Front Patterns Research Articles

Experimental heat transfer analysis of the effects of thermophysical properties on PCM at freezing conditions employing Particle Image Velocimetry

Cold chain logistics of fresh produce distribution are facing new challenges owing to the increasing consumer demand, often traveling long distances, and facing temperature variations during storage and distribution stages. Nowadays, solutions for improving food preservation by searching effective energy storage strategies, such as the use of PCM, are capturing more interest. Nevertheless, most studies are focused on organic PCM with ambient temperature melting points analyses. This leaves an important research gap in the experimentation of other types of eutectic materials with melting points below 0 °C, something of great interest for food preservation in the refrigeration industry. Velocity vector field and heat transfer via natural convection in a small cavity filled with two different PCM at below 0 °C conditions were experimentally investigated employing temperature measurements and Particle Image Velocimetry. In this regard, brine (18.8 wt%) and ethylene glycol-water (EGW) blend (30.5 wt%) PCM with equal melting temperature, but different thermophysical properties, were selected to compare their thermal behavior. It was investigated the effects of thermophysical properties such as density, specific heat capacity, thermal conductivity, and viscosity on melting front, heat transfer and flow patterns through the evaluation of liquid fraction, heat storage, Nu, Gr, Ra, and velocity field. The maximum Nu value for brine was almost the double of that of EGW. Pr values of EGW were in average 1.88 times higher than those of brine. Besides, Gr and Ra values of brine were in average 7.23 and 3.97 higher than those of EGW, respectively.

Effects of Balance and Proprioceptive Exercises on the Balance of Ice Hockey Players and the Risk of Lower Limb Injuries

Background. Most ice hockey injuries are contact, but about 15% are non-contact musculoskeletal injuries and lower body injuries account for 30-45% of all injuries in ice hockey players. It is believed that proprioception and balance training can improve neuromuscular control, improve its ability to synchronise the muscle joint to improve dynamic stability and improve human performance, so balance and proprioception are suggested exercises as a regular part of training. The aim. To determine the effects of a 6-week balance and proprioception training exercises on balance and lower extremity injury risk in ice hockey players. Material and methods. 20 men were randomly divided into experimental and control groups. Six weeks were applied to the research group balance and proprioception exercises, twice a week for 45 minutes next to their regular training. The control group continued with regular training. Before and after the study, static balance was assessed by the flamingo test, dynamic balance and lower extremity injury risk by the modified star excursion test, and injury risk assessment using the Functional Movement Assessment. Results. In the intervention group after 6 weeks the static balance of the right and left leg improved statistically significantly (p<0,05), the dynamic balance of the right and left leg in the front, posteromedial, posterolateral directions (p<0,05), but functional movement patterns did not change statistically significantly (p>0,05). A statistically significant difference was found between the groups in the dynamic balance of the left and right leg in the front, posteromedial, and posterolateral directions (p<0,05) and the static balance of the right leg (p<0,05). The results of the intervention group were better compared to the control group. Conclusions. After the application of balance and proprioception training exercises, the static and dynamic balance of ice hockey players improved and the risk of injury in ice hockey players decreased. Recommendations. Balance and proprioception exercises should be included in hockey physical training to improve static and dynamic balance and reduce the risk of injury. When performing balance and proprioception exercises, we recommend incorporating a variety of specific movements that are similar to those performed by athletes during training and competition. In order to determine the cause of injuries and their risk, it is very important to carry out regular tests, store them and analyse them. Keywords: balance, proprioception, hockey, injury risk

Implementation of the Pelagic Hotspot Index in detecting the habitat suitability area for bigeye tuna (Thunnus obesus) in the eastern Indian Ocean

