2,259 research outputs found

    Isolation and Identification of Air Borne Fungal Spores and Fragments in Buildings Within Usmanu Danfodiyo University Sokoto, Nigeria

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    - Indoor air contains a complex mixture of microorganisms, microorganism fragments, and by products such as molds, bacteria, endotoxins, mycotoxins, and volatile microbial organic compounds. Airborne fungi and bacteria can be toxic, allergenic and/or infectious. A research was conducted to determine the number and types of airborne fungal spores in Buildings of Usmanu Danfodiyo University Sokoto, Nigeria. Five (5) areas were chosen within the University for the Survey, these were student Hostel, Staff Quarters, Botanical garden, Microbiology laboratory and city campus of Usmanu Danfodiyo University. . A total number of fifteen (15) petri dishes containing potato dextrose agar each were vertically placed in each sampler and exposed at end of each height and site for 10 and 20 minutes respectively. A total of thirteen (13) different fungal specie were identified namely; Aspergillus Niger, A. flavus, A fumigates, A. ustus, A. terreus, Fusarium solani, F. oxysporum, Alterneria altenata, Rhizopus oryzae, R. stolonifer, Helminthosporum sp., Penicillum candidum and Absedia corymbifera. Aspergillus Niger had the highest frequency of occurrence of (14.9%), Helminthosporus species had the least frequency of occurrence of (1.5%). Conclusively it was observed that the concentration of fungal spores was high in the upper surface than the ground level at the time of the survey

    Transport on flexible Rydberg aggregates using circular states

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    Assemblies of interacting Rydberg atoms show promise for the quantum simulation of transport phenomena, quantum chemistry and condensed matter systems. Such schemes are typically limited by the finite lifetime of Rydberg states. Circular Rydberg states have the longest lifetimes among Rydberg states but lack the energetic isolation in the spectrum characteristic of low angular momentum states. The latter is required to obtain simple transport models with few electronic states per atom. Simple models can however even be realized with circular states, by exploiting dipole-dipole selection rules or external fields. We show here that this approach can be particularly fruitful for scenarios where quantum transport is coupled to atomic motion, in adiabatic excitation transport or quantum simulations of electron-phonon coupling in light harvesting. Additionally, we explore practical limitations of flexible Rydberg aggregates with circular states and to which extent interactions among circular Rydberg atoms can be described using classical models.Comment: 9 Pages, 5 Figure

    Interfacial shear in adiabatic downward gas/liquid co-current annular flow in pipes

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    Interfacial friction is one of the key variables for predicting annular two-phase flow behaviours in vertical pipes. In order to develop an improved correlation for interfacial friction factor in downward co-current annular flow, the pressure gradient, film thickness and film velocity data were generated from experiments carried out on Cranfield University’s Serpent Rig, an air/water two-phase vertical flow loop of 101.6 mm internal diameter. The air and water superficial velocity ranges used are 1.42–28.87 and 0.1–1.0 m/s respectively. These correspond to Reynolds number values of 8400–187,000 and 11,000–113,000 respectively. The correlation takes into account the effect of pipe diameter by using the interfacial shear data together with dimensionless liquid film thicknesses related to different pipe sizes ranging from 10 to 101.6 mm, including those from published sources by numerous investigators. It is shown that the predictions of this new correlation outperform those from previously reported studies

    Offshore Topside Rotating Packed Bed as Process Intensified Alternative for Natural Gas Sweetening and Dehydration

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    This work is aimed at investigating the benefits of replacing conventional process unit operations with process intensified ones in offshore applications. This ensures that better use is made of raw materials, lower energy consumption and a reduced plant volume was achieved. Specifically, a rotating packed bed technology has been used for gas dehydration and sweetening. To achieve the aim of this study, a process intensification approach is used to redesign mature absorption processes to more compact and efficient one. Process simulation using Aspen Hysys was carried out for Triethylene glycol dehydration and monoethanolamine sweetening. More than 36-fold absorption unit size reduction was achieved thereby effecting large decrease in capital and operating costs compared to the conventional packed columns currently utilized in the offshore oil and gas industry. The process intensified technologies therefore can be deployed for offshore applications where space and size considerations are of utmost importance

    Gas/liquid flow behaviours in a downward section of large diameter vertical serpentine pipes

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    An experimental study on air/water flow behaviours in a 101.6 mm i.d. vertical pipe with a serpentine configuration is presented. The experiments are conducted for superficial gas and liquid velocities ranging from 0.15 to 30 m/s and 0.07 to 1.5 m/s, respectively. The bend effects on the flow behaviours are significantly reduced when the flow reaches an axial distance of 30 pipe diameters or more from the upstream bend. The mean film thickness data from this study has been used to compare with the predicted data using several falling film correlations and theoretical models. It was observed that the large pipe data exhibits different tendencies and this manifests in the difference in slope when the dimensionless film thickness is plotted as a power law function of the liquid film Reynolds number

