bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal and mechanical analysis of the internal support for LNG cryogenic road tanker
Authors: Lisowski Filip , Lisowski Edward
Published: November 2019

Road tankers for liquefied natural gas are designed as double-walled vacuum insulated tanks. The temperature difference between the fluid in the inner vessel and the environmental temperature can reachup to 200 K. Supports holding the internal vessel must be able to transfer complex mechanical loads occurring under operating conditions and at the same time minimize the heat leakage to the tank. In this paper the construction of a steel support with a composite insert for a 25 m3 tank was considered. The proposed design was tested in thermal and mechanical finite element analysis using ANSYS software.
Field Synergy Principle For Natural Convective Rotating Fluid Flow Past a Vertical Cylinder
Authors: Rani H.P. , Naresh K , Rameshwar Y
Published: November 2019

In the present research work, the effects of thermal and induced magnetic fields on the natural convective rotating fluid flow past the vertical cylinder are presented. The numerical solution of the unsteady field variables is obtained by solving the governing non-dimensional non-linear equations. The effects of the Prandtl, Taylor and Chandrasekhar numbers on the induced magnetic field, average momentum and heat transfer coefficients are presented graphically. The field synergy/ coordination principleis discussed to understand the enhancement of convective heat transfer. Increasing values of synergy co–insides with the increasing rate of heat transfer.
Analysis of the Proton Exchange Membrane Fuel Cell in transient operation
Authors: Wilk Andrzej , Węcel Daniel
Published: November 2019

Currently, fuel cells are increasingly used in industrial installations, means of transport and household applications as a source of electricity and heat. The paper presents the results of experimental tests of PEMFC at variable load, which characterizes the cell's operation in real installations. The measurements made show changes in the performance of the fuel cell during step changing or smooth changing of an electric load. Load was carried out as a change in the current or a change in the resistance of the receiver. The analysis covered the times of reaching steady states and the efficiencyof the fuel cell system taking into account additional devices. The analysis of the measurement results will allow determining the possibility of using fuel cells in installations with a rapidly changingload profile and indicate possible solutions to improve the performance of the installation.
Thermal performance of a gas turbine based on an exergy analysis
Authors: Haouam Abdallah , Derbal Chaima , Mzad Hocine
Published: November 2019

This work concerns the calculation and the analysis of the thermal performance of the components ofan MS 7001 type gas turbine with a nominal power of 87 MW using the concept of exergy. The exergy balance is used in addition to the energy balance to estimate the irreversibility of the air compressor, the combustion chamber and the turbine. The exergy analysis is carried out by applying the equilibrium equations obtained from the general definitions of the irreversibility of the thermodynamic processes and the data provided by the manufacturer. The results show that the exergy destruction of the gas turbine depends on the variation of the thermodynamic parameters: ambient temperature, compression ratio, air–fuel ratio. The combustion chamber has the highest exergy destruction estimated at 36.34 MW. The air compressor has an exergy efficiency of 84.19% that of the combustion chamber is 75.91% whilethat of the turbine expansion is 92.58%. The total exergy destruction of the gas turbine is 53.51 MW and itsefficiency is 32.44%. Improving the performance of the gas turbine requires decreasing the temperatureof the intake air.
Investigations of influence of epoxy composite coatings on hydrodynamics and heat transfer processes of compact small diameter tube bundles
Authors: Gorobets Valery , Bohdan Yurii , Trokhaniak Viktor , Antypov Ievgen , Bohdan Alla
Published: November 2019

Tube bundles with cross flow heat carrier chart are widely used in many power systems due to their relatively simple design, low cost, low pressure drops, high efficiency etc. In order to exploitation these tube bundles in dirty and aggressive applications, protective coatings can be applied to the heat transfer surface to enhance effectiveness and minimize pollutant deposits. Protective coatings generally using for improving wear resistance, corrosion resistance, thermal conductivity to heat transfer surface and thermal insulation of frame surfaces of heat exchangers.

In this work physico-mechanical and thermophysical properties of heat conduct coating materials forheat transfer surface are investigated. Experimental and numerical investigations of hydrodynamics andheat transfer processes for compact small diameter tube bundles coated by epoxy composite with high thermal conductivity nanofillers are presented.

Experimental investigations of investigated tube bundles were carried out in open circuit section type wind tunnel of subsonic speeds.
Numerical analysis of a cooling of a hot plate by an array of microjets
Authors: Łapka Piotr , Cieplniński Adrian
Published: November 2019

In this paper heat transfer during impingement of an array of 8×8 microjets on a hot surface was investigated. The influence of a ratio of a distance between a nozzle and hot plate (H/d) and microjet diameter-based Reynolds number (Red) on the temperature and heat transfer coefficient (HTC) on the hot plate were numerically studied. The numerical model which was based on the steady-state compressible Navier-Stokes equations and SST k-ω turbulence model was developed and applied for the analysis. During simulations the ratio of the distance between the nozzle and hot plate to the microjet diameter was H/d = 3.125, 25 and 50, while the microjet diameter-based Reynolds number was equal to Red = 690, 1100 and 1510. The ratio of the microjet pitch to the microjet diameter was s/d = 31.25. It was found that both the H/d ratio and Red significantly influenced flow patterns in the gap between the nozzle and hot plate as well as the temperature and HTC on the surface of the hot plate. With increase of the H/d ratio a more uniform distributions of the plate temperature and HTC were observed, while the rise in the Red intensified heat transfer on the hot plate.
A numerical analysis of a HYBRID PV+WT power system
Authors: Jaszczur Marek , Hassan Qusay , Al-Anbagi Haidar N. , Palej Patryk
Published: November 2019

