Search results for: micro injection moulding

Authors: Irina P. Starodubtseva, Aleksandr N. Pavlenko

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Quenching is a term generally accepted for the process of rapid cooling of a solid that is overheated above the thermodynamic limit of the liquid superheat. The main objective of many previous studies on quenching is to find a way to reduce the total time of the transient process. Computational experiments were performed to simulate quenching by a falling liquid nitrogen film of an extremely overheated vertical copper plate with a structured capillary-porous coating. The coating was produced by directed plasma spraying. Due to the complexities in physical pattern of quenching from chaotic processes to phase transition, the mechanism of heat transfer during quenching is still not sufficiently understood. To our best knowledge, no information exists on when and how the first stable liquid-solid contact occurs and how the local contact area begins to expand. Here we have more models and hypotheses than authentically established facts. The peculiarities of the quench front dynamics and heat transfer in the transient process are studied. The created numerical model determines the quench front velocity and the temperature fields in the heater, varying in space and time. The dynamic pattern of the running quench front obtained numerically satisfactorily correlates with the pattern observed in experiments. Capillary-porous coatings with straight and reverse orientation of crests are investigated. The results show that the cooling rate is influenced by thermal properties of the coating as well as the structure and geometry of the protrusions. The presence of capillary-porous coating significantly affects the dynamics of quenching and reduces the total quenching time more than threefold. This effect is due to the fact that the initialization of a quench front on a plate with a capillary-porous coating occurs at a temperature significantly higher than the thermodynamic limit of the liquid superheat, when a stable solid-liquid contact is thermodynamically impossible. Waves present on the liquid-vapor interface and protrusions on the complex micro-structured surface cause destabilization of the vapor film and the appearance of local liquid-solid micro-contacts even though the average integral surface temperature is much higher than the liquid superheat limit. The reliability of the results is confirmed by direct comparison with experimental data on the quench front velocity, the quench front geometry, and the surface temperature change over time. Knowledge of the quench front velocity and total time of transition process is required for solving practically important problems of nuclear reactors safety.

Keywords: capillary-porous coating, heat transfer, Leidenfrost phenomenon, numerical simulation, quenching

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Authors: M. R. Vaezi, R. Ghasemi, A. Akramizadeh

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Frequency stability of microgrids under islanded operation attracts particular attention recently. A new cooperative frequency control strategy based on centralized multi-agent system (CMAS) is proposed in this study. On this strategy, agents sent data and furthermore each component has its own to center operating decisions (MGCC). After deciding on the information, they are returned. Frequency control strategies include primary and secondary frequency control and disposal of multi-stage load in which this study will also provide a method and algorithm for load shedding. This could also be a big problem for the performance of micro-grid in times of disaster. The simulation results show the promising performance of the proposed structure of the controller based on multi agent systems.

Keywords: frequency control, islanded microgrid, multi-agent system, load shedding

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Authors: Sharareh Sharifi

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In this study, the crude extracts of Virgularia gustavina were examined as antibacterial, antifungal and anti-inflammatory agent. To assess inflammation, Xylene was applied to the ear of mice. The mice of the experimental group were fed with doses of 10 mg/kg, 20 mg/kg, and 40 mg/kg of lipid extract of chloroform and hexane as a separate group and then statistical analysis was performed on the results. Chloroform and hexane extracts of sea pen have strong anti-inflammatory effects even at low doses which is probably due to 54% arachidonic acid. Antibacterial and antifungal effects of hexane and chloroform extracts were measured with MIC and MBC methods and it is shown that chloroform extract has best activity against Staphylococcus aureus on 125 µg/ml doze in MIC method.

Keywords: sea pen (virgularia gustaviana), lipid extract, anti-inflammatory and anti-bacterial activities, fatty acid

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Authors: M. Tang, S. M. Wen, D. W. Liu

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This paper presents the influences on the entrainment of serpentines by grinding and reagents during copper–nickel sulfide flotation. The previous bench flotation tests were performed to extract the metallic values from the ore in Yunnan Mine, China and the relatively satisfied results with recoveries of 86.92% Cu, 54.92% Ni, and 74.73% Pt+Pd in the concentrate were harvested at their grades of 4.02%, 3.24% and 76.61 g/t, respectively. However, the content of MgO in the concentrate was still more than 19%. Micro-flotation tests were conducted with the objective of figuring out the influences on the entrainment of serpentines into the concentrate by particle size, flocculants or depressants and collectors, as well as visual observations in suspension by OLYMPUS camera. All the tests results pointed to the presences of both “entrapped-in” serpentines and its coating on the hydrophobic flocs resulted from strong collectors (combination of butyl xanthate, butyl ammonium dithophosphate, even after adding carboxymethyl cellulose as effective depressant. And fine grinding may escalate the entrainment of serpentines in the concentrate.

