Initial Arrangement Research Articles

Simulation of composition and mass transfer behaviour of a membrane biofilm reactor using a two dimensional multi-species counter-diffusion model

The main objective of this paper is to study the growth and transport mechanisms of biofilms in Membrane Biofilm Reactors (MBfRs). A mathematical model incorporating biofilm characteristics is used to simulate the biofilm response and nitrification process to variations in the initial inoculation of biofilm and environmental conditions (in particular, to change in the concentration of substrates and temperature). The model is a highly nonlinear reaction-diffusion system with cross-diffusion that can describe the development of biofilm layers under the effects of counter-diffusion. The simulation results suggest the importance of multi-dimensional modeling to capture the heterogeneity in the biofilm structure. Furthermore, the results indicate that the initial composition and arrangement of biofilm colonies do not significantly affect membrane performance. In contrast, substrate concentrations do have a notable effect on the substrate transport fluxes and nitrification capacity of biofilms.

Optimasi Penjadwalan Kegiatan Pondok Pesantren Dengan Precedence Diagram Method (PDM)

Islamic boarding school is a place for those who want to further explore the science of Islam. Not only a place to gain religious knowledge, Islamic boarding schools also have an education system that handles the scheduling system. The schedule is something that must be present in every activity in the Islamic boarding school. The activities at the Islamic boarding school are also quite numerous and crowded. In boarding schools, the problem faced is determining the schedule of Islamic boarding school activities so that the schedule of activities can be arranged optimally. In preparing the activity schedule, there are several things that must be considered, including the human resources involved, the facilities or facilities and infrastructure used, as well as the time taken during the activity. Of all Islamic boarding school activities in one year, it is necessary to have a calculation to find out how optimal the arrangement of the activity schedule is according to 52 boarding school standards. This study uses the Precedence Diagram Method (PDM) method by using a network diagram that can be used to complete the duration of the activities at the Islamic Boarding School conducted. The results of this study obtained an optimal schedule of activities with less time spent than the initial schedule arrangement that takes a total of 116 hours to carry out activities within one year. Using PDM project management can schedule Islamic boarding school activities so that activities can be completed on time.

The role of microstructure on wear mechanisms and anisotropy of additively manufactured 316L stainless steel in dry sliding

Wear control, which relies on understanding the mechanisms of wear, is crucial in preserving the life of mechanical components and reducing costs. Additive manufacturing (AM) techniques can produce parts with tailored microstructure, however, little has been done to understand how this impacts the mechanisms of wear. Here we study the impact of initial grain arrangement and crystal orientation on the wear mechanisms of austenitic stainless steel (SS) in dry sliding contact. Specifically, the anisotropic sliding wear behavior of as-built, AM-ed 316L SS is compared against annealed, wire-drawn counterparts. We describe, in-detail, how the sliding wear mechanisms of delamination, abrasion, oxidation, and plastic deformation are attributed to the initial surface microstructure under different loading conditions using a number of techniques. This new understanding sheds light on how different AM-induced microstructures affect wear, thereby allowing for better utilization of this technology to develop components with enhanced wear properties.

Characteristics of a rotational windmill-shaped radio frequency magnetron sputtering plasma for effective target utilization

A rotational windmill-shaped radio frequency magnetron plasma source has been developed for improving the target utilization rate. Two kinds of magnet arrangements are designed by taking into account the E × B drift motion of electrons using simulated magnetic field profiles, where the electric field, E, is vertical to the target and the magnetic field, B, is parallel to the target, respectively. It is found that the Hall parameters of the electrons in the magnetron area have a higher value ranging from 12 to 110 for both magnet arrangements. This is high enough to magnetize electrons, while the electron Larmor radius is as low as 0.3–2.8 mm. The target utilization rate has attained approximately 65 % and 70 % for an initial and for an improved magnet arrangements, respectively. The improved magnet arrangement has a uniform profile of the target erosion compared with the initial magnet arrangement.

