Search results for: bone mineral density

Authors: Eugene Ivanov, Eduardo del-Rio, Igor Kapchenko, Maija Nystrӧm, Juha Kotila

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Series of low modulus beta Ti alloy billets and powders can be produced in commercial quantities using a combination of electron beam melting (EBM) and EIGA atomization processes. In the present study, TNZT alloy powder was produced and processed in the EOSINT M290 laser sintering system to produce parts for mechanical testing. Post heat treatments such as diffusion annealing to reduce internal stresses or hot isostatic pressing to remove closed pores were not applied. The density can visually be estimated to be > 99,9 %. According to EDS study Nb, Zr, and Ta are distributed homogeneously throughout the printed sample. There are no indications for any segregation or chemical inhomogeneity, i.e. variation of the element distribution. These points to the fact that under the applied experimental conditions the melt generated by the laser rapidly cools down in the SLM (Selective Laser Melting) process. The selective laser sintering yielded dense structures with relatively good surface quality. The mechanical properties, especially the elongation (24%) along with tensile strength ( > 500MPa) and modulus of elasticity (~60GPa), were found to be promising compared to titanium alloys in general.

Keywords: beta titanium alloys, additive manufacturing, powder, implants

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Authors: T. Kuchukhidze, N. Jalagonia, T. Korkia, V. Gabunia, N. Jalabadze, R. Chedia

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In this work, obtaining methods of ultrafine alumina powdery composites and high temperature pressing technology of matrix ceramic composites with different compositions have been discussed. Alumina was obtained by solution combustion synthesis and sol-gel methods. Metal carbides containing powdery composites were obtained by homogenization of finishing powders in nanomills, as well as by their single-step high temperature synthesis .Different types of matrix ceramics composites (α-Al2O3-ZrO2-Y2O3, α-Al2O3- Y2O3-MgO, α-Al2O3-SiC-Y2O3, α-Al2O3-WC-Co-Y2O3, α-Al2O3- B4C-Y2O3, α-Al2O3- B4C-TiB2 etc.) were obtained by using OXYGON furnace. Consolidation of powders were carried out at 1550- 1750°C (hold time - 1 h, pressure - 50 MPa). Corundum ceramics samples have been obtained and characterized by high hardness and fracture toughness, absence of open porosity, high corrosion resistance. Their density reaches 99.5-99.6% TD. During the work, the following devices have been used: High temperature vacuum furnace OXY-GON Industries Inc (USA), Electronic Scanning Microscopes Nikon Eclipse LV 150, Optical Microscope NMM- 800TRF, Planetary mill Pulverisette 7 premium line, Shimadzu Dynamic Ultra Micro Hardness Tester DUH-211S, Analysette 12 Dynasizer.

Keywords: α-alumina, consolidation, phase transformation, powdery composites

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Authors: Yousef Almutairi, Yajue Wu

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Various large-scale trends have characterized the current century thus far, including increasing shifts towards urbanization and greater movement. It is predicted that there will be 9.3 billion people on Earth in 2050 and that over two-thirds of this population will be city dwellers. Moreover, in larger cities worldwide, mass transportation systems, including underground systems, have grown to account for the majority of travel in those settings. Underground networks are vulnerable to fires, however, endangering travellers’ safety, with various examples of fire outbreaks in this setting. This study aims to increase knowledge of the impacts of extreme climatic conditions on fires, including the role of the high ambient temperatures experienced in Middle Eastern countries and specifically in Saudi Arabia. This is an element that is not always included when assessments of fire safety are made (considering visibility, temperatures, and flows of smoke). This paper focuses on a tunnel within Riyadh’s underground system as a case study and includes simulations based on computational fluid dynamics using ANSYS Fluent, which investigates the impact of various ventilation systems while identifying smoke density, speed, pressure and temperatures within this tunnel.

Keywords: fire, subway tunnel, CFD, mechanical ventilation, smoke, temperature, harsh weather

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Authors: Z. Khalifa, K. M. Hassan, M. Abdel Azzem

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Potential strategies for deriving useful forms of renewable high density energy from abundant energy stored in carbohydrates is direct conversion of glucose (GLU) to electrical power. A three novel versatile modified electrodes, synthesized by electrochemical polymerization of organic monomers on glassy carbon electrodes (GC), have been developed for biofuel cells results in stable and long-term power production. Electrocatalytic oxidation of glucose in alkaline solution on conducting polymers electrodes modified by incorporation of Ni nanoparticles (NiNPs) onto poly(1,5-aminonaphthalene) (1,5-PDAN), poly(1,8-diaminonaphthalene) (1,8-PDAN) and poly(1-amino-2-methyl-9,10-anthraquinone) (PAMAQ) was investigated. The electrocatalytic oxidation of glucose at NiNPs-modified 1,5-PDAN/GC, 1,8-PDAN/GC and PAMAQ/GC electrodes has been studied using voltammetry technique. The PDAN electrodes show a slight activity in the potential of interest. The prepared NiNPs/PAMAQ/GC catalyst showed a very interesting catalytic activity that was nicely comparable to the NiNPs/1,5-PDAN/GC, NiNPs/1,8-PDAN/GC modified electrodes. In advance, both shows a significant more catalytic activity compared to the reported data for electrodes for glucose electrocatalytic oxidation.