    Occurrence and dissolution of rigor-mortis in Bagrus bayad macropterus and Mormyrus rume from River Rima Sokoto

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    A total of eighty nine samples comprising 45 B. bayad and 44 M.rume from River. Rima were subjected to evaluation of rigor-mortis occurrence and dissolution; Total weight and total length of the species were measured using electric top loading balance (16000gm) and measuring board, respectively. Stop watch and calibrated thermometer were used for recording time and temperature to determine rigor mortis duration and temperature effect. The results showed that the duration from capture to dissolution of rigor was higher in M.rume than B. bayad, despite the fact that temperature ranges were similar. Factors such as size distribution and level of exhaustion might have contributed to the variations. In the light of the above, it is recommended that factors resulting to rapid exhaustion of B. bayad be looked into with a view to lowering it and subsequent elongation of the rigor period

    Numerical estimation of moisture content in spray dried juice powder

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    The moisture contents of powders is an important parameter that affects the quality and commercial value of spray dried products. The utility of predicted moisture content values from two droplet drying models were compared with experimental data for spray dried pineapple juice, using the Ranz-Marshal and its modified variants for the heat and mass transfer correlations. The droplet Diffusion model, using the Zhifu correlation, gave estimates with errors of about 8 at 165 °C, 9 at 171 °C, 26 at 179 °C and 2 at 185 °C. The Ranz-Marshal correlation also gave comparable results with this model while results using the Downing and modified Ranz-Marshall correlations widely diverged. The Energy balance model predicted completely dried juice particles, and short drying times, in contrast to the experimental data. The small error sizes of the Diffusion model improves on the wide error sizes of an earlier process model, making is useful as a first approximation choice, for spray drier design and simulation, especially for juices under comparable operating conditions

    Performance of groundnut genotypes under millet based intercropping systems in Sudan Savanna of Nigeria

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    Open access JournalSpatial arrangement of crops is critical in determining the growth and yield of lower crops in intercropping. The productivity of two spatial arrangements of pearl millet-groundnut intercrops was studied in the Sudan savanna of Nigeria during 2014 rainy season at Wasai (5ˈN, 08o62ˈE) in Minjibir of Kano state, and Rahama (11o40ˈN, 09o20ˈE) in Dutse of Jigawa state. The treatments were two millet varieties (Dankaranjo and SuperSosat), two intercropping systems (2:2 and 2:4; reflecting millet to groundnut row) and four groundnut genotypes (SAMNUT 21, SAMNUT 22, SAMNUT 23 and SAMNUT 24). The experiment was laid out in split-split plot design with four replications. Among the groundnut genotypes, pod yield was greater at 2:4 system at Minjibir, while SAMNUT 23 and SAMNUT 24 were significantly (P<0.05) better than SAMNUT 21 and SAMNUT 22, SAMNUT 21 was best in terms of pod yield (480 Kg ha-1) at Dutse followed by SAMNUT 22 and SAMNUT 23 and least was SAMNUT 24 (293 Kg ha-1). Higher haulm yields were produced by SAMNUT 21 and SAMNUT 22 at both locations followed by SAMNUT 23 and SAMNUT 24 which had similar haulm yields at Minjibir

    Towards video streaming in IoT environments: vehicular communication perspective

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    Multimedia oriented Internet of Things (IoT) enables pervasive and real-time communication of video, audio and image data among devices in an immediate surroundings. Today's vehicles have the capability of supporting real time multimedia acquisition. Vehicles with high illuminating infrared cameras and customized sensors can communicate with other on-road devices using dedicated short-range communication (DSRC) and 5G enabled communication technologies. Real time incidence of both urban and highway vehicular traffic environment can be captured and transmitted using vehicle-to-vehicle and vehicle-to-infrastructure communication modes. Video streaming in vehicular IoT (VSV-IoT) environments is in growing stage with several challenges that need to be addressed ranging from limited resources in IoT devices, intermittent connection in vehicular networks, heterogeneous devices, dynamism and scalability in video encoding, bandwidth underutilization in video delivery, and attaining application-precise quality of service in video streaming. In this context, this paper presents a comprehensive review on video streaming in IoT environments focusing on vehicular communication perspective. Specifically, significance of video streaming in vehicular IoT environments is highlighted focusing on integration of vehicular communication with 5G enabled IoT technologies, and smart city oriented application areas for VSV-IoT. A taxonomy is presented for the classification of related literature on video streaming in vehicular network environments. Following the taxonomy, critical review of literature is performed focusing on major functional model, strengths and weaknesses. Metrics for video streaming in vehicular IoT environments are derived and comparatively analyzed in terms of their usage and evaluation capabilities. Open research challenges in VSV-IoT are identified as future directions of research in the area. The survey would benefit both IoT and vehicle industry practitioners and researchers, in terms of augmenting understanding of vehicular video streaming and its IoT related trends and issues
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