Search results for: mechanical creep compression ratio

Authors: Aleš Florian, Lenka Ševelová

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Complex sensitivity analysis of stresses in a concrete slab of the real type of rigid pavement made from recycled materials is performed. The computational model of the pavement is designed as a spatial (3D) model, is based on a nonlinear variant of the finite element method that respects the structural nonlinearity, enables to model different arrangements of joints, and the entire model can be loaded by the thermal load. Interaction of adjacent slabs in joints and contact of the slab and the subsequent layer are modeled with the help of special contact elements. Four concrete slabs separated by transverse and longitudinal joints and the additional structural layers and soil to the depth of about 3m are modeled. The thickness of individual layers, physical and mechanical properties of materials, characteristics of joints, and the temperature of the upper and lower surface of slabs are supposed to be random variables. The modern simulation technique Updated Latin Hypercube Sampling with 20 simulations is used. For sensitivity analysis the sensitivity coefficient based on the Spearman rank correlation coefficient is utilized. As a result, the estimates of influence of random variability of individual input variables on the random variability of principal stresses s1 and s3 in 53 points on the upper and lower surface of the concrete slabs are obtained.

Keywords: concrete, FEM, pavement, sensitivity, simulation

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Authors: Tânia F. C. V. Silva, Eloísa S. S. Vieira, João Pinto da Costa, Rui A. R. Boaventura, Vitor J. P. Vilar

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Sanitary landfill leachates are characterized as a complex mixture of diverse organic and inorganic contaminants, which are usually removed by combining different treatment processes. Due to its simplicity, reliability, high cost-effectiveness and high nitrogen content (mostly under the ammonium form) inherent in this type of effluent, the activated sludge biological process is almost always applied in leachate treatment plants (LTPs). The purpose of this work is to assess the effect of the main nitrification and denitrification variables on the nitrogen's biological removal, from mature leachates. The leachate samples were collected after an aerated lagoon, at a LTP nearby Porto, presenting a high amount of dissolved organic carbon (1.0-1.3 g DOC/L) and ammonium nitrogen (1.1-1.7 g NH4+-N/L). The experiments were carried out in a 1-L lab-scale batch reactor, equipped with a pH, temperature and dissolved oxygen (DO) control system, in order to determine the reaction kinetic constants at unchanging conditions. The nitrification reaction rate was evaluated while varying the (i) operating temperature (15, 20, 25 and 30ºC), (ii) DO concentration interval (0.5-1.0, 1.0-2.0 and 2.0-4.0 mg/L) and (iii) solution pH (not controlled, 7.5-8.5 and 6.5-7.5). At the beginning of most assays, it was verified that the ammonium stripping occurred simultaneously to the nitrification, reaching up to 37% removal of total dissolved nitrogen. The denitrification kinetic constants and the methanol consumptions were calculated for different values of (i) volatile suspended solids (VSS) content (25, 50 and 100 mL of centrifuged sludge in 1 L solution), (ii) pH interval (6.5-7.0, 7.5-8.0 and 8.5-9.0) and (iii) temperature (15, 20, 25 and 30ºC), using effluent previously nitrified. The maximum nitrification rate obtained was 38±2 mg NH4+-N/h/g VSS (25ºC, 0.5-1.0 mg O2/L, pH not controlled), consuming 4.4±0.3 mg CaCO3/mg NH4+-N. The highest denitrification rate achieved was 19±1 mg (NO2--N+NO3--N)/h/g VSS (30ºC, 50 mL of sludge and pH between 7.5 and 8.0), with a C/N consumption ratio of 1.1±0.1 mg CH3OH/mg (NO2--N+NO3--N) and an overall alkalinity production of 3.7±0.3 mg CaCO3/mg (NO2--N+NO3--N). The denitrification process showed to be sensitive to all studied parameters, while the nitrification reaction did not suffered significant change when DO content was changed.

Keywords: mature sanitary landfill leachate, nitrogen removal, nitrification and denitrification parameters, lab-scale activated sludge biological reactor

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Authors: Abdulwahhab Khedr, Tamer Shehata, Hanaa El-Ghamry

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Venlafaxine HCl is a novel antidepressant drug used in the treatment of major depressive disorder, generalized anxiety disorder, social anxiety disorder and panic disorder. Conventional therapeutic regimens with venlafaxine HCl immediate-release dosage forms require frequent dosing due to short elimination half-life of the drug and reduced bioavailability. Hence, this study was carried out to develop sustained-release dosage forms of venlafaxine HCl to reduce its dosing frequency, to improve patient compliance and to reduce side effects of the drug. The polymers used were hydroxypropylmethyl cellulose, xanthan gum, sodium alginate, sodium carboxymethyl cellulose, Carbopol 940 and ethyl cellulose. The physical properties of the prepared tablets including tablet thickness, diameter, weight uniformity, content uniformity, hardness and friability were evaluated. Also, the in-vitro release of venlafaxine HCl from different matrix tablets was studied. Based on physical characters and in-vitro release profiles, certain formulae showing promising sustained-release profiles were subjected to film coating with 15% w/v EC in dichloromethane/ethanol mixture (1:1 ratio) using 1% w/v HPMC as pore former and 30% w/w dibutyl phthalate as plasticizer. The optimized formulations were investigated for drug-excipient compatibility using FTIR and DSC studies. Physical evaluation of the prepared tablets fulfilled the pharmacopoeial requirements for tablet friability test, where the weight loss of the prepared formulae did not exceed 1% of the weight of the tested tablets. Moderate release was obtained from tablets containing HPMC. FTIR and DSC studies for such formulae revealed the absence of any type of chemical interaction between venlafaxine HCl and the used polymers or excipients. Forced swimming test in rats was used to evaluate the antidepressant activity of the selected matrix tablets of venlafaxine HCl. Results showed that formulations significantly decreased the duration of animals’ immobility during the 24 hr-period of the test compared to non-treated group.

Keywords: antidepressant, sustained-release, matrix tablet, venlafaxine hydrochloride

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Authors: Hernan D. Mejia, Gilberto B. Gaitan, Mauricio A. Franco

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420 steel is normally used in the manufacture of dental and surgical instrumentation, as well as parts in the chemical, pharmaceutical, and food industries, among others, where they must withstand heavy loads and often be in contact with corrosive environments, which leads to wear and deterioration of these steels in relatively short times. In the case of medical applications, the instruments made of this steel also suffer wear and corrosion during the repetitive sterilization processes due to the relatively low achievable hardness of just 50 HRC and its hardly acceptable resistance to corrosion. In order to improve the wear resistance of 420 steel, TiAlN coatings were deposited, increasing the aluminum content in the alloy by varying the power applied to the aluminum target of 900, 1100, and 1300 W. Evaluations using XRD, Micro Raman, XPS, AFM, SEM, and TEM showed a columnar growth crystal structure with an average thickness of 2 microns and consisting of the TiN and TiAlN phases, whose roughness and grain size decrease with a higher Al content. The AlN phase also appears in the sample deposited at 1300W. The hardness, determined by nanoindentation, initially increases with the aluminum content from 9.7 GPa to 17.1 GPa, but then decreases to 15.4 GPa for the sample with the highest aluminum content due to the appearance of hexagonal AlN and a decrease of harder TiN and TiAlN phases. It was observed that the wear coefficient had a contrary behavior, which took values of 2.7; 1.7 and 6.6x10⁻⁶ mm³/N.m, respectively. All the coated samples significantly improved the wear resistance of the uncoated 420 steel.