Keywords: biofuel cells, glucose oxidation, electrocatalysis, nanoparticles and modified electrodes

Procedia PDF Downloads 237

Authors: Belkacem Ould Said, Nourddine Retiel, Abdelilah Benazza, Mohamed Aichouni

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In this paper, a numerical study of two-dimensional steady flow has been made of natural convection in a differentially heated vertical conical partially annular space. The heat transfer is assumed to take place by natural convection. The inner and outer surfaces of annulus are maintained at uniform wall temperature. The annulus is filled with air. The CFD FLUENT12.0 code is used to solve the governing equations of mass, momentum and energy using constant properties and the Boussinesq approximation for density variation. The streamlines and the isotherms of the fluid are presented for different annuli with different boundary conditions and Rayleigh numbers. Emphasis is placed on the influences of the height of the inner vertical cone on the flow and the temperature fields. In addition, the effects on the heat transfer are discussed for various values of physical parameters of the fluid and geometric parameters of the annulus. The heat transfer on the hot walls of the annulus is also calculated in order to make comparisons between the cylinder annulus for boundary conditions and several Rayleigh numbers. A good agreement of Nusselt number has been found between the present predictions and reference from the literature data.

Keywords: natural convection, heat transfer, numerical simulation, conical partially, annular space

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Authors: Mojtaba Valinejadshoubi, Azin Shakibabarough, Ashutosh Bagchi

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Facilities such as residential buildings, office buildings, and hospitals house large density of occupants. Therefore, a low-cost facility management program (FMP) should be used to provide a satisfactory built environment for these occupants. Facility management (FM) has been recently used in building projects as a critical task. It has been effective in reducing operation and maintenance cost of these facilities. Issues of information integration and visualization capabilities are critical for reducing the complexity and cost of FM. Building information modeling (BIM) can be used as a strong visual modeling tool and database in FM. The main objective of this study is to examine the applicability of BIM in the FM process during a building’s operational phase. For this purpose, a seven-storey office building is modeled Autodesk Revit software. Authors integrated the cloud-based environment using a visual programming tool, Dynamo, for the purpose of having a real-time cloud-based communication between the facility managers and the participants involved in the project. An appropriate and effective integrated data source and visual model such as BIM can reduce a building’s operational and maintenance costs by managing the building life cycle properly.

Keywords: building information modeling, facility management, operational phase, building life cycle

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Authors: Jinnan Guo, Daoyin Liu

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The quality of final products in the coating process significantly depends on particle fluidization and drying in the spray-fluidized bed. In this study, fluidizing gas temperature and velocity are changed, and their effects on particle flow, moisture content, and heat transfer in a spray fluidized bed are investigated by the CFD – Discrete Element Model (DEM). The gas flow velocity distribution of the fluidized bed is symmetrical, with high velocity in the middle and low velocity on both sides. During the heating process, the particles inside the central tube and at the bottom of the bed are rapidly heated. The particle circulation in the annular area is heated slowly and the temperature is low. The inconsistency of particle circulation results in two peaks in the probability density distribution of the particle temperature during the heating process, and the overall temperature of the particles increases uniformly. During the drying process, the distribution of particle moisture transitions from initial uniform moisture to two peaks, and then the number of completely dried (moisture content of 0) particles gradually increases. Increasing the fluidizing gas temperature and velocity improves particle circulation, drying and heat transfer in the bed. The current study provides an effective method for studying the hydrodynamics of spray fluidized beds with simultaneous processes of heating and particle fluidization.

Keywords: heat transfer, CFD-DEM, spray fluidized bed, drying

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Authors: Kittichai Thanasupsin, Satis Sukniam

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Pavement marking is an essential task of road construction and maintenance. One of several benefits of pavement markings has been used to provide information about road alignment and road conditions ahead. In some cases, retro-reflectivity of road marking at night may not meet the standard. This degradation may be caused by internal factors such as the size of glass beads and the number of glass beads or external factors such as traffic volume, lane width, vehicle weight, and so on. This research aims to investigate the reflective efficiency of thermoplastic road marking with the glass beads. Ratios of glass beads, ranging from 359 to 553 grams per square meter on an asphaltic concrete, have been tested. The reflective efficiency data was collected at the beginning and at a specific time interval for a total of 8 months. It was found that the difference in glass beads quantity affects the rate of retro-reflectivity but does not affect the diffuse reflectivity. It was also found that other factors affect retro-reflectivity, such as duration, the position of road marking, traffic density, the quantity of glass beads, and dirt coating on top. The dirt coating on top is the most crucial factor that deteriorating retro-reflectivity.

Keywords: thermoplastic pavement marking, retro-reflectivity, diffuse reflectivity, asphalt concrete

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Authors: Himali Gunasekara, Baddika Jayaratne