Abstract. Istnaeni ZD, Gaol JL, Zainuddin M, Fitrianah D. 2023. Implementation of the Pelagic Hotspot Index in detecting the habitat suitability area for bigeye tuna (Thunnus obesus) in the eastern Indian Ocean. Biodiversitas 24: 5044-5056. Bigeye tuna (Thunnus obesus Lowe, 1839) is a species with a high economic value that can migrate horizontally and vertically over a large area. Although sea temperature has been the main focus of previous findings, other variables can serve as a reasonable proxy. Here we used sea surface chlorophyll-a, sea surface height, subsurface sea salinity, and subsurface temperature to predict the suitable habitat area for bigeye tuna in the Eastern Indian Ocean Off Java. A Generalized Additive Model was performed to analyze the best-fit model evaluated from the p-value and Cumulative Deviance Explained. The suitability index of the selected model was calculated using Pelagic Hotspot Index constructed from multi-spectrum satellite data. The results showed that the high catches were located on the high suitable index value and supported by chlorophyll-a as the most significant factor, followed by sea surface height, temperature, and salinity. This condition was stimulated by the high feeding opportunity, which may relate to the EIO's oceanic front, eddies, and specific current patterns. This study helps identify ecological hotspots, track the migration, and monitor the seasonal closure for bigeye tuna, particularly in EIO.

Detonation behaviors of stoichiometric H2-O2 mixture diluted with He, N2, CO2 at different initial pressures

In this study, the detonation parameters for stoichiometric H2-O2 mixtures diluted with varying amount of He, N2, CO2 are measured and analyzed in a small bore tube at different initial pressure P0. Signals of flame front and cell patterns are obtained by photodiodes and smoked foil technique, respectively. Experimental results indicate that as dilution mole fraction increases, the average detonation velocity deviates more from the theoretical value, and the detonation velocity deficit increases. The detonation velocity deficit of the H2-O2-N2 mixtures is relatively smaller than that of the H2-O2-He mixtures. The maximum detonation velocity occurs at 65% He dilution fraction. The cell sizes of the H2-O2 mixture diluted with CO2 are most affected by P0. The dilution mole fraction less than 10% has little effect on the cell size at higher initial pressure. The H2-O2-He mixture can make the induction zone length shorter than that of H2-O2 mixture as P0 increases. The detonation instability increases as N2 or CO2 dilution fraction increases, and the cellular instability decreases as He dilution fraction increases. Detonation parameters such as reaction zone thickness are calculated to introduce a cell size predicting formula based on the Ng model. Linear relationships are determined by: λ = 42.457 Δi (H2-O2-N2 mixture), λ = 48.945 Δi (H2-O2-He mixture).

Resin Flow Analysis for the Foam Core Sandwich Spoiler by Vacuum-Assisted Resin Injection Process

This article presents the numerical analysis and experimental investigation for the manufacturing of a foam core sandwich spoiler by vacuum-assisted resin injection (VARI) process. To find an injection scheme that guarantees both a good impregnation of the preform and a filling time compatible with the process window, the finite element model (FEM) was applied to analyze the effect of different injection schemes on the resin flow front patterns. Based on the obtained results, two optimal injection schemes are selected to form the spoiler structure. The experimental results show that the best molding quality can be achieved from the thick-end injection with a thin-end exit scheme. The comparison between simulation and experimental results shows that the overall deviation of the numerical analysis on resin flow time is 15.9%.

Experimental Study of the Impact of Pore Structure on Drying Kinetics and Sublimation Front Patterns

Freeze-drying frozen maltodextrin solutions with solid contents of 5% and 30% (w/w) was experimentally investigated using neutron imaging at PSI Villigen/Switzerland. Different solid contents, as well as annealing at −5 °C for 11 h, were used to modify the porous structure of the samples, which was quantified using X-ray computed tomography. Annealing of the 5% (w/w) sample, with a pore size distribution (PSD) of 23.7 ± 11.1 µm, yielded a very open pore space with high porosity (ε = 0.96) and a PSD of 33.0 ± 27.0 µm. In contrast, the higher solid content resulted in small, lamellar, narrow pores with high anisotropy and a porosity of ε = 0.65, as well as a PSD of 13.5 ± 4 µm. In operando neutron imaging was used to show the impact of the structure of frozen maltodextrin on the overall drying kinetics and shape of the sublimation front during freeze-drying. For this purpose, a freeze-drying stage was employed, which allowed a novel approach to time- and space-resolved monitoring of the ice phase. The sublimation front propagation was quantitatively analyzed based on ice saturation profiles and sublimation rates. The dependence of drying velocity on structure is nicely demonstrated by the data. In addition, it is shown that the sublimation front widened during freeze-drying, resulting in either rather concave or convex shape depending on morphological parameters.