Keywords: serpentine, copper and nickel sulfides, flotation, entrainment

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Authors: Pooja Ichplani, Archna Kumar, Jessica Mayberry

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Community Video (CV) is a participatory medium that has immense potential to strengthen community communications and amplify the voice of people for their empowerment. By building capacities especially of marginalized community groups and providing a platform to freely voice their ideas, CV endeavours to bring about shifts towards more participatory, bottom up development processes and greater power in the hands of the people, especially the disadvantaged. In various parts of the world, among marginalized community groups, community video initiatives have become instrumental in facilitating micro-level, yet significant changes in communities. Video Volunteers (VV) is an organization that promotes community media and works towards providing disadvantaged communities with journalistic, critical thinking and creative skills they need for catalysing change in their communities. Working since 2002, VV has evolved a unique community media model fostering locally-owned and managed media production, as well as building people’s capacities to articulate and share their perspectives on the issues that matter to them – on a local and a global scale. Further, by integrating a livelihood aspect within its model, VV has actively involved people from poor marginalized communities and provided them a new tool for serving their communities whilst keeping their identities intact. This paper, based on a qualitative research, seeks to map the range of VV impacts in communities and provide an in-depth analysis of factors contributing to VV impacting change in communities. Study tools included content analysis of a longitudinal sample of impact videos produced, narratives of community correspondents using the Most Significant Change Technique (MSCT) and interviews with key informants. Using a multi-fold analysis, the paper seeks to gain holistic insights. At the first level, the paper profiles the Community Correspondents (CCs), spearheading change, and maps their personal and social context and their perceptions about VV in their personal lives. Secondly, at an organizational level, the paper maps the significance of impacts brought about in the CCs communities and their association, challenges and achievements while working with VV. Lastly, at the community level, it consists of analysis of the nature of impacts achieved and aspects influencing the same. Finally, the study critiques the functioning of Video Volunteers as a community media initiative using the tipping point theory emphasizing on the power of context that is constituted by their socio-cultural environment. It concludes how empowerment of its Community Correspondents, multifarious activities during pre and post video production, and other innovative mechanisms have enabled in center staging issues of marginalized communities and snowballing processes of change in communities.

Keywords: community media, empowerment, participatory communication, social change

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Authors: Darma Putra Sitepu, Dewi Larasati, Yohanes Wolter Hendrik George

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Sepsis is a life-threatening medical emergency frequently observed in intensive care unit (ICU). Surviving Sepsis Campaign in 2018 has recommended the administration of early vasopressor in the first hour of sepsis or septic shock but has not yet included de-resuscitation protocol. De-resuscitation in acute management of septic shock is where patient received active removal of accumulated fluid. It has been proposed by some studies and ongoing clinical trials. Here we present a case with early vasopressor and de-resuscitation. Male, 27 years old presenting to the emergency room with shortness of breath, altered mental status, and widespread blisters on his body and lips started a few hours prior, after receiving non-steroidal anti-inflammatory drug through intravenous injection. Patient was hypotensive, tachycardic, and tachypneic at admission, diagnosed with Steven Johnson Syndrome with Septic Shock. Patient received fluid resuscitation, early vasopressor, and diuresis agent aimed to actively remove fluid after the initial phase of resuscitation. Patient was admitted to ICU and progressively recovering. At day-10, patient was stabilized and was transferred to general ward. Early vasopressor and de-resuscitation are beneficial for the patient.

Keywords: sepsis, shock, de-resuscitation, vasopressor, fluid, case report

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Authors: Asmaa Mandour, Ramzia El-Bagary, Asmaa El-Zaher, Ehab Elkady

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Background: An UHPLC (ultra high performance liquid chromatography) method for the simultaneous determination of norfloxacin (NOR), metronidazole (MET) and tinidazole (TNZ) using monolithic column is presented. Purpose: The method is considered an environmentally friendly method with relatively low organic composition of the mobile phase. Methods: The chromatographic separation was performed using Phenomenex® Onyex Monolithic C18 (50mmx 20mm) column. An elution program of mobile phase consisted of 0.5% aqueous phosphoric acid : methanol (85:15, v/v). Where elution of all drugs was completed within 3.5 min with 1µL injection volume. The UHPLC method was applied for the stability indication of NOR in the presence of its acid degradation product ND. Results: Retention times were 0.69, 1.19 and 3.23 min for MET, TNZ and NOR, respectively. While ND retention time was 1.06 min. Linearity, accuracy, and precision were acceptable over the concentration range of 5-50µg mL-1for all drugs. Conclusions: The method is simple, sensitive and suitable for the routine quality control and dosage form assay of the three drugs and can also be used for the stability indication of NOR in the presence of its acid degradation product.

