Search results for: tandam mass spectrometry

Authors: R. Deju, M. Mincu, D. Gurau

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During the interim storage or final disposal of low level waste, migration/diffusion of radionuclides can occur when the waste comes in contact with water. The long-term leaching behaviour into surrounding fluid (demineralized water) of ¹³⁷Cs, ⁶⁰Co and ¹⁵²Eu radionuclides, artificially incorporated in mortar matrices made from natural aggregates (river sand) and recycled radioactive concrete was studied. Results presented in this work are obtained in two years of mortar testing and will be used for the safety increasing in the storage of low level radioactive waste. The study involved the influence of curing time, type and size distribution of the aggregates on leaching behaviour. The mortar samples were immersed in distilled water for 30 days. The leached activity of the mortar samples was measured on samples from the immersing water and analyzed through a gamma-ray spectrometry method using an HPGe detector with a GESPECOR code for efficiency evaluation. The long-term leaching behaviour of the radionuclides was evaluated from the leaching data calculating the apparent diffusion coefficient.

Keywords: gamma spectrometry, leaching behavior, reuse and recycling of radioactive concrete, waste management

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Authors: Man Chul Jeong, Hyoung Jin Lee, Sang Yoon Lee, Ji Hyun Park, Min Wook Chang, In-Seuck Jeung

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This study focus on the drag reduction effect of the base bleed at supersonic flow. Base bleed is the method which bleeds the gas on the tail of the flight vehicle and reduces the base drag, which occupies over 50% of the total drag in any flight speed. Thus base bleed can reduce the total drag significantly, and enhance the total flight range. Drag reduction ratio of the base bleed is strongly related to the mass flow rate of the bleeding gas. Thus selecting appropriate mass flow rate is important. However, since the flight vehicle has various flight speed, same mass flow rate of the base bleed can have different drag reduction effect during the flight. Thus, this study investigates the effect of the drag reduction depending on the flight speed by numerical analysis using STAR-CCM+. The analysis model is 155mm diameter projectile with boat-tailed shape base. Angle of the boat-tail is chosen previously for minimum drag coefficient. Numerical analysis is conducted for Mach 2 and Mach 3, with various mass flow rate, or the injection parameter I, of the bleeding gas and the temperature of the bleeding gas, is fixed to 300K. The results showed that I=0.025 has the minimum drag at Mach 2, and I=0.014 has the minimum drag at Mach 3. Thus as the Mach number is higher, the lower mass flow rate of the base bleed has more effect on drag reduction.

Keywords: base bleed, supersonic, drag reduction, recirculation

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Authors: Hosseini Siahi Zohreh, Sana Mohammad Jafar

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With increase in fat and over weight in children and its undesirable effects on different organisms of the body and since many of the sicknesses are due to over weight and with losing weight these sicknesses disappear, and on the other hand with mal nutrition and under weight in children other kind of sicknesses such as derogation of body's security system, frequent infection, insufficient growth, shortness, and delay in maturity etc. are some of the signs of being under weight. Therefore recognition of signs of over weight and under weight and their prevalence in children are important. To determine this difficulty we have used the body mass index as screening tool since it is very prevalent and a good and important guide and has very good relation with body fat in children. In this study 2321 students from primary schools in Behbahan have been chosen randomly and evaluated by height and weight and their body mass index have been calculated and then recorded on the BMI percentile diagram which is for age and gender. The following results obtained: The amount of total fat, over weight and slimness are 9.3, 12.1 and 12.32 percent respectively. Therefore 21.4% of the children were over weighted. It did not show any meaningful statistical relation in fat conditions among boys and girls, but there has been a meaningful statistical relation in slimness among boys and girls.

Keywords: assessment, students, Behbahan, Body Mass Index

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Authors: Jian-Li Shao

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Using Molecular Dynamic (MD) simulations, we simulated the microjet from the metal surface under decaying shock loading. The microjetting processes under release melting conditions are presented in detail, and some properties on the microjet mass and velocity are revealed. The phased increase of microjet mass with shock pressure is found. For all cases, the ratio of the maximal jetting velocity to the surface velocity approximately keeps a constant for liquid state. In addition, the temperature of the microjet can be always above the melting point. When introducing slow decaying profiles, the microjet mass begins to increase with the decay rate, which is dominated by the deformation of the bubble during pull-back. When the decay rate becomes fast enough, the microspall occurs as expected, meanwhile, the microjet appears to reduce because of the shock energy reduction.

Keywords: microjetting, shock, metal, molecular dynamics

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Authors: I. Karagjozova, B. Dejanova, J. Pluncevic, S. Petrovska, V. Antevska, L. Todorovska

