Search results for: heat and mass transfer

Authors: Mathieu Bourdeau, Philippe Basset, Julien Waeytens, Elyes Nefzaoui

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As residential buildings account for a third of the overall energy consumption and greenhouse gas emissions in Europe, building energy modeling is an essential tool to reach energy efficiency goals. In the energy modeling process, calibration is a mandatory step to obtain accurate and reliable energy simulations. Nevertheless, the comparison between simulation results and the actual building energy behavior often highlights a significant performance gap. The literature discusses different origins of energy performance gaps, from building design to building operation. Then, building operation description in energy models, especially energy usages and users’ behavior, plays an important role in the reliability of simulations but is also the most accessible target for post-occupancy energy management and optimization. Therefore, the present study aims to discuss results on the calibration ofresidential building energy models using real operation data. Data are collected through a sensor network of more than 180 sensors and advanced energy meters deployed in three collective residential buildings undergoing major retrofit actions. The sensor network is implemented at building scale and in an eight-apartment sample. Data are collected for over one year and half and coverbuilding energy behavior – thermal and electricity, indoor environment, inhabitants’ comfort, occupancy, occupants behavior and energy uses, and local weather. Building energy simulations are performed using a physics-based building energy modeling software (Pleaides software), where the buildings’features are implemented according to the buildingsthermal regulation code compliance study and the retrofit project technical files. Sensitivity analyses are performed to highlight the most energy-driving building features regarding each end-use. These features are then compared with the collected post-occupancy data. Energy-driving features are progressively replaced with field data for a step-by-step calibration of the energy model. Results of this study provide an analysis of energy performance gap on an existing residential case study under deep retrofit actions. It highlights the impact of the different building features on the energy behavior and the performance gap in this context, such as temperature setpoints, indoor occupancy, the building envelopeproperties but also domestic hot water usage or heat gains from electric appliances. The benefits of inputting field data from an extensive instrumentation campaign instead of standardized scenarios are also described. Finally, the exhaustive instrumentation solution provides useful insights on the needs, advantages, and shortcomings of the implemented sensor network for its replicability on a larger scale and for different use cases.

Keywords: calibration, building energy modeling, performance gap, sensor network

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Authors: Markus Nordlund, Arkadiusz K. Kuczaj

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Philip Morris International (PMI) is developing a range of novel tobacco products with the potential to reduce individual risk and population harm in comparison to smoking cigarettes. One of these products is the Tobacco Heating System 2.2 (THS 2.2), (named as the Electrically Heated Tobacco System (EHTS) in this paper), already commercialized in a number of countries (e.g., Japan, Italy, Switzerland, Russia, Portugal and Romania). During use, the patented EHTS heats a specifically designed tobacco product (Electrically Heated Tobacco Product (EHTP)) when inserted into a Holder (heating device). The EHTP contains tobacco material in the form of a porous plug that undergoes a controlled heating process to release chemical compounds into vapors, from which an aerosol is formed during cooling. The aim of this work was to investigate the aerosol formation characteristics for realistic operating conditions of the EHTS as well as for relevant gas mixture compositions measured in the EHTP aerosol consisting mostly of water, glycerol and nicotine, but also other compounds at much lower concentrations. The nucleation process taking place in the EHTP during use when operated in the Holder has therefore been modeled numerically using an extended Classical Nucleation Theory (CNT) for multicomponent gas mixtures. Results from the performed simulations demonstrate that aerosol droplets are formed only in the presence of an aerosol former being mainly glycerol. Minor compounds in the gas mixture were not able to reach a supersaturated state alone and therefore could not generate aerosol droplets from the multicomponent gas mixture at the operating conditions simulated. For the analytically characterized aerosol composition and estimated operating conditions of the EHTS and EHTP, glycerol was shown to be the main aerosol former triggering the nucleation process in the EHTP. This implies that according to the CNT, an aerosol former, such as glycerol needs to be present in the gas mixture for an aerosol to form under the tested operating conditions. To assess if these conclusions are sensitive to the initial amount of the minor compounds and to include and represent the total mass of the aerosol collected during the analytical aerosol characterization, simulations were carried out with initial masses of the minor compounds increased by as much as a factor of 500. Despite this extreme condition, no aerosol droplets were generated when glycerol, nicotine and water were treated as inert species and therefore not actively contributing to the nucleation process. This implies that according to the CNT, an aerosol cannot be generated without the help of an aerosol former, from the multicomponent gas mixtures at the compositions and operating conditions estimated for the EHTP, even if all minor compounds are released or generated in a single puff.

Keywords: aerosol, classical nucleation theory (CNT), electrically heated tobacco product (EHTP), electrically heated tobacco system (EHTS), modeling, multicomponent, nucleation

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Authors: Olubisi Friday Oluduro

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The Paris Agreement 2015, the result of negotiations under the United Nations Framework Convention on Climate Change (UNFCCC), after Kyoto Protocol expiration, sets a long-term goal of limiting the increase in the global average temperature to well below 2 degrees Celsius above pre-industrial levels, and of pursuing efforts to limiting this temperature increase to 1.5 degrees Celsius. An advancement on the erstwhile Kyoto Protocol which sets commitments to only a limited number of Parties to reduce their greenhouse gas (GHGs) emissions, it includes the goal to increase the ability to adapt to the adverse impacts of climate change and to make finance flows consistent with a pathway towards low GHGs emissions. For it achieve these goals, the Agreement requires all Parties to undertake efforts towards reaching global peaking of GHG emissions as soon as possible and towards achieving a balance between anthropogenic emissions by sources and removals by sinks in the second half of the twenty-first century. In addition to climate change mitigation, the Agreement aims at enhancing adaptive capacity, strengthening resilience and reducing the vulnerability to climate change in different parts of the world. It acknowledges the importance of addressing loss and damage associated with the adverse of climate change. The Agreement also contains comprehensive provisions on support to be provided to developing countries, which includes finance, technology transfer and capacity building. To ensure that such supports and actions are transparent, the Agreement contains a number reporting provisions, requiring parties to choose the efforts and measures that mostly suit them (Nationally Determined Contributions), providing for a mechanism of assessing progress and increasing global ambition over time by a regular global stocktake. Despite the somewhat global look of the Agreement, it has been fraught with manifold limitations threatening its very existential capability to produce any meaningful result. Considering these obvious limitations some of which were the very cause of the failure of its predecessor—the Kyoto Protocol—such as the non-participation of the United States, non-payment of funds into the various coffers for appropriate strategic purposes, among others. These have left the developing countries largely threatened eve the more, being more vulnerable than the developed countries, which are really responsible for the climate change scourge. The paper seeks to examine the mitigation and adaptation measures under the Paris Agreement 2015, appraise the present situation since the Agreement was concluded and ascertain whether the developing countries have been better or worse off since the Agreement was concluded, and examine why and how, while projecting a way forward in the present circumstance. It would conclude with recommendations towards ameliorating the situation.

Keywords: mitigation, adaptation, climate change, Paris agreement 2015, framework

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Authors: Zh. Karaulova, D. Baizhigitov

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At the Aktogay deposit, the oxidized ore section has been developed since 2015; by now, the reserves of easily enriched ore are decreasing, and a large number of copper-poor, difficult-to-enrich ores has been accumulated in the dumps of the KAZ Minerals Aktogay deposit, which is unprofitable to mine using the traditional mining methods. Hence, another technology needs to be implemented, which will significantly expand the raw material base of copper production in Kazakhstan and ensure the efficient use of natural resources. Heap and dump bacterial recovery are the most acceptable technologies for processing low-grade secondary copper sulfide ores. Test objects were the copper ores of Aktogay deposit and chemolithotrophic bacteria Leptospirillum ferrooxidans (L.f.), Acidithiobacillus caldus (A.c.), Sulfobacillus Acidophilus (S.a.), which are mixed cultures were both used in bacterial oxidation systems. They can stay active in the 20-400C temperature range. These bacteria were the most extensively studied and widely used in sulfide mineral recovery technology. Biocatalytic acceleration was achieved as a result of bacteria oxidizing iron sulfides to form iron sulfate, which subsequently underwent chemical oxidation to become sulfate oxide. The following results have been achieved at the initial stage: the goal was to grow and maintain the life activity of bacterial cultures under laboratory conditions. These bacteria grew the best within the pH 1,2-1,8 range with light stirring and in an aerated environment. The optimal growth temperature was 30-33оC. The growth rate decreased by one-half for each 4-5°C fall in temperature from 30°C. At best, the number of bacteria doubled every 24 hours. Typically, the maximum concentration of cells that can be grown in ferrous solution is about 107/ml. A further step researched in this case was the adaptation of microorganisms to the environment of certain metals. This was followed by mass production of inoculum and maintenance for their further cultivation on a factory scale. This was done by adding sulfide concentrate, allowing the bacteria to convert the ferrous sulfate as indicated by the Eh (>600 mV), then diluting to double the volume and adding concentrate to achieve the same metal level. This process was repeated until the desired metal level and volumes were achieved. The final stage of bacterial recovery was the transportation and irrigation of secondary sulfide copper ores of the oxidized ore section. In conclusion, the project was implemented at the Aktogay mine since the bioleaching process was prolonged. Besides, the method of bacterial recovery might compete well with existing non-biological methods of extraction of metals from ores.