Keywords: antibacterial, monolithic cilumn, simultaneous determination, UHPLC

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Authors: Elham Farahmand, Fatimah Ibrahim, Samira Hosseini, Ivan Djordjevic, Leo. H. Koole

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Compositions of different molar ratios of polymethylmethacrylate-co-methacrylic acid (PMMA-co-MAA) were synthesized via free- radical polymerization. Polymer coated surfaces have been produced on silicon wafers. Coated samples were analyzed by atomic force microscopy (AFM). The results have shown that the roughness of the surfaces have increased by increasing the molar ratio of monomer methacrylic acid (MAA). This study reveals that the gradual increase in surface roughness is due to the fact that carboxylic functional groups have been generated by MAA segments. Such surfaces can be desirable platforms for fabrication of the biosensors for detection of the viruses and diseases.

Keywords: polymethylmethacrylate-co-methacrylic acid (PMMA-co-MAA), polymeric material, atomic force microscopy, roughness, carboxylic functional groups

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Authors: M. Palizvan, M. T. Abadi, M. H. Sadr

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Due to variations in damage mechanisms in the microscale, the behavior of fiber-reinforced composites is nonlinear and difficult to model. To make use of computational advantages, homogenization method is applied to the micro-scale model in order to minimize the cost at the expense of detail of local microscale phenomena. In this paper, the effective stiffness is calculated using the homogenization of nonlinear behavior of a composite representative volume element (RVE) containing fiber-matrix debonding. The damage modes for the RVE are considered by using cohesive elements and contacts for the cohesive behavior of the interface between fiber and matrix. To predict more realistic responses of composite materials, different random distributions of fibers are proposed besides square and hexagonal arrays. It was shown that in some cases, there is quite different damage behavior in different fiber distributions. A comprehensive comparison has been made between different graphs.

Keywords: homogenization, cohesive zone model, fiber-matrix debonding, RVE

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Authors: Benchalak Muangmeesri

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Glazes ceramics are ceramic materials produced through controlled crystallization of a parent glass. The great variety of compositions and the possibility of developing special micro structures with specific technological properties have allowed glass ceramic materials to be used in a wide range of applications. At the same time, glazes ceramics need to improvement in the mechanical and chemical properties of glazed. The pick and place station is equipped with a three-axis module. test piece housings placed on the vacuum are detected module picks up a test piece insert from the slide and places it on the test piece housing. Overall, glazes ceramics are compared with automatically and manually of speed and position control. The handling modules of automatic transfer are a new generation of high speed and precision then these color results from absorption and thickness than manual is also included.

Keywords: glaze, PID control, pick and place, ceramic

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Authors: Aziz Ibrahim Abdulla, Omar Mohanad Mahdi

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The objective of this paper is to explore the effect of incorporating Nano-Silica with Silica-fume in ferrocement mortar to enhancing mechanical properties of it. One type of Nano silica with average diameter size 23nm and silica fume have been used with two percentage (1%, 2% Nano silica and 5%, 10% silica fume per weight of cement) and w/c with / without superplasticizer was been calculated by flow test method. Also three sand: cement ratios have been used (1.5, 2.0 and 2.5) with max. Aggregate size 0.6mm in this study for reference and other mixtures. Results reveal adding Nano silica with silica fume to ferrocement mortar enhances its physical and mechanical properties such as compressive strength and flexural strength. The SEM pictures and density with absorption ratio demonstrate that Nano silica with silica fume contributes to enhancement of mortar through yielding denser, more compact and uniform mixtures.

Keywords: nano silica, ferrocement mortar, compresion strength, flexural strength

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Authors: Sh. Minapoor, S. Ajeli, M. Javadi Toghchi

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Non-crimp 3D orthogonal fabric composite is one of the textile-based composite materials that are rapidly developing light-weight engineering materials. The present paper focuses on geometric and micro mechanical modeling of non-crimp 3D orthogonal carbon fabric and composites reinforced with it for aerospace applications. In this research meso-finite element (FE) modeling employs for stress analysis in different load conditions. Since mechanical testing of expensive textile carbon composites with specific application isn't affordable, simulation composite in a virtual environment is a helpful way to investigate its mechanical properties in different conditions.