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Introduction: Medical checking assessment is important in sports medicine. To follow the health condition in subjects who perform sports, body composition parameters, such as intracellular water, extracellular water, protein and mineral content, muscle and fat mass might be useful. The aim of the study was to show available parameters and to compare them to manual assessment. Material and methods: A number of 20 subjects (14 male and 6 female) at age of 20±2 years were determined in the study, 5 performed recreational sports, while others were professional ones. The mean height was 175±7 cm, the mean weight was 72±9 cm, and the body mass index (BMI) was 23±2 kg/m2. The measured compartments were as following: intracellular water (IW), extracellular water (EW), protein component (PC), mineral component (MC), skeletal muscle mass (SMM) and body fat mass (BFM). Lean balance were examined for right and left arm (LA), trunk (T), right leg (RL) and left leg (LL). The comparison was made between the calculation derived by manual made measurements, using Matejka formula and parameters obtained by body composition analyzer (BCA) - Inbody 720 BCA Biospace. Used parameters for the comparison were muscle mass (SMM), body fat mass (BFM). Results: BCA obtained values were for: IW - 22.6±5L, EW - 13.5±2 L, PC - 9.8±0.9 kg, MC - 3.5±0.3, SMM - 27±3 kg, BFM - 13.8±4 kg. Lean balance showed following values for: RA - 2.45±0.2 kg, LA - 2.37±0.4, T - 20.9±5 kg, RL - 7.43±1 kg, and LL - 7.49 ±1.5 kg. SMM showed statistical difference between manual obtained value, 51±01% to BCA parameter 45.5±3% (p<0.001). Manual obtained values for BFM was lower (17±2%) than BCA obtained one, 19.5±5.9% (p<0.02). Discussion: The obtained results showed appropriate values for the examined age, regarding to all examined parameters which contribute to overview the body compartments, important for sport performing. Due to comparison between the manual and BCA assessment, we may conclude that manual measurements may differ from the certain ones, which is confirmed by statistical significance.

Keywords: athletes, body composition, bio electrical impedance, sports medicine

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Authors: Malith Premarathne, Shehan Bandara, Kaushalya G. Batawala, Thilini U. Ariyadasa

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The rapid depletion of fossil fuel supplies and the emission of carbon dioxide by their continued combustion have paved the way for increased production of carbon-neutral biodiesel from naturally occurring oil sources. The high biomass growth rate and lipid production of microalgae make it a viable source for biodiesel production compared to conventional feedstock. In Sri Lanka, the production of biodiesel by employing indigenous microalgae species is at its emerging stage. This work was an attempt to compare the various pre-treatment methods before extracting lipids such as autoclaving, microwaving and sonication. A mixed culture of microalgae predominantly consisting of Chlorella sp. was obtained from Beire Lake which is an algae rich, organically polluted water body located in Colombo, Sri Lanka. After each pre-treatment method, a standard solvent extraction using Bligh and Dyer’s method was used to compare the total lipid content in percentage dry weight (% dwt). The fatty acid profiles of the oils extracted with each pretreatment method were analyzed using gas chromatography-mass spectrometry (GC-MS). The properties of the biodiesels were predicted by Biodiesel Analyzer© Version 1.1, in order to compare with ASTM 6751-08 biodiesel standard.

Keywords: biodiesel, lipid extraction, microalgae, pre-treatment

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Authors: Md. Najiur Rahman

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This hypothesis reveals a profound and symmetrical connection that goes beyond the boundaries of quantum physics and cosmology, revolutionizing our understanding of the fundamental building blocks of the cosmos, given its name ‘The Theory of the Mystery’. This theory has an elegantly simple equation, “R = ∆r / √∆m” which establishes a beautiful and well-crafted relationship between the radius (R) of an elementary particle or galaxy, the relative change in radius (∆r), and the mass difference (∆m) between related entities. It is fascinating to note that this formula presents a super synchronization, one which involves the convergence of every basic particle and any single celestial entity into perfect alignment with its respective mass and radius. In addition, we have a Supporting equation that defines the mass-radius connection of an entity by the equation: R=√m/N, where N is an empirically established constant, determined to be approximately 42.86 kg/m, representing the proportionality between mass and radius. It provides precise predictions, collects empirical evidence, and explores the far-reaching consequences of theories such as General Relativity. This elegant symmetry reveals a fundamental principle that underpins the cosmos: each component, whether small or large, follows a precise mass-radius relationship to exert gravity by a universal law. This hypothesis represents a transformative process towards a unified theory of physics, and the pursuit of experimental verification will show that each particle and galaxy is bound by gravity and plays a unique but harmonious role in shaping the universe. It promises to reveal the great symphony of the mighty cosmos. The predictive power of our hypothesis invites the exploration of entities at the farthest reaches of the cosmos, providing a bridge between the known and the unknown.

Keywords: unified theory, quantum gravity, mass-radius relationship, dark matter, uniform gravity

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Authors: Liu Canqi, Zeng Junsheng

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This study identifies two typical bottlenecks that occur when a vehicle cannot change lanes: car following and car stopping. The ideas of traffic field and traffic mass are presented in this work. When there are other vehicles in front of the target vehicle within a particular distance, a force is created that affects the target vehicle's driving speed. The characteristics of the driver and the vehicle collectively determine the traffic mass; the driving speed of the vehicle and external variables have no bearing on this. From a physical level, this study examines the vehicle's bottleneck when following a car, identifies the outside factors that have an impact on how it drives, takes into account that the vehicle will transform kinetic energy into potential energy during deceleration, and builds a calculation model for traffic mass. The energy-time conversion coefficient is created from an economic standpoint utilizing the social average wage level and the average cost of motor fuel. Vissim simulation program measures the vehicle's deceleration distance and delays under the Wiedemann car-following model. The difference between the measured value of deceleration delay acquired by simulation and the theoretical value calculated by the model is compared using the conversion calculation model of traffic mass and deceleration delay. The experimental data demonstrate that the model is reliable since the error rate between the theoretical calculation value of the deceleration delay obtained by the model and the measured value of simulation results is less than 10%. The article's conclusion is that the traffic field has an impact on moving cars on the road and that physical and socioeconomic factors should be taken into account while studying vehicle-following behavior. The deceleration delay value of a vehicle's driving and traffic mass have a socioeconomic relationship that can be utilized to calculate the energy-time conversion coefficient when dealing with the bottleneck of cars stopping and starting.