Keywords: hard coatings, magnetron sputtering, TiAlN coatings, surgical instruments, wear resistance

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Authors: Rocco Lioy, Tom Dusseldorf, Aline Lehnen, Romain Reding

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A study concerning both the rentability and ecological performance of dairy production in Luxembourg was carried out for the years 2017, 2018 and 2019. The data of 100 dairy farms, referring to the Greenhouse gas emissions (ecology) and the profitability (economy) of dairy production, were evaluated, and the average was compared to the corresponding figures of 80 Luxembourgish dairy farms evaluated in the years 2014, 2015 and 2016. The ecological evaluation could confirm that farm efficiency (especially defined as the lowest ratio between used feedstuff and produced milk) is the key driver for significantly reducing the level of emissions in dairy farms. In both farm groups and in the two periods, the efficient farms show almost the same level of emissions per kg ECM (1,17 kg CO2-eq) in comparison with intensive farms (1,13 kg CO2-eq), and at the same time a by far lowest level of emissions related to the production surface (9,9 vs. 13,9 t CO2-eq/ha). Concerning the economic performances, it could be observed that in the years 2017, 2018 and 2019, the intensive farms (we define intensity in the first place in terms of produced milk pro ha) reached a higher profit (incomes minus costs, only consideration for subsidies) than the efficient farms (4,8 vs. 2,6 €-cent/kg ECM), in contradiction with the observation of the years 2014, 2015 and 2015 (1,5 vs. 3,7 €-cent/kg ECM). The most important reason for this divergent behavior was a change in income and cost structure in the considered periods. In the last period (2017, 2018 and 2019), the milk price was considerably higher than in the previous period, and the production costs were lower. This was of advantage for intensive farms, which produce the highest quantity of milk with a high amount of production means. In the period 2014, 2015 and 2016, with lower milk prices but comparable production costs, the advantage was with efficient farms. In conclusion, we expect that in the next future, when especially the production costs will presumably be much higher than in the last years, the profitableness of dairy farming will decrease. In this case, we assume that efficient farms will provide not only an ecologically but also an economically better performance than production-intensive farms. High milk prices and low production costs are no good incentives for carbon-smart farming.

Keywords: efficiency, intensity, dairy, emissions, prices, costs

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Authors: R. S. Dinesh Madhavan, M. Logaraj

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Background: Recent studies have documented an increase in the risk of cardiovascular diseases (CVD) and a high rate of progression to hypertension in persons with pre hypertension. The risk factors for the growing burden of cardiovascular diseases especially hypertension, diabetes, overweight or obesity and waist hip ratio are increasing. Much study has not been done on cardiovascular risk factors associated with blood pressure (BP) among college students in Indian population. Objectives: The objective of our study was to estimate the prevalence of prehypertension among male students and to assess the association between prehypertension and risk factors for cardiovascular diseases. Material and Methods: A cross-sectional study was conducted among students of a university situated in the suburban area of Chennai. A total of 403 students was studied which included 200 medical and 203 engineering students. The information on selected socio-demographic variables were collected with the help of pre tested structured questionnaire. Measurements of height, weight, blood pressure and postprandial blood glucose were carried out as per standard procedure. Results: The mean age of the participants was 19.56 ± 1.67years. The mean systolic and diastolic blood pressure were 125.80±10.03 mm of Hg and 78.96 ±11.75mm of Hg. The average intake of fruits and vegetable per week were 4.34 ±3.47days and 6.55±4.39 days respectively. Use of smoke and smokeless tobacco were 27.3% and 3% respectively. About 30.3% of the students consume alcohol. Nearly 45.9 % of them did not practice regular exercise. About 29 % were overweight and 5.7% were obese, 24.8% were with waist circumference above 90 centimeters. The prevalence of pre hypertension and hypertension was 49.6% and 19.1% among male students. The prevalence of pre hypertension was higher in medical students (51.5%) compared to engineering students (47.8%). Higher risk of being pre hypertensive were noted above the age of 20 years (OR=4.32), fruit intake less than 3 days a week (OR= 1.03), smokers (OR= 1.13), alcohol intake (OR=1.56), lack of physical exercise (OR=1.90), BMI of more than 25 kg/m2 (OR=1.99). But statistically significant difference was noted between pre hypertensive and normotensive for age (p<0.0001), lack of physical exercise (p=0.004) and BMI (p=0.015). Conclusion: In conclusion nearly half of the students were pre hypertensive. Higher prevalence of smoking, alcohol intake, lack of physical exercise, overweight and increased waist circumference and postprandial blood sugar more than 140 mg/dl was noted among pre-hypertensive compared to normotensive.

Keywords: cardiovascular diseases, prehypertension, risk factors, undergraduate Students

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Authors: Toka M. Abufarag

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This research primarily studies the correlation between the existence of different spatial factors in relation to the perception of females towards safely participating in the labor force within selected areas of economic bustle in Historic Cairo. This research measures the following independent variables: (1) perception regarding spatial safety on the street as controlled by street network, (2) vegetation as a facilitator and inhibitor of feeling safe in public places, and (3) outdoor lighting; in relation to the following dependent variable: the perception of females towards safely participating in the labor force in Historic Cairo. The objective of this research lies within adding to the design guidelines of urban design and planning in terms of design recommendations, making them more inclusive, especially those dealing with conserving and enhancing the built environment of old and historic cities. It is hypothesized that a balanced male-to-female ratio in terms of street activity, increased visibility of street in terms of its volume, a decrease in street obstacles, creation of open sighted vegetation, and increased visibility due to proper lighting will show up as positive response relating to the female perception of safety. The site chosen as an area to host this exercise of data collection is Al-Ataba. The site is within the borders of Historic Cairo and was chosen for two reasons: firstly, it provides a major source of economic bustle in Historic Cairo; and secondly, it hosts retail economic activities. This is a cross-sectional study. The data collected will consist of three parts: (1) observations by the researcher regarding the percentage of female participation, as well as perception of females on site, (2) interviews with women working on-site regarding the percentage of female participation, as well as their perception on participating, and (3) an anonymous online survey that studies the perception of a random sample of women towards the site as a place to exist in. The survey will aid in producing design recommendations on how to design an open 'souk' that suits women’s perception of a safe space.