Keywords: bacterial recovery, copper ore, bioleaching, bacterial inoculum

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Authors: M. Kowalik, J. Masternak, K. Kazimierczuk, O. V. Khavryuchenko, B. Kupcewicz, B. Barszcz

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Recently, the growing interest of chemists in metal-organic coordination polymers (MOCPs) is primarily derived from their intriguing structures and potential applications in catalysis, gas storage, molecular sensing, ion exchanges, nonlinear optics, luminescence, etc. Currently, we are devoting considerable effort to finding the proper method of synthesizing new coordination polymers containing S- or N-heteroaromatic carboxylates as linkers and characterizing the obtained Pb(II) compounds according to their structural diversity, luminescence, and thermal properties. The choice of Pb(II) as the central ion of MOCPs was motivated by several reasons mentioned in the literature: i) a large ionic radius allowing for a wide range of coordination numbers, ii) the stereoactivity of the 6s2 lone electron pair leading to a hemidirected or holodirected geometry, iii) a flexible coordination environment, and iv) the possibility to form secondary bonds and unusual non-covalent interactions, such as classic hydrogen bonds and π···π stacking interactions, as well as nonconventional hydrogen bonds and rarely reported tetrel bonds, Pb(lone pair)···π interactions, C–H···Pb agostic-type interactions or hydrogen bonds, and chelate ring stacking interactions. Moreover, the construction of coordination polymers requires the selection of proper ligands acting as linkers, because we are looking for materials exhibiting different network topologies and fluorescence properties, which point to potential applications. The reaction of Pb(NO₃)₂ with 1H-pyrrole-2-carboxylic acid (2prCOOH) leads to the formation of a new four-nuclear Pb(II) polymer, [Pb4(2prCOO)₈(H₂O)]ₙ, which has been characterized by CHN, FT-IR, TG, PL and single-crystal X-ray diffraction methods. In view of the primary Pb–O bonds, Pb1 and Pb2 show hemidirected pentagonal pyramidal geometries, while Pb2 and Pb4 display hemidirected octahedral geometries. The topology of the strongest Pb–O bonds was determined as the (4·8²) fes topology. Taking the secondary Pb–O bonds into account, the coordination number of Pb centres increased, Pb1 exhibited a hemidirected monocapped pentagonal pyramidal geometry, Pb2 and Pb4 exhibited a holodirected tricapped trigonal prismatic geometry, and Pb3 exhibited a holodirected bicapped trigonal prismatic geometry. Moreover, the Pb(II) lone pair stereoactivity was confirmed by DFT calculations. The 2D structure was expanded into 3D by the existence of non-covalent O/C–H···π and Pb···π interactions, which was confirmed by the Hirshfeld surface analysis. The above mentioned interactions improve the rigidity of the structure and facilitate the charge and energy transfer between metal centres, making the polymer a promising luminescent compound.

Keywords: coordination polymers, fluorescence properties, lead(II), lone electron pair stereoactivity, non-covalent interactions

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Authors: A. I. Dovgjallo, A. B. Tsapkova, A. A. Shimanov

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The paper is devoted to one of engine types with external heating – a thermoacoustic engine. In thermoacoustic engine heat energy is converted to an acoustic energy. Further, acoustic energy of oscillating gas flow must be converted to mechanical energy and this energy in turn must be converted to electric energy. The most widely used way of transforming acoustic energy to electric one is application of linear generator or usual generator with crank mechanism. In both cases, the piston is used. Main disadvantages of piston use are friction losses, lubrication problems and working fluid pollution which cause decrease of engine power and ecological efficiency. Using of a bidirectional impulse turbine as an energy converter is suggested. The distinctive feature of this kind of turbine is that the shock wave of oscillating gas flow passing through the turbine is reflected and passes through the turbine again in the opposite direction. The direction of turbine rotation does not change in the process. Different types of bidirectional impulse turbines for thermoacoustic engines are analyzed. The Wells turbine is the simplest and least efficient of them. A radial impulse turbine has more complicated design and is more efficient than the Wells turbine. The most appropriate type of impulse turbine was chosen. This type is an axial impulse turbine, which has a simpler design than that of a radial turbine and similar efficiency. The peculiarities of the method of an impulse turbine calculating are discussed. They include changes in gas pressure and velocity as functions of time during the generation of gas oscillating flow shock waves in a thermoacoustic system. In thermoacoustic system pressure constantly changes by a certain law due to acoustic waves generation. Peak values of pressure are amplitude which determines acoustic power. Gas, flowing in thermoacoustic system, periodically changes its direction and its mean velocity is equal to zero but its peak values can be used for bi-directional turbine rotation. In contrast with feed turbine, described turbine operates on un-steady oscillating flows with direction changes which significantly influence the algorithm of its calculation. Calculated power output is 150 W with frequency 12000 r/min and pressure amplitude 1,7 kPa. Then, 3-d modeling and numerical research of impulse turbine was carried out. As a result of numerical modeling, main parameters of the working fluid in turbine were received. On the base of theoretical and numerical data model of impulse turbine was made on 3D printer. Experimental unit was designed for numerical modeling results verification. Acoustic speaker was used as acoustic wave generator. Analysis if the acquired data shows that use of the bi-directional impulse turbine is advisable. By its characteristics as a converter, it is comparable with linear electric generators. But its lifetime cycle will be higher and engine itself will be smaller due to turbine rotation motion.

Keywords: acoustic power, bi-directional pulse turbine, linear alternator, thermoacoustic generator

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Authors: María José Patiño-Ropero, Manuel Alcamí, Al Mokhtar Lamsabhi, José Luis Alonso-Prados, Pilar Sandín-España

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Tralkoxydim, commercialized under different trade names, among them Splendor® (25% active ingredient), is a cyclohexanedione herbicide used in wheat and barley fields for the post-emergence control of annual winter grass weeds. Due to their physicochemical properties, herbicides belonging to this family are known to be susceptible to reaching natural waters, where different degradation pathways can take place. Photolysis represents one of the main routes of abiotic degradation of these herbicides in water. This transformation pathway can lead to the formation of unknown by-products, which could be more toxic and/or persistent than the active substances themselves. Therefore, there is a growing need to understand the science behind such dissipation routes, which is key to estimating the persistence of these compounds and ensuring the accurate assessment of environmental behavior. However, to our best knowledge, any information regarding the photochemical behavior of tralkoxydim under natural conditions in an aqueous environment has not been available till now in the literature. This work has focused on investigating the photochemical behavior of tralkoxydim herbicide and its commercial formulation (Splendor®) in the ultrapure, river and spring water using simulated solar radiation. Besides, the evolution of detected degradation products formed in the samples has been studied. A reversed-phase HPLC-DAD (high-performance liquid chromatography with diode array detector) method was developed to evaluate the kinetic evolution and to obtain the half-lives. In both cases, the degradation rates of active ingredient tralkoxydim in natural waters were lower than in ultrapure water following the order; river water < spring water < ultrapure water, and with first-order half-life values of 5.1 h, 2.7 h and 1.1 h, respectively. These findings indicate that the photolytical behavior of active ingredients is largely affected by the water composition, and these components can exert an internal filter effect. In addition, tralkoxydim herbicide and its formulation showed the same half-lives for each one of the types of water studied, showing that the presence of adjuvants in the commercial formulation has not any effect on the degradation rates of the active ingredient. HPLC-MS (high-performance liquid chromatography with mass spectrometry) experiments were performed to study the by-products deriving from the photodegradation of tralkoxydim in water. Accordingly, three compounds were tentatively identified. These results provide a better understanding of the tralkoxydim herbicide behavior in natural waters and its fate in the environment.