Keywords: traffic field, social economics, traffic mass, bottleneck, deceleration delay

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Authors: I. M. Sujaul, M. A. Sobahan, A. A. Edriyana, F. M. Yahaya, R. M. Yunus

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This study was carried out to investigate the adverse effect of industrial waste water on surface water quality in Gebeng industrial estate, Pahang, Malaysia. Surface water was collected from 6 sampling stations. Physico-chemical parameters were characterized based on in-situ and ex-situ analysis according to standard methods by American Public Health Association (APHA). Selected heavy metals were determined by using Inductively Coupled Plasma Mass Spectrometry (ICP MS). The result reveled that the concentration of heavy metals such as Pb, Cu, Cd, Cr and Hg were high in samples. The result showed that the value of Pb and Hg were higher in the wet season in comparison to dry season. According to Malaysia National Water Quality Standard (NWQS) and Water Quality Index (WQI) all the sampling station were categorized as class IV (highly polluted). The present study reveled that the adverse effects of careless disposal of wastes and directly discharge of effluents affected on surface water quality. Therefore, the authorities should implement the laws to ensure the proper practices of waste water management for environmental sustainability around the study area.

Keywords: water, heavy metals, water quality index, Gebeng

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Authors: Turk Ayman, Ahn Jong Hoon, Khalife K. Hala, Gali-Muhtasib Hala, Lee Mi Kyeong

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Laurus nobilis is an aromatic plant widely distributed in the Mediterranean region. The leaves of this plant are frequently used as a spice and as a traditional medicine for several diseases. In our present study, the methanolic extract of L. nobilis leaves showed antioxidant activity. Chromatographic separations of the EtOAc fraction which had the highest antioxidant activity led to the isolation of 12 compounds. Among them, there was a new phenylpropanoid derivative, which was identified by 1D and 2D NMR experiments, as well as high resolution mass spectrometry. In addition, two major compounds, catechin and epicatechin, which showed strong antioxidant activity may be responsible for the antioxidant activity of L. nobilis leaves. Since different plant parts may contain different types of constituents which contribute to the biological activities, we investigated the antioxidant activity of different parts of L. nobilis such as leaves, stems and fruits. Stems of L. nobilis showed the most potent antioxidant activity, followed by leaves. Further quantitation of total phenol and flavonoids contents revealed a positive correlation between the content of these compounds and antioxidant activity. Taken together, phenolic compounds including flavonoids are responsible for antioxidant activity of L. nobilis. In addition, stem parts of L. nobilis are suggested as good sources for antioxidant activity. Conclusively, L. nobilis might be effective in several free radical mediated diseases.

Keywords: antioxidant activity, different parts, Laurus nobilis, phenolic compound

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Authors: Orkide Donma, Mustafa M. Donma

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Basal metabolic rate is questioned as a risk factor for weight gain. The relations between basal metabolic rate and body composition have not been cleared yet. The impact of fat mass on basal metabolic rate is also uncertain. Within this context, indices based upon total body mass as well as total body fat mass are available. In this study, the aim is to investigate the potential clinical utility of these indices in the adult population. 287 individuals, aged from 18 to 79 years, were included into the scope of the study. Based upon body mass index values, 10 underweight, 88 normal, 88 overweight, 81 obese, and 20 morbid obese individuals participated. Anthropometric measurements including height (m), and weight (kg) were performed. Body mass index, diagnostic obesity notation model assessment index I, diagnostic obesity notation model assessment index II, basal metabolic rate-to-weight ratio were calculated. Total body fat mass (kg), fat percent (%), basal metabolic rate, metabolic age, visceral adiposity, fat mass of upper as well as lower extremities and trunk, obesity degree were measured by TANITA body composition monitor using bioelectrical impedance analysis technology. Statistical evaluations were performed by statistical package (SPSS) for Windows Version 16.0. Scatterplots of individual measurements for the parameters concerning correlations were drawn. Linear regression lines were displayed. The statistical significance degree was accepted as p < 0.05. The strong correlations between body mass index and diagnostic obesity notation model assessment index I as well as diagnostic obesity notation model assessment index II were obtained (p < 0.001). A much stronger correlation was detected between basal metabolic rate and diagnostic obesity notation model assessment index I in comparison with that calculated for basal metabolic rate and body mass index (p < 0.001). Upon consideration of the associations between basal metabolic rate-to-weight ratio and these three indices, the best association was observed between basal metabolic rate-to-weight and diagnostic obesity notation model assessment index II. In a similar manner, this index was highly correlated with fat percent (p < 0.001). Being independent of the indices, a strong correlation was found between fat percent and basal metabolic rate-to-weight ratio (p < 0.001). Visceral adiposity was much strongly correlated with metabolic age when compared to that with chronological age (p < 0.001). In conclusion, all three indices were associated with metabolic age, but not with chronological age. Diagnostic obesity notation model assessment index II values were highly correlated with body mass index values throughout all ranges starting with underweight going towards morbid obesity. This index is the best in terms of its association with basal metabolic rate-to-weight ratio, which can be interpreted as basal metabolic rate unit.