The increase in global energy consumption and the expected exhaustion of traditional energy sources, especially in the last century, led to an increased search for alternative sources of energy.The use of renewable energy sources has become extremely important to reduce dependence on fossil fuels. Due to the stochastic nature of the renewable energy sources such as the wind speed fluctuation and the intensity of solar radiation the stable operation of the systems base single renewable source can be problematic. But the using two or more of these sources results in higher stability than relying on a single source. For this reason, hybrid renewable energy systems have become an attractive solution in thefield of renewable energy. A hybrid energy system is a combination of two or more renewable energy sources that can enhance each another to increase the reliability of the supplied energy. The objective of this paper is investigation about the energy supplying improvement and the energy efficiency utilisation by hybridisation using two renewable energy resources: wind energy and solar energy with respect two different optimisation objectives: economical to reduce the net present cost and ecological to reduce CO2 emissions. Presented system has been implemented to supply a single household with an electric load.
Variable temperature effects on TEG performance
Authors: Pfeiffelmann Björn , Özman Cansu , Benim Ali Cemal , Joos Franz
Published: November 2019

The present paper presents an experimental investigation of the variable temperature effects on the performance of a Thermoelectric Generator (TEG). In the conducted experiments, a sample TEG is analyzed by imposing variable temperature patterns on the cold side, while keeping the temperature uniformon the hot side. The achieved local temperature variations on the cold side has approximately been about 8% of the temperature difference between the hot and cold sides. The results reveal that the TEG performance shows some variation with the applied variable temperature patterns, which remains, however,rather small for the applied temperature variations. For achieving a more clear answer to the present question, further experiments need to be designed where more substantial temperature variations canbeobtained.
Computational study of active flow control drag reduction device for utility vehicle
Authors: Mosiężny Jęedrzej , Ziegler Bartosz
Published: November 2019

The study presents a computational study of a drag reduction device based on an active boundary layer control for a generic truck-trailer utility road vehicle. The conceptual device is in accordance with upcoming EU regulations regarding attachable aerodynamic devices for heavy utility vehicles. Design and principles of operation of the conceptual device are presented. The device is intended to increase decrease the trailer’s base drag coefficient by manipulation of the separated flow region behind the vehicle base. Results of a steady state Reynolds averaged analysis and Delayed Detached Eddy Simulation are presented to show the discrepancies of fluid flow patterns between baseline and augmented configuration as well as between mentioned CFD approaches. Results for drag reduction for baseline truck-trailer configuration and aerodynamically augmented configuration are presented.
Temperature distribution in a composite rod, taking into account nonlocal spatial effects
Authors: Kuvyrkin George , Savelyeva Inga , Kuvshinnikova Daria
Published: November 2019

One of the important directions in the field of creating new structural and functional materials is the study of materials with a complex structure and unique strength or temperature properties. Due to the heterogeneity of their structure, such materials are called “structurally sensitive”. The heterogeneity of the structure of such materials is justified by the technological features of their creation. Structurally sensitive materials can be obtained by compacting nanopowders, deposition on a substrate, etc. The paper considers a mathematical model of heat propagation in a composite rod. At one of the ends of the rod, a protective coating of structurally sensitive material is used. Using the finite element method, numerical solutions are found for a problem with conditions of ideal thermal contact of rod parts. The results of the numerical calculation for various materials are given. The influence of material parameters on the heat distribution in the rod is analysed.
Sequential Gaussian Simulation as a tool to improve PM10 sampling scheme in industrial sites
Authors: Alfaro Degan Guido , Coltrinari Gianluca , Lippiello Dario
Published: November 2019

This paper is focused on the role of spatial and variographic analysis in the phase of sampling design. In particular, when dealing with environmental variables such as airborne dust concentration all over a selected domain, the best approach to catch the spatial structure of the variable itself, implies the full and more detailed coverage of the domain. In this study this goal is achieved by means of about fifty airborne dust concentration field surveys all over a square area 350 mt wide in a quarry plant in the center of Italy. These data, sampled according with a regular pattern, did not allow to catch the spatial structure of the variable itself thus avoiding a satisfactory variographic modelling. To improve the sampling scheme an infilling procedure was performed by adding an increased number of samples. The selection of these further samples, less than 10% of the total amount, was carried out using sequential Gaussian simulations in those zones of the domain in which the highest variability was recorded. The final outcome shown a good result determining a good upgrade in terms of variographic modelling and final estimation at the cost of few further samples.
The two-domain model of solute transport in binary alloy
Authors: Seredynski Miroslaw , Banaszek Jerzy
Published: November 2019