Keywords: by-products, natural waters, photodegradation, tralkoxydim herbicide

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Authors: Majid Farsadrouh Rashti, Amir Shafiee Kisomi, Parisa Jahani

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The direct ethanol fuel cells (DEFCs) are contemplated as a promising energy source because, In addition to being used in portable electronic devices, it is also used for electric vehicles. The synthesis of bimetallic nanostructures due to their novel optical, catalytic and electronic characteristic which is precisely in contrast to their monometallic counterparts is attracting extensive attention. Galvanic replacement (sometimes is named to as cementation or immersion plating) is an uncomplicated and effective technique for making nanostructures (such as core-shell) of different metals, semiconductors, and their application in DEFCs. The replacement of galvanic does not need any external power supply compared to electrodeposition. In addition, it is different from electroless deposition because there is no need for a reducing agent to replace galvanizing. In this paper, a fast method for the palladium (Pd) wire nanostructures synthesis with the great surface area through galvanic replacement reaction utilizing copper nanowires (CuNWS) as a template by the assistance of ultrasound under room temperature condition is proposed. To evaluate the morphology and composition of Pd@ Copper nanowires/MultiWalled Carbon nanotubes-Chitosan, emission scanning electron microscopy, energy dispersive X-ray spectroscopy were applied. In order to measure the phase structure of the electrocatalysts were performed via room temperature X-ray powder diffraction (XRD) applying an X-ray diffractometer. Various electrochemical techniques including chronoamperometry and cyclic voltammetry were utilized for the electrocatalytic activity of ethanol electrooxidation and durability in basic solution. Pd@ Copper nanowires/MultiWalled Carbon nanotubes-Chitosan catalyst demonstrated substantially enhanced performance and long-term stability for ethanol electrooxidation in the basic solution in comparison to commercial Pd/C that demonstrated the potential in utilizing Pd@ Copper nanowires/MultiWalled Carbon nanotubes-Chitosan as efficient catalysts towards ethanol oxidation. Noticeably, the Pd@ Copper nanowires/MultiWalled Carbon nanotubes-Chitosan presented excellent catalytic activities with a peak current density of 320.73 mAcm² which was 9.5 times more than in comparison to Pd/C (34.2133 mAcm²). Additionally, activation energy thermodynamic and kinetic evaluations revealed that the Pd@ Copper nanowires/MultiWalled Carbon nanotubes-Chitosan catalyst has lower compared to Pd/C which leads to a lower energy barrier and an excellent charge transfer rate towards ethanol oxidation.

Keywords: core-shell structure, electrocatalyst, ethanol oxidation, galvanic replacement reaction

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Authors: Xianghe Dai, Dennis Lam, Therese Sheehan, Naveed Rehman, Jie Yang

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Concrete is one of the most used construction materials that may be made onsite as fresh concrete and then placed in formwork to produce the desired shapes of structures. It has been recognized that the raw materials and mix proportion of concrete dominate the mechanical characteristics of hardened concrete, and the curing method and environment applied to the concrete in early stages of hardening will significantly influence the concrete properties, such as compressive strength, durability, permeability etc. In construction practice, there are various curing methods to maintain the presence of mixing water throughout the early stages of concrete hardening. They are also beneficial to concrete in hot weather conditions as they provide cooling and prevent the evaporation of water. Such methods include ponding or immersion, spraying or fogging, saturated wet covering etc. Also there are various curing methods that may be implemented to decrease the level of water lost which belongs to the concrete surface, such as putting a layer of impervious paper, plastic sheeting or membrane on the concrete to cover it. In the concrete material laboratory, accelerated strength gain methods supply the concrete with heat and additional moisture by applying live steam, coils that are subject to heating or pads that have been warmed electrically. Currently when determining the mechanical parameters of a concrete, the concrete is usually sampled from fresh concrete on site and then cured and tested in laboratories where standardized curing procedures are adopted. However, in engineering practice, curing procedures in the construction sites after the placing of concrete might be very different from the laboratory criteria, and this includes some standard curing procedures adopted in the laboratory that can’t be applied on site. Sometimes the contractor compromises the curing methods in order to reduce construction costs etc. Obviously the difference between curing procedures adopted in the laboratory and those used on construction sites might over- or under-estimate the real concrete quality. This paper presents the effect of three typical curing methods (air curing, water immersion curing, plastic film curing) and of maintaining concrete in steel moulds on the compressive strength development of normal concrete. In this study, Portland cement with 30% fly ash was used and different curing periods, 7 days, 28 days and 60 days were applied. It was found that the highest compressive strength was observed from concrete samples to which 7-day water immersion curing was applied and from samples maintained in steel moulds up to the testing date. The research results implied that concrete used as infill in steel tubular members might develop a higher strength than predicted by design assumptions based on air curing methods. Wrapping concrete with plastic film as a curing method might delay the concrete strength development in the early stages. Water immersion curing for 7 days might significantly increase the concrete compressive strength.

Keywords: compressive strength, air curing, water immersion curing, plastic film curing, maintaining in steel mould, comparison

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Authors: Yi-Ting Chen, Yu-Fang Huang, Pei-Wei Wang, Hai-Wei Liang, Chun-Hao Lai, Mei-Lien Chen

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Background: Bisphenol A (BPA) is commonly used in consumer products, such as inner coatings of cans and polycarbonated bottles. BPA is considered to be an endocrine disrupting substance (EDs) that affects normal human hormones and may cause adverse effects on human health. Pregnant women and fetuses are susceptible groups of endocrine disrupting substances. Prenatal exposure to BPA has been shown to affect the fetus through the placenta. Therefore, it is important to evaluate the potential health risk of fetal exposure to BPA during pregnancy. The aims of this study were (1) to determine the urinary concentration of BPA in pregnant women, and (2) to investigate the association between BPA exposure during pregnancy and birth outcomes. Methods: This study recruited 117 pregnant women and their fetuses from 2012 to 2014 from the Taiwan Maternal- Infant Cohort Study (TMICS). Maternal urine samples were collected in the third trimester and questionnaires were used to collect socio-demographic characteristics, eating habits and medical conditions of the participants. Information about birth outcomes of the fetus was obtained from medical records. As for chemicals analysis, BPA concentrations in urine were determined by off-line solid-phase extraction-ultra-performance liquid chromatography coupled with a Q-Tof mass spectrometer. The urinary concentrations were adjusted with creatinine. The association between maternal concentrations of BPA and birth outcomes was estimated using the logistic regression model. Results: The detection rate of BPA is 99%; the concentration ranges (μg/g) from 0.16 to 46.90. The mean (SD) BPA levels are 5.37(6.42) μg/g creatinine. The mean ±SD of the body weight, body length, head circumference, chest circumference and gestational age at birth are 3105.18 ± 339.53 g, 49.33 ± 1.90 cm, 34.16 ± 1.06 cm, 32.34 ± 1.37 cm and 38.58 ± 1.37 weeks, respectively. After stratifying the exposure levels into two groups by median, pregnant women in higher exposure group would have an increased risk of lower body weight (OR=0.57, 95%CI=0.271-1.193), smaller chest circumference (OR=0.70, 95%CI=0.335-1.47) and shorter gestational age at birth newborn (OR=0.46, 95%CI=0.191-1.114). However, there are no associations between BPA concentration and birth outcomes reach a significant level (p < 0.05) in statistics. Conclusions: This study presents prenatal BPA profiles and infants in northern Taiwan. Women who have higher BPA concentrations tend to give birth to lower body weight, smaller chest circumference or shorter gestational age at birth newborn. More data will be included to verify the results. This report will also present the predictors of BPA concentrations for pregnant women.

Keywords: bisphenol A, birth outcomes, biomonitoring, prenatal exposure

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Authors: B. M. M. D. Mendis, L. I. Rajapaksa, P. S. K. Gunathunga, R. C. Fernando, M. Jayalath

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Background / introduction: During the year 2011, 8511 males received services from the sexual health clinics island wide. At present there is only limited information on the risk behaviours of male attendees. Information on risk behaviours related to STI /HIV transmission is helpful in planning suitable prevention interventions. Aim(s)/objectives: The objectives were to determines the sexual partners (other than the marital partner and regular partners) responsible for transmitting STI( Sexually transmitted infections)/ HIV and to understand the practice of safer sex. Methods: Study was a clinic based prospective study conducted for a one year period using an interviewer administered questionnaire. Results: 983 attendees were interviewed. . Mean age was 34.02 years. 75% of the sample had completed GCE O/L (ordinary level examination). Skilled labourers, drivers and forces/police comprised 40% of the sample. 50% admitted sex with a casual female, 12% with a casual male, and 13% with CSW (commercial sex workers) while MSW (male sex workers) exposures were minimal. It was identified that younger males had more contacts with males, and regular female partners while more older males with CSW. Anal sex among males was reported by 11.5%. 20.5% used alcohol frequently and 5.9% used drugs and 1.4% injected. Common STI were genital herpes (7.9%), Non gonococcal urethritis (6.2%) and gonorrhoea (6.2%). Among those who had contacts with FSW 6.7% gonorrhoea (GC), 8.2% non gonococcal urethritis (NGU), 7.5% genital herpes and 0.7% HIV. Non regular partner exposures 3.7% had gonorrhoea, 8.3% NGU, 6.6% genital herpes and 0.8% HIV. Among MSM contacts 10.6% had GC, 4.5% NGU, 5.3% genital herpes, 5.3% secondary syphilis and 0.8% HIV. Only 9.0% used condoms correctly. Friends, doctors, newspapers, internet, and forces were important sources of information on condoms. Non use of condoms were due to worry about satisfaction (24.6%) and faith in the partner (25.6%). Discussion/conclusion: Casual partners for unsafe sex is a concern. MSM and CSW are remained as an important source of infection. Early Syphilis and gonorrhoea infections were mostly seen among MSM exposures. The findings indicate that the male population in the sample had satisfactory education. However, still the unsafe sexual contacts are common. . Newspapers, internet were more important sources of information on condoms. Low condom use remains another concern.. More males contracted STI through casual partners. Therefore strategies used for prevention need to be revisited also emphasizing on general population where casual partners represent. . Increasing awareness of men and women through mass media and primary health care teams may be important strategies that can be used to keep the HIV epidemic in a low level.

