Structural and optical correlation of europium and dysprosium co-doped boro-telluro-dolomite glasses incorporated with silver nanoparticles

Rare earth ions doped glasses with tailored lasing and light emitting potency are active area of materials science research. In this view, a series of Eu3+ and of Dy3+ co-doped (at various concentrations) boro-telluro-dolomite (BTD) glasses included with silver nanoparticles (Ag NPs) were prepared by melt-quenching method and characterized for the first time. The role of co-dopants and Ag NPs contents on the optical and structural performance of the studied glasses was evaluated. X-Ray diffraction (XRD) patterns of the as-quenched samples affirmed their amorphous nature, and the energy dispersive X-ray (EDX) spectra showed the presence of actual chemical compositions of the glasses. The existence of Ag NPs with an average diameter of 25.50 nm in the glass matrix was verified using the high-resolution transmission electron microscopy (HRTEM) analyses. Ultrasonic and Vicker‘s micro-hardness analyses displayed high mechanical stability of these glasses. Fourier transformed infrared (FTIR) and Raman spectra of the glasses revealed various chemical functional units in their network structure. Ultraviolet-visible-near-infrared (UV-Vis-NIR) spectral data was used to estimate the optical band gap energies and refractive indices of the glasses using three different models. BTD1.0AgCl sample exhibited a distinct broad surface plasmon resonance (SPR) band at 479 nm. The photoluminescence spectra of the Eu3+-doped glasses (under 464 nm excitation) displayed five significant emission bands at 577, 591, 611, 652 and 702 nm matching with 5D0 7FJ transitions (with J 0, 1, 2, 3, and 4) wherein the band intensities were quenched beyond 1 mol% of Eu3+ doping. The symmetry of the ligands in the vicinity of Eu3+ and Dy3+ in addition to their bonding nature of the glasses were evaluated from the Judd-Ofelt intensity parameters Ω2, Ω4, and Ω6. The observed emission spectral overlap and change in the fluorescence lifetime indicated a substantial bi-directional energy transfer between Eu3+ and Dy3+ in the glass matrix, confirming the Forster-Dexter energy transfer process via the electric dipole–dipole interactions. Besides, the inclusion of Dy3+ altered the emission color of Eu3+ from red region with CIE coordinates of (0.638, 0.361, for BTD1.0Eu glass) to white light zone with CIE coordinates of (0.395, 0.317). The achieved hue was very close to the ideal red color phosphor value of (0.67, 0.33) and pure white light value of (0.33, 0.33). The calculated lasing parameters such as the transition probability, stimulated emission cross-section, luminescence branching ratio, optical gain, gain bandwidth, and radiative lifetime showed enhancement due to the incorporation of Dy3+ and Ag NPs. The produced glasses exhibited high color purity (ranged from 24 – 97.04%) and better quantum efficiency (ranged from 54.88 – 97.81%), wherein such improvements were mainly attributed to the efficient energy transfer between Eu3+ and Dy3+ as well as the Ag NPs SPR-induced local field effects. Overall, a correlation between the structural and optical features of the BTD glasses was determined. Based on the obtained results it can be concluded that the proposed glasses have great potential for the solid-state red laser and white light emitting devices applications

Physical and spectroscopic properties of lithium-borosulfophosphate glasses doped with dysprosium and europium ions