Solution combustion synthesis and Monte Carlo simulation of the formation of CuNi integrated nanoparticles

The fine bimetallic Cu-Ni integrated nanoparticles were obtained by the modified solution combustion synthesis in the air using glycine as a fuel. The synthesized nanoparticles were studied by XRD analysis using single- and two-phase approaches for Rietveld refinement simulation, by scanning TEM–EDX spectroscopy and HR TEM technics. The data analysis for nanoparticles' characteristics showed close integration of Cu and Ni crystalline structures, which tend to form a bimetallic alloy. The process of bimetallic nanoparticles’ formation was computer simulated using the Monte Carlo method in the temperature range from 300 to 600 K. The simulation established the patterns of neck formation for two cases of the initial arrangement of copper and nickel nanoparticles: direct contact and relative displacement of 0.2 nm. It was established, that in the case of relative displacement in comparison with the case of the direct contact the coalescence process is «delayed» by 60–80 K upon heating. A description of the energy spectra of two particles during the neck forming has been provided.

Early European Integration – Rivalry and Accession. Economic and Political Analysis on the Relation Between the European Economic Community, the United Kingdom and the Nordic Customs Union

The paper is concentrated on the pre-history that led to the so-called Northern enlargement of the European Community. Specifically, the economic and political reasons that led the United Kingdom, Norway, Denmark to drop their initial integration arrangements and seek membership in the European Economic Community. After an outlook of the European development after the Second World War, the respective developments in the named countries and their integration projects are analysed. At the end, some highlights about the rivalry caused by the creation of the continental scheme are presented, which ended with the establishing of the dominance of the European Community.

Silvicultural options for the transformation of even-aged Rhizophora apiculata stands to irregular and diverse mangroves – A simulation experiment

Mangrove rehabilitation efforts regularly intend to re-establish the former canopy cover quickly by establishing even-aged monocultures. However, there are concerns that these stands are less resilient to disturbances than structurally diverse forests and cannot provide ecosystem services as effectively. The objective of this study was to identify silvicultural systems for the transformation of even-aged Rhizophora apiculata stands to more irregular and species-diverse stands.The individual-based forest model KiWi was used to simulate the dynamics of a 1-ha sized Rhizophora apiculata stand under (1) passive management without intervention, (2) stand clearcutting, (3) group clearcutting, (4) expanding-gap shelterwood, and (5) crown thinning. As observed in the field, seedlings of the less shade-tolerant tree species Avicennia marina regenerated naturally under the canopy of R. apiculata. The transformation process was considered complete at the onset of the steady state characterized by a multi-layered forest structure as well as a stable basal area and stem size distribution.Without intervention, stands entered a steady state, on average, after 226 years under poor site conditions, or 179 years under good conditions. Silvicultural systems that required multiple entries, specifically expanding-gap shelterwood and crown thinning, halved this time by creating multi-layered stand structures while retaining a partial canopy cover. Moreover, continuous crown thinnings were necessary to maintain a species-diverse upper canopy. In contrast, small group clearcuts developed into two-layered stands and were ineffective. The removal of the upperstory through a stand clearcut or a large group clearcut reversed the initial planting arrangement but could develop into irregular stand structure only if propagules were supplied uninterruptedly. Intense forest operations were necessary to accelerate the transformation of even-aged mangrove stands. Forest managers should consider the potential future costs of transformation when planting even-aged stands instead of assisting the natural regeneration of former mangrove sites. Silvicultural field trials are proposed for the development of detailed guidelines.

A Critical Comparison between Manufacturing and Service Firms’ Mission Statements: Manage Your Firms’ Mission Statements with Care Using Readability and Lexical Techniques

This paper aims to investigate the Readability and Lexical Density of the mission statements of the large service and manufacturing firms. In respect of mission statements, a comparison between the service and manufacturing firms is drawn. For initial data arrangement, the mission statements of all selected service firms are grouped together, same was also done with the manufacturing firms separately. The mission statements are processed through the software for Readability (Gunning Fog, Flesch-Kincaid, SMOG, Coleman-Liau, Automated, Flesch Reading Ease score) and Lexical Density analysis in two categories, service firms and manufacturing firms. Result show that Service firms’ mission statements are more Lexically dense and possess higher average level than those of the manufacturing firms. This study contributes to the Strategic Management literature and practical implications to the service and manufacturing firms and their stakeholders. Also comes out of the ole ways of data analysis in management studies. Future researchers may carry out similar research in a specific industry.