Keywords: STI, HIV, Males, safe sex practices

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Authors: Perpetua Modjadji, Sphiwe Madiba

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Background: The growth patterns of children are good nutritional indicators of their nutritional status, health, and socioeconomic level. However, the maternal factors and the belief system of the society affect the growth of children promoting undernutrition. This study determined the influence of maternal factors on growth patterns of schoolchildren in a rural site. Methods: A convergent mixed method study was conducted among 508 schoolchildren and their mothers in Dikgale Health and Demographic Surveillance System Site, South Africa. Multistage sampling was used to select schools (purposive) and learners (random), who were paired with their mothers. Anthropometry was measured and socio-demographic, obstetrical, household information, maternal influence on children’s nutrition, and growth were assessed using an interviewer administered questionnaire (quantitative). The influence of the cultural beliefs and practices of mothers on the nutrition and growth of their children was explored using focus group discussions (qualitative). Narratives of mothers were used to best understand growth patterns of schoolchildren (mixed method). Data were analyzed using STATA 14 (quantitative) and Nvivo 11 (qualitative). Quantitative and qualitative data were merged for integrated mixed method analysis using a joint display analysis. Results: Mean age of children was 10 ± 2 years, ranging from 6 to 15 years. Substantial percentages of thinness (25%), underweight (24%), and stunting (22%) were observed among the children. Mothers had a mean age of 37 ± 7 years, and 75% were overweight or obese. A depressed socio-economic status indicated by a higher rate of unemployment with no income (82.3%), and dependency on social grants (86.8%) was observed. Determinants of poor growth patterns were child’s age and gender, maternal age, height and BMI, access to water supply, and refrigerator use. The narratives of mothers suggested that the children in most of their households were exposed to poverty and the inadequate intake of quality food. Conclusion: Poor growth patterns were observed among schoolchildren while their mothers were overweight or obese. Child’s gender, school grade, maternal body mass index, and access to water were the main determinants. Congruence was observed between most qualitative themes and quantitative constructs. A need for a multi sectoral approach considering an evidence based and feasible nutrition programs for schoolchildren, especially those in rural settings and educating mothers, cannot be over-emphasized.

Keywords: growth patterns, maternal factors, rural context, schoolchildren, South Africa

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Authors: Gizaw Mamo Gebeyehu, Marianna Pap, Geza Makkai, Tibor Z. Janosi, Shima Rashidian, Tibor A. Rauch

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Sepsis poses a significant global health threat, necessitating extensive exploration of indicators tied to its pathological mechanisms and multi-organ dysfunction. While murine studies have shed light on sepsis, the intricate cellular and molecular landscape in human sepsis remains enigmatic. Exploring the influence of activated monocyte-derived exosomes in sepsis sheds light on a promising pathway for understanding the intricate cellular and molecular mechanisms involved in this condition in humans. In sepsis, exosome-borne mRNA and miRNA orchestrate immune response gene expression in recipient cells. Yet, the specifics of exosome-mediated cell-to-cell communication, especially how mRNA cargoes modulate gene expression in recipient cells, remain poorly understood. This study aims to elucidate the precise molecular pathways through which exosomal mRNA cargo, particularly MAFB, contributes to the developing sepsis-induced molecular aberrations in liver tissues, employing rigorously defined cell culture conditions. THP-1 cells were treated with LPS to induce changes in exosomal RNA profiles. Exosomes were isolated and characterized using microscopy and mass spectrometry. RNA was extracted from exosomes and sequenced. The most abundant exosomal mRNAs were subjected to GO analysis for functional annotation analysis and KEGG database analysis to identify the involved enriched pathways. PCR (Polymerase Chain Reaction), RNA sequencing, and Western blotting were involved to analyze changes in gene expression, protein levels, and signaling pathways within the liver cells( HepG2) after exposure to exosomal MAFB. This study pinpoints exosomal MAFB as a potential key regulator linked to liver cell damage during sepsis, along with associated genes (miR155HG, H3F3A, and possibly JARD2) forming a crucial molecular pathway contributing to liver cell injury, Together, these elements indicate a vital molecular pathway that plays a significant role in the emergence of liver cell injury during sepsis.. These findings suggest the importance of further research on these components for potential therapeutic interventions in managing acute liver damage in sepsis.

Keywords: sepsis, exososome, exosomal MAFB, LPS-induced THP-1 cells, RNA profiles, sepsis-triggered liver injury

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Authors: Joseph Mwiti Marangu, Joseph Karanja Thiong'o, Jackson Muthengia Wachira

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The mechanical performance of hydrated cements mortars mainly depends on its compressive strength and setting time. These properties are crucial in the construction industry. Pozzolana based cements are mostly characterized by low 28 day compressive strength and long setting times. These are some of the major impediments to their production and diverse uses despite numerous technological and environmental benefits associated with them. The study investigated the effects of potential chemical activators on calcined clay- Portland cement blends with an aim to achieve high early compressive strength and shorter setting times in cement mortar. In addition, standard consistency, soundness and insoluble residue of all cement categories was determined. The test cement was made by blending calcined clays with Ordinary Portland Cement (OPC) at replacement levels from 35 to 50 percent by mass of the OPC to make test cement labeled PCC for the purposes of this study. Mortar prisms measuring 40mmx40mmx160mm were prepared and cured in accordance with KS EAS 148-3:2000 standard. Solutions of Na2SO4, NaOH, Na2SiO3 and Na2CO3 containing 0.5- 2.5M were separately added during casting. Compressive strength was determined at 2rd, 7th, 28th and 90th day of curing. For comparison purposes, commercial Portland Pozzolana cement (PPC) and Ordinary Portland Cement (OPC) were also investigated without activators under similar conditions. X-Ray Florescence (XRF) was used for chemical analysis while X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) were used for mineralogical analysis of the test samples. The results indicated that addition of activators significantly increased the 2nd and 7th day compressive strength but minimal increase on the 28th and 90th day compressive strength. A relatively linear relationship was observed between compressive strength and concentration of activator solutions up to 28th of curing. Addition of the said activators significantly reduced both initial and final setting time. Standard consistency and soundness varied with increased amount of clay in the test cement and concentration of activators. Amount of insoluble residues increased with increased replacement of OPC with calcined clays. Mineralogical studies showed that N-A-S-H is formed in addition to C-S-H. In conclusion, the concentration of 2 molar for all activator solutions produced the optimum compressive strength and greatly reduced the setting times for all cement mortars.

Keywords: activators, admixture, cement, clay, pozzolana

Procedia PDF Downloads 237

Authors: Isaura Bonneux

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District heating and cooling (DHC) is increasingly recognized as a viable path towards sustainable heating and cooling. While some countries like Sweden and Denmark have a longstanding tradition of DHC, Belgium is lacking behind. The Northern part of Belgium, Flanders, had only a total of 95 heating networks in July 2023. Nevertheless, it is increasingly exploring its possibilities to enhance the scope of DHC. DHC is a complex energy system, requiring a lot of collaboration between various stakeholders on various levels. Therefore, it is of interest to look closer at policy-related documents at the Flemish (regional) level, as these policies set the scene for DHC development in the Flemish region. This kind of analysis has not been undertaken so far. This paper has the following research question: “Who talks about DHC, and in which way and context is DHC discussed in Flemish policy-related documents?” To answer this question, the Overton policy database was used to search and retrieve relevant policy-related documents. Overton retrieves data from governments, think thanks, NGOs, and IGOs. In total, out of the 244 original results, 117 documents between 2009 and 2023 were analyzed. Every selected document included theme keywords, policymaking department(s), date, and document type. These elements were used for quantitative data description and visualization. Further, qualitative content analysis revealed patterns and main themes regarding DHC in Flanders. Four main conclusions can be drawn: First, it is obvious from the timeframe that DHC is a new topic in Flanders with still limited attention; 2014, 2016 and 2017 were the years with the most documents, yet this number is still only 12 documents. In addition, many documents talked about DHC but not much in depth and painted it as a future scenario with a lot of uncertainty around it. The largest part of the issuing government departments had a link to either energy or climate (e.g. Flemish Environmental Agency) or policy (e.g. Socio-Economic Council of Flanders) Second, DHC is mentioned most within an ‘Environment and Sustainability’ context, followed by ‘General Policy and Regulation’. This is intuitive, as DHC is perceived as a sustainable heating and cooling technique and this analysis compromises policy-related documents. Third, Flanders seems mostly interested in using waste or residual heat as a heating source for DHC. The harbors and waste incineration plants are identified as potential and promising supply sources. This approach tries to conciliate environmental and economic incentives. Last, local councils get assigned a central role and the initiative is mostly taken by them. The policy documents and policy advices demonstrate that Flanders opts for a bottom-up organization. As DHC is very dependent on local conditions, this seems a logic step. Nevertheless, this can impede smaller councils to create DHC networks and slow down systematic and fast implementation of DHC throughout Flanders.