A mixed model for micro-macroscopic computer simulation of binary alloy solidification is proposed. It involves a two-domain approach to solute conservation equations in the liquid and solid phases, whereas transport of momentum and energy in the two-phase region is modelled using the phase mixture theory. To distinguish regions of columnar and equiaxed crystal structures evolving in a cast during solidification, the special front tracking technique on non-structural triangular grids is included in the model. In this two-domain approach, solute conservation equations are averaged across solid and liquid phases, and the solute transport at the phase interface is included. Additionally, the microstructure evolution is modelled to capture the development of various complex grain structures and more accurately describe the solute transport between the phases. The accuracy of the proposed model is first verified by a grid refinement analysis, and then the model is used to predict the solute concentration and macro-segregation in the example problem of Pb-48%wt Sn alloy solidification in a 2D mould. The results obtained are next compared with the relevant ones predicted by the fully single-domain model, earlier developed by authors. Thus, the role of finite diffusion in liquid and solid phases is identified and discussed.
Improving geodynamic monitoring practice in underground gas storage areas
Authors: Shevchuk Stepan , Kvyatkovskaya Svetlana , Shevchuk Roman
Published: November 2019

This article consideres issues of geodynamic monitoring during the construction and operation of underground gas storage facilities. Existing methods of geodynamic monitoring used in Russia and other countries are reviewed. A brief overview of the accidents occurred during the construction and operation of underground gas storage facilities is presented. A suggestion is put forward to expand the scope of geodynamic monitoring carried out, taking into account current thinking on the nature of geodynamic hazard involved in operation of engineer constructions located underground
Three-dimensional cellular automaton model for the destruction of brittle heterogeneous materials
Authors: Kazunina Galina , Cherednichenko Allay
Published: November 2019

The article investigates the evolution modes of cluster damage structure in brittle heterogeneous materials by using a three-dimensional probabilistic cellular automaton. By comparing the data of computer and physical experiments, there was established the essential role of the model parameter, which describes the intensity of the material destruction process under the influence of local overstress near the existing damage clusters - the probability of perimeter germination. The comparison of kinetic curves of damage accumulation and correlation functions showed that, depending on the probability value for damage cluster perimeter germination, two qualitatively different modes of evolution of damage accumulation process are observed. In this case, the best correspondence of correlation functions in model and physical experiment on pulsed electromagnetic emission is observed for perimeter germination probability values smaller than 0.2.
Low temperature two STM tip tunneling measurements of a floating chemical potential Pb(111) surface
Authors: Soe We-Hyo , Durand Corentin , Joachim Christian
Published: November 2019

On a Pb(111) superconducting surface, low temperature dI/dV tunnelling spectra are recorded between two scanning tunnelling microscopes (STM) metallic tips with the Pb(111) sample metallic support non-grounded. The tunnelling current intensity I passing between the 2 tips through the sample is controlled by changing one or both STM vacuum tunnelling junction resistances. The chemical potential of this floating Pb(111) surface depends on the normalized ratio between those two quantum resistances. When ungrounded, the Pb(111) sample chemical potential balances between those of the 2 STM tips while tuning their respective tip end atomic apex to Pb(111) surface distances with a picometer precision without any physical contact between the STM tips and the surface.
Mandibular ascending branch and condyle reconstruction in adolescence by a costochondral rib graft with an observation period over 8 years
Authors: Scheller Konstanze , Scheller Christian , Reich Waldemar , Eckert Alexander W.
Published: November 2019

Introduction:The need to resect and reconstruct the condylar process of the mandible in a teenager is rare. Reconstruction strategy must be accurately assessed in terms of donor side morbidity, postoperative risks (ankylosis) and the possibility of sufficient development in a growing patient.Observation:A 14-year-old boy presented with the radiographic finding of a large cystic lesion of the right condylar process. There were no clinical symptoms as pain, a limitation of mouth opening or malocclusion. Pathohistological examination confirmed a solitary bony cyst. The resected ascending jaw and condylar process was reconstructed by a costochondral rib graft.Commentaries:Over 8 years the development of the reconstructed ascending jaw and condyle was observed. There was an undisturbed growth. The cartilaginous part of the costochondral graft remodeled to a sufficient condylar process without ankylosis, resorption or overgrowth.Conclusion:The reconstruction of the growing mandible and condylar process in an adolescent is a challenge. Observation over 8 years showed a sufficient reconstruction. Intraoperative the chondral portion of the graft has to be handled carefully to avoid a separating from the bony part. The growth potential of the costochondral rib transplant allows a functional reconstruction without substantial donor side morbidity in adolescent patients.
Die Rechtsfrage: Darf man kurz nach einer Knie-OP mit Patienten arbeiten?
Authors: Bossow Karsten
Published: November 2019

„Eine Therapeutin meldet sich nach einer Knie-OP wieder arbeitsfähig. Vorerst kann sie nur mit einer Orthese arbeiten. Darf sie dann überhaupt schon frisch operierte, instabile Patienten behandeln? Welche Konsequenzen hat es, wenn ein Unfall passiert?“

Therapeutin via E-Mail
Lernerfolg ist Teamarbeit – Lernorte der praktischen Ausbildung
Authors: Schaub Anette
Published: November 2019

Angehende Ergotherapeuten lernen während ihrer praktischen Ausbildung, die Theorie mit beruflichem Handeln zu verbinden. Damit das gelingt, ist eine gute Zusammenarbeit zwischen den Lernorten (Hoch-)Schule und Gesundheitseinrichtungen wie Praxen oder Kliniken unerlässlich.
Association of Hemorrhoid Vascular Injuries with Cigarette Smoking—An Evaluation with Interesting Prospects
Authors: Nagaraj Savitha V. , Mori Amit , Reddy Madhavi
Published: November 2019

Background Hemorrhoids are vascular structures in the anal canal which are seldom used to evaluate vascular diseases. Cigarette smoking is well-known to cause both arterial and venous vascular injuries. However, the impact of smoking on hemorrhoid vasculature is unknown.

