Search

Leucaena leucocephala is a leguminous shrub that has the potential for increasing animal production with diverse environmental and ecological significance. An experiment was conducted to investigate the effect of hot saline water treatment durations on the emergence of Leucaena seeds. The experiment was arranged in a completely randomized design with six treatments and three replicates. The treatments are control, soaking of seeds in hot saline water (20 g NaCl/1 L of distilled water) at 80°C for 1, 2, 3, 4 and 5-min durations. The percentage emergence, emergence index, plant height and leave numbers were measured. Hot saline water treatment durations had positive effect of breaking Leucaena seed dormancy and enhance germination. The highest percentage emergence and emergence index (53.9% and 7.95) were obtained at 2 min treatment durations but plant height and number of leaves were highest (6.29 cm and 7.00 cm) respectively in 4 min of treatment durations. It could be concluded that percentage emergence and seedling growth of Leucaena can be enhanced using 2 min hot saline water treatment duration. It is recommended that saline soils that have being degraded due to oil spillage to enable production of Leuceana as animal feed and control environmental degradation.

A field trial was conducted at Bauchi State university teaching and research farm Gadau during 2018 and 2019 rainy seasons, to study the effects of phosphorus fertilization and plant spacing on herbage yield of groundnut. The treatments consisted of four levels of phosphorus fertilizer (0, 30, 60 and 90 kg P2O5/ha) and three spacing (20 × 60 cm, 25 × 60 cm and 30 × 60 cm), factorially combined to give 12 treatments and laid out in a Randomized Complete Block Design (RCBD) replicated three times. The results of the experiment showed a significant (P < 0.01) difference among the treatments used throughout the study period. The result also revealed that, application of 60 and 90 kg P2O5/ha were observed to be statistically similar but significantly (P ≤ 0.05) recorded the highest number of branches, canopy spread, biomass, stover and pod yield than the other treatments used. However, all treatments were better than the control. In terms of spacing however, widest spacing (30 × 60 cm) significantly (P ≤ 0.05) gave the highest number of branches and canopy spread than the other spacing used. The result further indicated that, closest spacing (20 × 60 cm) recorded the highest biomass and stover yields throughout the study period. Years of study on the other hand, 2019 was proved to be significantly better than 2018 in all the characters observed. Based on the result of this findings, it can be concluded that, application of 60 to 90 kg/ha P2O5 and closest spacing (20 × 60 cm) gave the highest biomass and stover yields and is recommended to farmers for groundnut herbage production in the study area.

An experiment was conducted at teaching and research farm of the Abubakar Tafawa Balewa University Bauchi, during the dry and rainy seasons of 2016 to evaluate the effect of variety and phosphorus fertilization on the growth and yield of groundnut (Arachis hypogaea L.). The treatment consisted of two groundnut varieties (Samnut 24 and Samnut 25), two levels of phosphorus fertilizer (25kg and 50kg/ha) and a control, factorially combined to give six treatment combinations. These treatments were laid out in a randomized complete block design (RCBD) with four replications. Data were collected on the plant height, number of leaves, 100-grain weight and grain yield. All data collected were subjected Analysis of variance (ANOVA) and DMRT was adopted in separating the means. The result of the experiment showed that, there is a significant difference (P = 0.05) in both seasons on all the parameters observed. The results further indicated that, application of 25 kg P/ha produced statistically (P = 0.05) similar result with 50 kg P/ha, however the two treatments were better than the control. On varieties, Samnut 25 proved to be significantly (P = 0.05) better than Samnut 24 on most of the parameters observed. Based on the result of these findings, application of 25 kg P/ha to Samnut 25 can be adopted by farmers for profitable groundnut production in the study area.

An experiment was conducted at teaching and research farm of the Abubakar Tafawa Balewa University Bauchi, during the dry and rainy seasons of 2016 to evaluate the influence of variety and phosphorus fertilization on herbage yield of groundnut (Arachis hypogaea L.). The treatment consisted of two groundnut varieties (Samnut 24 and Samnut 25) and two levels of phosphorus fertilizer (25kg and 50kg/ha and a control) factorially combined to give six treatment combinations. These treatments were laid out in a randomized complete block design (RCBD) with four replications. Data was collected on number of branches, 100 pod weight, Harvest index, biomass yield and stover yield. All data collected were subjected Analysis of variance (ANOVA) and DMRT was adopted in separating the means. The result of the experiment revealed a significant (P = 0.05) difference in both seasons on all the parameters observed. The results further revealed that, application of 25 and 50 kgP/ha gave statistically (P = 0.05) similarly result but all the treatments were better than the control. Variety on the other hand, samnut 25 gave significantly (P = 0.05) higher herbage yield than samnut 24. Based on the result of this findings, application of 25 kg P/ha to Samnut 25 should be adopted by farmers for groundnut herbage production in the study area.