Keywords: urban design, women empowerment, safety perception, street markets, historic Cairo

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Authors: Rebecca M. Dagger, Katy Hadgraft, Matthew Teggart, Peter Angell

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Background: There is a growing body of evidence that demonstrates the association between sedentary behaviour, cardiometabolic risk and all-cause mortality. Since full time working adults spend approximately 8 hours per day in the workplace, interventions to reduce sedentary behaviour at work may alleviate some of the negative health outcomes associated with sedentary behaviour. The aims of this pilot study were to assess the impacts of using a Sit-Stand workstation on markers of cardiometabolic health in a cohort of desk workers. Methods: Twenty eight participants were recruited and randomly assigned to a control (n=5 males, 9 females, mean age 37 years ± 9.4 years) or intervention group (n= 5 males, 9 females, mean age 42 years ± 12.7 years). All participants attended the labs on 2 occasion’s pre and post intervention, following baseline measurements the intervention participants had the Sit Stand Workstations (Ergotron, USA) installed for a 10 week intervention period. The Sit Stand workstations allow participants to stand or sit at their usual workstation and participants were encouraged to the use the desk in a standing position at regular intervals throughout the working day. Cardiometabolic risk markers assessed were body mass, body composition (using bio impedance analysis; Tanita, Tokyo), fasting blood Total Cholesterol (TC), lipid profiles (HDL-C, LDL-C, TC: HDL-C ratio), triglycerides and fasting glucose (Cholestech LDX), resting systolic and diastolic blood pressure and resting heart rate. ANCOVA controlling for baseline values was used to assess the group difference in changes in risk markers between pre and post intervention. Results: The 10 week intervention was associated with significant reductions in some cardiometabolic risk factors. There were significant group effects on change in body mass (F (1,25)=5.915, p<0.05), total body fat percentage (F(1,25)=12.615, p<0.01), total fat mass (F (1,25)=6.954, p<0.05), and systolic blood pressure (F (1,25)=5.012, p<0.05). There were no other significant group effects on changes in other cardiometabolic risk markers. Conclusion: This pilot study highlights the importance of reducing sedentary behaviour in the workplace for reduction in cardiometabolic risk markers. Further research is required to support these findings.

Keywords: sedentary behaviour, caridometabolic risk, evidence, risk makers

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Authors: Muhammad Hassan, Kemal Celebi

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Developing a highly efficient electrochromic energy storage device with sufficient color fluctuation and significant electrochemical performance is highly desirable for practical energy-saving applications. Here, to achieve a highly stable material with a large electrochemical storage capacity, a W₁₈O₄₉ NW/Ti₃C₂Tₓ composite has been fabricated and deposited on a pre-assembled Ag and W₁₈O₄₉ NW conductive network by Langmuir-Blodgett technique. The resulting hybrid electrode composed of 15 layers of W₁₈O₄₉ NW/Ti₃C₂Tₓ exhibits an areal capacitance of 125 mF/cm², with a fast and reversible switching response. An optical modulation of 98.2% can be maintained at a current density of 5 mAcm⁻². Using this electrode, we fabricated a bifunctional symmetric electrochromic supercapacitor device having an energy density of 10.26 μWh/cm² and a power density of 0.605 mW/cm², with high capacity retention and full columbic efficiency over 4000 charge-discharge cycles. Meanwhile, the device displays remarkable electrochromic characteristics, including fast switching time (5 s for coloring and 7 s for bleaching) and a significant coloration efficiency of 116 cm²/C with good optical modulation stability. In addition, the device exhibits remarkable mechanical flexibility and fast switching while being stable over 100 bending cycles, which is promising for real-world applications.

Keywords: MXene, nanowires, supercapacitor, ion diffusion, electrochromic, coloration efficiency

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Authors: Khemakhem Nahed, Hammami Fatma, Trabelsi Houaida, Neji Sourour, Sellami Hayet, Makni Fattouma, Turki Hamida, Ayadi Ali

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Dermatophytoses are considered a public health problem and represent 10% of dermatological consultations in our region. Their epidemiology is influenced by various factors, such as lifestyle, human migration patterns, changes in the environment and the host relationship. The understanding of epidemiology has a major impact on their prevention and treatment. The aim of the study is to determine the prevalence pattern of aetiological agents and to describe the clinical characteristics of dermatophytoses between 1999 and 2019. Out of 65 059 subjects suspected to have superficial mycoses, 36 220 (55.67%) were affected with dermatophytoses. The mean age was 40.1 years (range: 10 days to 99 years). The sex ratio was 0.8. Our patients were from urban regions in 80.9% of cases. The most common type of infection was onychomycosis (42.64%), followed by tinea pedis (20.8%), intertrigo (18.3%), tinea corporis (8.48%) and tinea capitis (7.87%). The most isolated dermatophyte was Trichophyton rubrum (76.5%), followed by T. mentagrophytes complex (6.3%), Microsporum canis (5.8%), T. violaceum (5.3%), T. verrucosum (0.83%) and Epidermophyton floccosum (0.3%). Zoophilic agents have become more prevalent and their frequency has been increased from 6.46% in 1999 to 13% in 2019. It is interesting to note that M. canis has been on the rise since 2010 and it was the first etiological agent of tinea capitis (48%), while infections caused by T. violaceum continued to decrease from 1999 (16.2%) to 2019 (4.7%). Other dermatophytes have been rarely isolated: T. tonsurans (9 cases), T. schoenleinii (3 cases), T. soudanense (2 cases), M. fulvum (1 case), M. audouinii (1 case) and M. ferrugineum (2 cases).T. mentagrophytes var. quinckeanum was isolated from an inflammatory tinea capitis lesion in an a-3-year-old girl. T. mentagrophytes var. erinacei was isolated from the first case of tinea manuum, in-a-10-year-old girl. The same fungus was isolated from the hair and scales of the hedgehog. Our study showed significant changes in the dermatophytes spectrum in our region. The prevalence of zoophilic species increased in recent years due to people's behavioral changes with the adoption of pets and animal husbandry in urban settings. Molecular methods are often crucial that help us to refine the identification strains of dermatophytes and to identify their origin of the contamination.

Keywords: dermatophytoses, PCR-sequencing, spectrum, Sfax, Tunisia

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Authors: Yemane Hailu Fissuh, Zhongzhan Zhang

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In biomedical researches and randomized clinical trials, the most commonly interested outcomes are time-to-event so-called survival data. The importance of robust models in this context is to compare the effect of randomly controlled experimental groups that have a sense of causality. Causal estimation is the scientific concept of comparing the pragmatic effect of treatments conditional to the given covariates rather than assessing the simple association of response and predictors. Hence, the causal effect based semiparametric transformation model was proposed to estimate the effect of treatment with the presence of possibly time-varying covariates. Due to its high flexibility and robustness, the semiparametric transformation model which shall be applied in this paper has been given much more attention for estimation of a causal effect in modeling left-truncated and right censored survival data. Despite its wide applications and popularity in estimating unknown parameters, the maximum likelihood estimation technique is quite complex and burdensome in estimating unknown parameters and unspecified transformation function in the presence of possibly time-varying covariates. Thus, to ease the complexity we proposed the modified estimating equations. After intuitive estimation procedures, the consistency and asymptotic properties of the estimators were derived and the characteristics of the estimators in the finite sample performance of the proposed model were illustrated via simulation studies and Stanford heart transplant real data example. To sum up the study, the bias of covariates was adjusted via estimating the density function for truncation variable which was also incorporated in the model as a covariate in order to relax the independence assumption of failure time and truncation time. Moreover, the expectation-maximization (EM) algorithm was described for the estimation of iterative unknown parameters and unspecified transformation function. In addition, the causal effect was derived by the ratio of the cumulative hazard function of active and passive experiments after adjusting for bias raised in the model due to the truncation variable.

