National Security Challengesand Sustainable Economic Development: Evidence from Nigeria

Nigeria is one of the relatively secured nations in West African sub-region. In recent times, this endowed nation suddenly metamorphosed into an abode of serial bombing, hostage taking, armed robbery, cold-blooded killings and ethno-religious conflicts traceable to militant groups with conflicting ideological, political and religious agenda. Among these militant groups are Niger-Delta insurgents, Campus cults, Bakassi Boys, Armed robbers, O'odua People's Congress, Boko Haram et cetera. The resultant loss of lives, rising budgetary spending for security and destruction of valuable government facilities portend devastating consequences for sustainable economic development in the country. This paper examines the link between national security and sustainable economic development in Nigeria. The authors adopt quantitative method, which entails extraction of secondary data from the publications of Central Bank of Nigeria, National Bureau of Statistics and other reliable reports on the subject. The generated data were carefully analysed using descriptive and inferential statistics on the basis of which far-reaching conclusions were drawn. The research findings indicate that Nigeria's expenditure on national security is rising faster than spending on education, agriculture, health and construction. This unpleasant finding has negative effect on sustainable economic development in Nigeria. The paper proffers tripartite recommendations for governments, the citizens and policy-makers

Mutual Coupling Reduction in Antenna Using EBG on Double Substrate

In this paper, a mutual coupling studies is conducted between two-element array antenna on dual substrate. A single patch antenna is firstly designed on dual substrate layer to testify appropriate performance at 2.45 GHz. Subsequently, an array of two element patches on dual substrate are constructed with one of them is incorporated with three EBG unit cell on the bottom substrate. The radiating patch is on the top substrate, while the EBG unit cells is on the bottom substrate. With EBGs in separate layers from the antenna array, the antenna elements are closely separated by a distance of 22 mm with a significant reduced mutual coupling of -26.61 dB. This correspond to a distance reduction of 34.68%. The proposed structure implemented only three EBG unit cells. Apart from that, the study of overlapped case of EBG with the antenna is also presented

Dual Band to Wideband Pentagon-shaped Patch Antenna with Frequency Reconfigurability using EBGs

A dual band to wideband reconfigurable pentagon-shaped antenna with EBG unit cell is proposed. A minimal number of two EBG unit cell is deployed to realize frequency reconfigurable mechanism.  By varying the state of the EBG the antenna is capable to change its dual band operation to wideband alternately. There are three cases that have been analysed, first case is the EBG incorporated antenna with ideal and second is with the active EBG. Subsequently, the third cases is the fabricated ideal EBG incorporated antenna. The dual band operation is at 1.8 GHz and 5.2 GHz while the wide band from 1.6 GHz to 2.37 GHz (770 MHz). The proposed reconfigurable antenna is suitable to be implemented for LTE (1.6 GHz), Wi-Fi (5.2 GHz), WiMAX (2.3 GHz) and cognitive radio application

Evaluating thermogravimetric analysis for the measurement of drug loading in mesoporous silica nanoparticles (MSNs)

In this study, a thermogravimetric analysis (TGA) method for measuring the drug loading in mesoporous silica nanoparticles (MSNs) has been developed and evaluated in comparison with the drug loading quantification by high-performance liquid chromatography (HPLC). Indapamide was loaded into two different types of MSNs, namely Mobile Crystalline Material (MCM-41, pore size = 1.2 nm) and Santa Barbara Amorphous (SBA-15, pore size = 4.1 nm). Physical mixtures of the drug and silica gave a linear correlation between the observed and expected drug content for both TGA and HPLC, which were used for calibration purposes. The limit of detection (LOD) for the TGA method obtained from the physical mixture calibration curve was 0.77 % (w/w) and the r² value was 0.9936, whereas the HPLC had a LOD of 0.06 % (w/w) and an r² value of 0.9933. The sensitivity of the TGA method was well established using the drug loading studies, as it can detect the low loading of MCM-41 at 2.2 ± 0.21 % (w/w), compared to 5.1 ± 0.12 % (w/w) with the SBA-15. In all samples applied, the multiple comparison analysis showed an insignificant difference between the two methods (p > 0.05). The TGA data presented good evidence for using this technique as a sensitive, cost-effective, and low-variable quantitative analysis in the drug loading determination of the MSNs. TGA is not a selective method of quantification, but optimising the method using the pure and blank samples of MSNs and drug can significantly improve the sensitivity. This work provides a unique approach to apply TGA as a selective and more favourable method to characterise MSNs to do early formulation developments