This dissertation aims to shed light on the fundamental aspects of supercooled liquid gallium. First, the mechanical properties of the oxide skin encapsulating the supercooled liquid gallium droplet is investigated. By leveraging the supercooling behavior of gallium and the formation of its oxide skin, we characterized the emergence of wrinkling at the interface and adhesion energy between the liquid gallium and rigid substrate. An interfacial energy of 0.238 �� 0.008 J m-2 was measured between gallium droplet and flat glass. Second, seed induced crystallization of supercooled liquid gallium on the different substrate materials revealed the dependence of the kinetics of crystallization on thermal behavior of the substrate. Such approach further elucidates on the importance of interface temperature during crystallization with a preferred orientation. The third part of the dissertation reports an unprecedented liquid crystal structure in supercooled liquid gallium. By the use of techniques applied in liquid crystal (LC) research, observation of LC texture in supercooled liquid gallium was realized. Reflective polarized optical microscopy (R-POM) on liquid gallium sandwiched between glasses treated with rubbed polymers reveals the onset of an anisotropic reflection of possible dimer molecules or clusters at 120��C that increases on cooling and persists down to room temperature or below. On the other hand, when gallium is sandwiched between substrates that align conventional liquid crystal molecules normal to the surface, the reflection is isotropic. This observation of LC structure of a highly electrically conductive supercooled liquid gallium provides an unexpected new field of materials science and liquid crystal research.

The experiment was conducted at the teaching and research farm of the Abubakar Tafawa Balewa University, Bauchi (10°22' N and 9°47' E), to study the effects of poultry manure based compost, NPK fertilizer and spacing on the growth and yield of sorghum. The treatments consisted of Poultry manure based compost (0, 1 and 2 t/ha), NPK fertilizer (0, 30 and 60 kg/ha) and two spacings (25 cm x 75 cm and 30 cm x 75 cm). Factorially combined given 18 treatments combination, laid out in a randomized complete block design and replicated three times. Data collected was analysed using ANOVA and Duncan’s Multiple Range Test was adopted to separate significantly different treatments means. The result of the experiment revealed that, application of 60 kg NPK and 2 t/ha poultry manure based compost proved to be significantly (P=0.05) better in promoting growth and yield of sorghum than all other rates and all the rates were better than the control. Considering spacing however, growing sorghum spaced at 30 cm x 75 cm gave significantly (P=0.05) higher growth and yield than 25 cm x 75 cm. Study on interaction revealed that, combine application of 60 kg NPK/ha and 2 t/ha poultry manure based compost gave significantly (P=0.05) higher growth and yield of sorghum. Based on this result, combine application of NPK fertilizer and poultry manure based compost to sorghum spaced at 30 x 75 cm will address the issue of soil fertility in the study area.

Context: Kano State Refuse Management and Sanitation board workers are constantly exposed to bioaerosol inhalation, including toxins and biotoxins that are been released from the waste. Aims: The aim of this study is to evaluate and determine the respiratory health status of Workers. Methodology: The study was a cross-sectional survey with 129 participants recruited using a convenience sampling technique. Forced vital capacity, forced expiratory volume in 1 s and St. George questionnaire were used to collect data and the result was analysed using descriptive statistics of frequencies, percentages and graphs, while the differences and relationships were obtained using one-way ANOVA and Spearman rank correlation co-efficient, respectively. Results: The mean age of the participants was 34.2 years. Up to 75.2% of the participants were male, whereas 24.8% were female. Up to 40% of participants did not have any respiratory symptoms, 35% had mild symptoms, 14% had moderate symptoms and 11% had severe respiratory symptoms. The symptoms include dyspnea, coughing, excessive mucus secretion and breathlessness. Respiratory symptoms was positively related to the length of exposure (P = 0.029). There was no significant difference in respiratory symptoms between waste collectors, sweepers and drivers. Furthermore, no relationship was found between the age of the workers and respiratory symptom (P = 0.056). Significant difference (P = 0.003) was observed between gender of the participants and respiratory health. Conclusions: Waste disposal work has significant impact on respiratory health. The provision of health education for safety and proper use of personal protection is necessary to reduce the impact of pollutant on respiratory health.