Keywords: causal estimation, EM algorithm, semiparametric transformation models, time-to-event outcomes, time-varying covariate

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Authors: Sima Aznavi, Poria Fajri, Hanif Livani

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Smart homes are small energy systems which may be equipped with renewable energy sources, storage devices, and loads. Energy management strategy plays a main role in the efficient operation of smart homes. Effective energy scheduling of the renewable energy sources and storage devices guarantees efficient energy management in households while reducing the energy imports from the grid. Nevertheless, despite such strategies, independently day ahead energy schedules for multiple households can cause undesired effects such as high power exchange with the grid at certain times of the day. Therefore, the interactions between multiple smart home day ahead energy projections is a challenging issue in a smart grid system and if not managed appropriately, the imported energy from the power network can impose additional burden on the distribution grid. In this paper, a central energy management strategy for a network consisting of multiple households each equipped with renewable energy sources, storage devices, and Plug-in Electric Vehicles (PEV) is proposed. The decision-making strategy alongside the smart home energy management system, minimizes the energy purchase cost of the end users, while at the same time reducing the stress on the utility grid. In this approach, the smart home energy management system determines different operating scenarios based on the forecasted household daily load and the components connected to the household with the objective of minimizing the end user overall cost. Then, selected projections for each household that are within the same cost range are sent to the central decision-making system. The central controller then organizes the schedules to reduce the overall peak to average ratio of the total imported energy from the grid. To validate this approach simulations are carried out for a network of five smart homes with different load requirements and the results confirm that by applying the proposed central energy management strategy, the overall power demand from the grid can be significantly flattened. This is an effective approach to alleviate the stress on the network by distributing its energy to a network of multiple households over a 24- hour period.

Keywords: energy management, renewable energy sources, smart grid, smart home

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Authors: Nicola Menga, Giuseppe Carbone

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Although contact mechanics has been widely focused on the study of contacts between half-space, it has been recently pointed out that in presence of finite thickness elastic layers the results of the contact problem show significant difference in terms of the main contact quantities (e.g. contact area, penetration, mean pressure, etc.). Actually, there exist a wide range of industrial application demanding for this kind of studies, such as seals leakage prediction or pressure-sensitive coatings for electrical applications. In this work, we focus on the contact between a rigid profile and an elastic layer of thickness h confined under two different configurations: rigid constrain and applied uniform pressure. The elastic problem at hand has been formalized following Green’s function method and then numerically solved by means of a matrix inversion. We study different contact conditions, both considering and neglecting adhesive interactions at the interface. This leads to different solution techniques: Adhesive contacts equilibrium solution is found, in term of contact area for given penetration, making stationary the total free energy of the system; whereas, adhesiveless contacts are addressed defining an equilibrium criterion, again on the contact area, relying on the fracture mechanics stress intensity factor KI. In particular, we make the KI vanish at the edges of the contact area, as peculiar for adhesiveless elastic contacts. The results are obtained in terms of contact area, penetration, and mean pressure for both adhesive and adhesiveless contact conditions. As expected, in the case of a uniform applied pressure the slab turns out much more compliant than the rigidly constrained one. Indeed, we have observed that the peak value of the contact pressure, for both the adhesive and adhesiveless condition, is much higher for the rigidly constrained configuration than in the case of applied uniform pressure. Furthermore, we observed that, for little contact area, both systems behave the same and the pull-off occurs at approximately the same contact area and mean contact pressure. This is an expected result since in this condition the ratio between the layers thickness and the contact area is very high and both layer configurations recover the half-space behavior where the pull-off occurrence is mainly controlled by the adhesive interactions, which are kept constant among the cases.

Keywords: contact mechanics, adhesion, friction, thick layer

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Authors: Behcet Al, Mustafa Bogan, Mehmet Murat Oktay, Suat Zengin, Hasan Bayram

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Objective: In the last two decades there is a strong scientific interest regarding the role of aerosols for the Earth’s climate and associated changes. Aerosol particles are very important to the Earth-atmosphere climate system playing a crucial role in cloud and precipitation processes, air quality and climate. Here, we evaluated the association between saharran dust and emergency department admission, hospitalization, and mortality. Method: The records of admission to emergency department of Gaziantep University and the dust stroms of 31 months were studied. Patients admitted to ED at dust strom with chronic obstructive lung disease (COLD), asthma bronchiale (AB), serebrovascular events (SVE), acute myocardial infarction (AMI), stabile and unstabile angina pectoris (SAAP andUSAP); and the days with and without dust stroms were included. The study was realized from March 2010 to October 2012. The admission of three days before strom (group 1), during strom days (group 2) and three days after strom (group 3) were determined. The mean level of dust PM10 particulate was calculated, and the results were compared. Results: 5864 patients with chronic obstructive lung disease, asthma bronchiale, serebrovascular events, acute myocardial infarction, stabile and unstabile angyina pectoris admitted during the days with and without dust stroms. 28 dust stroms ocurred during 31 months. The totaliy of stroms continiued 78 days. Of admissions, 35.5% (n=2075) were in group1, 29.8% (n=1746) in group 2, and 34.8% (n=2043) were in group 3. The mean of PM10 for groups (group 1, 2 and 3) were 78.53 mg/m3 (range 19–276) particulate, 108.7 mg/m3 (range 34–631) particulate, and 60.9 mg/m3 (range 17–160) particulate respectively. The mean admission per a day for groups were 24.86, 22.55, and 24.50 respectively. The mortality was 12 in group 1, 12 in group 2, and 17 in grou 3. The hospitalization ratio for groups were 0.24, 0.27, and 0.27 respectively. Conclusion: However, the mean level of PM10 particulate for groups 2 (in dust strom days) is significantly higher (p=0.001) than the days before (group 1) and after (group 3) dust stroms, the mean admissions/day, hostilalization and mortality related to deseases (COLD, AB, SVE, AMI, SAAP andUSA) for group 2 is lower than the group 1 and group 3.