Keywords: woven composite, aerospace applications, finite element method, mechanical properties

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Authors: Sudhir Kumar Sharma, Abiy D. Woldetsadik, Mazin Magzoub, Ramesh Jagannathan

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It is well known that bioactive ceramics exhibit specific biological affinities, especially in the area of tissue re-generation. In this context, we report the development of an eminently scalable, novel, supercritical CO₂ based process for the fabrication of hierarchically porous 'soft' CaCO₃ scaffolds. Porosity at the macro, micro, and nanoscales was obtained through process optimization of the so-called 'coffee-ring effect'. Exposure of these CaCO₃ scaffolds to monocytic THP-1 cells yielded negligible levels of tumor necrosis factor-alpha (TNF-α) thereby confirming the lack of immunogenicity of the scaffolds. ECM protein treatment of the scaffolds showed enhanced adsorption comparable to standard control such as glass. In vitro studies using osteoblast precursor cell line, MC3T3, also demonstrated the cytocompatibility of hierarchical porous CaCO₃ scaffolds.

Keywords: supercritical CO2, CaCO3 scaffolds, coffee-ring effect, ECM proteins

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Authors: Reda Mankbadi

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There are several technologically-important flow situations in which there is a need to control the outcome of the fluid flow. This could include flow separation, drag, noise, as well as particulate separations, to list only a few. One possible approach is the passive control, in which the design geometry is changed. An alternative approach is the Active Flow Control (AFC) technology in which an actuator is imbedded in the flow field to change the outcome. Examples of AFC are pulsed jets, synthetic jets, plasma actuators, heating and cooling, Etc. In this work will present an overview of the development of this field. Some examples will include: Airfoil Noise Suppression: LES is used to simulate the effect of the synthetic jet actuator on controlling the far field sound of a transitional airfoil. The results show considerable suppression of the noise if the synthetic jet is operated at frequencies. Mixing Enhancement and suppression: Results will be presented to show that imposing acoustic excitations at the nozzle exit can lead to enhancement or reduction of the jet plume mixing. In a vertical takeoff of Aircraft or in Space Launch, we will present results on the effects of water injection on reducing noise, and on protect the structure and pay load from fatigue damage. Other applications will include airfoil-gust interaction and propulsion systems optimizations.

Keywords: aerodynamics, simulations, aeroacoustics, active flow control (AFC), Large-Eddy Simulations (LES)

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Authors: Tahmineh Hasanzadeh, Afshin Farahbakhsh

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There is some report about the hypoglycemic effect of Juglans rejia L. leaf in alloxan induced diabetic rats and hypoglycemic effect of its fruit peel administered intraperitoneally.In Iranian traditional medicine, septum of walnut shell (SWS) was recommended to reduce blood glucose. For this purpose, 41 male bulb/C mice 25-30 gm were divided into five groups. All the animals received IP injection of streptozotocin (STZ) (220 mg/kg). Two weeks later, the diabetic animals were received daily oral treatment of normal saline and aqueous extract of SWS (200, 400, 600 and 800 mg/kg) respectively for four weeks. Blood samples were taken from retro orbital sinus before the start of the experiment and repeated each two weeks. At the end of the experiment, the animals were sacrificed and the pancreatic tissues were fixed, prepared and stained by Hematoxylin-Eosin for light microscope studies. The results showed that in each group, the SWS extract reduced blood glucose in a long time (p < 0.05). metabolic extract in STZ- induced diabetic rats, which was accompanied by the hypoglycemic effect of leaf extract. However, this effect should be determined with scientific researches. Therefore, the aim of this study is to evaluate the effect of the aqueous extract of SWS on blood glucose and histopathological structure of pancreas.

Keywords: septum of walnut, blood glucose, pancreas, diabetes, walnut leaf, walnut peel, insulin

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Authors: Maryam Eskafi

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Purpose: Frequent referrals of the martyr offspring to The Martyr Foundation and studying divorce documents revealed the depth of family quarrels among the martyr families. For this reason, conducting the research of this type can be effective. Method: Research method is survey. Statistical population is the total of married offspring of the martyr living in Mashhad City of Iran. Data were gathered by using questionnaire administered with a sample of 250 selected by using cluster sampling method. Results: Family order may lead to the ground actions for divorce through life satisfaction. Conclusion: life satisfaction with -0.62 beta value has a strong negative effect on the ground actions for divorce.