A study had successfully been conducted on lithium-borosulfophosphate glasses to examine the effect of dysprosium and europium ions upon their physical and spectroscopic properties. The glass samples were synthesized via convectional melt quenching technique and characterized using density, X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), UV-Vis-NIR, and Photoluminescence (PL) measurements. The amorphous nature of the glass was confirmed using XRD studies. It is observed that the physical and optical properties of these glasses are found to be strongly influence by varying the glass composition. The glass density and refractive index increase proportionally with Dy2O3 and Eu2O3 concentration whereas the molar volume exhibits opposite behaviour. The result from FTIR spectra analysis indicates the presence of BO3, BO4, PO4 and SO42- groups in the host network structure. UV-Vis-NIR spectra of Dy3+ doped glass samples recorded seven absorption peaks while on the contrary, Eu3+ doped glass samples exhibits four peaks in UV-Visible region and two peaks in NIR region. The optical band gap was found to decrease gradually with increase in Dy3+ and Eu3+ concentration while the Ubach‘s energy shows inverse trend. Meanwhile the negative and positive value of the bonding parameters confirmed the corresponding ionic and covalent nature of Dy-O and Eu-O ligand bond in the host matrix. The luminescence spectra for Dy3+ doped samples at the excitation wavelength of 386 nm revealed two intense emission peaks at 494 nm (4F9/2?6H15/2), 585 nm (4F9/2?6H13/2) and a very weak peak at 673 nm (4F9/2?6H13/2). Conversely, doping the samples with Eu3+ ions gives rise to four emission peaks at 587 nm (5D0?7F1), 612 nm (5D0?7F2), 650 nm (5D0?7F2) and 698 nm (5D0?7F4) under the excitation wavelength of 394 nm. The superior features shown by the current glass material as a result of good correlations between the host network and dopant ions specifies its potentialities for lighting device applications

Influence of Poultry Manure on Aggregate Stability and Infiltration Rates of a Disturbed Sandy Loam Soil

An evaluation of soil aggregate stability and infiltration rate is significant in the assessment of soil management practice. The objective of this study was to evaluate the influence of poultry manure on aggregate stability and infiltration rate on a disturbed sandy loam soil of Bauchi. Poultry manure was applied at 0, 10, 15, 20, and 25 Mg/ha at three replications in a completely random design. Four weeks after, aggregate stability and infiltration rates were determined by wet sieving method and double ring infiltrometer respectively. Treatment levels showed an increase in aggregate stability of the soil by mean weight diameter (MWD) indices from 0.337mm (control ) to 0.473 – 0.934mm (for 10 – 25Mg/ha treatments).Infiltration rates also showed a significant increase as the manure was added from 1.3mm/min for the control plot, to 2.7 – 3mm/min for 10 – 25 Mg/ha treatment levels respectively. The results also indicates that application of poultry manure did significantly (P ˂ 0.05) affects aggregate stability and infiltration as determined by ANOVA. It was then concluded that poultry manure was effective in increasing soil aggregate stability and infiltration rates, but decreasing bulk density from 1.35g/cm3 for control plot to 1.33 – 1.25 g/cm3 for 10 – 25M g/ha treatment levels in the tillage zones. Keywords: – Aggregate stability, Poultry manure, Infiltration rates, Treatment levels, Sandy Loam and Bulk density

Structural and luminescence characterization of lithium-borosulfophosphate glasses containing dysprosium ions

Rare earth doped glasses have been a great deal of research interest due to their prominent applications in laser lighting technology. However, achieving highly efficient yellow light emission from these materials require the collective efforts of many researchers across the world. Hence, a series of high optical quality dysprosium doped lithium-borosulfophosphate glasses with chemical composition of 15Li2O-30B2O3-15SO3-(40-x)P2O5-xDy2O3 (where x = 0.1, 0.3, 0.5, 0.7 and 1.0 in mol%) were prepared by convectional melt quenching technique and characterized by X-Ray diffraction (XRD), Fourier Transform Infrared (FTIR) and Photoluminescence (PL) measurements. XRD pattern of the host glass confirms its amorphous nature while the results from FTIR spectra analysis indicates the presence of BO3, BO4, PO4 and SO42- groups in the host network structure. The photoluminescence spectral analysis revealed three emission bands at 494 nm, 585 nm and 673 nm attributed to the electronic transitions of 4F9/2→6H15/2, 4F9/2→6H13/2 and 4F9/2→6H15/2,respectively, under the excitation of 386 nm. Among all the prepared glass samples, 1.0 mol% Dy3+ contained glass sample exhibits an intense yellow emission at 585 nm which specifies its prospective suitability for yellow laser applications.Keywords: Borosulfophosphate glasses, Dysprosium ions, Fourier transform infrared spectroscopy, Photoluminescence analysi