Keywords: Saharran dust, PM10 particulate, emergency department admission, mortality

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Authors: O. A. Adebiyi, A. O. Oni, A. O. K. Adeshehinwa, I. O. Adejumo

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In forty nine (49) days, twenty four (24) growing pigs (Landrace x Large white) with an average weight of 17 ±2.1kg were allocated to four experimental treatments T1 (dry mash without probiotics), T2 (wet feed without probiotics), T3 (dry mash + Saccaromyces cereviseae probiotics) and T4 (wet feed + Saccaromyces cereviseae probiotics) which were replicated three times with two pigs per replicate in a completely randomised design. The basal feed (dry feed) was formulated to meet the nutritional requirement of the animal with crude protein of 18.00% and metabolisable energy of 2784.00kcal/kgME. Growth pattern, faecal microbial load and behavioural activities (eating, drinking, physical pen interaction and frequency of visiting the drinking troughs) were accessed. Pigs fed dry mash without probiotics (T1) had the highest daily feed intake among the experimental animals (1.10kg) while pigs on supplemented diets (T3 and T4) had an average daily feed intake of 0.95kg. However, the feed conversion ratio was significantly (p < 0.05) affected with pigs on T3 having least value of 6.26 compared those on T4 (wet feed + Saccaromyces cereviseae) with means of 7.41. Total organism counts varied significantly (p < 0.05) with pigs on T1, T2, T3 and T4 with mean values of 179.50 x106cfu; 132.00 x 106cfu; 32.00 x 106cfu and 64.50 x 106cfu respectively. Coliform count was also significantly (p < 0.05) different among the treatments with corresponding values of 117.50 x 106cfu; 49.00 x 106cfu, 8.00 x 106cfu for pigs in T1, T2 and T4 respectively. The faecal Saccaromyces cereviseae was significantly lower in pigs fed supplemented diets compared to their counterparts on unsupplemented diets. This could be due to the inability of yeast organisms to be voided easily through feaces. The pigs in T1 spent the most time eating (7.88%) while their counterparts on T3 spent the least time eating. The corresponding physical pen interaction times expressed in percentage of a day for pigs in T1, T2, T3 and T4 are 6.22%, 5.92%, 4.04% and 4.80% respectively. These behavioural responses exhibited by these pigs (T3) showed that little amount of dry feed supplemented with probiotics is needed for better performance. The water intake increases as a result of the dryness of the feed with consequent decrease in pen interaction and more time was spent resting than engaging in other possible vice-habit like fighting or tail biting. Pigs fed dry feed (T3) which was supplemented with Saccaromyces cereviseae probiotics had a better overall performance, least faecal microbial load than wet fed pigs either supplemented with Saccaromyces cereviseae or non-supplemented.

Keywords: behaviour, feed forms, feed utilization, growth, microbial

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Authors: Haileyesus Tessema Alemneh, Abiyu Enyew Molla, Oluwole Daniel Makinde

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Introduction: Faba bean is one of the most important grown plants worldwide for humans and animals. Several biotic and abiotic elements have limited the output of faba beans, irrespective of their diverse significance. Many faba bean pathogens have been reported so far, of which the most important yield-limiting disease is chocolate spot disease (Botrytis fabae). The dynamics of disease transmission and decision-making processes for intervention programs for disease control are now better understood through the use of mathematical modeling. Currently, a lot of mathematical modeling researchers are interested in plant disease modeling. Objective: In this paper, a deterministic mathematical model for chocolate spot disease (CSD) on faba bean plant with an optimal control model was developed and analyzed to examine the best strategy for controlling CSD. Methodology: Three control interventions, quarantine (u2), chemical control (u3), and prevention (u1), are employed that would establish the optimal control model. The optimality system, characterization of controls, the adjoint variables, and the Hamiltonian are all generated employing Pontryagin’s maximum principle. A cost-effective approach is chosen from a set of possible integrated strategies using the incremental cost-effectiveness ratio (ICER). The forward-backward sweep iterative approach is used to run numerical simulations. Results: The Hamiltonian, the optimality system, the characterization of the controls, and the adjoint variables were established. The numerical results demonstrate that each integrated strategy can reduce the diseases within the specified period. However, due to limited resources, an integrated strategy of prevention and uprooting was found to be the best cost-effective strategy to combat CSD. Conclusion: Therefore, attention should be given to the integrated cost-effective and environmentally eco-friendly strategy by stakeholders and policymakers to control CSD and disseminate the integrated intervention to the farmers in order to fight the spread of CSD in the Faba bean population and produce the expected yield from the field.

Keywords: CSD, optimal control theory, Pontryagin’s maximum principle, numerical simulation, cost-effectiveness analysis

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Authors: O. Casasayas, M. Vigo, R. Navarro, P. Ragazzi, P. Alvarez, A. Perez-Bellmunt

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Introduction: The blood flow restriction training (BFR) is a method of muscle training that allows increasing the stress of muscle tissue to enhance the muscle cross-section and strength. This type of training has clear benefits in the rehabilitation field since it can improve muscle strength using low mechanical loads. The aim of this study is to know in which knee pathologies BFR has been used, what methodology was used and what were the obtained results. Study design: We performed a systematic literature search using strategies for the concepts of “blood flow restriction OR blood flow restriction training AND knee” in Medline. Articles were screened by authors and included if they used the blood flow restriction training in pathology of the knee. Results: The pathology more frequently treated by BFR was knee osteoarthritis and the variables most analyzed were strength and pain. The vascular occlusion used was 80% in the major part of studies. The groups of BFR obtained an increase of strength with less pain but not always the results are statistically significant. The evidence levels are poor in the high number of studies because in some cases there is not a control group or the evaluators were not blinded. Conclusion: The use of BFR is useful to improve muscle strength in knee pathology since it does not increase the pain, but more studies are needed to see (comprehend) if this type of treatment obtains better results than a conventional therapy. No studies have been found that compare the different occlusion effects in both the strength improvement and the pain reduction. Neither studies that analyse the effects of BFR on the muscle contractile parameters have been found.

Keywords: blood flow restriction training, knee, arthroscopy knee, physical therapy

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Authors: Hossein Mottaghi T., Amir R. Masoodi

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This study presents a finite curved element for analyzing the static behavior of curved beams within the elastic range. The objective is to enhance accuracy while reducing the number of elements by incorporating first-order shear deformations of Timoshenko beams. Initially, finite element formulations are developed by considering polynomial initial functions for axial, shear, and rotational deformations for a three-node element. Subsequently, nodal interpolation functions for this element are derived, followed by the construction of the element stiffness matrix. To enable the utilization of the stiffness matrix in the static analysis of curved beams, the constructed matrix in the local coordinates of the element is transformed to the global coordinate system using the rotation matrix. A numerical benchmark example is investigated to assess the accuracy and effectiveness of this method. Moreover, the influence of spring stiffness on the rotation of the endpoint of a clamped beam is examined by substituting each support reaction of the beam with a spring. In the parametric study, the effect of the central angle of the beam on the rotation of the beam's endpoint in a cantilever beam under a concentrated load is examined. This research encompasses various mechanical, geometrical, and boundary configurations to evaluate the static characteristics of curved beams, thus providing valuable insights for their analysis and examination.