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Haematological abnormalities are known to cause Ischemic Stroke or Transient Ischemic Attack (TIA). The identification of haematological correlates plays an important role in a management and secondary prevention. The objective of this study was to describe haematological correlates of stroke and their association between stroke profile. The haematological correlates screened were Lupus Anticoagulant, Dysfibroginemia, Paroxysmal nocturnal haemoglobinurea (PNH), Sickle cell disease, Systemic Lupus Erythematosis (SLE) and Myeloploriferative Neoplasms (MPN). A cross sectional descriptive study was conducted in a sample of 152 stroke patients referred to haematology department of National Hospital of Sri Lanka for thrombophilia screening. Different tests were performed to assess each hematological correlate. Diluted Russels Viper Venom Test and Kaolin clotting time were done to assess Lupus anticoagulant. Full blood count (FBC), blood picture, Sickling test and High Performance Liquid Chromatography were the tests used for detection of Sickle cell disease. Paroxysmal nocturnal haemoglobinurea was assessed by FBC, blood picture, Ham test and Flowcytometry. FBC, blood picture, Janus Kinase 2 (V617F) mutation analysis, erythropoietin level and bone marrow examination were done to look for the Myeloproliferative neoplasms. Dysfibrinogenaemia was assessed by TT, fibrinogen antigen test, clot observation and clauss test. Anti nuclear antibody test was done to look for systemic lupus erythematosis. Among study sample, 134 patients had strokes and only 18 had TIA. The recurrence of stroke/TIA was observed in 13.2% of patients. The majority of patients (94.7%) have had radiological evidence of thrombotic event. One fourth of patients had past thrombotic events while 12.5% had family history of thrombosis. Out of haematological correlates screened, Lupus anticoagulant was the commonest haematological correlate (n=16 ) and dysfibrigonaemia(n=11 ) had the next high prevalence. One patient was diagnosed with Essential thrombocythaemia and one with SLE. None of the patients were positive for screening tests done for sickle cell disease and PNH. The Haematological correlates were identified in 19% of our study sample. Among stroke profile only presence of past thrombotic history was statistically significantly associated with haematological disorders (P= 0.04). Therefore, hematological disorders appear to be an important factor in etiological work-up of stroke patients particularly in patients with past thrombotic events.

Keywords: stroke, transient ischemic attack, hematological correlates, hematological disorders

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Authors: Siamak Jamshidi

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One of the major environmental problems in the southern coasts of the Caspian Sea is that the marine and coastal debris is being deposited and accumulated due to industrial, urban and tourism activities. Study, sampling and analysis on the type, size, amount and origin of human-made (anthropogenic) waste in the coastal areas of this sea can be very effective in implementing management, cultural and informative programs to reduce marine environmental pollutants. Investigation on marine litter distribution under impact of seawater dynamics was performed for the first time in this research. The rate of entry and distribution of marine and coastal pollutants and wastes, which are mainly of urban, tourist and hospital origin, has multiplied on the southern shore of the Caspian Sea in the last decade. According to the results, the two most important sources of hospital waste in the coastal areas are Tonekabon and Mahmoudabad. In this case, the effect of dynamic parameters of seawater such as flow (with speeds of up to about 1 m/s) and waves, as well as the flow of rivers leading to the shoreline are also influential factors in the distribution of marine litter in the region. Marine litters in the southern coastal region were transported from west to east by the shallow waters of the southern Caspian Sea. In other words, the marine debris density has been observed more in the eastern part.

Keywords: southern shelf, coastal oceanography, seawater flow, vertical structure, marine environment

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Authors: Krishnamoorthy Sathiyan, Shanti Gopal Patra, Ronen Bar-Ziv, Tomer Zidki

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Developing efficient non-noble metal catalysts that are cheap and durable for oxygen evolution reaction (OER) is a great challenge. Moreover, altering the electronic structure of the catalyst and structural engineering of the materials provide a new direction for enhancing the OER. Herein, we have successfully synthesized Fe and Co incorporated MoS₂ catalysts, which show improved catalytic activity for OER when compared with MoS₂, Fe-MoS₂, and Co-MoS₂. It was found that at an optimal ratio of Fe and Co, the electronic and structural modification of MoS₂ occurs, which leads to change in orientation and thereby enhances the active catalytic sites on the edges, which are more exposed for OER. The nanocomposites have been well characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray analysis (EDX), Elemental Mapping, transmission electron microscope (TEM), and high-resolution transmission electron microscope (HR-TEM) analysis. Among all, a particular ratio of FeCo-MoS₂ exhibits a much smaller onset with better catalytic current density. The remarkable catalytic activity is mainly attributed to the synergistic effect from the Fe and Co. Most importantly, our work provides an essential insight in altering the electronic structure of MoS₂ based materials by incorporating promoters such as Co and Fe in an optimal amount, which enhances OER activity.

Keywords: electrocatalysts, molybdenum disulfide, oxygen evolution reaction, transition metals

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Authors: Hossam Shalabi, George Hadjisophocleous

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The Canadian Nuclear Power Plants (NPPs) use some portions of NUREG/CR-6850 in carrying out Fire Probabilistic Risk Assessment (PRA). An assessment for the applicability of NUREG/CR-6850 to CANDU reactors was performed and a CANDU Fire PRA was introduced. There are 19 operating CANDU reactors in Canada at five sites (Bruce A, Bruce B, Darlington, Pickering and Point Lepreau). A fire load density survey was done for all Fire Safe Shutdown Analysis (FSSA) fire zones in all CANDU sites in Canada. National Fire Protection Association (NFPA) Standard 557 proposes that a fire load survey must be conducted by either the weighing method or the inventory method or a combination of both. The combination method results in the most accurate values for fire loads. An updated CANDU Fire PRA model is demonstrated in this paper that includes the fuel survey in all Canadian CANDU stations. A qualitative screening step for the CANDU fire PRA is illustrated in this paper to include any fire events that can damage any part of the emergency power supply in addition to FSSA cables.

