One-dimentional magnonic crystal as a medium with magnetically tunable disorder on a periodical lattice

We show that periodic magnetic nanostructures (magnonic crystals) represent an ideal system for studying excitations on disordered periodical lattices because of the possibility of controlled variation of the degree of disorder by varying the applied magnetic field. Ferromagnetic resonance (FMR) data collected inside minor hysteresis loops for a periodic array of Permalloy nanowires of alternating width and magnetic force microscopy images of the array taken after running each of these loops were used to establish convincing evidence that there is a strong correlation between the type of FMR response and the degree of disorder of the magnetic ground state. We found two types of dynamic responses: anti-ferromagnetic (AFM) and ferromagnetic (FM), which represent collective spin wave modes or collective magnonic states. Depending on the history of sample magnetization either AFM or FM state is either the fundamental FMR mode or represents a state of a magnetic defect on the artificial crystal. A fundamental state can be transformed into a defect one and vice versa by controlled magnetization of the sample.Comment: 4 pages, 3 figures, Letter paper, already submitted to PR

Coupled magnetic nanostructures: Engineering lattice configurations

We present a systematic investigation of tunable magnetization dynamics of coupled magnetic nanostructures, arranged in one-dimensional arrays of horizontally and vertically coupled linear chains and in two-dimensional arrays of square artificial spin ice lattice. The spatial distribution of the demagnetization field is markedly sensitive to the lattice arrangement, leading to a significant modification of the collective behavior of static and dynamic properties of the arrays. Using ferromagnetic resonance spectroscopy, the engineering of demagnetizing factors with various lattice arrangements has been established quantitatively. The signature of distinct spin wave modes, spatially localized in the constituent nanomagnets, was observed and tuned by the lattice arrangements and applied field orientation. The experimental results are well complemented with micromagnetic simulations

INFLUENCE OF CAPACITY BUILDING TRAINING BY AGRICULTURAL MEDIA RESOURCES AND EXTENSION CENTRE (AMREC) ON RURAL FARMERS’ LIVELIHOODS IN ODEDA LOCAL GOVERNMENT AREA OF OGUN STATE

The role of extension service providers as practical problem-solving organizations in rural settings is targeted at poverty reduction, various mechanisms including capacity building training is adopted in achieving this. Purposive selection of hundred and twelve (112) beneficiaries from 14 communities was made. The mean age of respondents is 39years. The household size is 6persons and the farm size is 2.3hectares. Farming experience is 8years and the average yield is 184.6kg, average annual income after the training is N15, 732.00k. 62.5% and 37.5% of farmers respectively benefitted from crop and livestock training and also have access to hybrid stems and seeds.  Results indicates positive relationship between farm size (r = 0.397, p = 0.001), farm yield (r = 0.555, p = 0.004) and farmers income (r = 0.808, p = 0.002), farmers’ sex, (χ2 =10.63, df = 1, P > 0.05) and the purpose of attending the training (χ2 =11.67, df = 4, P > 0.05). The mean score of farmers’ response on perception about the benefits of capacity building training on their livelihoods is 3.66. 95.5% and 80.4% strongly agreed that the training has assisted in poverty reduction and that it is a developmental issue targeted at building human resources.     &nbsp

Tunable 2-D magnonic crystals: effect of packing density

Magnonic crystals, periodic arrays of magnetic structures, have emerged as a promising platform for manipulating and controlling spin waves in magnetic materials. Magnetic antidot nanostructures, representing 2-D magnonic crystals, are versatile platforms for controlling and manipulating magnons. In this work, we systematically investigate the effects of inter-hole spacing and lattice (rhombic and honeycomb) arrangements on the dynamic properties of Ni80Fe20 antidot structures. The dynamic responses of antidot lattices of fixed hole diameter (d = 280 nm) and inter-hole spacing (s) between 90 and 345 nm are investigated using broadband ferromagnetic spectroscopy. Multiple resonance modes sensitive to s are observed due to the inhomogeneous internal field distribution induced by the presence of holes. There is a marked variation in mode frequency, mode intensity and the number of modes for rhombic antidot lattice as the inter-hole spacing and applied field direction are varied. Our experimental results are in good agreement with micromagnetic simulations. Our findings may find application in the design of magnonic-based devices