Objective Considering that vasculature in the hemorrhoids has the same anatomy and pathophysiology of vascular damage as other systemic vasculatures, we conducted this study to evaluate the relation between smoking and incidence of hemorrhoidal vascular injury.

Design and Data Analysis Retrospective review of all the screening colonoscopies performed at our Department of Gastroenterology (predominantly serving urban minority population) over 3 years was conducted and patients with recorded smoking history were included in the study (n = 242). Fisher's exact test with two-tailed p-value and odds ratio were used to evaluate for the association between smoking and incidence of hemorrhoids.

Results We studied 242 subjects and found statistically significant association between smoking and hemorrhoids (p < 0.05) with the risk of developing hemorrhoids among smokers being 2.4 times that of a nonsmoker. We further noted no significant difference in the incidence of hemorrhoidal vascular injuries between the past versus current smokers and male versus female smokers.

Conclusion This is one of the first studies to establish an association between smoking and hemorrhoids. Our study shows that the hemorrhoidal vasculature is impacted by smoking similar to other vascular systems. This study sheds light on the possibility of evaluating hemorrhoids for clues of other systemic and gastrointestinal vascular damage. This correlation can add clinical value especially given the flexibility of assessing hemorrhoids as an outpatient in a cost effective and comfortable manner.
Gating effects in antiferromagnetic CuMnAs
Authors: Grzybowski M. J. , Wadley P. , Edmonds K. W. , Campion R. P. , Dybko K. , Majewicz M. , Gallagher B. L. , Sawicki M. , Dietl T.
Published: November 2019

Antiferromagnets (AFs) attract much attention due to their potential applications in spintronics. Both the electric current and the electric field are considered as tools suitable to control the properties and the Néel vector direction of AFs. Among AFs, CuMnAs has been shown to exhibit specific properties that result in the existence of the current-induced spin-orbit torques commensurate with spin directions and topological Dirac quasiparticles. Here, we report on the observation of a reversible effect of an electric field on the resistivity of CuMnAs thin films, employing an ionic liquid as a gate insulator. The data allow us to determine the carrier type, concentration, and mobility independent of the Hall effect that may be affected by an anomalous component.
To pupate or not to pupate: a case study of an obligate pollination mutualism in Glochidion ferdinandi (Phyllanthaceae) and Epicephala colymbetella (Gracillariidae)
Authors: Henderson Emma , Missen Melika , Zalucki Jacinta
Published: November 2019

Obligate pollination mutualisms have recently been recorded in the Glochidion genus with Epicephala moth associates (leaf-flower and leaf-flower moths). There is limited literature on Australian Glochidion species and their pollinators. Glochidion ferdinandi occurs predominantly across the east coast of Queensland, Australia and has an obligate pollination association with Epicephala colymbetella. Early descriptions of G. ferdinandi describe the encapsulation of the adult moth within the fruit. In the present study, observations and fruit dissections were recorded to analyse the role of symbionts within this mutualism, pollinator life history and the flowering phenology of the host. Our study confirmed this rare behaviour in which E. colymbetella pupated within G. ferdinandi fruit in which adult moths were retained until fruit dehiscence. Fruit dissections identified two other species alongside E. colymbetella, a seed consuming Spilomelinae moth and parasitoid Bracon wasp. Although both moth species were found to reduce the number of surviving ovules in the fruit, E. colymbetella also provided a pollination benefit to G. ferdinandi. Furthermore, the life histories of E. colymbetella and phenology of G. ferdinandi were observed to be highly synchronous, with larvae developing concurrently with ovules after flower fertilisation. Retention of the adult moth in fruit has only previously been recorded in one other Epicephala (lanceolaria).
Seed germination biology of the Albany pitcher plant, Cephalotus follicularis
Authors: Just Michael P. , Merritt David J. , Turner Shane R. , Conran John G. , Cross Adam T.
Published: November 2019