Keywords: ground actions for divorce, life satisfaction, family order, satisfaction

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Authors: Abdelrazzag Elmajdoub

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The present study was designed to investigate the bio-equivalence of doxycycline in Dolistin® and Colidox® at a dose rate of 10 mg doxycycline/kg of body weight in 48 clinically normal broiler chickens. After oral administration, plasma levels of doxycycline peaked after 2 hours post-dosing without significant differences between the two products and it could be detected therapeutically and exceeded the minimum inhibitory concentration (MIC) for most micro-organisms sensitive to doxycycline for 12 hours. The disposition kinetics of doxycycline in the two products following oral administration revealed that the maximum plasma concentrations (Cmax.) were 22.65 and 21.80 µg/ml and attained at (Tmax.) 2.10 and 2.20 hours, respectively. Doxycycline in both of the products was eliminated with half- lives (t0.5α) equal to 7.70 and 6.93 hours, respectively. The mean systemic bio availabilities of doxycycline in both of the products after oral administration in chickens were 80.60 and 79.70%, respectively. It was concluded that doxycycline in the form of Dolistin® and Colidox® needs a dose equivalent to 20 mg doxycycline/kg of body weight a day is better to keep the plasma concentration higher than the MIC.

Keywords: tetracyclines, doxycycline, bioavailability, broilers, chickens

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Authors: Fatima Zohra Bissaad, Farid Bounaceur, Nassima Behidj, Nadjiba Chebouti, Fatma Halouane, Bahia Doumandji-Mitiche

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Effect of Beauveria bassiana and Metarhizium anisopliae var. acridum on the 5^th instar nymphs of Schistocerca gregaria was studied in the laboratory. Infection by these both entomopathogenic fungi caused reduction in the hemolymph total protein. The average amounts of total proteins were 2.3, 2.07, 2.09 µg/100 ml of haemolymph in the control and M. anisopliae var. acridum, and B. bassiana based-treatments, respectively. Three types of haemocytes were recognized and identified as prohaemocytes, plasmatocytes and granulocytes. The treatment caused significant reduction in the total haemocyte count and in each haemocyte type on the 9^th day after its application.

Keywords: Beauveria bassiana, haemolymph picture, haemolymph protein, Metarhizium anisopliae var. acridum, Schistocerca gregaria

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Authors: S. Jayasinghe, W. G. D. Wickramasingha, V. Karunaratne, D. N. Karunaratne, A. Ekanayake

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Multi-drug resistant microbial pathogens are a serious global health problem, and hence, there is an urgent necessity for discovering new drug therapeutics. However, finding alternatives is a one of the biggest challenges faced by the global drug industry due to the spiraling high cost and serious side effects associated with modern medicine. On the other hand, plants and their secondary metabolites can be considered as good sources of scaffolds to provide structurally diverse bioactive compounds as potential therapeutic agents. 6β-hydroxy betunolic acid is a triterpenoid isolated from bark of Schumacheria castaneifolia which is an endemic plant to Sri Lanka which has shown antibacterial activity against both Staphylococcus aureus (ATCC 29213) and methicillin-resistant S. aureus with Minimum Inhibition Concentration (MIC) of 16 µg/ml. The objective of this study was to determine the anti-bacterial activity for the derivatives of 6β- hydroxy betunolic acid against standard strains of Staphylococcus aureus (ATCC 29213 and ATCC 25923), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 35218 and ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), carbepenemas produce Kebsiella pneumonia (ATCC BAA 1705) and carbepenemas non produce Kebsiella pneumonia (ATCC BAA 1706) and four stains of clinically isolated methicillin resistance S. aureus and Acinetobacter. Structural analogues of 6β-hydroxy betunolic acid were synthesized by modifying the carbonyl group at C-3 to obtain olefin and oxime, the hydroxyl group at C-6 position to a ketone, the carboxylic acid at C-17 to obtain amide and halo ester and the olefin group at C-20 position to obtain epoxide. Chemical structures of the synthesized analogues were confirmed with spectroscopic data and antibacterial activity was determined through broth micro dilution assay. Results revealed that 6β- hydroxy betunolic acid shows significant antibacterial activity only against the Gram positive strains and it was inactive against all the tested Gram negative strains for the tested concentration range. However, structural modifications into oxime and olefin at C-3, ketone at C-6 and epoxide at C-20 decreased its antibacterial activity against the gram positive organisms and it was totally lost with the both modifications at C-17 into amide and ester. These results concluded that the antibacterial activity of 6β- hydroxy betunolic acid and derivatives is predominantly depending on the cell wall difference of the bacteria and the presence of carboxylic acid at C-17 is highly important for the antibacterial activity against Gram positive organisms.

Keywords: antibacterial activity, 6β- hydroxy betunolic acid, broth micro dilution assay, structure activity relationship

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Authors: Adam Janásek, Marek Pagáč

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The article is looking for an experimental determination of tool life tests for ceramic cutting inserts. Mentioned experimental determination should provide an added information about cutting process. The mechanism of tool wear, cutting temperature in machining, quality machined surface and machining process itself is the information, which are important for whole manufacturing process. Mainly, the roughness plays very important role in determining how a real object will interact with its environment. The main aim was to determine the number of machined inserts, tool life and micro-geometry, as well. On the basis of previous tests the tool-wear was measured at constant cutting parameter which is more typical for high volume manufacturing processes.