Influence of pores arrangement on stability of photonic structures during sintering

Discrete Element Method (DEM) has been used for numerical investigation of sintering-induced structural deformations occurring in inverse opal photonic structures. The influence of the initial arrangement of template particles on the stability of highly porous inverse opal α-Al2O3 structures has been analyzed. The material transport, densification, as well as formation of defects and cracks have been compared for various case studies. Three different stages of defects formation have been distinguished starting with local defects ending with intrapore cracks. The results show that the packing of the template particles defined during the template self-assembly process play a crucial role in the later structural deformation upon thermal exposure. The simulation results are in very good agreement with experimental data obtained from SEM images and previous studies by ptychographic X-ray tomography.

(Invited) Unveiling Changes in Surface Chemistry of Iridium Single Crystals and Metal Oxide Supported IrOx Nanoparticles in Oxygen Evolution Reaction Conditions

Gaining fundamental insights into the formation and the stability of iridium (Ir) surface oxides is pivotal to efficient and sustainable oxygen evolution reaction (OER) electrocatalysis, a key reaction in the field of power-to-fuels and power-to-chemicals. However, proton-exchange membrane water electrolysers (PEMWE) systems currently suffer from their high investment and operational costs, which are partly due to the use of micrometer-sized iridium oxide (IrOx) particles to electrocatalyze the OER. A passage to IrOx nanoparticles would be highly desirable but these nanomaterials face time-dependent changes in structure and chemical composition in OER conditions. To shed fundamental light into the mechanisms at stake, we used electrochemical techniques in combination to X-ray photoelectron spectroscopy (XPS), and inductively coupled mass plasma spectrometry (ICP-MS). Experiments on Ir(111), Ir(210) and nanostructured Ir(210) surfaces showed that the oxy-hydroxides layers forming in the pre-OER region feature mixed Ir oxidation states (presence of Ir(0), Ir(+III) and Ir(+IV) species), and that the fraction of each oxidation state depends on the crystallographic orientation. In the OER region, Ir(+III) species progressively dissolve leading to an enrichment of the surface and near-surface regions of the single crystals into Ir(+IV) species, and resulting in a decrease of their intrinsic activity towards the OER. The results indicate a convergence towards a more stable but less active surface state, which does not depend neither on the initial arrangement of surface atoms (crystallographic orientation, proportion of high- and low-coordinated atoms) nor on their oxidation state (initial state vs. electrochemically-activated Ir(hkl) surfaces) [1]. These findings were confirmed on more technologically relevant materials such as IrOx nanoparticles supported onto antimony-doped (ATO), niobium-doped (NTO) or tantalum-doped (TaTO) tin oxide aerogels [2]. Moreover, the combination of identical-location transmission electron microscopy (IL-TEM) and in situ ICP-MS helped in identifying which potential ranges are critical to the stability of IrOx nanocatalysts and their supports, and provided practical guidelines for the development of more active and more stable PEMWE anodes [3]. Ackowledgements This work was supported by the French National Research Agency in the frame of the MOISE project (grant number ANR-17-CE05-0033).

MAGNETOMETRÍA V-MOKE: ESCALEO ENTRE COMPONENTES DE LA MAGNETIZACIÓN EN EL PLANO DE LA MUESTRA

In this paper we introduce an alternative method to determine the scale factor necessary to quantitatively compare the two coplanar components of the magnetization (components in the plane of the surface of the sample) of a film using the v-MOKE technique (vectorial-MOKE). The proposed method has the advantage of not needing the reorientation ofthe electromagnet generating the magnetic field, since, depending on the dimensions and weight there of, this action can be difficult or directly impracticable. In this way, the experiment that allows for the acquisition of the two components in the plane of magnetization simultaneously, is executed without the need to modify the initial experimental arrangement (fixed assembly). As test samples, two 9 nm and 100 nm thick FePt films are used, presenting the first uniaxial anisotropy. All experiments were carried out at room temperature and using a MOKE system entirely built in the Surface Physics Group of the Instituto de Física del Litoral, allowing to simultaneously measure the two magnetization components coplanar with the surface sample (v-MOKE).

