Test Enclosure Research Articles

Improved Metallic Enclosure Electromagnetic Imaging Using Ferrite Loaded Antennas

Three-dimensional electromagnetic imaging can be used to monitor grain within metallic grain bins. Data acquisition requires multiple antennas surrounding the imaging space, which are used to transmit and receive the electromagnetic energy inside the bin. Due to their presence inside a metallic enclosure and due to very large mechanical forces these antennas are required to be low profile. In addition, since they are part of the imaging domain, they should be simple to model in the imaging software (i.e., using a point source). Existing half-loop magnetic field antennas meet these design criteria, but can be improved, particularly with better radiation efficiency. Herein, we present an enhanced antenna design: a ferrite-loaded shielded half-loop antenna designed to measure only the tangential component of the magnetic field against the metal enclosure wall, while rejecting the normal component of the electric field. Experimental results in two bins show that the enhanced design improves the signal level over existing probes by 6–18 dB inside a small-scale enclosure and around 20 dB inside a larger 28 m3 (800 bushel) bin. Full 3D imaging results of a high-moisture target within a low-moisture grain background inside the test enclosure show that the enhanced antennas improve the quality of the reconstructed results in the smaller bin, particularly where the antenna performance improvements are prominent.

Simulation and Measurement of Pressure Rise in GIS 145 kV due to Internal Arcing

Internal arc testing of metal-enclosed, SF6 gas insulated switchgear (GIS) is defined by IEC 62271-203 and is not a part of mandatory type tests.
 However, due to the increasing demands on the safety of personnel, more often the implementation of this test is required in the tender documentation. According to IEC, the duration of the electric arc is related to the performance of the protective system determined by the first and second stage of protection. For the rated short-circuit current equal or higher than 40 kA, during the first stage of protection (0.1 s), no external effects on enclosure other than the operation of pressure relief device is permitted. During the second stage of protection (≤0.3 s) no fragmentation is permitted, but burn-through is acceptable. The test should be carried out on the GIS compartment with the smallest volume at nominal gas pressure. Since a newly developed GIS 145 kV is designed as a three-phase encapsulated, arc initiation is achieved by short connecting of all three phase conductors in the vicinity of a partition by means of a thin metal wire. This ensures that two electric arcs burn simultaneously commutating between the phases, so the possibility of enclosure burn-through in this type of GIS is minimized. In order to prevent the release of SF6 gas in the atmosphere during the testing, a test enclosure should be placed in a protective gastight enclosure filled with air or more often SF6 gas at pressure of 0.1 MPa. This test object configuration significantly complicates the pressure rise calculation and increases the testing cost. In order to prevent enclosure fragmentation, the pressure difference between the test enclosure and the protective enclosure during the test should always be less than the bursting pressure of test enclosure. Also, the protective enclosure should be designed to withstand the maximum pressure rise that may occur after pressure relief device opens. In order to assess the likelihood of passing the upcoming type test for newly developed GIS, a computer program for calculation of pressure and temperature in the test enclosure and protective enclosure was developed. The mathematical model is based on the paper of the working group CIGRE A3.24, published in 2014. The basic model shown in the paper is enhanced by the real properties of the SF6 gas/plasma, evaporation of the electrode material and the insulator ablation. The contribution of exothermic/endothermic reactions between the gas and the electrode material on the pressure and temperature rise was also considered. At the same time, the measurements of pressure rise in GIS enclosure and protective enclosure were carried out in Končar High Power Laboratory. The experiments performed on a copper and aluminum electrodes in SF6 gas confirmed significantly higher contribution of aluminum electrodes to the pressure and temperature rise compared to the copper electrodes. The computer program is verified by measurement results.

Experimental study for the hold time of clean extinguishing agent interpreted as function of time

This paper proposes a new model to predict the hold time in enclosures protected with clean extinguishing agent (CEA). The limitations of three existing theoretical models are analyzed, and the proposed model is validated. Existing theoretical models employ the enclosure height as a variable in predicting the hold time of CEA; hence, the prediction of diffusion according to time change has limitation. In this study, a theoretical model is proposed in which species diffusion is defined as a function of time rather than elevation, based on the theory of diffusion in fluids. The proposed model was experimentally verified using five CEAs. The predicted hold time in each theoretical model was compared to the height-specific hold time measured in the test enclosure. Existing theoretical models, which are expressed as a function of elevation, will have varying errors between the predicted and measured hold times depending on the input parameters. Also, the maximum error range is approximately 46%. However, in the proposed model expressed as a function of time, the error of the hold time does not change. In addition, the maximum error range is approximately 16%, which increases the accuracy approximately 3 times compared to the existing theoretical model.