Keywords: basal metabolic rate, body mass index, children, diagnostic obesity notation model assessment index, obesity

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Authors: Arakelian Vigen, Geng Jing, Le Baron Jean-Paul

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The paper deals with the design of parallel manipulators with balanced inertia forces and moments. The balancing of the resultant of the inertia forces of 3-RRR planar parallel manipulators is carried out through mass redistribution and centre of mass acceleration minimization. The proposed balancing technique is achieved in two steps: at first, optimal redistribution of the masses of input links is accomplished, which ensures the similarity of the end-effector trajectory and the manipulator’s common centre of mass trajectory, then, optimal trajectory planning of the end-effector by 'bang-bang' profile is reached. In such a way, the minimization of the magnitude of the acceleration of the centre of mass of the manipulator brings about a minimization of shaking force. To minimize the resultant of the inertia moments (shaking moment), the active balancing via inertia flywheel is applied. However, in this case, the active balancing is quite different from previous applications because it provides only a partial cancellation of the shaking moment due to the incomplete balancing of shaking force.

Keywords: dynamic balancing, inertia force minimization, inertia moment minimization, 3-RRR planar parallel manipulator

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Authors: Thangaraj Arasakumar, Athar Ata, Palathurai Subramaniam Mohan

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A series of novel 4-quinolone-3-carboxylic acid grafted spiropyrrolidines as new type of antibacterial agents were synthesized via multicomponent 1,3-dipolar cycloaddition reaction of an azomethine ylides with a newly prepared (E)-4-oxo-6-(3-phenyl-acryloyl)-1,4-dihydro-quinoline-3-carboxylic acids in high regioselectivity with good yields. The structure of cycloadduct characterized by FT IR, mass, 1H, 13C, 2D NMR techniques and elemental analysis. Structure and spectrometry of compound 8a has been investigated theoretically by using HF and DFT approach at B3LYP, M05-2x/6-31G* levels of theories. The optimized geometries and calculated vibrational frequencies are evaluated via comparison with experimental values. A good agreement is found between the measured and calculated values. The DFT studies support the molecular mechanism of this cycloaddition reaction and determine the molecular electrostatic potential and thermodynamic properties. Furthermore, the antibacterial activities of synthesized compounds were evaluated against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria strains (Escherichia coli, Klebsiella pneumoniae). Among 21 compounds screened, 8f and 8p were found to be more active against tested bacteria.

Keywords: antibacterial activity, azomethine ylide, DFT calculation, spirooxindole

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Authors: Meena K. Yadav, Rupak Aryal, Michael D. Short, Ben Van Den Akker, Christopher P. Saint, Cobus Gerber

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Illicit drugs are considered as emerging contaminants of concern that have become an interesting issue for the scientific community from last few years due to their existence in the water environment. A number of the literature has revealed their occurrence in the environment. This is mainly due to the fact that some drugs are partially removed during wastewater treatment processes, and remaining being able to enter the environment and contaminate surface and groundwater and subsequently, drinking water. Therefore, this paper evaluates the occurrence of key illicit drugs in wastewater (influent and effluent) samples in 4 wastewater treatment plants across Adelaide, South Australia over a 1 year period. This paper also compares the efficiency of wastewater treatment plants adopting different technologies in the removal of selected illicit drugs, especially in the context of which technology has higher removal rates. The influent and effluent samples were analysed using Liquid Chromatography tandem Mass Spectrometry (LC-MS/MS). The levels of drugs detected were in the range of mg/L – ng/L in effluent samples; thus emphasising the influence on water quality of receiving water bodies and the significance of removal efficiency of WWTPs(Wastewater Treatment Plants). The results show that the drugs responded differently in the removal depending on the treatment processes used by the WWTPs.

Keywords: illicit drugs, removal efficiency, treatment technology, wastewater

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Authors: Monica Rosa Loizzo, Tiziana Falco, Marco Bonesi, Maria Concetta Tenuta, Mariarosaria Leporini, Rosa Tundis

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Extra Virgin Olive Oil (EVOO) is a major source of fat in the Mediterranean diet and its nutritional properties are the main reason for the increment of its consumption all over the world in recent years. In terms of olive oil production, Italy ranks the second in the world. EVOO is obtained exclusively by physical methods from the fruit of Olea europea L. Frantoio cv is spread in all the Italian territory. The aim of this work is to identify the phenolic and fatty acids profile of EVOO from Frantoio cv growing in different area of Calabria (Italy). The phenolic profile was obtained by HPLC coupled to a diode array detector and mass spectrometry. Analyses revealed the presence of phenolic alcohols, phenolic acid, several secoiridoids, and two flavones as main components. Hydroxytyrosol and tyrosol are present in reasonable content. Fatty acids were monitored by gas chromatography. Oleic acid was the most abundant compounds. A moderate level of linoleic acid, in accordance with the general observations for oils derived from Mediterranean countries, was also found.