Monte-Carlo Tree Search for Efficient Visually Guided Rearrangement Planning

We address the problem of visually guided rearrangement planning with many movable objects, i.e., finding a sequence of actions to move a set of objects from an initial arrangement to a desired one, while relying on visual inputs coming from an RGB camera. To do so, we introduce a complete pipeline relying on two key contributions. First, we introduce an efficient and scalable rearrangement planning method, based on a Monte-Carlo Tree Search exploration strategy. We demonstrate that because of its good trade-off between exploration and exploitation our method (i) scales well with the number of objects while (ii) finding solutions which require a smaller number of moves compared to the other state-of-the-art approaches. Note that on the contrary to many approaches, we do not require any buffer space to be available. Second, to precisely localize movable objects in the scene, we develop an integrated approach for robust multi-object workspace state estimation from a single uncalibrated RGB camera using a deep neural network trained only with synthetic data. We validate our multi-object visually guided manipulation pipeline with several experiments on a real UR-5 robotic arm by solving various rearrangement planning instances, requiring only 60 ms to compute the plan to rearrange 25 objects. In addition, we show that our system is insensitive to camera movements and can successfully recover from external perturbations.

Newly designed multi-stacked circular tray solid-state bioreactor: analysis of a distributed parameter gas balance during solid-state fermentation with influence of variable initial moisture content arrangements

BackgroundThe growth of Aspergillus awamori and Aspergillus oryzae in a self-designed, multi-stacked circular tray solid-state bioreactor (SSB), operating in solid-state fermentation (SSF) conditions at a laboratory scale, was studied. The bioreactor was divided into six layers by six circular perforated trays. Wheat bran was used as both a carrier of bound mycelia and nutrient medium for the growth of A. awamori and A. oryzae. The new tray SSB is equipped with instrumentation (an oxygen (O2)/carbon dioxide (CO2) gas analyser and a thermocouple) to continuously monitor O2 consumption and CO2 and heat evolved, which can directly be used to monitor the fungal biomass. The integrated Gompertz model was used to describe the accumulated evolution of CO2.ResultsThe results from the models strongly suggest that the evolved and accumulated CO2 can be used to excellently describe fungal growth. Another important parameter that can be determined by the gas balance method is the respiratory quotient (RQ). This is the ratio of the CO2 evolution rate (CER) to the O2 uptake rate (OUR). The use of CER and OUR confirmed that correlated measurements of microbial activity are available, and the determination of RQ may propose an explanation for differences from expected levels. The kinetic behaviour of the fungal culture, using raw CO2, which represents an accumulation term, was integrated with respect to time and fitted to a Gompertz model, a log-like equation. The model can be used to generate parameter values that may be used to verify the experimental data, and also to simulate and optimise the process.ConclusionOverall, A. awamori and A. oryzae have their own ability to degrade and utilise the complex compositions contained in the solid substrate, and fermentation conditions may lead to possible comparisons. In addition, multi-stacked circular tray SSB systems demonstrated an excellent system for further investigations of mass transfer and possibly for large-scale operation, though considerable optimisation work remains to be done; for example, the height/diameter ratio and total number of trays should be optimised.

Control of the geometric arrangement of material heterogeneities on strain localization at the brittle-to-ductile transition in experimentally deformed carbonate rocks