Keywords: fire safety, CANDU, nuclear, fuel densities, FDS, qualitative analysis, fire probabilistic risk assessment

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Authors: Wenting Zhang, Shishi Liu, Peihong Fu

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As an indicator of air quality and directly related to concentration of ground PM2.5, the spatial-temporal variation and impact factor analysis of Aerosol Optical Depth (AOD) have been a hot spot in air pollution. This paper concerns the non-stationarity and the autocorrelation (with Moran’s I index of 0.75) of the AOD in Wuhan agglomeration (WHA), in central China, uses the geographically weighted regression (GRW) to identify the spatial relationship of AOD and its impact factors. The 3 km AOD product of Moderate Resolution Imaging Spectrometer (MODIS) is used in this study. Beyond the economic-social factor, land use density factors, vegetable cover, and elevation, the landscape metric is also considered as one factor. The results suggest that the GWR model is capable of dealing with spatial varying relationship, with R square, corrected Akaike Information Criterion (AICc) and standard residual better than that of ordinary least square (OLS) model. The results of GWR suggest that the urban developing, forest, landscape metric, and elevation are the major driving factors of AOD. Generally, the higher AOD trends to located in the place with higher urban developing, less forest, and flat area.

Keywords: aerosol optical depth, geographically weighted regression, land use change, Wuhan agglomeration

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Authors: Polona Dobnik Dubrovski, Abhijit Majumdar

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The increasing awareness of negative effects of ultraviolet radiation and regular, effective protection are actual themes in many countries. Woven fabrics as clothing items can provide convenient personal protection however not all fabrics offer sufficient UV protection. Porous structure of the material has a great effect on UPF. The paper is focused on an overview of porosity in woven fabrics, including the determination of porosity parameters on the basis of an ideal geometrical model of porous structure. Our experiment was focused on 100% cotton woven fabrics in a grey state with the same yarn fineness (14 tex) and different thread densities (to achieve relative fabric density between 59 % and 87 %) and different type of weaves (plain, 4-end twill, 5-end satin). The results of the research dealing with the modelling of UPF and the influence of volume and open porosity of tested samples on UPF are exposed. The results show that open porosity should be lower than 12 % to achieve good UV protection according to AS/NZ standard of tested samples. The results also indicate that there is no direct correlation between volume porosity and UPF, moreover, volume porosity namely depends on the type of weave and affects UPF as well. Plain fabrics did not offer any UV protection, while twill and satin fabrics offered good UV protection when volume porosity was less than 64 % and 66 %, respectively.

Keywords: fabric engineering, UV radiation, porous materials, woven fabric construction, modelling

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Authors: Gi-Beom Park, Hyong-Gi Park, Seong-Yong Lee, Jaeho Choi, Seok Hong Min, Tae Kwon Ha

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The Nb silicide-based alloy has the excellent high-temperature strength and relatively lower density than the Ni-based superalloy; therefore, it has been receiving a lot of attention for the next generation high-temperature material. To enhance the high temperature creep property and oxidation resistance, Si was added to the Nb-based alloy, resulting in a multi-phase microstructure with metal solid solution and silicide phase. Since the silicide phase has a low machinability due to its brittle nature, it is necessary to fabricate components using the powder metallurgy. However, powder manufacturing techniques for the alloys have not yet been developed. In this study, we tried to fabricate Nb-based alloy powder by the hydrogenation-dehydrogenation reaction. The Nb-based alloy ingot was prepared by vacuum arc melting and it was annealed in the hydrogen atmosphere for the hydrogenation. After annealing, the hydrogen concentration was increased from 0.004wt% to 1.22wt% and Nb metal phase was transformed to Nb hydride phase. The alloy after hydrogenation could be easily pulverized into powder by ball milling due to its brittleness. For dehydrogenation, the alloy powders were annealed in the vacuum atmosphere. After vacuum annealing, the hydrogen concentration was decreased to 0.003wt% and Nb hydride phase was transformed back to Nb metal phase.

Keywords: Nb alloy, Nb metal and silicide composite, powder, hydrogenation-dehydrogenation reaction

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Authors: Stepan Hysek, Petra Gajdacova

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In recent years, alternative materials, such as annual plants or recycled and waste materials are becoming more and more popular input material for the production of composite materials. They can be used for the production of insulation boards, construction boards or furniture boards. Surface finishing of those boards is essential for utilization in furniture. However, some difficulties could occur during coating of boards from alternative materials; physical and chemical differences from conventional particleboards need to be considered. From the physical aspects, surface soundness and surface roughness mainly determine the quality of the surface. Since surface layers of boards from alternative materials have often lower density, these characteristics could be deteriorated and thus the production process needs to be optimized. Also, chemical reactions of board’s material with coating could be undesirable. The objective of this study is to evaluate the parameters affecting the surface quality of boards made form alternative materials and to find possibilities of the coating of these boards. In this study, boards of particles from rapeseed stems were produced using a laboratory press. Surface soundness, as representatives of mechanical properties and surface roughness, as representative of physical properties, were measured on boards from rapeseed stems. Results clearly indicated that produced boards had lower surface quality than commercially produced particle boards from wood. Therefore, higher thickness of surface coating on rapeseed based boards is needed.