Effect of Al and Mg Doping on Optical Properties of ZnO Thin Films Prepared by Spin Coating

This paper investigated the influence of aluminum and magnesium doping on the optical and electrical properties of zinc oxide (ZnO) thin films for solar cell application. zinc acetate dehydrates was used as starting material. Aluminum chloride and tin chloride were added to each solution to serve as dopants. X-ray diffractions were analyzed by X-ray diffraction (XRD) which revealed crystalline and hexagonal wurtzite structure. All the films showed more than 80% transparency in the visible region. The optical band gap of undoped znO thin film was found to be 3.12ev while that of Al-doped and Mg-doped znO film was estimated to be 3.16eV and 3.26eV respectively. The resistivity of the films measured were 2.51×10–4Ω cm for Al-doped, 2.53×10–4Ω cm for mg-doped and 2.61×10-4Ω cm for undoped znO respectively. The quality of the films deposited in this work is a promising window layer component of a solar cell. The variation in the band gap observed in this work could be explained by Burstein–Moss effect which was fully explained in the discussion section of this work

Interfacial reaction analysis of Sn-Ag-Cu solder reinforced with 0.01wt% CNTs with isothermal aging

This study focused on the formation and growth of intermetallic compound (IMC) layer at the interfaces of pad finishes. The thickness of IMC layer, wetting angle, and defects such as floating IMC and voids formation after as reflow and isothermal aging were discussed. In this study, SAC237 (Sn: 99 wt.%, Ag: 0.3 wt.%, Cu: 0.7wt.%) reinforced with 0.01 wt.% of Multi-Walled Carbon Nanotubes (MWCNTs) were soldered on Electroless Nickel Immersion Gold (ENIG) and Immersion Tin (ImSn) pad finishes. Isothermal aging at 150°C for 400h, 800h, and 1200h were conducted after as reflow process. The IMC layer were analysed using optical microscope with image analyzer. The results shows the thickness of IMC layer for both ENIG and ImSn increased as the isothermal aging period increases. The increament was found from 1.49 μm to 1.73 μm for ENIG and 2.51 μm to 5.49 μm for ImSn. Floating IMC and voids formation were also observed on both pad finishes. Wetting angle for ENIG and ImSn varied from 16.21° to 36.85° and 24.27° to 34.41° respectively

Метод виділення основного тону на основі модифікованої математичної моделі слухової системи людини

Розпізнавання голосів є важливою складовою надійної системи біометричної ідентифікації людини, які набувають більшої актуальності в сучасному комп’ютеризованому світі. Однією з ознак, що використовуються для розпізнавання голосів, є частота (період) основного тону голосу, інформативність якої суттєво знижується за присутності в мовному сигналі низькочастотних шумів. Запропоновано метод виділення частоти основного тону, який, на відміну від існуючих, є стійкішим до наявності в мовному сигналі низькочастотних шумів

Sesamum indicum diet prevents hyperlipidemia in experimental rats

Cardiovascular diseases and metabolic complications caused by hyperlipidemia are the leading cause of death globally. In this study, the hypolipidemic potency of Sesamum indicum (SI) seeds was investigated. Of the thirty-five (35) male rats used in the study, five (5) were randomly selected for baseline measurements and thirty (30) were fed high fat diet (HFD) for four (4) weeks before random assignment into three (3) groups. The experimental group was treated with 50% SI seed, the positive control group was given a hypolipidemic drug, atorvastatin (5 mg/kg/day) while the untreated group served as the negative control. With SI administration, the dyslipidemia induced by the HFD consumption in the plasma and the investigated body organs was reversed to a comparable degree with that of atorvastatin treatment. Taken together, this study demonstrates the hypolipidemic potency of SI in ameliorating hyperlipidemia and its associated complications, facilitated by the inhibition of HMG-CoA reductase activity

Метод нормалізації тривалості звучання парольних фраз для системи розпізнавання мовців

Авторами запропоновано метод нормалізації тривалості звучання записів мовних сигналів, орієнтовану на інтеграцію в систему ідентифікації мовця за індивідуальними особливостями його голосу. Метод дозволяє мінімізувати втрати інформації про індивідуальні властивості мовних сигналів при зміні тривалості їх звучання за рахунок аналізу та сегментації мовного сигналу відповідно до його вмісту та застосування динамічного коефіцієнту стиснення, який визначається результатами сегментації