Locomotion asymmetry in young Standardbred trotters in training and links to future racing career

This study evaluated whether front and hind limb symmetry patterns observed from 1.5 through 3 years of age in Standardbred trotters in training affect racing activity at older age. The hypothesis tested was that asymmetries observed during this period are linked to reduced number of lifetime races and low earnings. Sixteen Standardbreds were subjected to a controlled training and dietary programme from the age of 1.5 years until December as 3-year-olds (P1) and then continued their career with other trainers. On 17 occasions during P1, locomotion asymmetry (vector sum) in front and hind limbs during trot in hand was recorded with a sensor-based system. By 10 years of age, data on lifetime number of races and earnings of the horses were obtained from the Swedish Trotting Association. Horses were divided in groups based on the number of lifetime races performed, i.e. more or less than the median of the cohort born the same year. Mean asymmetry levels did not differ between horses performing more or less lifetime races than the cohort median. However, horses that showed the poorest lifetime race activity showed elevated hind limb asymmetry in August at the age of 3 years, compared to horses with more races (group <median: 9±6 mm vs group >median: 6±2 mm (P=0.02)). There were no correlations between individual mean and peak asymmetries and lifetime earnings. It is concluded that locomotion symmetry observed during trot in hand at the age of 1.5-year-olds to December as 3-year-olds was not a simple and straight-forward predictor of future racing career. However, hind limb asymmetries of around 10 mm in the late season as 3-year-olds could be a warning of impaired future performance.

Equilibrium states of the ice-water front in a differentially heated rectangular cell (a) (a)Contribution to the Focus Issue Turbulent Thermal Convection edited by Mahendra Verma and Jörg Schumacher.

We study the conductive and convective states of phase change of pure water in a rectangular container where two opposite walls are kept respectively at temperatures below and above the freezing point and all the other boundaries are thermally insulating. The global ice content at the equilibrium and the corresponding shape of the ice-water interface are examined, extending the available experimental measurements and numerical simulations. We first address the effect of the initial condition, either fully liquid or fully frozen, on the system evolution. Secondly, we explore the influence of the aspect ratio of the cell, both in the configurations where the background thermal gradient is parallel to the gravity, namely the Rayleigh-Bénard (RB) setting, and when they are perpendicular, i.e., vertical convection (VC). We find that for a set of well-identified conditions the system in the RB configuration displays multiple equilibrium states, either conductive rather than convective, or convective but with different ice front patterns. The shape of the ice front appears to be always determined by the large scale circulation in the system. In RB, the precise shape depends on the degree of lateral confinement. In the VC case the ice front morphology is more robust, due to the presence of two vertically stacked counter-rotating convective rolls for all the studied cell aspect ratios.

Relative rates of fluid advection, elemental diffusion and replacement govern reaction front patterns