Triaxial high temperature (900 °C) deformation experiments were conducted at constant strain rate in a Paterson-type deformation apparatus on cylinders of Carrara marble with two right or left stepping, non-overlapping weak inclusions of Solnhofen limestone, oriented at 45° to the cylinders’ longitudinal axes. Applying different values of confinement (30, 50, 100 and 300 MPa) we induced various amounts of brittle deformation in the marble matrix and investigated the effect of brittle precursors on the initiation and development of heterogeneity-induced high temperature shear zones.Viscosity contrast between the matrix and the inclusions induces local stress concentration at the tips of these latter. The initial arrangement of the inclusions results in either an overpressured (contractional) or underpressured (extensional) domain in the step-over region of the sample. At low confinement (30 and 50 MPa) abundant brittle deformation is observed, but the spatial distribution of microfractures is dependent on the kinematics of the step-over region: microcracks occur either along the shearing plane between inclusions (in extensional bridge samples), or broadly distributed outside the step-over region (contractional bridge samples). Accordingly, ductile deformation localizes along the inclusions plane in the extensional bridge samples as opposed to distributing over large areas of the matrix in the contractional bridge samples. If microcracking is suppressed (high confinement), strain is accommodated by viscous creep and strain progressively de-localizes in extensional bridge samples. Our experiments demonstrate that brittle precursors enhance the degree of localization in the ductile deformation regime, but only if the interaction of pre-existing heterogeneities induces an extensional mean stress regime in between.

Development and growth of auricular cartilage and muscles: A study using human fetuses

ObjectivesThe auricle is a key target in pediatric plastic surgery and is considered to develop from a ring- or funnel-like arrangement of six hillocks in the embryo. However, there has been no report showing the morphologies of the auricular muscle and cartilage after midterm in humans. MethodsWe examined histological sections of 20 near-term human fetuses (29–40 weeks) and those from 7 midterm fetuses (15–16 weeks). ResultsAt midterm, the auricular cartilage was a single wavy plate with the helicis major muscle (HMM). The superior and posterior auricular muscles (SAM, PAM) were inserted into the middle parts, and the anterior auricular muscle (AAM) was inserted into the lowest part of the cartilage plate, while the tragus and antitragus were not clearly identified. In near-term fetuses, the cartilage plate varied in size and shape between specimens. The scapha and antihelix were separated from the cartilage plate with major or minor involvement of the HMM from the initial mass along the helix. The SAM inserted to the crus helix or the developing scapha, while the insertion sites of the AAM and PAM into the helix were stable. The tragus–antitragus cartilages were well-developed and they sandwiched a deep notch of skin below the helix tail. The antitragicus muscle was more evident than the tragicus muscle. An unnamed muscle was evident along the external acoustic meatus. The other intrinsic muscles, including the transverse and oblique muscles, might develop from the HMM after birth. ConclusionsDevelopment of the auricle was advanced after midterm. However, a single wavy plate-like cartilage was maintained until late-stage. Near term, the antihelix and scapha developed from the plate-like core of the auricle and the tragus and antitragus were added in the antero-inferior side of the cartilage plate. Establishment of muscle arrangements was markedly delayed compared to cartilage development. Altogether, the classical concept of an initial funnel-like arrangement of cartilage anlagen might have been biased by studies of adult morphology.

Simulation and characterization of circular hexagonal braiding fabricstructure

Hexagonal braiding technology is a kind of state-of-the-art braiding method, which uses hexagonal horngears to driveyarn carriers and make yarns intertwined into fabrics. In terms of hexagonal braiding principles, the braiding parameterslike initial arrangement of yarn carriers, yarn number and horngears sequence were defined, and then the movementpaths of yarn carriers in hexagonal braiding process and stitch length were obtained, which could be converted intocoordinates on the xoy plane and the coordinates along z-axis. In that case, a group of spatial coordinates were got tocreate the yarn trajectories and fabric structures in Matlab. And then, B-spline curve was utilized to fit the yarntrajectories. Considering the compactness of hexagonal fabric, the coordinates conversion algorithm and conversionmatrix were utilized to optimize the fabric structure, so a more compact fabric structure was established. The braidingangle variation and volume fraction of fabric showed that after coordinates conversion the braiding angles became morestable than original fabric model, and the fiber volume fraction of fabric was improved too. So the fabric structure modelwas available to describe hexagonal fabric structure, which can offer the reference for the further study on properties ofhexagonal braiding technology and application of hexagonal braided fabric

Effect of secondary arm orientation on unusual overgrowth at converging grain boundary during directional solidification in 3D