Cephalotus follicularis is an ecologically unique, taxonomically isolated and range-restricted carnivorous plant that occurs exclusively within vulnerable wetland habitats in coastal south-western Australia. Very little is known about the reproductive biology of this iconic plant species, particularly in relation to seed dormancy and the specific requirements for germination. This knowledge gap must be filled to facilitate the establishment of conservation and management initiatives for the species, as Cephalotus is increasingly impacted by habitat loss, alteration to natural hydrological and fire regimes and, in recent times, climatic change. This study aimed to determine the type of seed dormancy that the seeds of Cephalotus possess, determine the optimum conditions required for seed germination, and examine the storage behaviour of seeds. The seeds of Cephalotus are small (1.0 × 0.5 mm), lightweight (0.1 mg) and remain indehiscent within a wind-dispersed hairy achene. Results suggest that the seeds may exhibit some sensitivity to desiccation and appear to be short lived (<12 months) when stored at 23°C. Maximum germination was achieved after 16 weeks incubation at 15°C for seeds removed from the protective outer layer of the achene, while seeds retained within the protective outer layer displayed lower germination success. The post-ripening morphological changes in the embryo, limited response to gibberellic acid, and the long time period required for germination suggests that the seeds exhibit morphophysiological dormancy, with a fraction of seeds remaining dormant for a period of time post-dispersal. These results highlight the importance of limiting hydrological alteration within the few remaining habitats that continue to support Cephalotus, but to ensure its long-term protection, further research focusing on phenology and in situ recruitment is required.
Strong seasonality in the cadmium and phosphate cycling at the subtropical convergence, south-eastern New Zealand
Authors: Frew R. D. , Adu T. , Gault-Ringold M. , Hamidian A. , Currie K. I. , Armstrong E. , Hunter K. A.
Published: November 2019

The global distribution of dissolved cadmium (Cd) in the world’s oceans is generally well understood. However, information on seasonal variability of this and other trace metals in the open ocean is difficult to obtain and, therefore, our understanding is limited. Here, we present a 3-year time series of field measurements of dissolved and particulate Cd and phosphate (PO4) from a transect across the subtropical convergence, south-eastern New Zealand. In the final year of study, the bioactive trace metals (iron, Fe; zinc, Zn; cobalt, Co) and nutrients (nitrate, NO3; silicate, Si(OH)4) were also measured to identify their influence on Cd cycling in the region. Cadmium varied seasonally from 0.009 to 0.137nM in the sub-Antarctic surface waters (SASW). Zinc in SASW varied between 0.03 and 0.011nM, which is low enough to suggest Zn limitation year-round. The seasonal input of dissolved Fe may stimulate phytoplankton growth in summer where microplankton (especially diatoms) dominate the phytoplankton distribution. The Cd:PO4 ratio also varied strongly with season (0.015×10–3 to 0.05×10–3). This seasonal variation in the Cd:PO4 ratio is productivity driven as revealed in the characteristic trend in the Cd:PO4 ratio, particulate Cd and chlorophyll-a measurements. The high seasonal variability between Cd and PO4 complicates the application of the Cd proxy for the reconstruction of historical PO4 concentrations in SASW.
Pre-trialling considerations and activities.
Authors: Sitepu B. , Laksono N. D. , Setiawati U. , Nur F. , Rahmaningsih M. , Anwar Y. , Widodo P. , Forster B. P. , Purba A. R.
Published: November 2019

Before trialling can begin, various considerations and preparations need to be made. First it is beneficial to know if the trait of interest is governed mainly by genetic or environmental factors. If the trait is controlled by genes which are little affected by the environment then field trials may be set up in a narrow range of environments. If, however, the trait is strongly affected by environment, for example, soil type or climate, then trials need to be more extensive to give an estimate of the environmental and genotype x environment interaction. Multi-locational trials can determine the extent of genetic versus environmental factors involved. Plant breeding is an essential pre-trialling activity as it supplies progeny that have potential for crop improvement (see Setiawati et al., 2018, this series). Field performance testing, in turn, is essential in selecting the progenies or palms sought. Materials for field trialling are seedlings. These are made ready for trialling in the nursery (see Laksono et al., 2019, this series). Coordination is therefore required in preparing planting materials and land preparation for the trial. These aspects are discussed.
Material preparation.
Authors: Sitepu B. , Laksono N. D. , Setiawati U. , Nur F. , Rahmaningsih M. , Anwar Y. , Widodo P. , Forster B. P. , Purba A. R.
Published: November 2019

The aim of oil palm trialling is to evaluate field performance among a range of genotypes and to select those of interest. A basic necessity is the provision of good quality planting material, usually produced from deliberate cross-pollinations. Details of methods in pre-trialling activities, i.e. in crossing, seed production and the production of field-ready planting materials, are given in Kelanaputra et al. (2018), Setiawati et al. (2018) and Laksono et al. (2019), respectively (this series of manuals). Thus, only brief overviews of these operations are given here.
Anti-fraud measures in Southern Africa
Authors: Mykhalchenko Nataliya , Wiegratz Jörg
Published: November 2019

In response to the rising levels of fraud in many countries and the global economy more generally, public and private actors in both the global North and the global South have in recent years introduced initiatives in the name of countering fraud in the ‘private sector’. This briefing explores such anti-fraud measures in four countries in the Southern African region: Malawi, Botswana, South Africa and Zambia. Using online data (news outlets and reports on websites of private companies and governmental agencies), the authors provide a country-by-country account of some of the drivers and characteristics of these measures.
Extracellular vesicles and coagulation in blood from healthy humans revisited
Authors: Berckmans René J. , Lacroix Romaric , Hau Chi M. , Sturk Auguste , Nieuwland Rienk
Published: November 2019