Replacement reactions during fluid infiltration into porous media, rocks and buildings are known to have important implications for reservoir development, ore formation as well as weathering. Natural observations and experiments have shown that in such systems the shape of reaction fronts can vary significantly ranging from smooth, rough to highly irregular. It remains unclear what process-related knowledge can be derived from these reaction front patterns. In this contribution we show a numerical approach to test the effect of relative rates of advection, diffusion, and reaction on the development of reaction fronts patterns in granular aggregates with permeable grain boundaries. The numerical model takes (i) fluid infiltration along permeable grain boundaries, (ii) reactions and (iii) elemental diffusion into account. We monitor the change in element concentration within the fluid, while reactions occur at a pre-defined rate as a function of the local fluid concentration. In non-dimensional phase space using Péclet and Damköhler numbers, results show that there are no rough fronts without advection (Péclet<70) nor if the reaction is too fast (Damköhler>10−3). As advection becomes more dominant and reaction slower, roughness develops across several grains with a full microstructure mimicking replacement in the most extreme cases. The reaction front patterns show an increase in roughness with increasing Péclet number from Péclet 10 to 100 but then a decrease in roughness towards higher Péclet numbers controlled by the Damköhler number. Our results indicate that reaction rates are crucial for pattern formation and that the shape of reaction fronts is only partly due to the underlying transport mechanism.

A case study on organization of roof-tile production during the Tang Dynasty: Focusing on tile ends with Lotus patterns unearthed from Ximing Temple

Roof tiles are the most frequently unearthed remains from the sites of imperial-period cities in China. These include tile ends, decorated roof tiles designed to attach to the first row of imbrices laid along the eaves. This study investigated a large number of tile ends containing lotus patterns excavated from Ximing Temple in Chang'an, present-day Xi'an, which was once the capital of the Tang Dynasty. In addition to an examination of aspects of tile ends that were controlled consciously by artisans, such as front surfaces, patterns, and sizes, this study also focused on gathering information through an analysis of aspects resulting from the mechanical process such as minor variations in size, pattern, tool marks, and the proportion of the edge to the diameter. We measured the intentional standardization and mechanical standardization of tile ends using the aspects mentioned above, and the degree of standardization in an assemblage can be used to infer the organization of production. This study thus expands on artifact typology to analyze the organization of and changes in tile-end production at the Ximing Temple workshop. With reference to other samples and historical records of the Tang Dynasty, it also provides evidence that can shed light on general cultural variations and socio-economic changes in this period.

Mathematical modeling of spatiotemporal patterns formed at a traveling reaction front.

In some chemical systems, the reaction proceeds in the form of a propagating wave. An example is the propagation of a combustion wave. At the front of such a wave, different oscillatory regimes and the appearance of spatiotemporal structures can be observed. We propose a qualitative mechanism for the formation of patterns at the front of the reaction. It is assumed that the reason is the interaction of two subsystems, one corresponding to the propagating front and the other describing the emerging patterns. The appropriate mathematical model contains two blocks: for the travelling front, we use a model of the Fisher-Kolmogorov-Petrovsky-Piskunov type, while patterns at the front are described by the FitzHugh-Nagumo type model. Earlier, we applied this approach to explain the occurrence of autowaves-target waves and spirals-at the front of the reaction. In the present paper, we demonstrate in numerical simulations that this approach also works effectively to explain stationary relative to the front patterns, the so-called Turing or cellular structures, that are observed experimentally, in particular, at the front of a combustion wave. We also investigate the dependence of these patterns on the thickness of the front and its speed, as well as on the degree of diffusion instability achieved within the front layer.

P400Spatial relationship between atrial fibrillation drivers identified by dipole density mapping and left atrial fibrosis