Strengths, Weaknesses, Opportunities and Threats to Extension Service Delivery in Kaduna State, Nigeria

This study examined strengths, weakness, opportunities and threat within the extension service delivery in Kaduna State, Nigeria. The total population (130) of extension agents was used for the study. A structured questionnaire and focus group discussion schedule were used to elicit information. Percentages, mean were used to analyse the data collected. The findings showed Insecurity, high farmer-to-extension agent ratio and inadequate training facilities as challenging factors that affect extension service delivery. The study concluded that extension service delivery was highly ineffective because of low extension-farmer ratio and low motivation among the agents. It is recommended that government need to employ more extension agents to reduce the possible imbalance in extension service delivery to farmers

Strengths, Weaknesses, Opportunities and Threats to Extension Service Delivery in Kaduna State, Nigeria

This study examined strengths, weakness, opportunities and threat within the extension service delivery in Kaduna State, Nigeria. The total population (130) of extension agents was used for the study. A structured questionnaire and focus group discussion schedule were used to elicit information. Percentages, mean were used to analyse the data collected. The findings showed Insecurity, high farmer-to-extension agent ratio and inadequate training facilities as challenging factors that affect extension service delivery. The study concluded that extension service delivery was highly ineffective because of low extension-farmer ratio and low motivation among the agents. It is recommended that government need to employ more extension agents to reduce the possible imbalance in extension service delivery to farmers

Determination of onset, cessation of rains and hydrological growing season in Dadin Kowa and Gombe for agricultural planning

This study determined the onset, cessation of rains and length growing season (HGS) in the Sahel Sudan of northeastern Nigeria. Two stations were selected for the study; Gombe town in Gombe LGA and Dadin Kowa in Yamaltu Deba LGA of Gombe State. Daily rainfall data was obtained from NIMETS and Upper Benue River Basin, Dadin Kowa, Gombe State. The rainfall cumulative model was adopted for this study. The first step of the method was to derive the daily rainfall that occured at each five-day interval in a year. A rainy day in this study is a day with zero point two five millimeters that occured within twenty-four hours. This is followed by computing the total of the five-day period. Finally, when the cumulative rainfall total is plotted against time through the year, the first point of maximum positive curvature on the graph corresponds to the time of rainfall onset, while the last point of maximum negative curvature corresponds to rainfall cessation. The difference between the onset and cessation in days is hydrological growing season (LGS). Result shows that onset dates for Gombe town and Dadin Kowa are 25 and 30 May, with a variability of +10 and +15 days, respectively. While cessation dates, is 12 October, for Gombe town and Dadin Kowa with a variability of + 10 days. The hydrological growing seasons is 140 days with a variability of + 10 days for Gombe town and 137 days with a variability of + 15 days for Dadin Kowa. A radar diagram was used to compare onset, cessation and length of growing season in the two locations temporally from 2001 to 2017. Results revealed that onset and length of growing season followed same trend with Gombe town having the dominant late onset while Dadin Kowa had the longest length of rainy season between 2001 and 2017. In terms of cessation from 2001 to 2017, Dadin Kowa on the average had late cessation. The results of this study would be useful to farmers and other stakeholders in planning agricultural calendars.Keywords: Onset, Cessation, Hydrological Growing Season (HGS) and radar diagra

In vitro trypanocidal effect of methanolic extract of some Nigerian savannah plants

Methanol extracts from twenty three plants harvested from the Savannah vegetation belt of Nigeria were analyzed in vitro for trypanocidal activity against Trypanosoma brucei brucei and Trypanosoma congolense at concentrations of 4 mg/ml, 0.4 mg/ml and 0.04 mg/ml. Extracts of Khaya senegalensis, Piliostigma reticulatum, Securidaca longepedunculata and Terminalia avicennoides were strongly trypanocidal to both organisms while extracts of Anchomanes difformis, Cassytha spp, Lannea kerstingii, Parkia clappertioniana, Striga spp, Adansonia digitata and Prosopis africana were trypanocidal to either T. brucei brucei or T. congolense. These findings provide evidence of the effects of some plants in the traditional management of trypanosomiasis. Key words: Savannah, medicinal plants, trypanocidal effects, trypanosomiasis, trypanosome, in vitro model. African Journal of Biotechnology Vol.2(9) 2003: 317-32