Background: In 2001, we studied the presence and coagulant properties of “microparticles” in the blood of healthy humans. Since then, multiple improvements in detection, isolation and functional characterization of the now called “extracellular vesicles” (EVs) have been made, and shortcomings were identified. Aim: To revisit the presence and function of EVs in blood from healthy humans. Methods: Blood was collected from 20 healthy donors. EV‐containing plasma was prepared according to new guidelines, and plasma was diluted to prevent swarm detection. Single EVs were measured by flow cytometry with known sensitivity of fluorescence and light scatter. The haemostatic properties of EVs were measured by thrombin‐, fibrin‐, and plasmin generation. Plasma concentrations of thrombin‐antithrombin complexes and prothrombin fragment 1 + 2 were measured to assess the coagulation status in vivo. Results: Compared to 2001, the total concentrations of detected EVs increased from 190‐ to 264‐fold. In contrast to 2001, however, EVs are non‐coagulant which we show can be attributed to improvements in blood collection and plasma preparation. No relation is present between the plasma concentrations of EVs and either TAT or F1 + 2. Finally, we show that EVs support plasmin generation. Discussion: Improvements in blood collection, plasma preparation and detection of EVs reveal that results from earlier studies have to be interpreted with care. Compared to 2001, higher concentrations of EVs are detected in blood of healthy humans which promote fibrinolysis rather than coagulation.
Acoustic Vortex Beam Generation by a Piezoelectric Transducer Using Spiral Electrodes*
Authors: Zhang Han , Gao Yang
Published: November 2019

We propose an innovative method to generate acoustic vortex waves based on a disc piezoelectric transducer that is coated with multi-arm coiled electrodes. Finite element simulation results for single-arm to four-arm coiled electrodes indicate that the method could modulate amplitude and phase spatial distribution of the acoustic waves near the acoustic axis by acoustic field synthesis principle, making the waves rotate spirally in space and form stable focused vortex beams. Compared with the traditional method that requires electronic control of an array consisting of a large number of transducers, this method provides a more effective and compact solution.
Observation of Simplest Water Chains on Surface Stabilized by a Hydroxyl Group at One End*
Authors: Dong An-Ning , Sun Li-Huan , Tang Xiang-Qian , Yao Yi-Kun , An Yang , Hao Dong , Shan Xin-Yan , Lu Xing-Hua
Published: November 2019

The key to fully understanding water-solid interfaces relies on the microscopic nature of hydrogen bond networks, including their atomic structures, interfacial interactions, and dynamic behaviors. Here, we report the observation of two types of simplest water chains on Au(111) surface which is expected unstable according to the rules of hydrogen network on noble metal surfaces. A common feature at the end of chain structures is revealed in high resolution scanning tunneling microscopy images. To explain the stability in observed hydrogen bond networks, we propose a structure model of the water chains terminated with a hydroxyl group. The model is consistent with detailed image analysis and molecular manipulation. The observation of simplest water chains suggests a new platform for exploring fundamental physics in hydrogen bond networks on surfaces.
Applications of solar dryer for seaweed and cassava starch
Authors: Suherman Suherman , Susanto Evan Eduard , Busairi Abdullah
Published: November 2019

In this paper, the comparisons of seaweed and cassava starch drying using a newly-designed solar dryer is invesigated. The drying operation was done in 2 days, from 8.00 A.M until 4.00 P.M on each day. Both seaweed and cassava starch were rewetted and prepared before drying. Experimental results showed that drying time affects the value of relative humidity and drying temperature. It was shown that drying temperature is invesely proportional to relative humidity. The relative humidity and temperature curves of seaweed drying and starch drying show relatively similar results. The drying process was able to reduce seaweed’s moisture content from 72,6% to 12,6% in tray 1, and from 72,6% to 14,1% in tray 2, while the cassava starch’s moisture content is reduced from 52,6% to 7,05% on tray 1 from 52,6% to 13,81% on tray 2. All results have met their respective standards of moisture content. The drying rate fluctuates as the drying time changes, with drying temperature significantly affects the drying rate. The product qualities of seaweed and cassava starch show acceptable results based on their respective standards. It can be concluded that solar dryer is a suitable alternative for easier drying and good product quality.
Optimization for Production Tert-Butyl Glycoside Nonionic Surfactant Using Response Surface Methodology
Authors: Pawignya Harsa , Kusworo T. D. , Pramudono B.
Published: November 2019

It is necessary to develop a surfactant production process using environmentally friendly raw materials and products. For raw materials such as surfactants are carbohydrate-based material utilization example, glucose, which is reacted with tert-butanol, to form tert-butyl glycoside (TBG). This study aims to obtain the optimum conditions TBG production process of acetalization reactions, glucose and tert-butanol, catalyst the para toluene sulfonic acid using response surface method to reach optimum yield TBG. The independent variable used is the mole ratio of glucose with tert-butanol, percent of the catalyst and a temperature. Optimization results obtained optimum conditions of mole ratios of 1: 5.06; 2.87 percent of the catalyst and the temperature of 71.21 °C with a TBG yield of 99.13%, with a TBG content of 61.2 %. The optimum process conditions are verified to strengthen the model equations obtained by the response surface method. Based on the Hydrophilic-Lipophilic Balance value of the surfactant TBG is 4.60, then these surfactants can be used as an emulsifier of water-in-oil.
Production of solketal (2,2-Dimethyl-1,3-dioxolane-4-methanol) from glycerol and acetone by using homogenous acidic catalyst at the boiling temperature (preliminarry study)
Authors: Mahreni  , Marnoto Tjukup , Nur Muhamad Maulana Azimatun
Published: November 2019