Consumer Preference for Rice Consumption in Nigeria

Rice consumption is of interest to the Nigerian economy because of the huge amount of foreign exchange being spent on its importation and the consequent depletion of scarce resources on which the level of economic activities and productivity are based. This study was aimed at identifying the quality of rice preferred by Nigerians for rice food recipes and consequently efforts made to improve the quality of locally produced rice to the taste of Nigerians. A total of 23 rice varieties were acquired from experimental fields of National Cereal Research Institute (NCRI), International Institute of Tropical Agriculture (IITA) in Ibadan and Badegi Rice Breeding Centre in Bida. Consumer preference survey of boiled rice and ‘Tuwo’ foods were carried out in 6 major commercial and traditional cities of Nigeria to determine the quality of rice preferred for boiled rice and ‘Tuwo’ rice foods. The survey was in questionnaire format and was carried out in Bida (Niger State), Zaria (Kaduna State), Maiduguri (Borno State), Benin (Edo State), Port-Harcourt (Rivers state) and Ibadan (Oyo State). Consumers preferred parboiled over unparboiled rice and moderate to flaky rice quality over to soft and sticky rice foods. The rating by taste panelists in Bida, Zaria and Maiduguri metropolis indicated IRAT 112, FARO 15, ITA 117 and ITA 123 were most preferred for ‘Tuwo’ foods, while the least-preferred varieties were ITA 132 and TOX 1768. Consumers also preferred high amylose rice for ‘Tuwo’ to low amylose, sticky rice quality. Also the rating of 6 rice varieties with respect to boiled rice indicated that ITA 117, IART 112 and FARO 15 were most preferred for boiled rice, while TOX 1768 and ITA 132 were the least-preferred in Rivers, Edo, and Oyo States perhaps as a result of people’s preference for flaky rice quality for most of their rice recipes. The results indicated that most Nigerians prefer rice with moderate to high flaky rice quality suggesting that in any rice improvement programme in Nigeria these characteristics should be given a premium. &nbsp

COTTON FARMERS’ PERCEPTION ON CLIMATE CHANGE AND ADAPTATION STRATEGIES IN OGUN STATE, NIGERIA

Climate change has been a major threat to agriculture in Nigeria. This study was carried out in Imeko Afon Local Government Area. Purposive selection of all practicing cotton farmers (54) at the time of survey was made from the study area. The mean age of respondents is 56years. The household size is 7persons and the average annual income is N9, 972.00k. The mean score of famers’ perception about the climate change and its effects on cotton production is 2.62. Farmers’ stated that there is an increase temperature due to change in climatic condition (Ẍ= 3.45, S.D ± 1.152), and fluctuation in rainfall pattern (Ẍ= 4.04, S.D ± 0.999). Adopted coping strategies to cushion effects of climate change include; increase use of agro-chemicals (Ẍ = 3.35, S.D ± 0.677), integrated weed pest management (Ẍ = 3.44, S.D ± 0.839) and application of fertilizer to improve the depleted soil nutrients (Ẍ = 3.19, S.D ± 0.646). Results indicates a significant relationship between respondents perceived effects on climate change and coping strategies (r =0.890**, P< 0.05). The study recommends that government agricultural and meteorological agencies should provide timely information to farmers on the climate and means of ameliorating the effects of climate change.     &nbsp

Physico-Chemical and Functional Properties of Cookies Produced from Sweet Potato- Maize Flour Blends

This study was carried out to observe the physico-chemical and functional properties of cookies produced from sweet potato- maize flour blends. Substitution of maize flour with sweet potato flour reduced the protein from 6.8-4.4%, moisture from 5.3-5.0%, crude fibre 3.4-2.5% and fat 9.8-8.5% of the composite flours and the cookies. The ash and sugar contents were increased from 4.3-5.8% for ash and 2.1-3.9% for sugar with increase in sweet potato flour substitution. The calorific value of the cookies decreased from 457-397cal/100g as the percentage of sweet potato flour increased in the maize flour cookies. The water binding capacity increased from 0.9-1.7 and the starch swelling power decreased from 10.1-5.3 at 950C with increase in sweet potato flour content in the flour mixture. The bulk density and dispensability decreased from 4.6-3.3g/ml and 48.3-47.1ml/g respectively in the flour as the content of the sweet potato in the composition increased. Keywords: cookies, sweet potato, maize, flour, quality

Collective spin waves in arrays of Permalloy nanowires with single-side periodically modulated width

We have experimentally and numerically investigated the dispersion of collective spin waves prop-agating through arrays of longitudinally magnetized nanowires with periodically modulated width. Two nanowire arrays with single-side modulation and different periodicity of modulation were studied and compared to the nanowires with homogeneous width. The spin-wave dispersion, meas-ured up to the third Brillouin zone of the reciprocal space, revealed the presence of two dispersive modes for the width-modulated NWs, whose amplitude of magnonic band depends on the modula-tion periodicity, and a set of nondispersive modes at higher frequency. These findings are different from those observed in homogeneous width NWs where only the lowest mode exhibits sizeable dis-persion. The measured spin-wave dispersion has been satisfactorily reproduced by means of dynam-ical matrix method. Results presented in this work are important in view of the possible realization of frequency tunable magnonic device