Assessment of the Cost-returns and Profitability Patterns of Tomato Production in Yamaltu-Deba Local Government Area of Gombe State, Nigeria

The study examined profitability of tomato production in Yamaltu-Deba Local Government Area of Gombe State. A three-stage sampling technique was used to select 96 tomato producers. Data were collected using a structured questionnaire and were analysed using descriptive statistics, farm budget model, and t-test analysis. The results revealed that, the mean age of tomato producers was 38.94 years, 92.48% were males, 71.56% were married with the majority (95.44%) had family size ranging from 1 – 6 persons, and had 6.55 mean years of farming experience, having an average of 0.6 ha farm size holding. Furthermore, the result revealed that only 8.74% that have attained tertiary education. The results also revealed average variable costs constituted 88.98% and 88.84% of the average total costs of production in the dry and rainy seasons respectively. The per hectare average net income realised were found to be ₦ 154,444.20 ($398.05) and ₦ 39,725.14 ($ 102.38) in the dry and rainy seasons respectively. Hence, the returns per naira invested was ₦ 0.67 ($0.00173) in dry season and ₦ 0.18 ($0.00046) in rainy season (P<0.05). Moreover, the results revealed positive and desirable gross and operating ratios of < 1; implying the tomato farms in the study area maintained profitability levels both in the short and long run. However, inadequate capital was critical; which was attributed to lack of affordable sources of credits. Lack of storage and processing facilities were among the impediments to large scale tomato production in the study area. However, improvement in the existing patterns and as well as the provision of adequate essential factors of production will help expand the present scale of operations. Therefore, governments and other financial institutions should do more to provide soft loans to the farmers to improve efficiency

Genotypic detection of extended spectrum beta lactamases from selected bacterial isolates in the Specialist Hospital Sokoto, Nigeria

There are numerous reported cases of extended spectrum beta lactamases (ESBLs) producing Enterobacteriaceae in Nigeria, with little effort done on the molecular detection. Epidemiological studies around the world have investigated the prevalence of ESBL-producing enterobacteriaceae and they have seen multiple mechanisms of drug-resistance. Our study was designed to detect ESBLs genes such as CTX-M, SHV, and TEM using PCR from clinical isolates in a tertiary hospital in Sokoto metropolis. Clinical isolates from the Microbiology laboratory of the tertiary hospital was collected for 3 months. These isolates were identified using standard microbiological methods. They were tested against 8 antibiotics using the modified Kirby Bauer disc diffusion method. Multidrug resistant isolates were screened for ESBL production, and further confirmed by the Double Disc Synergy Test (DDST). Genotypic confirmation was carried out using multiplex Polymerase Chain Reaction (PCR). A total of 47 isolates made up of 21 E. coli (44.6%), 13 Klebsiella spp (27.6%), 7 Salmonella spp (14.9%), 5 Proteus mirabilis (10.6%), and 1 Enterobacter spp (2.1%) were obtained from urine, stool, and wound swab. Out of the 47 isolates, (45) 95.7% were multidrug resistant. Twenty-five (53.2%) were potential ESBL producers, while only 5 (20.0%) were confirmed phenotypically using a DDST. PCR results revealed 4 out of 5 of the isolates were possessing ESBL genes. It also revealed that 3 isolates co-produce TEM and SHV at 403bp and 293bp respectively. Only 1 isolate produced CTX-M gene at 569bp. The prevalence of ESBL production in the Gram negative enterobacteriaceae in our study did not indicate a high prevalence as reported by some studies in Sokoto and Northwest Nigeria.Keywords: Molecular detection, ESBLs, Clinical isolates, PC