Keywords: curved beam, finite element method, first-order shear deformation theory, elastic support

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Authors: Izian Abd. Karim, Kachalla Mohammed, Nora Farah Abd Aznieta Aziz, Law Teik Hua

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The economic use and ease of construction of profiled deck composite slab is marred with the complex and un-economic strength verification required for the serviceability and general safety considerations. Beside these, albeit factors such as shear span length, deck geometries and mechanical frictions greatly influence the longitudinal shear strength, that determines the ultimate strength of profiled deck composite slab, and number of methods available for its determination; partial shear and slope-intercept are the two methods according to Euro-code 4 provision. However, the complexity associated with shear behavior of profiled deck composite slab, the use of these methods in determining the load carrying capacities of such slab yields different and conflicting values. This couple with the time and cost constraint associated with the strength verification is a source of concern that draws more attentions nowadays, the issue is critical. Treating some of these known shear strength influencing factors as random variables, the load carrying capacity violation of profiled deck composite slab from the use of the two-methods defined according to Euro-code 4 are determined using reliability approach, and comparatively studied. The study reveals safety values from the use of m-k method shows good standing compared with that from the partial shear method.

Keywords: composite slab, first order reliability method, longitudinal shear, partial shear connection, slope-intercept

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Authors: Lina Yang, Mao Wen, Jianhong Chen, Kan Zhang

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Molybdenum disulfide (MoS₂) represents a highly sought lubricant for reducing friction based on intrinsic layered structure, but for this reason, practical applications have been greatly restricted due to the fact that its low hardness would cause severe wear. Here, a novel TiMoN/MoSₓ composite coatings with TiMoN solid solution grains embedded into MoSₓ-based amorphous matrix has been successfully designed and synthesized, through magnetron co-sputtering technology. Desirably, in virtue of such special microstructure, superhardness and excellent toughness can be well achieved, along with an ultra-low wear rate at ~2×10⁻¹¹ mm³/Nm in the air environment, simultaneously, low friction at ~0.1 is maintained. It should be noted that this wear level is almost two orders of magnitude lower than that of pure TiN coating, and is, as we know, the lowest wear rate in dry sliding. Investigations of tribofilm reveal that it is amorphous MoS₂ in nature, and its formation arises directly from the MoSₓ amorphous matrix. Which contributes to effective lubrication behavior, coupled with excellent mechanical performances of such composite coating, exceptionally low wear can be guaranteed. The findings in this work suggest that the special composite structure makes it possible for the synthesis of super-hard and super-durable lubricative coating, offering guidance to synthesize ultrahigh performance protective coating for industrial application.

Keywords: hardness, MoS₂-containing composite coatings, toughness, tribological properties

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Authors: Haftay Abraha Tadesse, Dawit Gebreegziabiher Hagos, Atsebaha Gebrekidan Kahsay, Mahumd Abdulkader

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Background: Salmonella species and Escherichia coli (E. coli) are important foodborne pathogens affecting humans and animals. They are among the most important causes of infection that are associated with the consumption of contaminated food. This study was aimed to determine the prevalence, antimicrobial susceptibility patterns and associated risk factors for Salmonella species and E. coli in raw meat from butchery houses of Mekelle, Northern Ethiopia. Method: A cross-sectional study was conducted from January to December 2019. Socio-demographic data and risk factors were collected using a predesigned questionnaire. Meat samples were collected aseptically from the butchery houses and transported using icebox to Mekelle University, College of Veterinary Sciences for the isolation and identification of Salmonella species and E. coli. Antimicrobial susceptibility patterns were determined using Kirby disc diffusion method. Data obtained were cleaned and entered into Statistical Package for the Social Sciences version 22 and logistic regression models with odds ratio were calculated. P-value < 0.05 was considered as statistically significant. Results: A total of 153 out of 384 (39.8%) of the meat specimens were found to be contaminated. The contamination of Salmonella species and E. coli were 15.6% (n=60) and 20.8%) (n=80), respectively. Mixed contamination (Salmonella species and E. coli) was observed in 13 (3.4 %) of the analyzed. Poor washing hands regularly (AOR = 8.37; 95% CI: 2.75-25.50) and not using gloves during meat handling (AOR=11. 28; 95% CI:(4.69 27.10) were associated with overall bacterial contamination. About 100% of the tested isolates were sensitive to ciprofloxacin, gentamicin, Co trimoxazole , sulphamethoxazole, ceftriaxone, and trimethoprim and ciprofloxacin, gentamicin, and norfloxacine of E. coli and Salmonella species, respectively, while the resistance of amoxyclav_amoxicillin and erythromycin were both isolated bacteria species. The overall multidrug resistance pattern for Salmonella and E. coli were 51.4% (n=19) and 31.8% (14), respectively. Conclusion: Of the 153 (153/384) contaminated raw meat, 60 (15.6%) and 80 (20.8%) were contaminated by Salmonella species and E. coli, respectively. Poor handwashing practice and not using glove during meat handling showed a significant association with bacterial contamination. Multidrug-resistant showed in Salmonella species, and E. coli were 19 (51.4%) and 14 (31.8%), respectively.

Keywords: antimicrobial susceptibility test, butchery houses, E. coli, raw meat, salmonella species

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Authors: Ehsan Asgari, Meisam Afazeli, Nezhla Attarchian

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Post-earthquake fire is considered as a major threat in seismic areas. After an earthquake, fire is possible in structures. In this research, the effect of post-earthquake fire on steel moment frames with and without fireproofing coating is investigated. For this purpose, finite element method is employed. For the verification of finite element results, the results of an experimental study carried out by previous researchers are used, and the predicted FE results are compared with the test results, and good agreement is observed. After ensuring the accuracy of the predictions of finite element models, the effect of post-earthquake fire on the frames is investigated taking into account the parameters including the presence or absence of fire protection, frame design assumptions, earthquake type and different fire scenario. Ordinary fire and post-earthquake fire effect on the frames is also studied. The plastic hinges induced by earthquake in the structure are determined in the beam to the column connection and in panel zone. These areas should be accurately considered when providing fireproofing coatings. The results of the study show that the occurrence of fire beside corner columns is the most damaging scenario that results in progressive collapse of structure. It was also concluded that the behavior of structure in fire after a strong ground motion is significantly different from that in a normal fire.