Keywords: district heating and cooling, flanders, overton database, policy analysis

Procedia PDF Downloads 22

Authors: Gabrielle Peck, Ryan Hayes

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Current large scale fire tests focus on flammability and heat release measurements. Smoke toxicity isn’t considered despite it being a leading cause of death and injury in unwanted fires. A key reason could be that the practical difficulties associated with quantifying individual toxic components present in a fire effluent often require specialist equipment and expertise. Fire effluent contains a mixture of unreactive and reactive gases, water, organic vapours and particulate matter, which interact with each other. This interferes with the operation of the analytical instrumentation and must be removed without changing the concentration of the target analyte. To mitigate the need for expensive equipment and time-consuming analysis, a portable gas analysis system was designed, constructed and tested for use in large-scale fire tests as a simpler and more robust alternative to online FTIR measurements. The novel equipment aimed to be easily portable and able to run on battery or mains electricity; be able to be calibrated at the test site; be capable of quantifying CO, CO2, O2, HCN, HBr, HCl, NOx and SO2 accurately and reliably; be capable of independent data logging; be capable of automated switchover of 7 bubblers; be able to withstand fire effluents; be simple to operate; allow individual bubbler times to be pre-set; be capable of being controlled remotely. To test the analysers functionality, it was used alongside the ISO/TS 19700 Steady State Tube Furnace (SSTF). A series of tests were conducted to assess the validity of the box analyser measurements and the data logging abilities of the apparatus. PMMA and PA 6.6 were used to assess the validity of the box analyser measurements. The data obtained from the bench-scale assessments showed excellent agreement. Following this, the portable analyser was used to monitor gas concentrations during large-scale testing using the ISO 9705 room corner test. The analyser was set up, calibrated and set to record smoke toxicity measurements in the doorway of the test room. The analyser was successful in operating without manual interference and successfully recorded data for 12 of the 12 tests conducted in the ISO room tests. At the end of each test, the analyser created a data file (formatted as .csv) containing the measured gas concentrations throughout the test, which do not require specialist knowledge to interpret. This validated the portable analyser’s ability to monitor fire effluent without operator intervention on both a bench and large-scale. The portable analyser is a validated and significantly more practical alternative to FTIR, proven to work for large-scale fire testing for quantification of smoke toxicity. The analyser is a cheaper, more accessible option to assess smoke toxicity, mitigating the need for expensive equipment and specialist operators.

Keywords: smoke toxicity, large-scale tests, iso 9705, analyser, novel equipment

Procedia PDF Downloads 55

Authors: Mustafa Metin Donma, Orkide Donma

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Obesity in children particularly draws attention because it may threaten the individual’s future life due to many chronic diseases it may lead to. Most of these diseases, including obesity itself altogether are related to inflammation. For this reason, inflammation-related parameters gain importance. Within this context, complete blood cell counts, ratios or indices derived from these counts have recently found some platform to be used as inflammatory markers. So far, mostly adipokines were investigated within the field of obesity. The liver is at the center of the metabolic pathways network. Metabolic inflammation is closely associated with cellular dysfunction. In this study, hematologic inflammatory markers and two major hepatokines, cytokines produced predominantly by the liver, fibroblast growth factor-21 (FGF-21) and fetuin A were investigated in pediatric obesity. Two groups were constituted from seventy-six obese children based on World Health Organization criteria. Group 1 was composed of children whose age- and sex-adjusted body mass index (BMI) percentiles were between 95 and 99. Group 2 consists of children who are above the 99ᵗʰ percentile. The first and the latter groups were defined as obese (OB) and morbid obese (MO). Anthropometric measurements of the children were performed. Informed consent forms and the approval of the institutional ethics committee were obtained. Blood cell counts and ratios were determined by an automated hematology analyzer. The related ratios and indexes were calculated. Statistical evaluation of the data was performed by the SPSS program. There was no statistically significant difference in terms of neutrophil-to lymphocyte ratio, monocyte-to-high density lipoprotein cholesterol ratio and the platelet-to-lymphocyte ratio between the groups. Mean platelet volume and platelet distribution width values were decreased (p<0.05), total platelet count, red cell distribution width (RDW) and systemic immune inflammation index values were increased (p<0.01) in MO group. Both hepatokines were increased in the same group; however, increases were not statistically significant. In this group, also a strong correlation was calculated between FGF-21 and RDW when controlled by age, hematocrit, iron and ferritin (r=0.425; p<0.01). In conclusion, the association between RDW, a hematologic inflammatory marker, and FGF-21, an inflammation-related hepatokine, found in MO group is an important finding discriminating between OB and MO children. This association is even more powerful when controlled by age and iron-related parameters.

Keywords: childhood obesity, fetuin A , fibroblast growth factor-21, hematologic markers, red cell distribution width

Procedia PDF Downloads 174

Authors: David Edgar

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To understand how the brain’s subconscious and conscious functions, we must conquer the physics of Unity, which leads to duality’s algorithm. Where the subconscious (bottom-up) and conscious (top-down) processes function together to produce and consume intelligence, we use terms like ‘time is relative,’ but we really do understand the meaning. In the brain, there are different processes and, therefore, different observers. These different processes experience time at different rates. A sensory system such as the eyes cycles measurement around 33 milliseconds, the conscious process of the frontal lobe cycles at 300 milliseconds, and the subconscious process of the thalamus cycle at 5 milliseconds. Three different observers experience time differently. To bridge observers, the thalamus, which is the fastest of the processes, maintains a synchronous state and entangles the different components of the brain’s physical process. The entanglements form a synchronous cohesion between the brain components allowing them to share the same state and execute in the same measurement cycle. The thalamus uses the shared state to control the firing sequence of the brain’s linear subconscious process. Sharing state also allows the brain to cheat on the amount of sensory data that must be exchanged between components. Only unpredictable motion is transferred through the synchronous state because predictable motion already exists in the shared framework. The brain’s synchronous subconscious process is entirely based on energy conservation, where prediction regulates energy usage. So, the eyes every 33 milliseconds dump their sensory data into the thalamus every day. The thalamus is going to perform a motion measurement to identify the unpredictable motion in the sensory data. Here is the trick. The thalamus conducts its measurement based on the original observation time of the sensory system (33 ms), not its own process time (5 ms). This creates a data payload of synchronous motion that preserves the original sensory observation. Basically, a frozen moment in time (Flat 4D). The single moment in time can then be processed through the single state maintained by the synchronous process. Other processes, such as consciousness (300 ms), can interface with the synchronous state to generate awareness of that moment. Now, synchronous data traveling through a separate faster synchronous process creates a theoretical time tunnel where observation time is tunneled through the synchronous process and is reproduced on the other side in the original time-relativity. The synchronous process eliminates time dilation by simply removing itself from the equation so that its own process time does not alter the experience. To the original observer, the measurement appears to be instantaneous, but in the thalamus, a linear subconscious process generating sensory perception and thought production is being executed. It is all just occurring in the time available because other observation times are slower than thalamic measurement time. For life to exist in the physical universe requires a linear measurement process, it just hides by operating at a faster time relativity. What’s interesting is time dilation is not the problem; it’s the solution. Einstein said there was no universal time.

Keywords: neural synchronization, natural intelligence, 99.95% IoT data transmission savings, artificial subconscious intelligence (ASI)

Procedia PDF Downloads 107

Authors: Yuta Kurashina, Chikahiro Imashiro, Kiyoshi Ohnuma, Kenjiro Takemura

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Research objectives and goals: To realize clinical applications of regenerative medicine, a mass cell culture is highly required. In a conventional cell culture, trypsinization was employed for cell detachment. However, trypsinization causes proliferation decrease due to injury of cell membrane. In order to detach cells using an enzyme-free method, therefore, this study proposes a novel cell detachment method capable of detaching adherent cells using acoustic radiation pressure exposed to the dish by the assistance of serum-free medium with ITS liquid medium supplement. Methods used In order to generate acoustic radiation pressure, a piezoelectric ceramic plate was glued on a glass plate to configure an ultrasonic transducer. The glass plate and a chamber wall compose a chamber in which a culture dish is placed in glycerol. Glycerol transmits acoustic radiation pressure to adhered cells on the culture dish. To excite a resonance vibration of transducer, AC signal with 29-31 kHz (swept) and 150, 300, and 450 V was input to the transducer for 5 min. As a pretreatment to reduce cell adhesivity, serum-free medium with ITS liquid medium supplement was spread to the culture dish before exposed to acoustic radiation pressure. To evaluate the proposed cell detachment method, C2C12 myoblast cells (8.0 × 104 cells) were cultured on a ø35 culture dish for 48 hr, and then the medium was replaced with the serum-free medium with ITS liquid medium supplement for 24 hr. We replaced the medium with phosphate buffered saline and incubated cells for 10 min. After that, cells were exposed to the acoustic radiation pressure for 5 min. We also collected cells by using trypsinization as control. Cells collected by the proposed method and trypsinization were respectively reseeded in ø60 culture dishes and cultured for 24 hr. Then, the number of proliferated cells was counted. Results achieved: By a phase contrast microscope imaging, shrink of lamellipodia was observed before exposed to acoustic radiation pressure, and no cells remained on the culture dish after the exposed of acoustic radiation pressure. This result suggests that serum-free medium with ITS liquid inhibits adhesivity of cells and acoustic radiation pressure detaches cells from the dish. Moreover, the number of proliferated cells 24 hr after collected by the proposed method with 150 and 300 V is the same or more than that by trypsinization, i.e., cells were proliferated 15% higher with the proposed method using acoustic radiation pressure than with the traditional cell collecting method of trypsinization. These results proved that cells were able to be collected by using the appropriate exposure of acoustic radiation pressure. Conclusions: This study proposed a cell detachment method using acoustic radiation pressure by the assistance of serum-free medium. The proposed method provides an enzyme-free cell detachment method so that it may be used in future clinical applications instead of trypsinization.