Keywords: coating, surface, annual plant, composites, particleboard

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Authors: Haoyang Liang, Dandong Ge

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With the rapid development of Chinese cities, traffic congestion has become more and more serious. At the same time, there are many closed old residential area in Chinese cities, which seriously affect the connectivity of urban roads and reduce the density of urban road networks. After reopening the restricted old residential area, the internal roads in the original residential area were transformed into urban roads, which was of great help to alleviate traffic congestion. This paper uses the spatial syntactic theory to analyze the urban road network and compares the roads with the integration and connectivity degree to evaluate whether the opening of the roads in the residential areas can improve the urban traffic. Based on the road network system within the first loop road in Kunming, the Space Syntax evaluation model is established for status analysis. And comparative analysis method will be used to compare the change of the model before and after the road openness of the old urban residential district within the first-ring road in Kunming. Then it will pick out the areas which indicate a significant difference for the small dimensions model analysis. According to the analyzed results and traffic situation, the evaluation of road openness in the old urban residential district will be proposed to improve the urban residential districts.

Keywords: Space Syntax, Kunming, urban renovation, traffic jam

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Authors: Juan C. Martínez-Alfaro, Aracely Zúñiga, Fernando Ruíz-Zarate

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In recent years, the Katahdin sheep breeds have been one of the breeds with greater acceptance by sheep farmers in southwestern Mexico. The Hair Sheep breeds from tropical latitudes (16° to 21° North Latitude) show low estrus activity from January to May. By contrast, these breeds of sheep exhibit high estrus activity from August to December. However, the reproductive management of Hair Sheep crossbred is very limited, independently of the socioeconomic levels of sheep farmers. Thus, in crossbred of Hair Sheep, occurrence of lambing is greater in autumn (84%) than spring (16%). In this sense, the aim of this study was to determine the lambing in Crossbred of Katahdin sheep during different seasons of the year. The Hypothesis was that in crossbred of Katahdin sheep, the lambing period has a behavior seasonal in the Southwestern Mexico. The study design consisted in evaluating the lambing proportion in one herds of Katahdin ewes crossbred during one year (October 1st, 2015 to October 1st, 2016). The study was realized in a farm located in the municipality of Jiquipilas, in the State of Chiapas, Mexico (16° North Latitude). A total of 40 female sheep homogeneous in terms of physical condition, age and physiological state were selected; and they were fed in grazing continuous, mainly with Africa star grass (Cynodon lemfuensis) and they are provided with water and mineral salts ad libitum; during the dry season, the ewes were supplemented with a diet of maize and sorghum, and the reproductive management was continuous mating. The lambing proportion was analyzed by chi-squared test, using SAS statistical software. The proportion of Katahdin ewes crossbred that lambed during the study period was high (100%; 40/40), the prolificacy was 1.42 (lamb/lambing). The proportion of lambing was higher (P<0.05) in autumn (67.5%; 27/40), than winter, spring and summer (32.5%; 13/40; 0%; 0/40; 0%; 0/40; respectively). The proportion of lambing was greater (P<0.05) in November (50%; 20/40), compared to October, December and January (2.5%; 1/40; 27.5%; 11/40; 20%; 8/40, respectively). The results are consistent with the fact that in the Hair Sheep Breeds, the lambing appears behave seasonally. The most important finding is that the lambing period in the crossbred of Katahdin Sheep is similar to the crossbred of Hair Sheep in tropical regions of Mexico. Therefore, the period of greater sexual activity occurs in the spring season. In conclusion, the period of lambing in crossbred of Katahdin ewes appears behave seasonally. Further researches to assess the ovarian activity in different breeds of Hair Ewes are under assessment.

Keywords: Katahdin ewes, lambing, prolificacy, seasonality

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Authors: Samuel E. Okere, Anthony E. Ataga

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Introduction: This paper evaluated the mineral compositions, disease resistance elicitors in Pleurotus ostratus (POWESMS), and Pleurotus tuber-regium water extract spent mushroom substrate (PTWESMS) on the growth, yield, and management of cassava mosaic disease. Materials and Methods: The cassava plantlet (tms 98/0505) were generated through meristem tip culture at the Tissue Culture Laboratory, National Root Crop Research Institute, Umudike before they were transferred to the screen house, University of Port Harcourt Research Farm. The minerals and elicitors contained in the two spent mushroom substrates were evaluated using standard procedures. The treatments for this investigation comprised cassava plants treated with POWESMS, PTWESMS, and untreated cassava as control, which were inoculated with viral inoculum seven days after treatment application. The experiment was laid out in a completely randomized block design with 3 replicates. The data generated were subjected to analysis of variance (ANOVA). Means were separated using Fishers Least Significant Difference at p=0.05. Results: The results obtained revealed that POWESMS contained 19.3, 0.52, and 0.1g/200g substrate of carbohydrate polymers, glycoproteins, and lipid molecules elicitors respectively while it also contained 3.17, 212.1, 17.9,21.8, 58.8 and 111.0 mg/100g substrate for N, P, K, Na, Mg and Ca respectively. Further, PTWESMS contain 1.6, 0.04, and 0.2g/200g of the substrate as carbohydrate polymers, glycoprotein, and lipid respectively; the minerals contained in this substrate were 3.4, 204.8, 8.9, 24.2, 32.2 and 105.5 mg respectively for N, P, K, Na, and Ca. There were also significant differences in the mean values of the number of storage roots, root length, fresh root weight, fresh weight plant biomass, root girth, and whole plant dry biomass, but no significant difference was recorded for harvest index. The result also revealed significant differences in mean values of disease severity index evaluated at 4, 8, 12, 16, 20, 24, and 28 weeks after inoculation (WAI). Conclusion: The aqueous extract of these spent mushrooms substrate have shown outstanding prospect in managing cassava mosaic disease and also improvement in growth and yield of cassava due to the high level of the minerals and elicitors they contain when compared with the control. However, more work is recommended, especially in understanding the mechanism of this induced resistance.