Keywords: extra virgin olive oils, frantoio cv, phenolic compounds, fatty acids

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Authors: Mahboobeh Hemmati, Tahar Messadi, Hongmei Gu

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Today, life cycle assessment (LCA) is a leading method in mitigating the environmental impacts emerging from the building sector. In this paper, LCA is used to quantify the Green House Gas (GHG) emissions during the construction phase of the largest mass timber residential structure in the United States, Adohi Hall. This building is a 200,000 square foot 708-bed complex located on the campus of the University of Arkansas. The energy used for buildings’ operation is the most dominant source of emissions in the building industry. Lately, however, the efforts were successful at increasing the efficiency of building operation in terms of emissions. As a result, the attention is now shifted to the embodied carbon, which is more noticeable in the building life cycle. Unfortunately, most of the studies have, however, focused on the manufacturing stage, and only a few have addressed to date the construction process. Specifically, less data is available about environmental impacts associated with the construction of mass timber. This study presents, therefore, an assessment of the environmental impact of the construction processes based on the real and newly built mass timber building mentioned above. The system boundary of this study covers modules A4 and A5 based on building LCA standard EN 15978. Module A4 includes material and equipment transportation. Module A5 covers the construction and installation process. This research evolves through 2 stages: first, to quantify materials and equipment deployed in the building, and second, to determine the embodied carbon associated with running equipment for construction materials, both transported to, and installed on, the site where the edifice is built. The Global Warming Potential (GWP) of the building is the primary metric considered in this research. The outcomes of this study bring to the front a better understanding of hotspots in terms of emission during the construction process. Moreover, the comparative analysis of the mass timber construction process with that of a theoretically similar steel building will enable an effective assessment of the environmental efficiency of mass timber.

Keywords: construction process, GWP, LCA, mass timber

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Authors: Kooshan Nayebzadeh, Maryam Enteshari

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In this study, the oxidative stability of soybean oil under different storage temperatures (4 and 25 ˚C) and during 6-month shelf-life was investigated by various analytical methods and headspace-liquid phase microextraction (HS-LPME) coupled to gas chromatography-mass spectrometry (GC-MS). Oxidation changes were monitored by analytical parameters consisted of acid value (AV), peroxide value (PV), p-Anisidine value (p-AV), thiobarbituric acid value (TBA), fatty acids profile, iodine value (IV) and oxidative stability index (OSI). In addition, concentrations of hexanal and heptanal as secondary volatile oxidation compounds were determined by HS-LPME/GC-MS technique. Rate of oxidation in soybean oil which stored at 25 ˚C was so higher. The AV, p-AV, and TBA were gradually increased during 6 months, while the amount of unsaturated fatty acids, IV, and OSI decreased. Other parameters included concentrations of both hexanal and heptanal, and PV exhibited increasing trend during primitive months of storage; then, at the end of third and fourth months a sudden decrement was understood for the concentrations of hexanal and heptanal and the amount of PV, simultaneously. The latter parameters increased again until the end of shelf-time. As a result, the temperature and time were effective factors in oxidative stability of soybean oil. Also intensive correlations were found for soybean oil at 4 ˚C between AV and TBA (r2=0.96), PV and p-AV (r2=0.9), IV and TBA (-r2=0.9), and for soybean oil stored at 4 ˚C between p-AV and TBA (r2=0.99).

Keywords: headspace-liquid phase microextraction, oxidation, shelf-life, soybean oil

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Authors: Suguru Miyauchi, Toshiyuki Hayase

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Biological membranes have selective permeability, and the capsules or cells enclosed by the membrane show the deformation by the osmotic flow. This mass transport phenomenon is observed everywhere in a living body. For the understanding of the mass transfer in a body, it is necessary to consider the mass transfer phenomenon across the membrane as well as the deformation of the membrane by a flow. To our knowledge, in the numerical analysis, the method for mass transfer across the moving membrane has not been established due to the difficulty of the treating of the mass flux permeating through the moving membrane with selective permeability. In the existing methods for the mass transfer across the membrane, the approximate delta function is used to communicate the quantities on the interface. The methods can reproduce the permeation of the solute, but cannot reproduce the non-permeation. Moreover, the computational accuracy decreases with decreasing of the permeable coefficient of the membrane. This study aims to develop the numerical method capable of treating three-dimensional problems of mass transfer across the moving flexible membrane. One of the authors developed the numerical method with high accuracy based on the finite element method. This method can capture the discontinuity on the membrane sharply due to the consideration of the jumps in concentration and concentration gradient in the finite element discretization. The formulation of the method takes into account the membrane movement, and both permeable and non-permeable membranes can be treated. However, searching the cross points of the membrane and fluid element boundaries and splitting the fluid element into sub-elements are needed for the numerical integral. Therefore, cumbersome operation is required for a three-dimensional problem. In this paper, we proposed an improved method to avoid the search and split operations, and confirmed its effectiveness. The membrane shape was treated implicitly by introducing the level set function. As the construction of the level set function, the membrane shape in one fluid element was expressed by the shape function of the finite element method. By the numerical experiment, it was found that the shape function with third order appropriately reproduces the membrane shapes. The same level of accuracy compared with the previous method using search and split operations was achieved by using a number of sampling points of the numerical integral. The effectiveness of the method was confirmed by solving several model problems.