Investigation of the fluid dynamic of the modified Hartmann tube equipment by high-speed video processing

Hartmann tube equipment is used in the dust explosion experimental test to screen the flammability of powdered materials (according to ISO 80079-20) and to determine the Minimum ignition energy of dust (UNI EN 13824:2004). For the test, the nominal concentration, as the ratio between the dust sample mass and the chamber test volume (1.2 liters), is considered, assuming a uniform concentration distribution. Even though adopted as standard procedure, this approach does not consider the dust cloud's non-stationary conditions inside the tube: the effect of turbulence decrease and dust sedimentation during the test duration will affect the dust concentration locally and globally within the test enclosure. Moreover, it is well known that the turbulence intensity influences Minimum Ignition Energy.This work derives from previous investigation on describing the dust cloud behavior within dust explosibility laboratory apparatuses. High-speed video recordings have recently been adopted to support the dust cloud dynamic analysis and visualize the cloud dispersion within a standard test setup, as the 20 L sphere and the modified Hartmann tube. This work intends to use different high-speed videos of dust dispersions in the modified Hartmann tube, with different injection pressure and sample mass, to focus on the behavior of the cloud at the typical delay time of the MIE measurement, i.e., 60-180 ms. Each video is processed frame by frame to reveal information on the cloud dynamics, otherwise hidden. The dust dynamic is accounted for calculating the variation in time of the brightness of pixels.This way, it is possible to obtain a set of data that incorporate the effects of the dust cloud distribution and the velocity of the particles’ clusters. The experimental data processing will help to focus on the time-scale and the length scale of the turbulence. The next study will focus on evaluating the time and space scale of the dust cloud and identifying the effect of ignition time delay on the MIE measurement to provide indications to operate at the most conservative conditions (higher concentration) and to avoid issues and under/overestimates due to agglomeration, sedimentation or segregation of dust particles.

Experimental study of water spray dispersion around a surface-mounted cube in atmospheric boundary layer flow

Processes of spray dispersion around bluff bodies in wind are central to many engineering applications; notably the design of wildfire sprinkler systems and spray cooling systems for urban areas. Simulation methods such as computational fluid dynamics (CFD) have been widely used for the prediction and analysis of such wind-body-spray interactions. However, there has been a lack of high-quality experimental data against which simulations can be validated. In this study, detailed outdoor experiments were performed on the dispersion of water sprays near an isolated 2.4 m cube mounted on the ground and immersed in the atmospheric boundary layer. Sixteen experiments were conducted, each with either a butterfly or hollow-cone sprinkler implemented on the windward or leeward side of the cube. The deposition of water was measured on the cube surfaces and ground, and high-frequency air velocity measurements were taken at three heights to characterise the atmospheric boundary layer flow. Separate experiments were conducted in a test enclosure using a high-speed videography technique to measure the spatial and temporal distributions of mass flow rate, droplet size, and droplet velocity within each spray. Comprehensive data is presented that is well suited for use in validating simulations of wind-body-spray interactions.

Small scale simulation of artificial smoke optical properties

The use of numerical simulations in Fire Safety Engineering provides faster and more affordable ways of research and development, with the drawback that their use is often conditioned by available expertise and thorough validation. In this paper, the results of two small scale numerical simulations of artificially generated smoke are being validated by comparison of the smoke’s light extinction coefficient values and those of the visibility levels in the testing enclosures with the results obtained through experimental testing. The influence of grid size on simulation accuracy and computational time is evaluated by presenting the small gain in accuracy and the important increase in computational time for different sized meshes, showing that at least in numerical simulations dealing with artificial smoke, a larger grid size can produce fairly accurate results. A comparative evaluation of the effect that the positioning of the measuring devices inside the testing enclosure has on the results is also performed, both for the experimental setup and the numerical simulations.