The field experiment was conducted at the Abubakar Tafawa Balewa University Bauchi teaching and research farm during the rainy season of 2016. Bauchi state belongs to savannah agro-ecological zone and geographically located between latitude 10°74’ E and 9°47’ E and 690.3 m above the sea level. The experiment was conducted to determine the effect of organic and inorganic fertilizer on the growth and yield of sorghum. The design used for the experiment was randomized complete block design (RCBD) and replicated three times. The treatment consisted of three levels of cow manure (0, 1 and 2 ton/ha) and four levels of NPK 15:15:15 (0, 15, 30 and 45 kg/ha), these were factorially combined to give 12 treatment combinations. The result of the experiment indicated that, there is a significant ((P

Mikroakışkanlar, çok küçük hacimlere sahip sıvıları, mikrometrelik kanallarda kontrol etme bilimidir. Mikroakışkanlar, kısa tepkime süresi ile çabuk analiz edilebilme ve taşınabilir özellikleriyle başlıca kimyasal ve biyolojik analizler olmak üzere daha birçok alanda teknolojik olarak uygulama bulmaktadır. Günümüzde mikroakiskan temelli cihazlar, litografi ve mikro-imalat gibi yöntemler ile cip üstü laboratuvar aygıtları olarak üretilmektedir. Ancak söz konusu üretim teknikleri, esneklik, biyolojik uyum, harici bileşenlerle bütünleşme ve üretim maliyetleri gibi yüksek önem arz eden konularda kısıtlamalara sahiptirler.Bu çalışmada, yüzeyi şekillendirilmiş polimer fiberler, ekonomik açıdan uygun mikroakışkan cihazların üretimi için yeni bir platform olarak sunulmuştur. Isıl fiber çekme metodu kullanılarak üretilen onlarca metre uzunluğundaki fiberler, yüzeylerinde 'V' şeklinde yivlerden oluşan yirmi kanal içermektedir. Fiber yüzeylerinin polidopamin (PDA) ve Ultraviyole/Ozon (UV/O) gibi işleme tekniklerle modifiye edilmesinden sonra fiberlerin üstündeki yivler boyunca kılcal hareketten kaynaklanan yayılma yönüne bağlı olarak sıvı akışkanlığı gözlemlenmiştir. Üç boyutlu esnek fiberlerden oluşan diziler üzerinde, herhangi bir harici pompa veya hareketlendirici mekanizma olmaksızın önceden belirlenmiş kanallarda kendiliğinden sıvı aktarımı sağlanabilmektedir. Ayrıca, yüzeyi organik olarak modifiye edilmiş nano parçacıklar V yapılı yivlerin üzerinde kullanılarak fiber yüzeylerin hidrofobikliği arttırılmıştır. Yüzeyleri şekillendirilmiş fiberlerin, esnek, sağlam, hafif ve ekonomik mikrodamlacık tabanlı aygıtların üretimi için oldukça uygun olduğuna ve mikroakışkan aygıtların kullanım alanlarını yeni ilaç keşifleri, tıbbi tanılama, yiyecek ve su kaynaklarının kalitesinin denetlenmesini de kapsayacak şekilde genişleteceğine inanılmaktadır. Microfluidics is the science of controlling low volumes of fluids in a microchannel. It is used in diverse area of applications such as chemical and biological analysis. Benefits of microfluidics are fast analysis, short reaction times, and portability of device. Current fabrication techniques of lab-on-a-chip microfluidic devices are soft lithography and micromachining. However, these methods suffer from design limitations such as flexibility of product, high cost, integration of external components, and biocompatibility.Surface textured polymer fibers are utilized as a novel platform for the fabrication of affordable microfluidic devices. Fibers are produced by thermal drawing technique tens of meters-long at a time and comprise twenty continuous and ordered V-grooves channels on their surfaces. Extreme anisotropic wetting behavior due to capillary action along the grooves of fibers is observed after surface modifications with polydopamine (PDA) coating and Ultraviolet/Ozone (UV/O) treatment. Three-dimensional arrays of flexible fibers spontaneously spread liquid on predefined paths without the need of external pumps or actuators. In addition, surface modification with organically modified silica nanoparticles was added on top of the V-grooves to enhance the hydrophobicity of the fiber surfaces. Surface textured fibers are well suited for the fabrication of flexible, robust, lightweight and affordable microfluidic devices which is believed to expand the role of microfluidics in a scope of fields including drug discovery, medical diagnostics and monitoring food and water quality. 116