Keywords: finite element method, level set method, mass transfer, membrane permeability

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Authors: O. E. Ogunjinmi, N. O. Olawore, L. A. Usman, S. O. Ogunjinmi

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An essential oil is any concentrated, hydrophobic liquid containing volatile aroma compounds produced by plants. It has been established that several factors affect the component of the plants such as the texture of the soil, relative humidity, wind, and collection time. This study is aimed at investigating the effect of collection time on the chemical composition of this essential oil. Pulverized leaves (500 g) of Hoslundia opposite harvested in the morning (7 am) and afternoon (2 pm) of the same day were separately hydrodistilled using Clevenger apparatus to obtain the essential oils from the leaves. The leaf oils collected in the morning (7 am) and afternoon (2 pm) harvests yielded 0.54 and 0.65 %w/w respectively. Analysis of the leaf oil obtained in the morning, using gas chromatography (GC) and gas chromatography combined mass spectrometry (GC-MS) revealed the presence of twenty-three (23) compounds which made up 81.8% of the total oil while nineteen (19) compounds (93.2%) were identified in the afternoon leaf essential oil. The most abundant components of the leaf oil collected in the morning (7 am) harvest were p-cymene (28.7%), sabinene (7.1%) and 1,8-cineole (6.6%) Meanwhile the major components of leaf oil in the afternoon (2 pm) harvest were p-cymene (26.4%), thymol (15.3%), 1,8-cineole (15.0%) and g-terpinene (10.4%). The composition pattern of leaf oil obtained in the morning and afternoon harvests of Hoslundia opposite revealed significant differences in qualitative and quantitative.

Keywords: essential oil, Hoslundia opposita, para cymene, 1, 8-cineole

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Authors: Dagnija Blumberga, Toms Prodanuks, Ivars Veidenbergs, Andra Blumberga

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Gas condensing units with inner tubes heat exchangers represent third generation technology and differ from second generation heat and mass transfer units, which are fulfilled by passive filling material layer. The first one improves heat and mass transfer by increasing cooled contact surface of gas and condensate drops and film formed in inner tubes heat exchanger. This paper presents a selection of significant factors which influence the heat and mass transfer. Experimental planning is based on the research and analysis of main three independent variables; velocity of water and gas as well as density of spraying. Empirical mathematical models show that the coefficient of heat transfer is used as dependent parameter which depends on two independent variables; water and gas velocity. Empirical model is proved by the use of experimental data of two independent gas condensing units in Lithuania and Russia. Experimental data are processed by the use of heat transfer criteria-Kirpichov number. Results allow drawing the graphical nomogram for the calculation of heat and mass transfer conditions in the innovative and energy efficient gas cooling unit.

Keywords: gas condensing unit, filling, inner heat exchanger, package, spraying, tunes

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Authors: A. M. Metak, T. T. Ajaal, Amal Metak, Tawfik Ajaal

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Commercial nanocomposite food packaging type nano-silver containers were characterised using scanning electron microscopy (SEM) and energy-dispersive X-Ray spectroscopy (EDX). The presence of nanoparticles consistent with the incorporation of 1% nano-silver (Ag) and 0.1% titanium dioxide (TiO2) nanoparticle into polymeric materials formed into food containers was confirmed. Both nanomaterials used in this type of packaging appear to be embedded in a layered configuration within the bulk polymer. The dimensions of the incorporated nanoparticles were investigated using X-Ray diffraction (XRD) and determined by calculation using the Scherrer Formula; these were consistent with Ag and TiO2 nanoparticles in the size range 20-70nm both were spherical shape nanoparticles. Antimicrobial assessment of the nanocomposite container has also been performed and the results confirm the antimicrobial activity of Ag and TiO2 nanoparticles in food packaging containers. Migration assessments were performed in a wide range of food matrices to determine the migration of nanoparticles from the packages. The analysis was based on the relevant European safety directives and involved the application of inductively coupled plasma mass spectrometry (ICP-MS) to identify the range of migration risk. The data pertain to insignificance levels of migration of Ag and TiO2 nanoparticles into the selected food matrices.

Keywords: nano-silver, antimicrobial food packaging, migration, titanium dioxide

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Authors: Neda Azimi, Masoud Rahimi, Faezeh Mohammadi

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Computational fluid dynamics (CFD) simulation was performed to investigate the effect of ferrofluid stimulation on hydrodynamic and mass transfer characteristics of two immiscible liquid phases in a Y-micromixer. The main purpose of this work was to develop a numerical model that is able to simulate hydrodynamic of the ferrofluid flow under magnetic field and determine its effect on mass transfer characteristics. A uniform external magnetic field was applied perpendicular to the flow direction. The volume of fluid (VOF) approach was used for simulating the multiphase flow of ferrofluid and two-immiscible liquid flows. The geometric reconstruction scheme (Geo-Reconstruct) based on piecewise linear interpolation (PLIC) was used for reconstruction of the interface in the VOF approach. The mass transfer rate was defined via an equation as a function of mass concentration gradient of the transported species and added into the phase interaction panel using the user-defined function (UDF). The magnetic field was solved numerically by Fluent MHD module based on solving the magnetic induction equation method. CFD results were validated by experimental data and good agreements have been achieved, which maximum relative error for extraction efficiency was about 7.52 %. It was showed that ferrofluid actuation by a magnetic field can be considered as an efficient mixing agent for liquid-liquid two-phase mass transfer in microdevices.