Design and Analysis of a Thermoelectric Air-conditioning System

Thermoelectric devices use the Peltier effect which creates a heat flux between the junctions of two different types of materials. The thermoelectric module also referred to as a heat pump transfers heat from one side to the other when a DC current is applied.
 This study carried out the theoretical and experimental analysis of a thermoelectric air conditioning system. A prototype thermoelectric air conditioner of 286 W cooling capacity was built and a testing enclosure made from plywood and Styrofoam was also constructed in order to validate the theoretical result with an experimentation. It was discovered that thermoelectric air conditioning took 4 minutes to reach its desired temperature of 22℃ whereas the standard air conditioning system (Refrigeration Cycle) took 20 minutes to cool to a room temperature. Economically it was also discovered that thermoelectric air conditioning system is 50% cheaper than the refrigeration cycle air conditioning systems.
 The thermoelectric air conditioner has cheaper maintenance and greater estimated life span of 7 years more than the refrigeration air conditioner. This is because the air conditioner that operates on the refrigeration cycle uses a rotating compressor while the thermoelectric air conditioner uses thermometric module.

Design of an Arsine Gas Free Rapid Arsenic Detector Using a Novel Luminescent Metal-Organic Framework

An estimated 140 million people have access to drinking water with an excessively high concentration of arsenic. Many of them are located in countries that lack the infrastructure and funding to support laboratories, thus requiring the use of cheaper rapid field tests to determine arsenic levels in water. These tests typically first reduce all the dissolved arsenic to arsine gas, then a paper strip laden with mercuric bromide is inserted into the reaction vessel. The arsine gas reacts with the mercuric bromide on the strip for a colorimetric change. Semi-quantitative results can be determined by comparing the color change to a provided color chart. These rapid tests are non-ideal since the user can be easily exposed to toxic arsine gas if the test enclosure is poorly sealed. Additionally, the colorimetric reaction between mercuric bromide and arsine gas does not work if the paper strip gets wet and likely has reduced performance in high humidity conditions.To improve the safety and ease of testing arsenic in water, we propose the use of a Zinc-Trimesic acid metal-organic framework (MOF) functionalized with 8-Hydroxyquiniline (ZnQ@Zn-BTC). When exposed to arsenate ions, the ZnQ@Zn-BTC MOF exhibits fluorescence quenching upon excitation with UV light. This luminescent reaction required no intermediate reactions, thereby simplifying the assay and eliminating the need for arsine gas. The MOF is available in a dehydrated solid form which can be re-suspended in solution to prepare for testing. The addition of microlitre-scale volumes of sample is enough for detection, indicating that the MOF may be amenable for low-volume detection applications.Preliminary testing in solution has been performed where an arsenic-laden water sample was first added to a ZnQ@Zn-BTC suspension in ethanol and allowed to rest for 10 minutes for binding events. The fluorescence of the sample was then measured using fluorescence spectroscopy, with excitation using 387 nm light, and peak emission observed at 510nm. The quenching was subsequently calculated as the simple difference between the fluorescence of the sample and the fluorescence of a control ZnQ@Zn-BTC solution. Current tests in solution reveal sensitivity for arsenic compounds down to a concentration of 100 ppb for sample volumes as small as 20 µL. There is maximum fluorescence quenching at 1.5 ppm of arsenic and samples with concentrations higher than this level would likely not demonstrate further quenching.Future development includes immobilization of the ZnQ@Zn-BTC on a paper substrate for an easy, rapid and quantitative arsenic testing method. By moving to a paper-based platform the assay can be simplified to a one-step process: simply introduce the sample and the capillary action of the paper will handle the rest. In addition, a reader for the strip can be developed for quantitative results with greater reliability than the color chart comparison that current rapid tests utilize. Paper-based microfluidics also has the advantages of being easily scalable and extremely stable, with little influence from environmental factors. These qualities make it suitable for deployment in less developed countries that may lack resources for more complex assays.Early identification of arsenic in water sources is a key step towards the reduction and prevention of arsenic poisoning. By introducing the proposed assay with a suitable education and awareness program, identification of arsenic in water can be performed quicker and its negative effects on the health of the community can be restrained faster.

Development of Fireground Exposure Simulator (FES) Prop for PPE Testing and Evaluation

Research on the performance of personal protective equipment (PPE) for the Fire Service is challenged by the ability to repeatedly and feasibly test new designs, interventions and wear trials in realistic conditions that appropriately simulate end use environments. To support firefighter PPE research and firefighter PPE acclimation/training, a multidisciplinary team has developed a low cost, easily replicable approach for simulating conditions commonly encountered by firefighters operating on the interior of a residential structure fire. The testing enclosure can be used with either stationary mannequins or firefighters conducting typical fireground activities, providing a method to study a wide range of PPE and physiological studies as well as training activities that may support developing new technologies and standardized testing opportunities. Environmental gas concentrations and firefighters’ local temperatures were measured during trials and compared to data collected from simulated fireground activities and fireground responses with good agreement.