Currently, solketal is produced from glycerol and acetone by using heterogeneous catalyst. However, a solid heterogeneous catalyst is not preferable since water contained in the glycerol, is adsorbed on the surface of the catalyst. Water could act as inhibitor in the reaction and lowering the activity of the catalyst. Therefore, homogenous acid catalyst is proposed to avoid the inhibition during the reaction. The aim of this research was to utilize sulphuric acid as the homogenous acid catalyst, to explore the effect of the mole ratio glycerol:acetone to the conversion, and determine the entrophy and entaphy of the reaction . The process was carried out in a three neck reactor equipped with a heater, temperature control, cooler and stirrer. The reaction conditions were set at a constant boiling temperature, the reaction time was varied at 4 - 12 h, and the mole ratio of acetone to glycerol was varied in the range of 2:1 - 7: 1. Results indicated that the highest conversion (>80 %) was recorded at 62°C, 10 h, and 6.9:1 mole ratio. The conversion of glycerol to solketal was influenced by mole ratio which is consistent to Lecatelier principle. From the entropy ΔS =280.02 J. mole K−1) and enthalpy ΔH= 95.948 J. mole−1), it can be concluded that the reaction of solketal formation was exothermic.
Response surface methodology optimization of α-mangostin extraction using betaine-1,2-propanediol deep eutectic solvent
Authors: Mulia Kamarza , Faisal Pane Irfan , Krisanti Elsa
Published: November 2019

Mangosteen pericarp contains α-mangostin, the most abundant xanthone that is useful as an antioxidant. Deep eutectic solvent (DES) was used in this study as a green solvent for extraction of α-mangostin. Our previous study shows that a DES, consisting of betaine as the hydrogen bond acceptor and 1,2-propanediol as the hydrogen bond donor, having the highest extraction yields compared to other betain-based DESs. In this study, the operating condition of the solvent extraction process has been optimized using the response surface methodology approach, based on the Box-Behnken design. The highest calculated α-mangostin extraction yield obtained was 4.2% (w/w), corresponding to an extraction temperature of 56.5 °C, mangosteen powder to DES mass ratio of 0.12, and extraction time of 6.9 hours. The optimum temperature was found to be the combined effect of enhanced leaching of the mangosteen pericarp matrix by the DES and α-mangostin degradation at higher temperatures.
Production of natural colorant powder from Clitoria ternatea l. using tray dryer which is dehumidified by zeolite
Authors: Mauludifia F , Astrinia S D , Meiranti K A , Djaeni M
Published: November 2019

One of food additives that are usually added to food is coloring agents. The use of synthetic colorant in food products often causes health problems. Telang flowers, or Clitoria ternatea L., have blue color that indicates the presence of anthocyanins. Anthocyanin is a flavonoid compound that has positive health benefits. Referring to this, the flowers can potentially become natural coloring agents. This research aims to examine the effect of pH on anthocyanins, the effect of maltodextrin concentration and temperature on water content. So that the best conditions are obtained for the drying process and obtained powder that has anthocyanin content with low water content. The research was conducted in several stages, namely extraction, drying and analysis of results. The extract is varied in its pH to obtain pH with highest anthocyanin. Drying was carried out with variations in maltodextrin concentrations of 0 and 8%, and temperatures of 40, 60 and 80°C. Water content analysis for 120 minutes every 10 minutes. The results showed that at pH 2, the highest total anthocyanin was obtained. The higher the drying temperature and maltodextrin concentration that is added, the time needed to dry the extract will be faster. Lower moisture content is produced with higher maltodextrin concentration and temperature.
Effectiveness of Eugenol as An Antibacterial Toward Staphylococcus epidermidis
Authors: Firyanto R , Fatarina P E , Azizah N
Published: November 2019

Eugenol is generally used as raw materials of perfumes, but now eugenol was developed as an antioxidant, antifungal, antibacterial and antiseptic. This study aims to determine the effect of eugenol concentration and pH and the effectiveness of eugenol as an antibacterial against Staphylococcus epidermidis. The experiments were carried out at concentrations of 1%, 2%, 4%, 6% and 8% with pH 6, 7 and 8. Data were collected and analyzed by two-way ANOVA method with interaction level of 5% (α = 0.05). The results showed that eugenol has an antibacterial effect in inhibiting the growth of bacteria Staphylococcus Epidermidis and included in the category of strong to very strong antibacterial. The optimum yield diameter of the inhibitory zone is 22.27 mm, obtained at pH 8 and the concentration of eugenol is 8%.
Adsorption of Cobalt-60(II) on silica xerogel from rice husk
Authors: Kundari N.A. , Permadi M.G. , Megasari K. , Nurliati G.
Published: November 2019