Keywords: characterization, elicitors, mosaic, mushroom

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Authors: Shengping Zhong, Qimin Shi, Yaling Deng, Shoufeng Yang

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Additive manufacturing has exerted a tremendous fascination on the development of the manufacturing and materials industry in the past three decades. Zirconia-based advanced ceramic has been poured substantial attention in the interest of structural and functional ceramics. As a novel material jetting process for selectively depositing nanoparticles, NanoParticle Jetting™ is capable of fabricating dense zirconia components with a high-detail surface, precisely controllable shrinkage, and remarkable mechanical properties. The presence of NPJ™ gave rise to a higher elevation regarding the printing process and printing accuracy. Emphasis is placed on the performance evaluation of NPJ™ printed ceramic components by which the physical, chemical, and mechanical properties are evaluated. The experimental results suggest the Y₂O₃-stabilized ZrO₂ boxes exhibit a high relative density of 99.5%, glossy surface of minimum 0.33 µm, general linear shrinkage factor of 17.47%, outstanding hardness and fracture toughness of 12.43±0.09 GPa and 7.52±0.34 MPa·m¹/², comparable flexural strength of 699±104 MPa, and dense and homogeneous grain distribution of microstructure. This innovative NanoParticle Jetting system manifests an overwhelming potential in dental, medical, and electronic applications.

Keywords: nanoparticle jetting, ZrO₂ ceramic, materials jetting, performance evaluation

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Authors: Eric Neidhardt

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A well-functioning public transport system that is accepted and used by the general population contributes a lot to a sustainable city. Especially young and elderly people rely on public transport to get to work, go shopping, visit a doctor, and take advantage of entertainment options. The sustainability of a public transport system can be considered from different points of view. In urban areas, acceptance is particularly important. As many people as possible should use public transport and not their private vehicle. This reduces traffic jams and increases air quality. In rural areas, the cost efficiency of public transport is especially important. Longer distances and a low population density mean that these modes of transportation can rarely be used cost-effectively. It is crucial to avoid a low utilization, because empty rides are neither sustainable nor cost-effective. With a demand-oriented approach, we try to both improve flexibility and therefore attractiveness for the user and improve cost- efficiency. The vehicles only operate when they are needed and only where they are needed. Empty rides are avoided to improve sustainability. In the subproject "Autonomous public driving" of the project RealLabHH, such a system was implemented and tested in Hamburg-Bergedorf, a suburb of Hamburg. In this paper, some of the steps necessary for this are considered from a technical point of view, and problems that arose in real-life use are addressed.

Keywords: public transport, demand-oriented, autonomous driving, RealLabHH

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Authors: Giorgio Visentin, Inna S. Kalinina, Alexei A. Buchachenko

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In the ambit of intermolecular interactions, a combination rule is defined as a relation linking a potential parameter for the interaction of two unlike species with the same parameters for interaction pairs of like species. Some of their most exemplificative applications cover the construction of molecular dynamics force fields and dispersion-corrected density functionals. Here, an extended combination rule is proposed, relating the dipole-dipole dispersion coefficients for the interaction of like target species to the same coefficients for the interaction of the target and a set of partner species. The rule can be devised in two different ways, either by uniform discretization of the Casimir-Polder integral on a Gauss-Legendre quadrature or by relating the dynamic polarizabilities of the target and the partner species. Both methods return the same system of linear equations, which requires the knowledge of the dispersion coefficients for interaction between the partner species to be solved. The test examples show a high accuracy for dispersion coefficients (better than 1% in the pristine test for the interaction of Yb atom with rare gases and alkaline-earth metal atoms). In contrast, the rule does not ensure correct monotonic behavior of the dynamic polarizability of the target species. Acknowledgment: The work is supported by Russian Science Foundation grant # 17-13-01466.

Keywords: combination rule, dipole-dipole dispersion coefficient, Casimir-Polder integral, Gauss-Legendre quadrature

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Authors: Takele Nemomsa, Girma Mamo, Tesfaye Balemi

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Climate change refers to a change in the state of the climate that can be identified (e.g. using statistical tests) by changes in the mean and/or variance of its properties and that persists for an extended period, typically decades or longer. In Ethiopia; Maize production in relation to climate change at regional and sub- regional scales have not been studied in detail. Thus, this study was aimed to analyse the impact of climate change on maize yield in Ambo Districts, Central Ethiopia. To this effect, weather data, soil data and maize experimental data for Arganne hybrid were used. APSIM software was used to investigate the response of maize (Zea mays) yield to different agronomic management practices using current and future (2020s–2080s) climate data. The climate change projections data which were downscaled using SDSM were used as input of climate data for the impact analysis. Compared to agronomic practices the impact of climate change on Arganne in Central Ethiopia is minute. However, within 2020s-2080s in Ambo area; the yield of Arganne hybrid is projected to reduce by 1.06% to 2.02%, and in 2050s it is projected to reduce by 1.56 While in 2080s; it is projected to increase by 1.03% to 2.07%. Thus, to adapt to the changing climate; farmers should consider increasing plant density and fertilizer rate per hectare.