Abstract Background Atrial fibrillation (AF) is a complex arrhythmia and several mechanisms that might coexist have been proposed. Recent technical advances opened the way to better mapping possibilities and might contribute to target more specific components of the AF substrate. Objective The aim of this study was to evaluate a spatial correlation between AF drivers as determined by a novel non-contact unipolar high-resolution system and atrial fibrosis assessed by cardiac magnetic resonance imaging (MRI). Methods Patients undergoing a first ablation procedure for persistent AF were included. Prior to ablation, a Late Gadolinium-Enhancement (LGE) MRI was performed to detect the fibrotic atrial tissue. The procedure was performed using a new non-contact unipolar high-resolution system allowing a 3D anatomy reconstruction with a continuous dipole density mapping. Three different wave front patterns were analyzed in the left atrium (LA): 1) focal activity (FA), 2) localized rotational activation (LRA) and 3) localized irregular activation (LIA). The spatial distribution of these AF drivers was analyzed prior to AF ablation. Results A total of 49 patterns in 6 patients were identified, among them 22 FA, 14 LRA and 13 LIA. The posterior (n = 14), anterior wall (n = 13) and roof (n = 8) were identified as predominant driver sites. 31/49 (59%) drivers had a strong correlation with late enhancement in MRI. Most of the LIA, LRA and FA were embedded infibrotic areas (LIA 10/13 (77%); LRA 9/14 (64%) and FA 12/22 (54%). The postero-inferior LA showed the best correlation between drivers and fibrosis, the antero-septal LA the weakest one. Conclusion There is a significant overlap between AF driver regions identified by dipole density mapping and atrial fibrosis assessed by MRI. Most of AF drivers are embedded in fibrotic areas, particularly in case of localized irregular activity and at the posterior LA. Abstract Figure.

P6146Atmospheric front patterns and acute cardiovascular diseases, a new perspective in the cardiovascular threat of global climate change

Abstract Background There is substantial evidence that the health threat of global climate change is real and it could be a medical emergency. The impact of climate change on health is mediated through atmospheric parameters which are direct environmental stressors on the human body and have a potential cardiovascular (CV) morbidity and mortality effect. Acute cardiovascular diseases (ACVDs) are already major public health issues and in the future unfavourable atmospheric situations, such as increasingly volatile fronts and their negative effects can further increase this problem. Despite evidence about the importance of different atmospheric parameters on health outcomes, there have been few results for atmospheric front patterns' CV effects. Weather fronts are the most complex atmospheric phenomena therefore these atmospheric parameters might have the greatest influence on ACVDs. Purpose We aimed to explore the effects of atmospheric front patterns on ACVDs. Methods A time series Poisson-regression analysis was used to analyse 6499 ACVD hospital admissions, during a five-year period (2009–2013), in light of front patterns. Covariates were three-day (target day and the two previous days) front sequence patterns comprised of the five major front types (no front, warm front, occluded front, cold front, stationary front). Relative risk (RR) estimates for front effects were adjusted for seasonality. The relationship on all ACVDs combined and separately on patient groups by major CV risk factors (hypertension, hyperlipidaemia, diabetes, previous CV diseases) was examined. Results We found that in general, front patterns containing warm front days had a detrimental effect. A warm front, when followed by two days with no fronts present, increased RR by 46% (CI: 4–89%, p=0,015). Cold fronts however were protective. A no front – cold front – occluded front pattern corresponded to a 28% (CI: 8–49%, p=0,037) decrease in RR, with this pattern being present in 1.1% of all days of the study period. Out of the group specific results an occluded front, following days with no fronts present, showed to have the largest effect on hyperlipidaemic patients, increasing RR by 144% (CI: 51–295%, p&lt;0.001). Conclusions This work provides both independent evidence of front patterns' CV effects and a novel tool to investigate and help the understanding of complex associations between atmospheric fronts and ACVDs. The importance of our findings is growing in the context that extreme atmospheric conditions and changes are likely to become more common in the future as a result of climate change. Medical meteorology may open up a new horizon and become an important field of preventive cardiology in the future. In conclusion, a better understanding of atmospheric front effects is of particular importance in order to help identify possible targets for future prevention strategies.

An Experimental Investigation of Flow Regimes in Imbibition and Drainage Using a Microfluidic Platform

Instabilities in immiscible displacement along fluid−fluid displacement fronts in porous media are undesirable in many natural and engineered displacement processes such as geological carbon sequestration and enhanced oil recovery. In this study, a series of immiscible displacement experiments are conducted using a microfluidic platform across a wide range of capillary numbers and viscosity ratios. The microfluidic device features a water-wet porous medium, which is a two-dimensional representation of a Berea sandstone. Data is captured using a high-resolution camera, enabling visualization of the entire domain, while being able to resolve features as small as 10 µm. The study reports a correlation between fractal dimensions of displacement fronts and displacement front patterns in the medium. Results are mapped on a two-dimensional parameter space of log M and log Ca, and stability diagrams proposed in literature for drainage processes are superimposed for comparison. Compared to recent reports in the literature, the results in this work suggest that transition regimes may constitute a slightly larger portion of the overall flow regime diagram. This two-phase immiscible displacement study helps elucidate macroscopic processes at the continuum scale and provides insights relevant to enhanced oil recovery processes and the design of engineered porous media such as exchange columns and membranes.