Keywords: CFD modeling, hydrodynamic, micromixer, ferrofluid, mixing

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Authors: Qian You, Ibrahim Hassan, Lyes Kadem

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An experiment is conducted to fundamentally investigate flow oscillation characteristics in different sizes of single microtubes in vertical upward flow direction. Three microtubes have 0.889 mm, 0.533 mm, and 0.305 mm hydraulic diameters with 100 mm identical heated length. The mass flux of the working fluid FC-72 varies from 700 kg/m2•s to 1400 kg/m2•s, and the heat flux is uniformly applied on the tube surface up to 9.4 W/cm2. The subcooled inlet temperature is maintained around 24°C during the experiment. The effect of hydraulic diameter and mass flux are studied. The results showed that they have interactions on the flow oscillations occurrence and behaviors. The onset of flow instability (OFI), which is a threshold of unstable flow, usually appears in large microtube with diversified and sustained flow oscillations, while the transient point, which is the point when the flow turns from one stable state to another suddenly, is more observed in small microtube without characterized flow oscillations due to the bubble confinement. The OFI/transient point occurs early as hydraulic diameter reduces at a given mass flux. The increased mass flux can delay the OFI/transient point occurrence in large hydraulic diameter, but no significant effect in small size. Although the only transient point is observed in the smallest tube, it appears at small heat flux and is not sensitive to mass flux; hence, the smallest microtube is not recommended since increasing heat flux may cause local dryout.

Keywords: flow boiling instability, hydraulic diameter effect, a single microtube, vertical upward flow

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Authors: William Middleton, Nodumo Zulu, Sue Harrison

Abstract:

Open raceway ponds are currently the most used system for the commercial cultivation of algal biomass, as it is a cost-effective means of production. However, raceway ponds suffer from lower algal productivity when compared to closed photobioreactors. This is due to poor gas exchange between the fluid and the atmosphere. Carbon dioxide (CO₂) mass transfer is a large concern in the production of algae in raceway pond systems. The utilization of atmospheric CO₂ does not support maximal growth; however, CO₂ supplementation in the form of flue gas or concentrated CO₂ is not cost-effective. The introduction of slopes into the raceway system presents a possible improvement to the mass transfer from the air, as seen in previous work conducted at CeBER. Slopes improve turbulence (decreasing the concentration gradient of dissolved CO₂) and can cause air entrainment (allowing for greater surface area and contact time between the air and water). This project tests the findings of previous studies conducted in an indoor lab-scale raceway on a larger scale under outdoor conditions. The addition of slopes resulted in slightly increased CO₂ mass transfer as well as algal growth rate and productivity. However, there were reductions in energy consumption and average fluid velocity in the system. These results indicate a potential to improve the economic feasibility of algal biomass production, but further economic assessment would need to be carried out.

Keywords: algae, raceway ponds, mass transfer, algal culture, biotechnology, reactor design

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Authors: Chul Ho Han, Kyoung Hoon Kim

Abstract:

This paper carries out a performance analysis based on the first and second laws of thermodynamics for heat recovery vapor generator (HRVG) of ammonia-water mixture when the heat source is low-temperature energy in the form of sensible heat. In the analysis, effects of the ammonia mass concentration and mass flow ratio of the binary mixture are investigated on the system performance including the effectiveness of heat transfer, entropy generation, and exergy efficiency. The results show that the ammonia concentration and the mass flow ratio of the mixture have significant effects on the system performance of HRVG.

Keywords: entropy, exergy, ammonia-water mixture, heat exchanger

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Authors: A. Guechi, M. Chegaar

Abstract:

This study investigates how AlGaAs/GaAs thin film solar cells perform under varying global solar spectrum due to the changes of environmental parameters such as the air mass and the atmospheric turbidity. The solar irradiance striking the solar cell is simulated using the spectral irradiance model SMARTS2 (Simple Model of the Atmospheric Radiative Transfer of Sunshine) for clear skies on the site of Setif (Algeria). The results show a reduction in the short circuit current due to increasing atmospheric turbidity, it is 63.09% under global radiation. However increasing air mass leads to a reduction in the short circuit current of 81.73%.The efficiency decrease with increasing atmospheric turbidity and air mass.

Keywords: AlGaAs/GaAs, solar cells, environmental parameters, spectral variation, SMARTS

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Authors: Vasile Simulescu, Jakub Mondek, Miloslav Pekař

Abstract:

Hyaluronic acid (HA) is an anionic glycosaminoglycan distributed throughout connective, epithelial and neural tissues. The importance of hyaluronic acid increased in the last decades. It has many applications in medicine and cosmetics. Hyaluronic acid has been used in attempts to treat osteoarthritis of the knee via injecting it into the joint. Bovine serum albumin (also known as BSA) is a protein derived from cows, which has many biochemical applications. The aim of our research work was to compare the thermal degradation of hyaluronic acid and BSA in powder and in solution, by determining changes in molar mass and conformation, by using SEC-MALLS (size exclusion chromatography -multi angle laser light scattering). The aim of our research work was to observe the degradation in powder and in solution of different molar mass hyaluronic acid samples, at different temperatures for certain periods. The degradation of the analyzed samples was mainly observed by modifications in molar mass.