Experimental and Computational Study of the Implementation of mPCM-Modified Gypsum Boards in a Test Enclosure

The application of phase change materials (PCM) in the thermal envelope of buildings has proven to be an alternative to reduce energy consumption and to improve thermal comfort conditions. The present work evaluates the thermal behavior of gypsum boards modified with a microencapsulated PCM (mPCM) in a cubic test enclosure, considering the climatic conditions of Santiago de Chile in the September–November period of 2017. The design of the test enclosure was performed considering the minimization of parameters that affect the variation of its inner temperature and favoring the heat flow through the gypsum boards. Experimentally, the results reflect the main effects of the implementation of a mPCM, among which the displacement of the maximum heat load and the decrease in the daily oscillation of the internal temperature of the test enclosure (up to 2 °C) stand out. In addition, the mPCM modified gypsum board was thermally characterized to carry out a thermal simulation of the enclosures using EnergyPlus™. The obtained numerical results agree with those obtained experimentally, including the behavior of the transient heat flux through the gypsum boards. Moreover, it was found that considering a null infiltration rate gives place to unrealistic results, suggesting that this parameter should be controlled.

Numerical investigations of convective phenomena of oil impingement on end‐windings

A novel experimental rig for analysing intensive liquid cooling of highly power-dense electrical machine components has been developed. Coupled fluid flow and heat transfer has been modelled, using computational fluid dynamics (CFD), to inform the design of a purpose-built enclosure for optimising the design of submerged oil jet cooling approaches for electrical machine stators. The detailed modelling methodology presented in this work demonstrates the value in utilising CFD as a design tool for oil-cooled electrical machines. The predicted performance of the final test enclosure design is presented, as well as examples of the sensitivity studies which helped to develop the design. The sensitivity of jet flow on resulting heat transfer coefficients has been calculated, whilst ensuring parasitic pressure losses are minimised. The CFD modelling will be retrospectively validated using experimental measurements from the test enclosure.

Internal pressures in a full-scale test enclosure with windward wall openings

A single opening on the windward wall which generates large internal pressures in a building often defines the critical wind loading structural design criterion. This paper presents internal pressure fluctuations in a sealed Full-Scale Test Enclosure (FSTE) for a range of single windward wall opening configurations induced by atmospheric wind flow, to assess the influence opening size (i.e. S* = (A3/2/V)(as/U¯h)2) has on the internal pressure. Damped Helmholtz resonance was observed for S* > 0.88, with peak and standard deviation internal pressures being about 5% higher than the external pressures when S* > 1.9. Internal pressure fluctuations are attenuated when S* < 0.75. The inertial coefficient CI is between 1.3 and 1.5 and the loss coefficient CL increases with increasing opening area (0.88 < S* < 5.8) between 10 and 20. These parameters have a significant influence on the internal pressure fluctuations, and this controlled full-scale study carried out for the first time provides data for validating analytical and model-scale studies on internal pressure fluctuations in buildings.

Experimental and numerical study of Buoyancy-driven low turbulence flow in rectangular enclosure partially filled with isolated solid blockages

This paper considers the natural convection inside an air filled enclosure having several isolated cylindrical blockages distributed within it, and arranged parallel to two vertical walls of the enclosure. These two walls are maintained at different temperatures resulting in a natural convection process inside the enclosure. The objectives are to provide experimental temperature data and to investigate the influence of the blockages proximity within and outside the active vertical wall hydrodynamic boundary layer of the natural convection flow and heat transfer. Experiments were designed with high degree of accuracy to provide reliable temperature data-bank for a range of blockages proximity to the active vertical walls. The test enclosure is an air filled rectangular cavity fixed at 0.97 m × 0.4 m × 1 m, corresponding to the height, width and depth respectively. The top and bottom walls are conducting surface and the temperature difference between the active vertical walls was maintained at 42.2 °C resulting in a characteristic Rayleigh number of 4.04 × 109 based on the enclosure height. All the walls of the enclosure were insulated externally while the inner surfaces were covered with conducting plate. The test cavity capability of establishing low turbulence natural convection flows was verified. All temperature data were obtained at steady state and it was verified to be reproducible by repeating the experiment at different times. Also, two-dimensionality was verified via rigorous temperature readings over a period of time. Additional temperature readings were recorded for the air and cylinder surfaces at several distinct locations. Further investigations were conducted using a numerical approach to supplement and validate the experiments.Experimental temperature data collated at various locations within the enclosure show excellent comparison with numerical results and as such provide a useful experimental benchmark temperature data for the validation of low turbulence natural convection flow in enclosure partially filled with isolated solid objects. Our result shows that a significant increment or reduction in air temperature and wall heat transfer could be achieved by varying the blockages proximity, and especially when the blockages are positioned within the hydrodynamic boundary layers of the active vertical walls.