Understanding the origin of structural ordering in supercooled liquid gallium (Ga) has been a great scientific quest in the past decades. Here, reflective polarized optical microscopy on Ga sandwiched between glasses treated with rubbed polymers reveals the onset of an anisotropic reflection at 120 degrees C that increases on cooling and persists down to room temperature or below. The polymer rubbing usually aligns the director of thermotropic liquid crystals (LCs) parallel to the rubbing direction. On the other hand, when Ga is sandwiched between substrates that align conventional LC molecules normal to the surface, the reflection is isotropic, but mechanical shear force induces anisotropic reflection that relaxes in seconds. Such alignment effects and shear-induced realignment are typical to conventional thermotropic LCs and indicate a LC structure of liquid Ga. Specifically, Ga textures obtained by atomic force and scanning electron microscopy reveal the existence of a lamellar structure corresponding to a smectic LC phase, while the nanometer-thin lamellar structure is transparent under transmission polarized optical microscopy. Such spatial molecular arrangements may be attributed to dimer molecular entities in the supercooled liquid Ga. The LC structure observation of electrically conductive liquid Ga can provide new opportunities in materials science and LC applications., Advanced Materials, 33 (38), ISSN:0935-9648, ISSN:1521-4095

We combine materials engineering and digital processing to design and print cellulose-based continuous stiffness gradients., Functionally graded materials (FGMs) enable applications in fields such as biomedicine and architecture, but their fabrication suffers from shortcomings in gradient continuity, interfacial bonding, and directional freedom. In addition, most commercial design software fail to incorporate property gradient data, hindering explorations of the design space of FGMs. Here, we leveraged a combined approach of materials engineering and digital processing to enable extrusion-based multimaterial additive manufacturing of cellulose-based tunable viscoelastic materials with continuous, high-contrast, and multidirectional stiffness gradients. A method to engineer sets of cellulose-based materials with similar compositions, yet distinct mechanical and rheological properties, was established. In parallel, a digital workflow was developed to embed gradient information into design models with integrated fabrication path planning. The payoff of integrating these physical and digital tools is the ability to achieve the same stiffness gradient in multiple ways, opening design possibilities previously limited by the rigid coupling of material and geometry.

Although substrates play an important role upon crystallization of supercooled liquids, the influences of surface temperature and thermal property have remained elusive. Here, the crystallization of supercooled phase-change gallium (Ga) on substrates with different thermal conductivity is studied. The effect of interfacial temperature on the crystallization kinetics, which dictates thermo-mechanical stresses between the substrate and the crystallized Ga, is investigated. At an elevated surface temperature, close to the melting point of Ga, an extended single-crystal growth of Ga on dielectric substrates due to layering effect and annealing is realized without the application of external fields. Adhesive strength at the interfaces depends on the thermal conductivity and initial surface temperature of the substrates. This insight can be applicable to other liquid metals for industrial applications, and sheds more light on phase-change memory crystallization., Max Planck Society

Surface microrollers are promising microrobotic systems for controlled navigation in the circulatory system thanks to their fast speeds and decreased flow velocities at the vessel walls. While surface propulsion on the vessel walls helps minimize the effect of strong fluidic forces, three-dimensional (3D) surface microtopography, comparable to the size scale of a microrobot, due to cellular morphology and organization emerges as a major challenge. Here, we show that microroller shape anisotropy determines the surface locomotion capability of microrollers on vessel-like 3D surface microtopographies against physiological flow conditions. The isotropic (single, 8.5 μm diameter spherical particle) and anisotropic (doublet, two 4 μm diameter spherical particle chain) magnetic microrollers generated similar translational velocities on flat surfaces, whereas the isotropic microrollers failed to translate on most of the 3D-printed vessel-like microtopographies. The computational fluid dynamics analyses revealed larger flow fields generated around isotropic microrollers causing larger resistive forces near the microtopographies, in comparison to anisotropic microrollers, and impairing their translation. The superior surface-rolling capability of the anisotropic doublet microrollers on microtopographical surfaces against the fluid flow was further validated in a vessel-on-a-chip system mimicking microvasculature. The findings reported here establish the design principles of surface microrollers for robust locomotion on vessel walls against physiological flows., Proceedings of the National Academy of Sciences of the United States of America, 118 (13), ISSN:0027-8424, ISSN:1091-6490