Keywords: thermal degradation, hyaluronic acid, BSA, SEC-MALLS

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Authors: Leonce Dusengemungu

Abstract:

Filamentous fungi indigenous to heavy metals (HMs) contaminated environments have a considerable biosorption potential yet are currently under-investigated in developing countries. In the work presented herein, the biosorption potential of three indigenous filamentous fungi (Aspergillus transmontanensis, Cladosporium cladosporioides, and Geotrichum candidum) isolated from copper and cobalt mining wasteland sites in Zambia's Copperbelt province was investigated. In Cu and Co tolerance tests, all the fungal isolates were shown to be tolerant, with mycelial growth at HMs concentrations of up to 7000 ppm. However, exposure to high Cu and Co concentrations hindered the growth of the three strains to varying degrees, resulting in reduced mycelial biomass (evidenced by loss of the infrared bands at 887 and 930 cm-1 of the 1,3-glucans backbone) as well as morphological alterations, sporulation, and pigment synthesis. In addition, gas chromatography-mass spectrometry characterization of the fungal biomass extracts allowed to detect changes in the chemical constituents upon exposure to HMs, with profiles poorer in maltol, 1,2-cyclopentadione, and n-hexadecanoic acid, and richer in furaldehydes. Biosorption tests showed that A. transmontanensis and G. candidum showed better performance as bioremediators than C. cladosporioides, with biosorption efficiencies of 1645, 1853 and 1253 ppm at pH 3, respectively, and may deserve further research in field conditions.

Keywords: bioremediation, fungi, biosorption, heavy metal

Procedia PDF Downloads 43

Authors: A. Soria-Salinas, M.-P. Zorzano, J. Martín-Torres, J. Sánchez-García-Casarrubios, J.-L. Pérez-Díaz, A. Vakkada-Ramachandran

Abstract:

The current state-of-the-art methods of mass gauging of Electric Propulsion (EP) propellants in microgravity conditions rely on external measurements that are taken at the surface of the tank. The tanks are operated under a constant thermal duty cycle to store the propellant within a pre-defined temperature and pressure range. We demonstrate using computational fluid dynamics (CFD) simulations that the heat-transfer within the pressurized propellant generates temperature and density anisotropies. This challenges the standard mass gauging methods that rely on the use of time changing skin-temperatures and pressures. We observe that the domes of the tanks are prone to be overheated, and that a long time after the heaters of the thermal cycle are switched off, the system reaches a quasi-equilibrium state with a more uniform density. We propose a new gauging method, which we call the Improved PVT method, based on universal physics and thermodynamics principles, existing TRL-9 technology and telemetry data. This method only uses as inputs the temperature and pressure readings of sensors externally attached to the tank. These sensors can operate during the nominal thermal duty cycle. The improved PVT method shows little sensitivity to the pressure sensor drifts which are critical towards the end-of-life of the missions, as well as little sensitivity to systematic temperature errors. The retrieval method has been validated experimentally with CO₂ in gas and fluid state in a chamber that operates up to 82 bar within a nominal thermal cycle of 38 °C to 42 °C. The mass gauging error is shown to be lower than 1% the mass at the beginning of life, assuming an initial tank load at 100 bar. In particular, for a pressure of about 70 bar, just below the critical pressure of CO₂, the error of the mass gauging in gas phase goes down to 0.1% and for 77 bar, just above the critical point, the error of the mass gauging of the liquid phase is 0.6% of initial tank load. This gauging method improves by a factor of 8 the accuracy of the standard PVT retrievals using look-up tables with tabulated data from the National Institute of Standards and Technology.

Keywords: electric propulsion, mass gauging, propellant, PVT, xenon

Procedia PDF Downloads 322

Authors: Sapan Tiwari, Namrata Ghosh

Abstract:

In urban mass transit, crew scheduling always plays a significant role. It deals with the formulation of work timetables for its staff so that an organization can meet the demand for its products or services. The efficient schedules of a specified timetable have an enormous impact on staff demand. It implies that an urban mass transit company's financial outcomes are strongly associated with planning operations in the region. The research aims to demonstrate the state of the crew scheduling studies and its practical implementation in mass transit businesses in metropolitan areas. First, there is a short overview of past studies in the field. Subsequently, the restrictions and problems with crew scheduling and some models, which have been developed to solve the related issues with their mathematical formulation, are defined. The comments are completed by a description of the solution opportunities provided by computer-aided scheduling program systems for operational use and exposures from urban mass transit organizations. Furthermore, Bus scheduling is performed using the Hungarian technique of problem-solving tasks and mathematical modeling. Afterward, the crew scheduling problem, which consists of developing duties using predefined tasks with set start and end times and places, is resolved. Each duty has to comply with a set line of work. The objective is to minimize a mixture of fixed expenses (number of duties) and varying costs. After the optimization of cost, the outcome of the research is that the same frequency can be provided with fewer buses and less workforce.

Keywords: crew scheduling, duty, optimization of cost, urban mass transit

Procedia PDF Downloads 128