Keywords: APSIM, downscaling, response, SDSM

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Authors: K. Durairaj, I. N. Umar

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The asynchronous discussion forum is one of the most widely used activities in learning management system environment. Online forum allows participants to interact, construct knowledge, and can be used to complement face to face sessions in blended learning courses. However, to what extent do the students perceive the benefits or advantages of forum remain to be seen. Through content and social network analyses, instructors will be able to gauge the students’ engagement and knowledge construction level. Thus, this study aims to analyze the students’ level of knowledge construction and their participation level that occur through online discussion. It also attempts to investigate the relationship between the level of knowledge construction and their social interaction patterns. The sample involves 23 students undertaking a master course in one public university in Malaysia. The asynchronous discussion forum was conducted for three weeks as part of the course requirement. The finding indicates that the level of knowledge construction is quite low. Also, the density value of 0.11 indicating that the overall communication among the participants in the forum is low. This study reveals that strong and significant correlations between SNA measures (in-degree centrality, out-degree centrality) and level of knowledge construction. Thus, allocating these active students in a different groups aids the interactive discussion takes place. Finally, based upon the findings, some recommendations to increase students’ level of knowledge construction and also for further research are proposed.

Keywords: asynchronous discussion forums, content analysis, knowledge construction, social network analysis

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Authors: Heather E. Ewart, Keith Jensen, Rebecca N. Cliffe

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Fragmentation and changes in the structural composition of tropical forests – as a result of intensifying anthropogenic disturbance – are increasing pressures on local biodiversity. Species with low dispersal abilities have some of the highest extinction risks in response to environmental change, as even small-scale environmental variation can substantially impact their space use and energetic balance. Understanding the implications of forest disturbance is therefore essential, ultimately allowing for more effective and targeted conservation initiatives. Here, the impact of different levels of forest disturbance on the space use, energetics, movement and behavior of 18 brown-throated sloths (Bradypus variegatus) were assessed in the South Caribbean of Costa Rica. A multi-scale framework was used to measure forest disturbance, including large-scale (landscape-level classifications) and fine-scale (within and surrounding individual home ranges) forest composition. Three landscape-level classifications were identified: primary forests (undisturbed), secondary forests (some disturbance, regenerating) and urban forests (high levels of disturbance and fragmentation). Finer-scale forest composition was determined using measurements of habitat structure and quality within and surrounding individual home ranges for each sloth (home range estimates were calculated using autocorrelated kernel density estimation [AKDE]). Measurements of forest quality included tree connectivity, density, diameter and height, species richness, and percentage of canopy cover. To determine space use, energetics, movement and behavior, six sloths in urban forests, seven sloths in secondary forests and five sloths in primary forests were tracked using a combination of Very High Frequency (VHF) radio transmitters and Global Positioning System (GPS) technology over an average period of 120 days. All sloths were also fitted with micro data-loggers (containing tri-axial accelerometers and pressure loggers) for an average of 30 days to allow for behavior-specific movement analyses (data analysis ongoing for data-loggers and primary forest sloths). Data-loggers included determination of activity budgets, circadian rhythms of activity and energy expenditure (using the vector of the dynamic body acceleration [VeDBA] as a proxy). Analyses to date indicate that home range size significantly increased with the level of forest disturbance. Female sloths inhabiting secondary forests averaged 0.67-hectare home ranges, while female sloths inhabiting urban forests averaged 1.93-hectare home ranges (estimates are represented by median values to account for the individual variation in home range size in sloths). Likewise, home range estimates for male sloths were 2.35 hectares in secondary forests and 4.83 in urban forests. Sloths in urban forests also used nearly double (median = 22.5) the number of trees as sloths in the secondary forest (median = 12). These preliminary data indicate that forest disturbance likely heightens the energetic requirements of sloths, a species already critically limited by low dispersal ability and rates of energy acquisition. Energetic and behavioral analyses from the data-loggers will be considered in the context of fine-scale forest composition measurements (i.e., habitat quality and structure) and are expected to reflect the observed home range and movement constraints. The implications of these results are far-reaching, presenting an opportunity to define a critical index of habitat connectivity for low dispersal species such as sloths.

Keywords: biodiversity conservation, forest disturbance, movement ecology, sloths

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Authors: Alyaa M. Younes, Nermine Harraz, Mohammad H. Elwany

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Lithium ion batteries are currently used for many applications including satellites, electric vehicles and mobile electronics. Their ability to store relatively large amount of energy in a limited space make them most appropriate for critical applications. Evaluation of the life of these batteries and their reliability becomes crucial to the systems they support. Reliability of Li-Ion batteries has been mainly considered based on its lifetime. However, another important factor that can be considered critical in many applications such as in electric vehicles is the cycle duration. The present work presents the results of an experimental investigation on the degradation behavior of a Laptop Li-ion battery (type TKV2V) and the effect of applied load on the battery cycle time. The reliability was evaluated using an accelerated life test. Least squares linear regression with median rank estimation was used to estimate the Weibull distribution parameters needed for the reliability functions estimation. The probability density function, failure rate and reliability function under each of the applied loads were evaluated and compared. An inverse power model is introduced that can predict cycle time at any stress level given.