Keywords: ceramic, insert, machining, surface roughness, tool-life, tool-wear

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Authors: Vijay Korra

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The main focus of this paper is to examine the performance, outcomes and impacts of MGNREGA Scheme in particular on migrant beneficiary households. This article is based on a field survey carried out in 2010 in three randomly selected villages in Mahabubnagar district of Telangana State, India. It was found that majority of the job card holders are only able to get employment/work between 30-60 days and receive wages maximum between Rs.60 to 70 per day wherein wage discrimination was prevalent in line with gender. It concludes by saying that the government sponsored employment programme has indeed given rural poor a sense of hope about livelihood security through guaranteed employment. On the other hand, the scheme is defected in providing full employment days, wages, and thus unable to prevent the working class from migrating to cities/towns in search of employment mainly due to malpractices involved in the implementation of the scheme.

Keywords: MGNREGA(s), labour, employment, wages, livelihood, seasonal migration

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Authors: Tiffany Baetens, Sophie Halliez, Luc Buée, Emiliano Pallecchi, Vincent Thomy, Steve Arscott

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We demonstrate here a viable stretchable bio-microelectromechanical systems (BioMEMS) technology for use with biological studies concerned with the effect of high mechanical strains on living cells. An example of this is traumatic brain injury (TBI) where neurons are damaged with physical force to the brain during, e.g., accidents and sports. Robust, miniaturized integrated systems are needed by biologists to be able to study the effect of TBI on neuron cells in vitro. The major challenges in this area are (i) to develop micro, and nanofabrication processes which are based on stretchable substrates and to (ii) create systems which are robust and performant at very high mechanical strain values—sometimes as high as 100%. At the time of writing, such processes and systems were rapidly evolving subject of research and development. The BioMEMS which we present here is composed of an elastomer substrate (low Young’s modulus ~1 MPa) onto which is patterned robust electrodes and insulators. The patterning of the thin films is achieved using standard photolithography techniques directly on the elastomer substrate—thus making the process generic and applicable to many materials’ in based systems. The chosen elastomer used is commercial ‘Sylgard 184’ polydimethylsiloxane (PDMS). It is spin-coated onto a silicon wafer. Multistep ultra-violet based photolithography involving commercial photoresists are then used to pattern robust thin film metallic electrodes (chromium/gold) and insulating layers (parylene) on the top of the PDMS substrate. The thin film metals are deposited using thermal evaporation and shaped using lift-off techniques The BioMEMS has been characterized mechanically using an in-house strain-applicator tool. The system is composed of 12 electrodes with one reference electrode transversally-orientated to the uniaxial longitudinal straining of the system. The electrical resistance of the electrodes is observed to remain very stable with applied strain—with a resistivity approaching that of evaporated gold—up to an interline strain of ~50%. The mechanical characterization revealed some interesting original properties of such stretchable BioMEMS. For example, a Poisson effect induced electrical ‘self-healing’ of cracking was identified. Biocompatibility of the commercial photoresist has been studied and is conclusive. We will present the results of the BioMEMS, which has also characterized living cells with a commercial Multi Electrode Array (MEA) characterization tool (Multi Channel Systems, USA). The BioMEMS enables the cells to be strained up to 50% and then characterized electrically and optically.

Keywords: BioMEMS, elastomer, electrical impedance measurements of living cells, high mechanical strain, microfabrication, stretchable systems, thin films, traumatic brain injury

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Authors: Reza Hadjiaghaie Vafaie, Aysan Madanpasandi, Behrooz Zare Desari, Seyedmohammad Mousavi

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High lamination in microchannel is one of the main challenges in on-chip components like micro total analyzer systems and lab-on-a-chips. Electro-osmotic force is highly effective in chip-scale. This research proposes a microfluidic-based micropump for low ionic strength solutions. Narrow microchannels are designed to generate an efficient electroosmotic flow near the walls. Microelectrodes are embedded in the lateral sides and actuated by low electric potential to generate pumping effect inside the channel. Based on the simulation study, the fluid velocity increases by increasing the electric potential amplitude. We achieve a net flow velocity of 100 µm/s, by applying +/- 2 V to the electrode structures. Our proposed low voltage design is of interest in conventional lab-on-a-chip applications.