The effect of front pattern perforation shape on thermal sensations of occupants in personalized ventilation systems

The aim of this study was to find the most favourable shape of the front panel perforation shape, which would allow us to obtain the greatest cooling effect and – at the same time – be positively perceived by the people. The capacity of the personalized ventilation (PV) system to affect human thermal sensation, with different shapes of front panel perforation used, was analyzed.Once the pilot study was conducted, it used a rectangular nozzle of front pattern size 320 mm × 125 mm and six different front patterns perforation shapes with round holes were tested. Operational parameters such as: airflow 20 l/s, supply air temperature at 24 °C or ambient temperature at 28 °C were invariable. The experiment consisted of a two-stage analysis of air jets characteristics and of tests in which people participated. Twenty-five male volunteers, at the age of 22–23 were engaged. They their assessed thermal sensation and completed relevant questionnaires.On the basis of the results of the above study, differences in jet characteristics depending on the pattern shapes and their different impact on thermal sensation of the volunteers were demonstrated. The biggest cooling effect was obtained using front panels with small hole size (d = 5 mm). These perforations allowed us to obtain a more even air outflow from the entire panel. This ensured a broader airflow of lower velocity, reaching and affecting a larger area. With holes of larger size (d = 15 mm), air outflow occurred mainly through the central part, which produced narrow jets of higher velocity.

Predicting human dimensions in body images for automatic generation of female pants patterns

This study proposed a method on how to obtain and predict body measurements from frontal and side images of a subject for the individualized pattern generation of women's pants. According to the relationship between front and back patterns and a body torso, 32 important pattern dimensions relevant to certain body dimensions were determined by the graphic flattening method. For the body dimensions (such as perimeters) that could not be directly extracted from the body images, the prediction models were established based on the available width and depth measurements. The body measurements from the body images of 425 subjects were compared with the corresponding manual measurements, which showed a good correlation between the automated and manual measurements. The tried-on test showed that the pants made with the generated patterns demonstrated good fitting effect at the important characteristic landmarks of a participating subject. This method can accelerate the pattern-making process for women's pants based on body measurements, reducing human efforts, costs and production time.

Three-dimensional numerical and experimental investigation of the behavior of solar salts within thermal storage devices during phase change

Experiments and three-dimensional computational simulations of melting and solidifying solar salts in an aluminum container are performed in order to obtain a fuller picture of the thermal and flow behavior of this commonly-used phase change material. A heating element is placed under a closed aluminum container filled with solar salts, both with and without aluminum fins. Accurate simulations are performed in part by identifying thermal properties that lead to the accurate reproduction of experimental results; the thermal properties of the solar salts are found to differ significantly from values in the literature. The numerical results are then used to describe the dynamics of the solid-liquid front and flow patterns within the container during melting and solidification. The combined experimental and computational results provide insight into the thermal, flow, and melt behavior of solar salts. The experimentally validated simulation capability can be used for the design of efficient thermal storage devices using solar salts.