The primary cooling water system of a nuclear reactor contains Co-60 which requires treatments to avoid adverse effects on society and the environment. Experiment of Co-60 adsorption by using silica xerogel has been done. This experiment was intended to study the isothermal adsorption equilibrium and to determine thermodynamic parameters. Silica xerogel was made from rice husk ash using sol-gel method. The prepared of silica xerogel has a specific surface area of 142.034 m2/g. The adsorption experiments were carried out in a batch wise until it reaches an equilibrium state with variation of the initial concentration and temperature. The results show that Co (II) adsorption by silica xerogel following the Langmuir isotherm than Fruendlich model. Based on the experiment at three different temperatures, the maximum adsorption capacities depend on the temperature there are 25.71; 26.25; and 26.81 mg/g successively at a temperature of 30; 35; and 40 °C. The thermodynamic parameters showed that the cobalt-60 adsorption process by silica xerogel is spontaneous and endothermic with values of ΔH 117.084 kJ / mol and ΔS 35.582 kJ/K/mol. The use of the silica xerogel on the adsorption of reactor cooling water system containing Co-60 showed a decreasing of activity of the waste until 85% from the initial activity. These results indicate that the silica xerogel can be utilized as material to treat radioactive liquid waste containing Co-60.
Design of Air Quality Monitoring System Based On Web Using Wireless Sensor Network
Authors: Purwanto P , Suryono S , Sunarno S
Published: November 2019

Air pollution (O3, SO2, CO, NOx, PM, and Pb) can have a severe impact on environmental damage and human health problems. Therefore, monitoring of pollutant levels in the air is essential to find out how much that gas levels can cause air pollution. In general, air quality monitoring is carried out using a conventional system. Inside the system requires large-sized equipment, long time for analysis, expensive, and with limited space resolution. It becomes inefficient, amid the development of technology that can carry out online monitoring, real-time, low cost, small size and a wide range of distance. The technology is known as the wireless sensor network system. The aim of this research is to design an air quality monitoring system using a Wireless Sensor Network (WSN) that can be accessed via the web and smartphone. The developing of WSN systems consist of two steps, are design and implementation device. The first step is done by assembling sensor nodes and hosting a web server. And after the device was finished, the next step is testing and calibrating of the system. The results of experiment show that the system is able to detect various air pollution, such as SO2, NOX, CO, and other environmental factors such as temperature, humidity and wind speed.
Co-Digestion of Bagasse and Waterhyacinth for Biogas Production with Variation of C/N and Activated Sludge
Authors: Hadiyarto A , Soetrisnanto D , Rosyidin I , Fitriana A
Published: November 2019

One of the factors that influence biogas production is the C/N ratio of the substrates. In this study the bagasse as a carbon-rich substrate (C/N=58) is combined with nitrogen-rich substrate namely is water hyacinth (C/N=19) so that the C/N ratio is in the range of 20-30. The research was carried out by preparing a filtered substrate with a 200 mesh sieve. Microbes needed to decompose the substrate are cow rumen, activated sludge from rotten bagasse and rotten water hyacinth. At the stationary phase, the ratio F/M of 0.5 and C/N ratio of 20, 25, 30, the each of biogas yield produced (liter/kg COD removed) are 381, 351 and 339.
Morphological and Optical Properties of Polylactic Acid Bionanocomposite Film Reinforced with Oil Palm Empty Fruit Bunch Nanocrystalline Cellulose
Authors: Indarti E , Marwan  , Wan Rosli W D.
Published: November 2019

Nanocrystalline cellulose (NCC) was derived from oil palm empty fruit bunch (OPEFB) by soda pulping and followed by 2,2,6,6-tetramethylpiperidine-1-oxy (TEMPO) oxidation reaction method. The NCC was used as reinforcing agent in Polylactic acid (PLA) biopolymer film matrix with 0 to 20% loadings. Bionanocomposite film was prepared by dilution in Chloroform and casted on the flat glass with 0.03-0.05 mm casting thickness. TEM shows that the nanocrystalline cellulose (NCC) has a rod like shape of 2-6 nm width and 200-500 nm length. SEM micrograph shows that the surface of PLA-NCC bionanocomposites has a relative good dispersion at low NCC loading (1, 3 and 5 wt.%), and a rougher surface at higher NCC loadings. The PLA bionanocomposites film as obviously seen exhibits decrease in transparency as the NCC content increased. The transparency of neat PLA film has higher transmission value compare to other PLA-NCC and tend to reduce the transmission percentage as the NCC loading increase, especially for 10 and 20%.
Nano-ZnO impregnated – cellulose acetate hybrid membrane for increasing eugenol content in clove oil
Authors: Kusworo T D , Widayat  , Budiyono  , Siahaan A A , Iskandar G K , Utomo D P
Published: November 2019

Clove oil is an essential oil that is obtained from cloves leaf. Indonesia is one of the largest producer of clove oil in the world. However, the quality of clove oil which is directly obtained from cloves leaf has low quality. This is due to the low concentration of eugenol in crude clove oil that is 60-80%. The purpose of this research is to increase the quality of clove oil by increasing the concentration of eugenol. In this research, clove oil is being purified by using Cellulose Acetate (CA)-ZnO nanofiltration membrane. The membranes were fabricated by dry-wet phase inversion method from dope polymer solution in acetone. The SEM results revealed the formation of nano-particles framework among the polymer matrix. The additions of 0.5 wt-% of nano-ZnO slightly increase the content of eugenol in permeate from 69% to 72%. However, the further addition of nano-ZnO decreases the content of eugenol drastically to 69% (no separation occurs) with the addition of 1.0 and 1.5 wt-%. The addition of high concentration of nano-ZnO (more than 0.5 wt-%) will produce large nano-particle cluster with macro-voids around the cluster which decreases the membrane selectivity.