Keywords: integration, electrokinetic, on-chip, fluid pumping, microfluidic

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Authors: Yusuf Emirov, Abdullatif Hakami, Prasanta K Biswas, Elias K Stefanakos, Sesha S Srinivasan

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This study is aimed to develop microencapsulated thermochromic materials and the analysis of core-shell formation using high resolution electron microscopy. The candidate metal oxides (e.g., titanium oxide and silicon oxide) used for the microencapsulation of thermochromic materials are based on the microemulsion route that involves the micelle formation using different surfactants. The effectiveness of the core-shell microstructure formationrevealed the influence of surfactants and the metal oxide precursor concentrations. Additionally, a detailed thermal and color chromic behavior of these core-shell microcapsules are evaluated with the pristine thermochromic dye particles.

Keywords: core-shell thermochromic materials, core-shell microstructure formation, thermal and color chromic behavior of core-shell microcapsules, development micro-capsulated thermochromic materials

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Authors: George Madalin Danila, Mihaiella Cretu, Cristian Puscasu

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Glycol-based anti-freeze liquids, commonly composed of ethylene glycol or propylene glycol, have important uses in automotive cooling, but they should be handled with care due to their toxicity; ethylene glycol is highly toxic to humans and animals. A fast, accurate, precise, and robust method was developed for the simultaneous quantification of 7 most important glycols and their isomers. Glycols were analyzed from diluted sample solution of coolants using gas-chromatography coupled with mass spectrometry in single ion monitoring mode. Results: The method was developed and validated for 7 individual glycols (ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol and tripropylene glycol). Limits of detection (1-2 μg/mL) and limit of quantification (10 μg/mL) obtained were appropriate. The present method was applied for the determination of glycols in 10 different anti-freeze liquids commercially available on the Romanian market, proving to be reliable. A method that requires only a two-step dilution of anti-freeze samples combined with direct liquid injection GC-MS was validated for the simultaneous quantification of 7 glycols (and their isomers) in 10 different types of anti-freeze liquids. The results obtained in the validation procedure proved that the GC-MS method is sensitive and precise for the quantification of glycols.

Keywords: glycols, anti-freeze, gas-chromatography, mass spectrometry, validation, recycle

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Authors: F. Karim

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In this paper, triangular lattice index-guiding photonic crystal fibers (PCFs) are synthesized to compensate the chromatic dispersion of a single mode fiber (SMF-28) for an 80 km optical link operating at 1.55 µm, by using the directed tabu search algorithm. Hole-to-hole distance, circular air-hole diameter, solid-core diameter, ring number and PCF length parameters are optimized for this purpose. Three Synthesized PCFs with different physical parameters are compared in terms of their objective functions values, residual dispersions and compensation ratios.

Keywords: triangular lattice index-guiding photonic crystal fiber, dispersion compensation, directed tabu search, synthesis

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Authors: R. R. Mankbadi

Abstract:

There are several technologically-important flow situations in which there is a need to control the outcome of the fluid flow. This could include flow separation, drag, noise, as well as particulate separations, to list only a few. One possible approach is the passive control, in which the design geometry is changed. An alternative approach is the Active Flow Control (AFC) technology in which an actuator is embedded in the flow field to change the outcome. Examples of AFC are pulsed jets, synthetic jets, plasma actuators, heating, and cooling, etc. In this work will present an overview of the development of this field. Some examples will include Airfoil Noise Suppression: Large-Eddy Simulations (LES) is used to simulate the effect of synthetic jet actuator on controlling the far field sound of a transitional airfoil. The results show considerable suppression of the noise if the synthetic jet is operated at frequencies. Mixing Enhancement and suppression: Results will be presented to show that imposing acoustic excitations at the nozzle exit can lead to enhancement or reduction of the jet plume mixing. In vertical takeoff of Aircrafts or in Space Launch, we will present results on the effects of water injection on reducing noise, and on protecting the structure and payload from fatigue damage. Other applications will include airfoil-gust interaction and propulsion systems optimizations.

Keywords: aeroacoustics, flow control, aerodynamics, large eddy simulations

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Authors: Mark Davey

Abstract:

Communications on a Network on Chip (NoC) produce timing information, i.e., network injection delays, packet traversal times, throughput metrics, and other attributes relating to the traffic being sent across the chip. The security requirements of a platform encompass each node to operate with confidentiality, integrity, and availability (ISO 27001). Inherently, a shared NoC interconnect is exposed to analysis of timing patterns created by contention for the network components, i.e., links and switches/routers. This phenomenon is defined as information leakage, which represents a ‘side channel’ of sensitive information that can be correlated to platform activity. The key algorithm presented in this paper evaluates how an adversary can control two platform neighbouring nodes of a target node to obtain sensitive information about communication with the target node. The actual information obtained is the period value of a periodic task communication. This enacts a breach of the expected confidentiality of a node operating in a multiprocessor platform. An experimental investigation of the side channel is undertaken to judge the level and significance of inferred information produced by access times to the NoC. Results are presented with a series of expanding task set scenarios to evaluate the efficacy of the side channel detection algorithm as the network load increases.