Environmental scaling influences the use of local but not global geometric cues during spatial reorientation.

During spatial reorientation, the use of local geometric cues (e.g., corner angles) and global geometric cues (e.g., principal axis) is differentially influenced by enclosure size. Local geometric cues exert more influence in large enclosures compared to small enclosures, whereas the use of global geometric cues is not influenced by changes in enclosure size. Such effects are suggested to occur because of differences in training enclosures sizes or differences in testing enclosure sizes, but investigations of enclosure-size effects on spatial cue use have been confounded by environmental scaling between training and testing. We trained participants in a trapezoid-shaped enclosure to respond to a corner uniquely specified by both local and global geometric cues and tested participants in a rectangle (isolating the use of global geometric cues) and in a parallelogram (placing local and global geometric cues in conflict). Between groups, participants experienced different training environment sizes but identical testing environment sizes or identical training environment sizes but different testing environment sizes, and this allowed categorization with respect to the direction of environmental scaling. We found that environmental scaling between training and testing size (but not training size differences or testing size differences) influenced the relative use of local geometric cues. The use of global geometric cues was not influenced by enclosure size. Results challenge prior explanations of the influence of enclosure size on relative spatial cue use during spatial reorientation. (PsycINFO Database Record

Preference for the mother does not last long after weaning at 3 months of age in sheep

Ewes develop a strong selective bond with their offspring, which is set immediately after lambing and maintained until weaning, which in domestic sheep occurs when lambs are 4–5 months old. However, in productive systems lambs are weaned earlier, when they are 2–5 months old. The aim of this experiment was to determine how long the preference for the mother is maintained after abrupt weaning in lambs that have been nursed by their dam for 3 months. Eighty-two single Corriedale lambs stayed with their mother until weaning at 3 months of age, when they were abruptly separated from their mothers and moved to another paddock located 1500 m away, avoiding any mother-young communication. Preference for the mother was tested using a two-choice test between their own and another mother from the same flock, matched for age and physiological status. Lambs were tested in a 10 m × 10 m × 7 m triangular testing enclosure with one ewe placed in each of the two holding pens. A wire mesh plastic fence prevented lambs from approaching the ewes at less than 1 m. A proximity zone near the ewes was defined (1 × 2 m). The location of the mother and the familiar ewe in the holding pens was alternated between tests. During 3 min were recorded: the proximity zone reached first, the latencies to enter each proximity zone, the total time spent in each proximity zone, and the number of bleats produced by the lamb while it was in each zone. All the lambs were tested 3 days before weaning, and 30 (n = 25), 40 (n = 15) or 60 days (n = 42) after weaning. Before weaning, there were no difference in the first proximity zone entered, but in the other variables lambs showed a strong preference for their mother rather than for the familiar ewe. Lambs still preferred their mother 30 days after weaning, although this preference was weakened. However, lambs tested 40 and 60 days after weaning did not show any preference. We concluded that after being weaned at three months of age, the preference of lambs for their mother in comparison to a familiar ewe decreases within 30 days, and finally disappeared 60 days after weaning.

Do juvenile rats use specific ultrasonic calls to coordinate their social play?