Keywords: post earthquake fire, moment frame, finite element simulation, coupled temperature-displacement analysis, fire scenario

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Authors: Yang-Ho Jang, Soon-Ok Jee, Hae-Chul Park, Jeong-Woo Kang, Byung-Jae So, Sung-Shik Shin, Kyu-Sung Ahn, Kwang-Jick Lee

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Introduction: Antibiotics have been used as feed additives for the growth promotion and performance in food-producing animals. However, the possibility of selection of antimicrobial resistance and the concerns of residue in animal products led to ban the use of antibiotics in farm animals at 2011 in Korea. This strategy is also adjusted to anticoccidial drugs soon but these are still allowed for the time being to use in a diet for the treatment and control for the enteric necrosis in poultry. Therefore substantial focus has been given to find alternatives to antimicrobial agents. Several phytogenic materials have been reported to have positive effects on coccidiosis. This study was to evaluate the effects on anti-coccidial effect of oregano oil based herb mixture on Eimeria spp. in poultry. Materials and Methods: A total of one day-old boiler chickens divided into six groups (each group=30 chkckens) were used in this study. The herbal mixture was fed with water freely as follows: two groups, one infected with Eimeria spp. and the other group served as controls without herbal mixture respectively; 0.2ml/L of oregano oil; 0.2ml/L of oregano oil and Sanguisorbae radix; 0.2ml/L of Sanguisorbae radix; last group was fed with dichlazuril diet as positive control. Sporulated Eimeria spp. was infected at 14 day-old. Following infection, survival rate, bloody diarrhea, OPG (oocyst per gram) and feed conversion ratios were determined. The experimental period was lasted for 4 weeks. Results: Herbal mixture feeding groups (Group 3,4,5) showed low feed conversion ratio comparing with negative control. Oregano oil group and positive control group recorded the highest survival rate. The grade of bloody diarrhea was scored 0 to 5. Herbal mixture feeding groups showed 2, 3 and 1 score respectively however, group 2 (infection and no-treatment) showed 4. OPG results in herbal mixture feeding group were 3 to 4 times higher than diclazuril diet feeding group. Conclusions: These results showed that oregano oil and Sanguisorbae radix mixture may have an anti-coccidial effect and also affect chick performance.

Keywords: anticoccidial effects, oregano oil based herb mixture, herbal mixture, antibiotics

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Authors: Zhiqiang Yan, Chen Fan, Yafei Wang, Beicheng Xia

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Urban lakes play an invaluable role in urban water systems such as flood control, water supply, and public recreation. However, over 38% of the urban lakes have suffered from severe eutrophication in China. Chlorine that could remarkably inhibit the growth of phytoplankton in eutrophic, has been widely used in the agricultural, aquaculture and industry in the recent past. However, little information has been reported regarding the effects of chlorine on the lake ecosystem, especially on the main aquatic species.To investigate the ecological response of main aquatic species and system stability to chlorine interference in shallow urban lakes, a mini system dynamic model was developed based on the competition and predation of main aquatic species and total phosphorus circulation. The main species of submerged macrophyte, phytoplankton, zooplankton, benthos, spiroggra and total phosphorus in water and sediment were used as variables in the model,while the interference of chlorine on phytoplankton was represented by an exponential attenuation equation. Furthermore, the eco-exergy expressing the development degree of ecosystem was used to quantify the complexity of the shallow urban lake. The model was validated using the data collected in the Lotus Lake in Guangzhoufrom1 October 2015 to 31 January 2016.The correlation coefficient (R), root mean square error-observations standard deviation ratio (RSR) and index of agreement (IOA) were calculated to evaluate accuracy and reliability of the model.The simulated values showed good qualitative agreement with the measured values of all components. The model results showed that chlorine had a notable inhibitory effect on Microcystis aeruginos，Rachionus plicatilis, Diaphanosoma brachyurum Liévin and Mesocyclops leuckarti (Claus).The outbreak of Spiroggra.spp. inhibited the growth of Vallisneria natans (Lour.) Hara, leading to a gradual decrease of eco-exergy and the breakdown of ecosystem internal equilibria. This study gives important insight into using chlorine to achieve eutrophication control and understand mechanism process.

Keywords: system dynamic model, urban lake, chlorine, eco-exergy

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Authors: A. M. Tiara, Sudipto Chakraborty, S. K. Pal

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Impinging jets and their different configurations are important from the viewpoint of the fluid flow characteristics and their influence on heat transfer from metal surfaces due to their complex flow characteristics. Such flow characteristics results in highly variable heat transfer from the surface, resulting in varying cooling rates which affects the mechanical properties including hardness and strength. The overall objective of the current research is to conduct a fundamental investigation of the heat transfer mechanisms for an impinging coolant jet. Numerical simulation of the cooling process gives a detailed analysis of the different parameters involved even though employing Computational Fluid Dynamics (CFD) to simulate the real time process, being a relatively new research area, poses many challenges. The heat transfer mechanism in the current research is actuated by jet cooling. The computational tool used in the ongoing research for simulation of the cooling process is ANSYS Workbench software. The temperature and heat flux distribution along the steel strip with the effect of various flow parameters on the heat transfer rate can be observed in addition to determination of the jet impingement patterns, which is the major aim of the present analysis. Modelling both jet and air atomized cooling techniques using CFD methodology and validating with those obtained experimentally- including trial and error with different models and comparison of cooling rates from both the techniques have been included in this work. Finally some concluding remarks are made that identify some gaps in the available literature that have influenced the path of the current investigation.

Keywords: CFD, heat transfer, impinging jets, numerical simulation

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Authors: Mohamed M. Diab, Fahmy E. Mohamed, Alaa Balbaa

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Background: Myofascial pain syndrome a common type of non-articular musculoskeletal pain, is a condition associated with regional pain and muscle tenderness characterized by the presence of hypersensitive nodules. Objectives: the purpose of this study is to compare between the effects of manual progressive ischemic pressure versus the effect of post isometric facilitation in the treatment of Rhomboid latent myofascial trigger points. Methods: six patients had participated in this study. Patients divided into two groups. Group A treated by manual progressive ischemic pressure and traditional physical therapy program. Group B treated by post isometric facilitation and traditional physical therapy program. Treatment program was for 6 sessions over two week’s period. Result: Statistical analysis revealed that there is no significant difference in post treatment from pretreatment in pain severity (VAS) in myofascial trigger points with Rhomboid muscles) and Pain pressure threshold (PPT) for tenderness at both groups (A,B). Conclusion: ischemic pressure technique appear to be no more effective than post isometric facilitation in treatment of rhomboids latent myofacial trigger point.