Keywords: embedded systems, multiprocessor, network on chip, side channel

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Authors: Rwei-Ching Chang, Bo-Yu Su

Abstract:

Adhesion of copper thin films deposited on polyethylene terephthAdhesion of copper thin films deposited on polyethylene terephthalate substrate by direct current sputtering with different sputtering parameters is discussed in this work. The effects of plasma treatment with 0, 5, and 10 minutes on the thin film properties are investigated first. Various argon flow rates at 40, 50, 60 standard cubic centimeters per minute (sccm), deposition power at 30, 40, 50 W, and film thickness at 100, 200, 300 nm are also discussed. The 3-dimensional surface profilometer, micro scratch machine, and optical microscope are used to characterize the thin film properties. The results show that the increase of the plasma treatment time on the polyethylene terephthalate surface affects the roughness and critical load of the films. The critical load increases as the plasma treatment time increases. When the plasma treatment time was adjusted from 5 minutes to 10 minutes, the adhesion increased from 8.20 mN to 13.67 mN. When the argon flow rate is decreased from 60 sccm to 40 sccm, the adhesion increases from 8.27 mN to 13.67 mN. The adhesion is also increased by the condition of higher power, where the adhesion increased from 13.67 mN to 25.07 mN as the power increases from 30 W to 50 W. The adhesion of the film increases from 13.67 mN to 21.41mN as the film thickness increases from 100 nm to 300 nm. Comparing all the deposition parameters, it indicates the change of the power and thickness has much improvement on the film adhesion.alate substrate by direct current sputtering with different sputtering parameters is discussed in this work. The effects of plasma treatment with 0, 5, and 10 minutes on the thin film properties are investigated first. Various argon flow rates at 40, 50, 60 standard cubic centimeters per minute (sccm), deposition power at 30, 40, 50 W, and film thickness at 100, 200, 300 nm are also discussed. The 3-dimensional surface profilometer, micro scratch machine, and optical microscope are used to characterize the thin film properties. The results show that the increase of the plasma treatment time on the polyethylene terephthalate surface affects the roughness and critical load of the films. The critical load increases as the plasma treatment time increases. When the plasma treatment time was adjusted from 5 minutes to 10 minutes, the adhesion increased from 8.20 mN to 13.67 mN. When the argon flow rate is decreased from 60 sccm to 40 sccm, the adhesion increases from 8.27 mN to 13.67 mN. The adhesion is also increased by the condition of higher power, where the adhesion increased from 13.67 mN to 25.07 mN as the power increases from 30 W to 50 W. The adhesion of the film increases from 13.67 mN to 21.41mN as the film thickness increases from 100 nm to 300 nm. Comparing all the deposition parameters, it indicates the change of the power and thickness has much improvement on the film adhesion.

Keywords: flexible substrate, sputtering, adhesion, copper thin film

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Authors: Salim Cerig, Fatime Geyikoglu, Pınar Akpulat, Suat Colak, Hasan Turkez, Murat Bakir, Mirkhalil Hosseinigouzdagani, Kubra Koc

Abstract:

This study was designed to evaluate whether carvacrol (CAR) could provide protection against lung injury by acute pancreatitis development. The rats were randomized into groups to receive (I) no therapy; (II) 50 μg/kg cerulein at 1h intervals by four intraperitoneal injections (i.p.); (III) 50, 100 and 200 mg/kg CAR by one i.p.; and (IV) cerulein+CAR after 2h of cerulein injection. 12h later, serum samples were obtained to assess pancreatic function the lipase and amylase values. The animals were euthanized and lung samples were excised. The specimens were stained with hematoxylin-eosin (H&E), periodic acid–Schif (PAS), Mallory's trichrome and amyloid. Additionally, oxidative DNA damage was determined by measuring as increases in 8-hydroxy-deoxyguanosine (8-OH-dG) adducts. The results showed that the serum activity of lipase and amylase in AP rats were significantly reduced after the therapy (p<0.05). We also found that the 100 mg/kg dose of CAR significantly decreased 8-OH-dG levels. Moreover, the severe pathological findings in the lung such as necrosis, inflammation, congestion, fibrosis, and thickened alveolar septum were attenuated in the AP+CAR groups when compared with AP group. Finally, the magnitude of the protective effect on lung is certain, and CAR is an effective therapy for lung injury caused by AP.

Keywords: antioxidant activity, acute pancreatitis, carvacrol, experimental, lung injury, oxidative DNA damage

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