Play fighting in juvenile rats is associated with a high occurrence of 50 kHz vocalizations. These calls are varied in form, ranging from long, flat calls to short, frequency-modulated ones. We hypothesize that at least some types of calls serve as play signals to facilitate play. In the present study, pairs of juvenile male rats that were unfamiliar with one another were paired in a neutral test enclosure to which they had been habituated. Video and audio records were made of the encounters. Pairs were of two types: both pairs could vocalize or only one partner could do so. There were some differences between the play of pairs containing a devocalized partner, but overall, the pattern of play, the frequency and types of calls were similar between the two types of pairs. We used a Monte Carlo shuffling technique to analyse the correlations between the playful actions performed and the types and frequencies of various 50 kHz calls that were produced. The analyses revealed that there were strong associations between types of calls and types of social contact: an approach followed by playful nape contact was associated with calls, but an approach followed by nonplayful contact (e.g. anogenital sniffing) was not. Similarly, different calls were associated with different actions, such as nape contact, evade and wrestling, with most of these calls being uttered by the initiator of the action, not the recipient. However, coordinating calls reciprocally with complementary calls uttered by participants as they engaged in complementary actions (e.g. attacking, being attacked) appeared to be a way in which calls could potentially be used as play signals to influence the ongoing cooperation needed to sustain play fights.

Experimental investigation on helium distribution and stratification in unventilated vertical cylindrical enclosure – Effect of jet release rates and total release volume

Hydrogen leakages into enclosed spaces may occur in hydrogen storage and usage facilities and in nuclear power plants (NPP) following a severe accident. In the absence of either mitigation or combustion processes, hydrogen leaked into the enclosed space may accumulate and form large cloud of explosive mixture with air. This, when gets ignited, can lead to a strong deflagration or even detonation and cause huge threat to both life and property. In NPP, such events can cause over-pressurization of the containment, causing problems in the structural integrity of the containment and consequently result in the leakage of radioactivity into the environment. The present study reports the experimental investigation of the phenomenology of hydrogen distribution inside a cylindrical test enclosure (AIHMS). Different hydrogen leak scenarios are experimentally simulated using helium gas, which is its inert surrogate. The effect of helium release velocities on mixing and distribution of helium within the enclosure, for different quantities of helium released has been experimentally investigated. The experimental studies are conducted in a test enclosure having a volume of around 2 cubic-meters, specifically designed for the purpose and the results have been presented systematically.

The Nonrecursive Plating Algorithm (NRPA) for Computing the Total Radiative Exchange Factors in Enclosures

Many numerical methods for computing radiation exchange in enclosures are based on the computation of direct exchange areas (DEAs) and total exchange areas (TEAs). Excessively long computation times can be associated with TEAs computation. Among the best performing methods, the plating algorithm (PA) computes TEAs from DEAs based on a set of simple recursive equations. An efficient CPU and GPU parallelization of the PA are represented. Nevertheless, PA computation complexity is O(N 3). A novel formulation, the nonrecursive plating algorithm (NRPA), is introduced. It allows the computation of TEAs with a single nonrecursive step. Its equations are formulated by identification to the PA equations giving TEAs from DEAs, requiring one simple assumption. The NRPA is then written in matrix form as mainly a square matrix multiplication operation. Based on advancement in matrix multiplication computation, the NRPA complexity is proven to be O(N 2.38) for the number of multiplications. CPU and GPU NRPA are implemented based on the optimized linear algebra library BLAS for CPU and cuBLAS for GPU CUDA programs. NRPA is found to highly outperform PA in both CPU and GPU computation times. Finally, a test enclosure is considered and serves to validate the accuracy of the NRPA by comparison to the PA.

Evidence of a relational spatial strategy in learning the centre of enclosures in human children (Homo sapiens)

Three- to five-year-old children were trained to localize a sensor hidden underneath the floor, in the centre of a square-shaped enclosure (1.5m×1.5m). Walking over the sensor caused a pleasant music to be played in the environment, thus engaging children in a playful spatial search. Children easily learned to find the centre of the training environment starting from random positions. After training, children were tested in enclosures of different size and/or shape: a larger square-shaped enclosure (3m×3m), a rectangle-shaped enclosure (1.5m×3m), an equilateral triangle-shaped enclosure (side 3m) and an isosceles triangle-shaped enclosure (base 1.5m; sides 3m). Children searched in the central region of the enclosures, their precision varying as a function of the similarity of the testing enclosure's shape to the shape of the training enclosure. This suggests that a relational spatial strategy was used, and that it depended on the encoding of geometrical shape. This result highlights a distinctive role of the geometric centre of enclosed spaces in place learning in children, as already observed in nonhuman species.

CA3 Sees the Big Picture while Dentate Gyrus Splits Hairs

The dentate gyrus (DG) and area CA3 of the hippocampus have been long hypothesized to perform pattern separation and pattern completion, respectively. A new study published in this issue of Neuron, Neunuebel and Knierim (2014), provides strong empirical support for this functional dissociation.