Keywords: accelerated life test, inverse power law, lithium-ion battery, reliability evaluation, Weibull distribution

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Authors: Hanbey Hazar, Hakan Gul, Ugur Ozturk

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In order to decrease the hazardous emissions of the internal combustion engines and to improve the combustion and thermal efficiency, thermal barrier coatings are applied. In this experimental study, cylinder, piston, exhaust, and inlet valves which are combustion chamber components have been coated with a ceramic material, and this earned the engine LHR feature. Cylinder, exhaust and inlet valves of the diesel engine used in the tests were coated with ekabor-2 commercial powder, which is a ceramic material, to a thickness of 50 µm, by using the boriding method. The piston of a diesel engine was coated in 300 µm thickness with bor-based powder by using plasma coating method. Pumpkin seeds oil methyl ester (PSME) was produced by the transesterification method. In addition, dimethoxymethane additive materials were used to improve the properties of diesel fuel, pumpkin seeds oil methyl ester (PSME) and its mixture. Dimethoxymethane was blended with test fuels, which was used as a pilot fuel, at the volumetric ratios of 4% and 8%. Due to thermal barrier coating, the diesel engine's CO, HC, and smoke density values decreased; but, NOx and exhaust gas temperature (EGT) increased.

Keywords: boriding, diesel engine, exhaust emission, thermal barrier coating

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Authors: Premrudee Promdet, Fan Cui, Gi Byoung Hwang, Ka Chuen To, Sanjayan Sathasivam, Claire J. Carmalt, Ivan P. Parkin

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A novel single-step fabrication of Cu nanoparticle embedded ZnO (Cu.ZnO) thin films was developed by aerosol-assisted chemical vapor deposition for stable and efficient hydrogen production in Photoelectrochemical (PEC) cell. In this approach, the Cu.ZnO nanoplate thin films were grown by using acetic acid to promote preferential growth and enhance surface active sites, where Cu nanoparticles can be formed under chemical deposition by reduction of Cu salt. Studies using photoluminescence spectroscopy indicate the enhanced photocatalytic performance is attributed to hot electron generated from SPR. The Cu metal in the composite material is functioning as a sensitizer to supply electrons to the semiconductor resulting in enhanced electron density for redox reaction. This work not only describes a way to obtain photoanodes with high photocatalytic activity but also suggests a low-cost route towards production of photocatalysts for hydrogen production. This work also supports a vital need to understand electron transfer between photoexcited semiconductor materials and metals, a requirement for tailoring the properties of semiconductor/metal composites.

Keywords: photocatalysis, photoelectrochemical cell (PEC), aerosol-assisted chemical vapor deposition (AACVD), surface plasmon resonance (SPR)

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Authors: N. P. Tien, S. Songsermpong, T. H. Quan

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Mung bean vermicelli is a popular food in Asian countries and is made from mung bean starch. The preparation process involves several steps, including drying, which affects the structure and quality of the vermicelli. This study aims to examine the effects of different drying technologies on the rehydration time and quality of mung bean vermicelli. Three drying technologies, namely hot air drying, microwave continuous drying, and microwave vacuum drying, were used for the drying process. The vermicelli strands were dried at 45°C for 12h in a hot air dryer, at 70 Hz of conveyor belt speed inverter in a microwave continuous dryer, and at 30 W.g⁻¹ of microwave power density in a microwave vacuum dryer. The results showed that mung bean vermicelli dried using hot air drying had the longest rehydration time of 12.69 minutes. On the other hand, vermicelli dried through microwave continuous drying and microwave vacuum drying had shorter rehydration times of 2.79 minutes and 2.14 minutes, respectively. Microwave vacuum drying also resulted in larger porosity, higher water absorption, and cooking loss. The tensile strength and elasticity of vermicelli dried using hot air drying were higher compared to microwave drying technologies. The sensory evaluation did not reveal significant differences in most attributes among the vermicelli treatments. Overall, microwave drying technology proved to be effective in reducing rehydration time and producing good-quality mung bean vermicelli.

Keywords: mung bean vermicelli, drying, hot air, microwave continuous, microwave vacuum

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Authors: M. R. Noor El-Din, Marwa R. Mishrif, R. E. Morsi, E. A. El-Sharaky, M. E. Haseeb, Rania T. M. Ghanem

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This paper studies the physical and rheological behaviours of water/in/diesel fuel nanoemulsions prepared by modified low energy method. Twenty of water/in/diesel fuel nanoemulsions were prepared using mixed nonionic surfactants of sorbitan monooleate and polyoxyethylene sorbitan trioleate (MTS) at Hydrophilic-Lipophilic Balance (HLB) value of 10 and a working temperature of 20°C. The influence of the prepared nanoemulsions on the physical properties such as kinematic viscosity, density, and calorific value was studied. Also, nanoemulsion systems were subjected to rheological evaluation. The effect of water loading percentage (5, 6, 7, 8, 9 and 10 wt.%) on rheology was assessed at temperatures range from 20 to 60°C with temperature interval of 10 for time lapse 0, 1, 2 and 3 months, respectively. Results show that all of the sets nanoemulsions exhibited a Newtonian flow character of low-shear viscosity in the range of 132 up to 191 1/s, and followed by a shear-thinning region with yield value (Non-Newtonian behaviour) at high shear rate for all water ratios (5 to 10 wt.%) and at all test temperatures (20 to 60°C) for time ageing up to 3 months. Also, the viscosity/temperature relationship of all nanoemulsions fitted well Arrhenius equation with high correlation coefficients that ascertain their Newtonian behavior.

Keywords: alternative fuel, nanoemulsion, surfactant, diesel fuel

Procedia PDF Downloads 303