Keywords: Rhmoiboid trigger point, myofacila trigger point, ischemic pressure, post isometric facilitation

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Authors: Antoine Karam, Lotfi Khiari, Bruno Breton, Alfred Jaouich

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Anthropogenic sources of zinc (Zn), including industrial emissions and effluents, Zn–rich fertilizer materials and pesticides containing Zn, can contribute to increasing the concentration of soluble Zn at levels toxic to plants in acid sandy soils. The application of municipal sewage sludge or biosolids (MBS) which contain metal immobilizing agents on coarse-textured soils could improve the metal sorption capacity of the low-CEC soils. The purpose of this experiment was to evaluate the sorption of Zn in surface samples (0-15 cm) of six Quebec (Canada) soils amended with MBS (pH 6.9) from Val d’Or (Quebec, Canada). Soil samples amended with increasing amounts (0 to 20%) of MBS were equilibrated with various amounts of Zn as ZnCl2 in 0.01 M CaCl2 for 48 hours at room temperature. Sorbed Zn was calculated from the difference between the initial and final Zn concentration in solution. Zn sorption data conformed to the linear form of Freundlich equation. The amount of sorbed Zn increased considerably with increasing MBS rate. Analysis of variance revealed a highly significant effect (p ≤ 0.001) of soil texture and MBS rate on the amount of sorbed Zn. The average values of the Zn-sorption capacity of MBS-amended coarse-textured soils were lower than those of MBS-amended fine textured soils. The two sandy soils (86-99% sand) amended with MBS retained 2- to 5-fold Zn than those without MBS (control). Significant Pearson correlation coefficients between the Zn sorption isotherm parameter, i.e. the Freundlich sorption isotherm (KF), and commonly measured physical and chemical entities were obtained. Among all the soil properties measured, soil pH gave the best significant correlation coefficients (p ≤ 0.001) for soils receiving 0, 5 and 10% MBS. Furthermore, KF values were positively correlated with soil clay content, exchangeable basic cations (Ca, Mg or K), CEC and clay content to CEC ratio. From these results, it can be concluded that (i) municipal biosolids provide sorption sites that have a strong affinity for Zn, (ii) both soil texture, especially clay content, and soil pH are the main factors controlling anthropogenic Zn sorption in the municipal biosolids-amended soils, and (iii) the effect of municipal biosolids on Zn sorption will be more pronounced for a sandy soil than for a clay soil.

Keywords: metal, recycling, sewage sludge, trace element

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Authors: Sophio Kobauri, Tengiz Kantaria, Temur Kantaria, David Tugushi, Nina Kulikova, Ramaz Katsarava

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Polymeric disperse systems such as nanoparticles (NPs) are of high interest for numerous applications in contemporary medicine and nanobiotechnology to a considerable potential for treatment of many human diseases. The important technological advantages of NPs usage as drug carriers (nanocontainers) are their high stability, high carrier capacity, feasibility of encapsulation of both hydrophilic or hydrophobic substances, as well as a high variety of possible administration routes, including oral application and inhalation. NPs can also be designed to allow controlled (sustained) drug release from the matrix. These properties of NPs enable improvement of drug bioavailability and might allow drug dosage decrease. The targeted and controlled administration of drugs using NPs might also help to overcome drug resistance, which is one of the major obstacles in the control of epidemics. Various degradable and non-degradable polymers of both natural and synthetic origin have been used for NPs construction. One of the most promising for the design of NPs are amino acid-based biodegradable polymers (AABBPs) which can clear from the body after the fulfillment of their function. The AABBPs are composed of naturally occurring and non-toxic building blocks such as α-amino acids, fatty diols and dicarboxylic acids. The particles designed from these polymers are expected to have an improved bioavailability along with a high biocompatibility. The present work deals with a systematic study of the preparation of NPs by cost-effective polymer deposition/solvent displacement method using AABBPs. The influence of the nature and concentration of surfactants, concentration of organic phase (polymer solution), and the ratio organic phase/inorganic(water) phase, as well as of some other factors on the size of the fabricated NPs have been studied. It was established that depending on the used conditions the NPs size could be tuned within 40-330 nm. At the next step of this research was carried out an evaluation of biocompability and bioavailability of the synthesized NPs using a stable human cell culture line – A549. It was established that the obtained NPs are not only biocompatible but they stimulate the cell growth.

Keywords: amino acids, biodegradable polymers, bioavailability, nanoparticles

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Authors: Ghodratollah Rostami Paydar

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The Baba-Ali and Galali iron deposits are located in northwest Hamedan and the Iranian Sanandaj-Sirjan geological structural zone. The host rocks of these deposits are metavolcanosedimentary successions of Songhor stratigraphic series with permo-trriassic age. Field investigation, ore geometry, textures and structures and paragenetic sequence of minerals, all indicate that the ore minerals are crystallized in four stages: primary volcanosedimentary stage, secondary regional metamorphism with formation of ductile shear zones, contact metamorphism and metasomatism stage and the finally late hydrothermal mineralization within uplift and exposure. Totally 29 samples of sulfide, oxide-silicate and carbonate minerals of iron orees and gangue has been purified for stable isotope analysis. The isotope ratio data assure that occurrence of dynamothermal metamorphism in these areas typically involves a lengthy period of time, which results in a tendency toward isotopic homogenization specifically in O and H stable isotopes and showing the role of metamorphic waters in mineralization process. Measurement of δ34S (CDT) in first generation of pyrite is higher than another ones, so it confirms the volcanogenic origin of primary iron mineralization. δ13C data measurements in Galali carbonate country rocks show a marine origin. δ18O in magnetite and skarn forming silicates, δ18O and δ13C in limestone and skarn calcite and δ34S in sulphides are all consistent with the interaction of a magmatic-equilibrated fluid with Galali limestone, and a dominantly magmatic source for S. All these data imply skarn formation and mineralisation in a magmatic-hydrothermal system that maintained high salinity to relatively late stages resulting in the formation of the regional Na metasomatic alteration halo. Late stage hydrothermal quartz-calcite veinlets are important for gold mineralization, but the economic evaluation is required to detailed geochemical studies.

Keywords: iron, polygenetic, stable isotope, BabaAli, Galali

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Authors: John M. Frimpong, Matilda K. Owusu-Bio, Caleb Annan

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Business today is highly competitive, and the automobile industry is no exception. Therefore, it is necessary to determine the customer value and service quality measures that lead to customer satisfaction which in turn lead to customer loyalty. However, in the automobile industry, the role of logistics service support in these relationships cannot be undermined. It could be inferred that logistics service supports and its management has a direct correlation with customer service and or service quality. But this is not always the same for all industries. Therefore, this study was to investigate how automobile companies implement the concept of customer service through logistics service supports. In order to ascertain this, two automobile companies in Ghana were selected, and these are Toyota Ghana Limited and Mechanical Lloyd Company Ltd. The study developed a conceptual model to depict the study’s objectives from which questionnaires were developed from for data collection. Respondents were made up of customers and staff of the two companies. The findings of the study revealed that the automobile industry partly attributes their customer satisfaction to the customer value, service quality or customer value. It shows a positive relationship between logistics service supports and service quality and customer value. However, the results indicate that customer satisfaction is not predicted by logistics services. This implies that in the automobile industry, it is not always the case that when customer service is implemented through logistics service supports, it leads to customer satisfaction. Therefore, there is the need for all players and stakeholders in the automobile industry investigate other factors which help to increase customer satisfaction in addition to logistics service supports. It is recommended that logistics service supports should be geared towards meeting customer expectations and not just based on the organization’s standards and procedures. It is necessary to listen to the voice of the customer to tailor the service package to suit the needs and expectations of the customer.

Keywords: customer loyalty, customer satisfaction, customer service, customer value, logistics service supports

Procedia PDF Downloads 473