The competitive growth of two converging grains with multiple dendrite rows during directional solidification in three dimensions (3D) was investigated through phase-field simulations. We studied the effect of secondary arm orientation on the overgrowth of favorably oriented (FO) dendrite by unfavorably oriented (UO) dendrite, i.e. the so-called unusual overgrowth. It is observed that, when the initial spatial arrangement of FO and UO dendrites varies, the effect of secondary arm orientation on the unusual overgrowth will also be different. In addition to the unusual overgrowth similar to that previously illustrated in two dimensions (2D) and thin samples, we have observed a more complicated unusual overgrowth manner when the initial spatial arrangement between the FO dendrites and UO dendrites was the stagger configuration and there is a rotation of the secondary arm in either the FO grain or the UO grain. In these cases, the spatial arrangements of some UO dendrites with respect to FO dendrites can be automatically adjusted from the initial stagger configuration to the face-to-face configuration. Such an adjustment results in the interaction of FO dendrite not only with the UO dendrite penetrating into the liquid gap but also with the face-to-face UO dendrite. Hence, the unusual overgrowth of FO dendrites occurs easier than in the cases with only face-to-face interaction, i.e., the cases in 2D and thin samples. These findings illustrate the inconsistency between previous simulations and experiments regarding the effect of secondary arm orientation on the unusual overgrowth.

Classical Solution and Edge Effect in the Problem of Stability of an Axially Compressed Cylindrical Shell

The classical solution for critical stresses in the problem of stability of a circular longitudinally compressed cylindrical shell consists of two terms, reflecting the ability of the shell to resist buckling due to bending and membrane deformations. However, with usual boundary conditions the classical solution appears only with the absence of the Poisson expansion of a shell. With a non-zero Poisson's ratio, an axisymmetric edge effect presents. It reduces the critical load and causes the initial arrangement of its own forms to change as the load increases.

Modeling of Adhesive Particles Using a Combination of the Two-Body Interaction and Phase-Field Methods

Discrete materials such as powders and granular materials have been widely used due to their specific characteristics. The precise evaluation is accordingly becoming important, and various numerical schemes have been developed. However, the interactions among the constituent particles are still difficult to model precisely. Especially, contact conditions, which vary with material properties and circumstances, are difficult to formulate. In this study, a computational model for simulating adhesive particles on contact in a many-particle system is proposed. The interaction between the particles was represented by a two-body repulsive force that depends on the distance between particles and an additional adhesive force at the contact point. A phase-field variable was introduced to express the surface of each particle, and the adhesive force was formulated using the phase-field distribution. As a result, the adhesion of particles was properly expressed. For a mono-particle system, neighboring particles adhered and uniformly aggregated, while for a dual-particle system, several characteristic patterns were obtained depending on the initial arrangement of the particles. Repulsive contact was also considered as a specific case, and the corresponding results were obtained.

Structural evolution of topologically closed packed phase in a Ni-based single crystal superalloy

This work investigates the evolution of the crystal structure of the topologically closed packed orthorhombic P phase precipitate in a Re-containing Ni-based single crystal superalloy during thermal exposure. The P phase is formed with a thin needle morphology. The precipitate is formed from the matrix with an initial complex atomic arrangement which continues to evolve during the process of thermal exposure. Based on the experimental evidence of this study and the theoretically predicted structure reported in the literature, a mechanism of the structural transformation is proposed. The initial structure is composed of a parallelogram (P) atomic arrangement configuration, which gradually evolve into a rectangle (R) atomic arrangement configuration in the [100]P projection. In the [010] projection, the initial structure is composed of alternating rows of a larger parallelogram (P') and a larger rectangle (R') configurations, which gradually evolve into an intricate structure of P'-R' along the length [001]P direction and P'P'-R'R' along the transverse [100]P direction. The initial structure is formed for its structural similarities to the γ phase to minimize lattice mismatch. The final structure is evolved over time to conform to its thermodynamically more stable state. The structural evolution is achieved by collective atomic shuffling. These intricate atomic arrangements gives rise to the very faint and highly dense parallel striation lines along the transverse [010]P direction in [100]P view and along the length [010]P direction in [010]P view under transmission electron microscopy observation.