Mobile Technology to Assess Balance During Sit to Stand Manuever Among Older Adults at Risk for Falling

Older adults over age 65 are susceptible to loss of balance for a variety of reasons including drops in blood pressure with standing (orthostatic hypotension [OH]; Gray-Miceli, Ratcliffe, Thomasson, Quigley, Li &amp; Craelius, 2016). OH is a treatable condition, and cause of falls if detected. Nearly 50% of the 1.43 million older adults in long-term care experience falls (National Center for Injury Prevention and Control, 2017). Falls often occur among older adults in long term care during periods of transitioning, where older adults are susceptible to loss of balance and increased risk to fall. As found in our prior work, older adults with OH may not always experience classic dizziness symptoms that may accompany OH (Gray-Miceli, Ratcliffe, Liu, Wantland &amp; Johnson, 2012; Gray). To better understand this phenomenon, our project adapted a cellphone as an inertial measurement unit attached to the person’s center of mass to determine body sway. The objective of this pilot study was to determine if a relationship was observable during the sit to stand maneuver (StS) while older adults wore a Smartphone measuring three dimensions of motion among older adults who had evidenced of symptoms or OH. A sample of four older adults from a rehabilitation facility who were 65 years of age, receiving physical therapy at the time of testing, were cognitively intact, able to perform the StS maneuver and had no active cancer, fractures or serious injuries were recruited and enrolled. Oh determinations, pulse rate and symptoms of dizziness were elicited during a 30 second StS maneuver. In Patient A and Patient B we present the Z-axis and X-axis of front acceleration and patterns of motion side by side for case comparison while highlighting clinical findings. In Patient B, a greater degree of sway at the start of the StS maneuver is noted. Patient B’s blood pressure also dropped 33 mmHg and there were symptoms of dizziness. Drops in mean arterial blood pressure were greater among those with symptomatic OH. Limitations of this pilot include noise, selection of filters and time stamping of the data. Project aims are to help clinicians prevent falls by further assessing symptoms among elders who suffer from LOB and OH.

Topographic effects on dispersal patterns of Phytophthora cinnamomi at a stand scale in a Spanish heathland.

Phytophthora cinnamomi is one of the most important plant pathogens in the world, causing root rot in more than a thousand plant species. This observational study was carried out on a P. cinnamomi infected heathland of Erica umbellata used as goat pasture. The patterns and shapes of disease foci and their distribution were described in a spatial and temporal context using an aerial photograph record. A set of topographic traits was selected on the basis of a disease dynamic hypothesis and their effects on observed spatial disease patterns were analyzed. Incipient infections situated in flat terrain expanded as compact circular front patterns with a low growth rate. On slopes, disease patches developed more rapidly down slope, forming parabolic shapes. The axis direction of the parabolas was highly correlated with terrain aspect, while the parabolic amplitude was associated with land curvature and slope. New secondary foci appeared over the years producing an accelerated increase of the affected surface. These new foci were observed in sites where disease density was higher or near sites more frequently visited by animals such as the stable or the forage crop. In contrast, a smaller number of disease foci occur in areas which animals are reluctant to visit, such as where they have a short range of vision. Our results suggest that 1) the growth of existing P. cinnamomi foci is controlled by a combination of root-to-root contact and water flows, 2) the increase in the diseased area arises mainly from the multiplication of patches, 3) the formation of new foci is mediated by long-distance transport due to the movement of animals and humans along certain preferential pathways, and 4) geomorphology and topography traits are associated with the epidemiology of this soil-borne pathogen.

Integrated Front–Rear-Grid Optimization of Free-Form Solar Cells

Free-form solar cells expand solar power beyond traditional rectangular geometries. With the flexibility of being installed on objects of daily use, they allow making better use of available space and are expected to bring in new possibilities of generating solar power in the coming future. In addition, their customizable shape can add to the aesthetics of the surroundings. Evidently, free-form solar cells need to be efficient as well. One way to improve their performance is to optimize the metallization patterns for these cells. This work introduces an optimization strategy to optimize the metallization designs of a solar cell such that its performance can be maximized. For the purpose of optimization, we model an existing transparent free-form solar cell design, including front and rear electrode patterns, to validate it against previously published experimental results. The front and rear metallizations of this transparent free-form solar cell are subsequently redesigned using topology optimization. More than 50% improvement in output power is achieved by using topology optimization.