Keywords: acoustic radiation pressure, cell detachment, enzyme free, ultrasonic transducer

Procedia PDF Downloads 236

Authors: Gedefaye Nibret Mihretie

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Background: Transactional sex is casual sex between two people to receive material incentives in exchange for sexual favors. Transactional sex is associated with negative consequences, which increase the risk of sexually transmitted diseases, including HIV/AIDS, unintended pregnancy, unsafe abortion, and physiological trauma. Many primary studies in Sub-Saharan Africa have been conducted to assess the prevalence and associated factors of transactional sex among women. These studies had great discrepancies and inconsistent results. Hence, this systematic review and meta-analysis aimed to synthesize the pooled prevalence of the practice of transactional sex among women and its associated factors in Sub-Saharan Africa. Method: Cross-sectional studies were systematically searched from March 6, 2022, to April 24, 2022, using PubMed, Google Scholar, HINARI, Cochrane Library, and grey literature. The pooled prevalence of transactional sex and associated factors was estimated using DerSemonial-Laird Random Effect Model. Stata (version 16.0) was used to analyze the data. The I-squared statistic was used to assess the studies' heterogeneity. A funnel plot and Egger's test were used to check for publication bias. A subgroup analysis was performed to minimize the underline heterogeneity depending on the study years, source of data, sample sizes and geographical location. Results: Four thousand one hundred thirty articles were extracted from various databases. The final thirty-two studies were included in this systematic review, including 108,075 participants. The pooled prevalence of transactional sex among women in Sub-Saharan Africa was 12.55%, with a confidence interval of 9.59% to 15.52%. Educational status (OR = .48, 95%CI, 0.27, 0.69) was the protective factors of transactional sex whereas, alcohol use (OR = 1.85, 95% CI: 1.19, 2.52), early sex debut (OR = 2.57, 95%CI, 1.17, 3.98), substance abuse (OR = 4.21, 95% CI: 2.05, 6.37), having history of sexual experience abuse (OR = 4.08, 95% CI: 1.38, 6.78), physical violence abuse (OR = 6.59, 95% CI: 1.17, 12.02), and sexual violence abuse (OR = 3.56, 95% CI: 1.15, 8.27) were the risk factors of transactional sex. Conclusion: The prevalence of transactional sex among women in Sub-Saharan Africa was high. Educational status, alcohol use, substance abuse, early sex debut, having a history of sexual experiences, physical violence, and sexual violence were predictors of transaction sex. Governmental and other stakeholders are designed to reduce alcohol utilization, provide health information about the negative consequences of early sex debut, substance abuse, and reduce sexual violence, ensuring gender equality through mass media, which should be included in state policy.

Keywords: women’s health, child health, reproductive health, midwifery

Procedia PDF Downloads 70

Authors: Gabriel Wosiak, Felipe Staciaki, Eryka Nobrega, Ernesto Pereira

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Hydrogen is an energy carrier with potential applications in various industries. Alkaline electrolysis is a commonly used method for hydrogen production; however, its energy cost remains relatively high compared to other methods. This is due in part to interfacial pH changes that occur during the electrolysis process. Interfacial pH changes refer to the changes in pH that occur at the interface between the cathode electrode and the electrolyte solution. These changes are caused by the electrochemical reactions at both electrodes, which consume or produces hydroxide ions (OH-) from the electrolyte solution. This results in an important change in the local pH at the electrode surface, which can have several impacts on the energy consumption and durability of electrolysers. One impact of interfacial pH changes is an increase in the overpotential required for hydrogen production. Overpotential is the difference between the theoretical potential required for a reaction to occur and the actual potential that is applied to the electrodes. In the case of water electrolysis, the overpotential is caused by a number of factors, including the mass transport of reactants and products to and from the electrodes, the kinetics of the electrochemical reactions, and the interfacial pH. An increase in the interfacial pH at the anode surface in alkaline conditions can lead to an increase in the overpotential for hydrogen production. This is because the lower local pH makes it more difficult for the hydroxide ions to be oxidized. As a result, there is an increase in the required energy to the process occur. In addition to increasing the overpotential, interfacial pH changes can also lead to the degradation of the electrodes. This is because the lower pH can make the electrode more susceptible to corrosion. As a result, the electrodes may need to be replaced more frequently, which can increase the overall cost of water electrolysis. The method presented in the paper addresses the issue of interfacial pH changes by using a cell design with a different cell design, introducing the electrode asymmetry. This design helps to mitigate the pH gradient at the anode/electrolyte interface, which reduces the overpotential and improves the energy efficiency of the electrolyser. The method was tested using a multivariate approach in both laboratory and industrial current density conditions and validated the results with numerical simulations. The results demonstrated a clear improvement (11.6%) in energy efficiency, providing an important contribution to the field of sustainable energy production. The findings of the paper have important implications for the development of cost-effective and sustainable hydrogen production methods. By mitigating interfacial pH changes, it is possible to improve the energy efficiency of alkaline electrolysis and make it a more competitive option for hydrogen production.

Keywords: electrolyser, interfacial pH, numerical simulation, optimization, asymmetric cell

Procedia PDF Downloads 53

Authors: Ernest Nweke, Enkhtuya Bavuudorj

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The harsh realities of the scandalous failure of several notable corporations in the past two decades have inextricably resulted in a surge in corporate governance studies. Nevertheless, little or no attention has been paid to corporate governance studies in Mongolian firms and much less to the comprehension of the correlation among ownership structure, corporate governance mechanisms and trend of innovative activities. Innovation is the bed rock of enterprise success. However, the funding and support for innovative activities in many firms are to a great extent determined by the incentives provided by the firm’s internal and external governance mechanisms. Mongolia is an East Asian country currently undergoing a fast-paced transition from socialist to democratic system and it is a widely held view that private ownership as against public ownership fosters innovation. Hence, following the privatization policy of Mongolian Government which has led to the transfer of the ownership of hitherto state controlled and state directed firms to private individuals and organizations, expectations are high that sufficient motivation would be provided for firm managers to engage in innovative activities. This research focuses on the relationship between ownership structure, corporate governance on one hand and the level of innovation on the hand. The paper is empirical in nature and derives data from both reliable secondary and primary sources. Secondary data for the study was in respect of ownership structure of Mongolian listed firms and innovation trend in Mongolia generally. These were analyzed using tables, charts, bars and percentages. Personal interviews and surveys were held to collect primary data. Primary data was in respect of corporate governance practices in Mongolian firms and were collected using structured questionnaire. Out of a population of three hundred and twenty (320) companies listed on the Mongolian Stock Exchange (MSE), a sample size of thirty (30) randomly selected companies was utilized for the study. Five (5) management level employees were surveyed in each selected firm giving a total of one hundred and fifty (150) respondents. Data collected were analyzed and research hypotheses tested using Chi-Square test statistic. Research results showed that corporate governance mechanisms were better and have significantly improved overtime in privately held as opposed to publicly owned firms. Consequently, the levels of innovation in privately held firms were considerably higher. It was concluded that a significant and positive relationship exists between private ownership and good corporate governance on one hand and the level of funding provided for innovative activities in Mongolian firms on the other hand.

