipid analysis gave result (%) of phosphatidic > phosphatidylinositol > phospatidyserine > phosphatidyethanolamine concentrations. Generally, the processing methods showed deviations in fatty acid and phospholipid components from the raw seeds. There was a clear indication that the raw and processed samples of B. eurycoma seed oils contained a high level of polyunsaturated fatty acids, making them a healthy low fat food. Keywords: Brachystegia eurycoma, processing, seed oils, fatty acids, phospholipids