Keywords: corporate governance, innovation, ownership structure, stock exchange

Procedia PDF Downloads 170

Authors: Anietie J. Atangwho, Udeme E. Asibong, Item J. Atangwho, Ndifreke E. Udonwa

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Diabesity, a syndrome where diabetes and obesity occur simultaneously in a single patient, has emerged as a recent challenge to the medical world and is already at epidemic proportion in some countries. Therefore, this study aimed to determine the prevalence of diabesity among adult patients attending the General Outpatient clinic of three healthcare facilities in Calabar in a bid to improve healthcare delivery to patients at risk. A cross-sectional descriptive study design was employed using a mixed method approach that comprised quantitative and qualitative components i.e., Focused Group Discussion (FGD) and Key Informant Interview (KII). One hundred and ninety (190) participants aged 18 to 72 years and body mass index (BMI) ≥ 30kg/m2 were recruited as the study population for the quantitative study using systematic random sampling technique and analysed using SPSS version 25. The qualitative component performed 4 FGDs and 3 KIIs. Results of sociodemographic variables showed respondents aged 35 – 44 as highest in number (37.3%). Of this number, 83.7% were females, 76.8% married, and 3.7% earned USD1,110.00 monthly. Whereas majority of the participants (65.8 %) were within class 1 obesity, only 38% considered themselves obese. Diabesity occurrence was found to be 12.6% (i.e. BMI ≥ 30 to 45.2kg/m2 vs FBS ≥ 7.0 – 14.8mmo/l), with 38% of them being previously undiagnosed. About 48.4 % of the respondents ate two meals only per day; with 90.5% eating between meals. Snacking was predominant, mostly pastries (67.9%), with 58.9% taking cola drinks alongside. Sixty-one percent participated in one form of exercise or the other, with walking/trekking as the most common; 34.4 % had no regular exercise schedule. Only about 39.5% of the participants spent less than an hour on devices like phone, television, and laptops. Additionally, previously known and newly diagnosed hypertensive patients were 27.9% and 7.2%, respectively. Qualitative assessment with KII and FGDs showed eating unhealthy diets and lack of exercise as major factors responsible for diabesity. The bivariate analysis revealed significant association between diabesity with marital status and hypertension (p = 0.007 and p = 0.005, respectively). Also, positive association with diabesity were eating snacking (p = 0.017) and number of times a respondent snacks per day (p = 0.035). Overall, the study has revealed the occurrence of diabesity in Calabar at 12.6 % of the study population, with 38 % of them previously undiagnosed; it identified unhealthy diets and lack of exercise as causative factors as well as hypertension as snacking associatory indicators of diabesity.

Keywords: diabesity, obesity, diabetes, unhealthy diet

Procedia PDF Downloads 48

Authors: Muttamas Wongwanich, John R. Bryson, Catherine E. Harris

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Science parks are an essential component of localized innovation ecosystems. Science Parks have played a critical role in enhancing local innovation ecosystems in developed market economies. Attempts have been made to replicate best practice in other national contexts. To our best knowledge, the study about the development of Science Parks has not been undertaken on the economic impact on the developing countries. Further research is required to understand the adoption of Science Park policies in developing and emerging economies. This study explores the implementation of Science Park policy and its impacts on economic growth and development in Thailand, focusing on the relationship between universities and businesses. The Thailand context is essential. Thailand’s economy is dominated by agriculture and tourism. The Science Park policy is trying to develop an agriculturally orientated innovative ecosystem. Thailand established four Science Parks based on a policy that highlighted the importance of cooperation between government, HEIs, and businesses. These Science Parks are intended to increase small and medium enterprises’ (SMEs) innovativeness, employment, and regional economic growth by promoting collaboration and knowledge transfer between HEIs and the private sector. This study explores one regional Science Park in Thailand with an emphasis on understanding the implementation and operation of a triple helix innovation policy. The analysis explores the establishment of the Science Park and its impacts on firms and the regional economy through interviews with Science Parks directors, firms, academics, universities, and government officials. The analysis will inform Science Park policy development in Thailand to support the national objective to develop an innovation ecosystem based on the integration of technology with innovation policy, supporting technology-based SMEs in the creation of local jobs. The finding shows that the implementation of the Science Park policy in Thailand requires support and promotion from the government. The regional development plan must be related to the regional industry development strategy, considering the strengths and weaknesses of local entrepreneurs. The long time in granting a patent is the major obstacle in achieving the government’s aim in encouraging local economic activity. The regional Science Parks in Thailand are at the early stage of the operation plan. Thus, the impact on the regional economy cannot be measured and need further investigation in a more extended period. However, local businesses realize the vital of research and development (R&D). There have been more requests for funding support in doing R&D. Furthermore, there is the creation of linkages between businesses, HEIs, and government authorities as expected.

Keywords: developing country, emerging economy, regional development, science park, Thailand, triple helix

Procedia PDF Downloads 129

Authors: Satoko Yamasaki, Hiromi Kawasaki, Kotomi Yamashita, Susumu Fukita, Kei Sounai

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People are susceptible to rumors when the cause of their health problems is unknown or invisible. In order for individuals to be unaffected by rumors, they need basic knowledge and correct information. Community health nursing classes use cases where basic knowledge of radiation can be utilized on a regular basis, thereby teaching that basic knowledge is important in preventing anxiety caused by rumors. Nursing students need to learn that preventive activities are essential for public health nursing care. This is the same methodology used to reduce COVID-19 anxiety among individuals. This study verifies the learning effect concerning the basic knowledge of radiation necessary for case consultation by emergency distance learning. Sixty third-year nursing college students agreed to participate in this research. The knowledge tests conducted before and after classes were compared, with the chi-square test used for testing. There were five knowledge questions regarding distance lessons. This was considered to be 5% significant. The students’ reports which describe the results of responding to health consultations, were analyzed qualitatively and descriptively. In this case study, a person living in an area not affected by radiation was anxious about drinking water and, thus, consulted with a student. The contents of the lecture were selected the minimum amount of knowledge used for the answers of the consultant; specifically hot spots, internal exposure risk, food safety, characteristics of cesium-137, and precautions for counselors. Before taking the class, the most correctly answered question by students concerned daily behavior at risk of internal exposure (52.2%). The question with the fewest correct answers was the selection of places that are likely to be hot spots (3.4%). All responses increased significantly after taking the class (p < 0.001). The answers to the counselors, as written by the students, were 'Cesium is strongly bound to the soil, so it is difficult to transfer to water' and 'Water quality test results of tap water are posted on the city's website.' These were concrete answers obtained by using specialized knowledge. Even in emergency distance learning, the students gained basic knowledge regarding radiation and created a document to utilize said knowledge while assuming the situation concretely. It was thought that the flipped classroom method, even if conducted remotely, could maintain students' learning. It was thought that setting specific knowledge and scenes to be used would enhance the learning effect. By changing the case to concern that of the anxiety caused by infectious diseases, students may be able to effectively gain the basic knowledge to decrease the anxiety of residents due to infectious diseases.

Keywords: effect of class, emergency distance learning, nursing student, radiation

Procedia PDF Downloads 98

Authors: Saeed Bagherifam, Trevor Brown, Chris Fellows, Ravi Naidu

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Over the last century, rapid urbanization, industrial emissions, and mining activities have resulted in widespread contamination of the environment by heavy metal(loid)s. Arsenic (As) is a toxic metalloid belonging to group 15 of the periodic table, which occurs naturally at low concentrations in soils and the earth’s crust, although concentrations can be significantly elevated in natural systems as a result of dispersion from anthropogenic sources, e.g., mining activities. Bioavailability is the fraction of a contaminant in soils that is available for uptake by plants, food chains, and humans and therefore presents the greatest risk to terrestrial ecosystems. Numerous attempts have been made to establish in situ and ex-situ technologies of remedial action for remediation of arsenic-contaminated soils. In situ stabilization techniques are based on deactivation or chemical immobilization of metalloid(s) in soil by means of soil amendments, which consequently reduce the bioavailability (for biota) and bioaccessibility (for humans) of metalloids due to the formation of low-solubility products or precipitates. This study investigated the effectiveness of two different types of synthetic manganese and iron oxides (birnessite and goethite) for stabilization of As in a soil spiked with 1000 mg kg⁻¹ of As and treated with 10% dosages of soil amendments. Birnessite was made using HCl and KMnO₄, and goethite was synthesized by the dropwise addition of KOH into Fe(NO₃) solution. The resulting contaminated soils were subjected to a series of chemical extraction studies including sequential extraction (BCR method), single-step extraction with distilled (DI) water, 2M HNO₃ and simplified bioaccessibility extraction tests (SBET) for estimation of bioaccessible fractions of As in two different soil fractions ( < 250 µm and < 2 mm). Concentrations of As in samples were measured using inductively coupled plasma mass spectrometry (ICP-MS). The results showed that soil with birnessite reduced bioaccessibility of As by up to 92% in both soil fractions. Furthermore, the results of single-step extractions revealed that the application of both birnessite and Goethite reduced DI water and HNO₃ extractable amounts of arsenic by 75, 75, 91, and 57%, respectively. Moreover, the results of the sequential extraction studies showed that both birnessite and goethite dramatically reduced the exchangeable fraction of As in soils. However, the amounts of recalcitrant fractions were higher in birnessite, and Goethite amended soils. The results revealed that the application of both birnessite and goethite significantly reduced bioavailability and the exchangeable fraction of As in contaminated soils, and therefore birnessite and Goethite amendments might be considered as promising adsorbents for stabilization and remediation of As contaminated soils.

Keywords: arsenic, bioavailability, in situ stabilisation, metalloid(s) contaminated soils

Procedia PDF Downloads 113

Authors: Naohiro Nakamura, Takuya Kinoshita, Hiroshi Fukuyama

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The 2011 off The Pacific Coast of Tohoku Earthquake caused considerable damage to wide areas of eastern Japan. A large number of earthquake observation records were obtained at various places. To design more earthquake-resistant buildings and improve earthquake disaster prevention, it is necessary to utilize these data to analyze and evaluate the behavior of a building during an earthquake. This paper presents an earthquake response simulation analysis (hereafter a seismic response analysis) that was conducted using data recorded during the main earthquake (hereafter the main shock) as well as the earthquakes before and after it. The data were obtained at a high-rise steel-reinforced concrete (SRC) building in the bay area of Tokyo. We first give an overview of the building, along with the characteristics of the earthquake motion and the building during the main shock. The data indicate that there was a change in the natural period before and after the earthquake. Next, we present the results of our seismic response analysis. First, the analysis model and conditions are shown, and then, the analysis result is compared with the observational records. Using the analysis result, we then study the effect of soil-structure interaction on the response of the building. By identifying the characteristics of the building during the earthquake (i.e., the 1st natural period and the 1st damping ratio) by the Auto-Regressive eXogenous (ARX) model, we compare the analysis result with the observational records so as to evaluate the accuracy of the response analysis. In this study, a lumped-mass system SR model was used to conduct a seismic response analysis using observational data as input waves. The main results of this study are as follows: 1) The observational records of the 3/11 main shock put it between a level 1 and level 2 earthquake. The result of the ground response analysis showed that the maximum shear strain in the ground was about 0.1% and that the possibility of liquefaction occurring was low. 2) During the 3/11 main shock, the observed wave showed that the eigenperiod of the building became longer; this behavior could be generally reproduced in the response analysis. This prolonged eigenperiod was due to the nonlinearity of the superstructure, and the effect of the nonlinearity of the ground seems to have been small. 3) As for the 4/11 aftershock, a continuous analysis in which the subject seismic wave was input after the 3/11 main shock was input was conducted. The analyzed values generally corresponded well with the observed values. This means that the effect of the nonlinearity of the main shock was retained by the building. It is important to consider this when conducting the response evaluation. 4) The first period and the damping ratio during a vibration were evaluated by an ARX model. Our results show that the response analysis model in this study is generally good at estimating a change in the response of the building during a vibration.

Keywords: ARX model, response analysis, SRC building, the 2011 off the Pacific Coast of Tohoku Earthquake

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Authors: R. Abdulrahman, A. Eardley, A. Soliman

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The proliferation in the development of mobile learning (m-learning) has played a vital role in the rapidly growing electronic learning market. This relatively new technology can help to encourage the development of in learning and to aid knowledge transfer a number of areas, by familiarizing students with innovative information and communications technologies (ICT). M-learning plays a substantial role in the deployment of learning methods for nursing students by using the Internet and portable devices to access learning resources ‘anytime and anywhere’. However, acceptance of m-learning by students is critical to the successful use of m-learning systems. Thus, there is a need to study the factors that influence student’s intention to use m-learning. This paper addresses this issue. It outlines the outcomes of a study that evaluates the unified theory of acceptance and use of technology (UTAUT) model as applied to the subject of user acceptance in relation to m-learning activity in nurse education. The model integrates the significant components across eight prominent user acceptance models. Therefore, a standard measure is introduced with core determinants of user behavioural intention. The research model extends the UTAUT in the context of m-learning acceptance by modifying and adding individual innovativeness (II) and quality of service (QoS) to the original structure of UTAUT. The paper goes on to add the factors of previous experience (of using mobile devices in similar applications) and the nursing students’ readiness (to use the technology) to influence their behavioural intentions to use m-learning. This study uses a technique called ‘convenience sampling’ which involves student volunteers as participants in order to collect numerical data. A quantitative method of data collection was selected and involves an online survey using a questionnaire form. This form contains 33 questions to measure the six constructs, using a 5-point Likert scale. A total of 42 respondents participated, all from the Nursing Institute at the Armed Forces Hospital in Saudi Arabia. The gathered data were then tested using a research model that employs the structural equation modelling (SEM), including confirmatory factor analysis (CFA). The results of the CFA show that the UTAUT model has the ability to predict student behavioural intention and to adapt m-learning activity to the specific learning activities. It also demonstrates satisfactory, dependable and valid scales of the model constructs. This suggests further analysis to confirm the model as a valuable instrument in order to evaluate the user acceptance of m-learning activity.

Keywords: mobile learning, nursing institute students’ acceptance of m-learning activity in Saudi Arabia, unified theory of acceptance and use of technology model (UTAUT), structural equation modelling (SEM)

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Authors: Priyal Sepaha

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A refugee crisis is manifested by challenges, both for the refugees and the asylum giving state. The situation turns into a mega-crisis when the situation is prejudicially handled by the home state, inappropriate refugee laws, exploding refugee population, and above all, no hope of any foreseeable solution or remedy. This paper studies the impact on the capability of stateless Rohingyas to migrate and seek refuge due to the enforcement of rigid criteria of movement imposed both by Myanmar as well as the adjoining countries in the name of national security. This theoretical study identifies the issues and the key factors and players which have precipitated the crisis. It further discusses the possible ramifications in the home, asylum giving, and the adjoining countries for not discharging their roles aptly. Additionally, an attempt has been made to understand the scarce response given to the impending crisis by the regional organizations like SAARC, ASEAN and CHOGAM as well as international organizations like United Nations Human Rights Council, Security Council, Office of High Commissioner for Refugees and so on, in the name of inadequacy of monetary funds and physical resources. Based on the refugee laws and practices pertaining to the case of Rohingyas, this paper analyses that the Rohingya Crisis is in dire need of an effective action plan to curb and resolve the biggest humanitarian crisis situation of the century. This mounting human tragedy can be mitigated permanently, by strengthening existing and creating new interdependencies among all stakeholders, as further ignorance can drive the countries of the Indian Sub-continent, in particular, and South East Asia, by and large into a violent civil war for seizing long-awaited civil rights by the marginalized Rohingyas. To curb this mass crisis, it will require the application of coercive pressure and diplomatic pursuance on the home country to acknowledge the rights of its fleeing citizens. This further necessitates mustering adequate monetary funds and physical resources for the asylum providing state. Additional challenges such as devising mechanisms for the refugee’s safe return, comprehensive planning for their holistic economic development and rehabilitation plan are needed. These, however, can only come into effect with a conscious strive by the regional and international community to fulfil their assigned role.

Keywords: asylum, citizenship, crisis, humanitarian, human rights, refugee, rohingya

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Authors: Wageeh A. Nafei

Abstract:

This paper explores the role of Paradoxical Leadership (PL) in enhancing Organizational Success (OS) at private hospitals in Egypt. Based on the collected data from employees in private hospitals (doctors, nursing staff, and administrative staff). The researcher has adopted a sampling method to collect data for the study. The appropriate statistical methods, such as Alpha Correlation Coefficient (ACC), Confirmatory Factor Analysis (CFA), and Multiple Regression Analysis (MRA), are used to analyze the data and test the hypotheses. The research has reached a number of results, the most important of which are (1) there is a statistical relationship between the independent variable represented by PL and the dependent variable represented by Organizational Success (OS). The paradoxical leader encourages employees to express their opinions and builds a work environment characterized by flexibility and independence. Also, the paradoxical leader works to support specialized work teams, which leads to the creation of new ideas, on the one hand, and contributes to the achievement of outstanding performance on the other hand. (2) the mentality of the paradoxical leader is flexible and capable of absorbing all suggestions from all employees. Also, the paradoxical leader is interested in enhancing cooperation among them and provides an opportunity to transfer experience and increase knowledge-sharing. Also, the sharing of knowledge creates the necessary diversity that helps the organization to obtain rich external information and enables the organization to deal with a rapidly changing environment. (3) The PL approach helps in facing the paradoxical demands of employees. A paradoxical leader plays an important role in reducing the feeling of instability in the work environment and lack of job security, reducing negative feelings for employees, restoring balance in the work environment, improving the well-being of employees, and increasing the degree of job satisfaction of employees in the organization. The study referred to a number of recommendations, the most important of which are (1) the leaders of the organizations must listen to the views of employees and their needs and move away from the official method of control. The leader should give sufficient freedom to employees to participate in decision-making and maintain enough space among them. The treatment between the leaders and employees must be based on friendliness, (2) the need for organizational leaders to pay attention to sharing knowledge among employees through training courses. The leader should make sure that every information provided by the employee is valuable and useful, which can be used to solve a problem that may face his/her colleagues at work, (3) the need for organizational leaders to pay attention to sharing knowledge among employees through brainstorming sessions. The leader should ensure that employees obtain knowledge from their colleagues and share ideas and information among them. This is in addition to motivating employees to complete their work in a new creative way, which leads to employees’ not feeling bored of repeating the same routine procedures in the organization.

Keywords: paradoxical leadership, organizational success, human resourece, management

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