Large Geometry Research Articles

NaI:Tl,6Li-PVT composite scintillator toward neutron and gamma discrimination

Efficient and affordable scintillators with the capability of neutron (n) and gamma (γ)-ray discrimination have become increasingly urgent for homeland security and radiation protection applications. In this work, a composite scintillator prototype made of NaI:Tl,6Li (NTL) single crystals and poly(vinyltoluene) (PVT) plastic scintillators was synthesized toward n and γ rays discrimination. The composite scintillator, with a size of 53 mm diameter × 30 mm height, is comprised of four 12 mm × 12 mm × 20 mm rectangular cuboid NTL crystals encapsulated in a PVT-based plastic scintillator matrix. PVT enable the scalability of scintillator to large geometries, and it also serves as light guide and wavelength shifter for NTL scintillation. The synthesized NTL-PVT composite has a high scintillation yield of 36,600 ± 4000 photons/MeV (equivalent to stand-alone NTL crystals), and a decent n and γ-ray pulse shape discrimination (PSD) capability with a figure-of-merit (FOM) of 1.2. These results highlight the feasibility of NTL-PVT composites as cost-effective scintillators with sufficient n and γ-ray detection performance.

Numerical Simulation of the Influence of Hydrogen Concentration on Detonation Diffraction Mechanism

In this study, the impact of hydrogen concentration on deflagration to detonation transition (DDT) and detonation diffraction mechanisms was investigated. The combustion chamber was an ENACCEF facility, with nine obstacles at a blockage ratio of 0.63 and three mixtures with hydrogen concentrations of 13%, 20%, and 30%. Detonation diffraction mechanisms were numerically investigated by a density-based solver of OpenFOAM CFD toolbox named ddtFoam. In this simulation, for the low Mach numbers, the pddtFoam solver was applied, and for high speeds, the pddtFoam solver switched to the ddtFoam solver to simulate flame propagation without resolving all microscopic details in the flow in the CFD grid, and to provide a basis for simulating flame acceleration (FA) and the onset of detonation in large three-dimensional geometries. The results showed that, for the lean H2–air mixture with 13% hydrogen concentration, intense interaction between propagating flame and turbulent flow led to a rapid transition from slow to fast deflagration. However, the onset of detonation did not occur inside the tube. For the H2–air mixture with 20% hydrogen concentration, the detonation initiation appeared in the acceleration tube. It was also found that following the diffraction of detonation, the collision of transverse waves with the wall of the tube and the reflection of transverse waves were the most essential and effective parameters in the re-initiation of the detonation. For the H2–air mixture with 30% hydrogen concentration, the detonation initiation occurred while passing through the obstacles. Subsequently, at detonation diffraction, the direct initiation mechanism was observed.

Contourite on the Limpopo Corridor, Mozambique margin: Long‐term evolution, facies distribution and Plio‐Quaternary processes

AbstractBottom currents are key processes that contribute to the shaping of submarine slopes, with the redistribution of sediments in contourite systems. Despite numerous recent studies on contourite systems, the complexity and diversity of these sedimentary systems are still not fully understood and often underestimated. Their understanding requires comprehensive works integrating all scales from seismic architecture to microfacies. This paper focuses on a contouritic ridge located between 2000 m and 2500 m water depth on the Mozambique margin. Bathymetry, seismic data and piston cores collected during the PAMELA‐MOZ3 cruise allow a multi‐scale study from large depositional geometries to sedimentary facies. At the seismic scale, the contouritic ridge shows three stages of evolution with: (i) initiation and development of the drift/moat system; (ii) an intermediate stage with successive incisions and aggradations; and (iii) moat infill and drift erosion during the Plio‐Quaternary. Plio‐Quaternary deposits are composed of hemipelagic, turbiditic and contouritic facies filling the moat. Coarse‐grained contouritic facies, dominated by planktonic foraminifera, are identified on the western flank of the ridge between the moat infill and the erosional area at the top of the ridge. They consist of condensed deposits, with sedimentation rate about 0.3 cm/ka, indicating a strong and stable bottom current that winnows away the fine‐grained component. This facies could be present more generally in an intermediate position between erosion and depositional areas in contourite systems. At present, the contourite system is located at the transition depth between North Atlantic Deep Water and Antarctic Intermediate Water. Trajectories of bottom currents are complex and interact with sporadic turbidity currents and anti‐clockwise eddies that participate in reshaping the sea floor morphology. Although Plio‐Quaternary depositional geometries indicate the end of drift/moat development, the moat filling and drift erosion are also related to bottom currents and constitute atypical contouritic sedimentation.

Hysteretic behaviors reinforcement of Dou-Gong brackets: Experimental and numerical study

Mantou tenon joints have the largest geometry and are subjected to the most complex internal force in a Dou-Gong bracket in ancient palace-style timber buildings, meanwhile, they are also the key connections affecting the hysteretic behaviors of the Dou-Gong bracket. In this study, in order to improve the hysteretic behaviors of the Dou-Gong brackets, wood and lead were used as materials for reinforcement. Three full-scale specimens were fabricated, in which the Mantou tenon joints between the Da-Dou and the Pingban-Fang were the traditional square-sectional Mantou tenon, the circular-sectional Mantou tenon, and the lead rod, respectively. Failure patterns, hysteretic and skeleton curves, stiffness degradation, strength degradation, and energy dissipation capacities were investigated through quasi-static loading tests. Parameter analyses were carried out by the FE method to determine the sectional diameter and the length of the Mantou tenon when the hysteretic behaviors of the Dou-Gong brackets were optimal. The results indicate that the failure pattern of the Dou-Gong bracket with a circular-sectional Mantou tenon does not change, the larger ultimate load and initial stiffness, the smaller stiffness and strength degradation, and stable energy dissipation capacities are exhibited in the reinforced Dou-Gong brackets. However, for the Dou-Gong brackets with a circular-sectional lead rod, bearing capacities, ductility, and the initial stiffness decrease, the rate of stiffness degradation is faster and the Da-Dou is damaged. With the increase of the sectional diameters of the Mantou tenon, the yielding and ultimate load of the Dou-Gong brackets increase evidently. But as the lengths of the tenon increase, the ultimate bearing capacities of the Dou-Gong bracket increase slightly. In terms of the reinforcement suggestions, the mortise should be properly reamed and drilled deeper, and the original Mantou tenon is replaced with a circular one with larger sectional diameters and longer lengths.

An efficient explicit immersed boundary-reconstructed lattice Boltzmann flux solver for isothermal fluid-structure interaction problems with large deformations and complex geometries

In this paper, a novel approach for isothermal fluid-structure interaction (FSI) problems is proposed that not only inherits the advantages of a reconstructed lattice Boltzmann flux solver (RLBFS) in solving the fluid field, but also retains the efficiency found in the explicit boundary condition-enforced immersed boundary method (EIB) for implementation of boundary conditions on the solid wall. Hence, the new approach (EIB-RLBFS) is highly suitable for complex FSI problems such as large deformations and complex geometries. Furthermore, the arbitrary Lagrangian-Eulerian (ALE) approach is integrated with EIB-RLBFS to solve moving boundary problems efficiently. The structural dynamics are solved by a finite difference method for moving objects and flexible structures. The overall framework of EIB-RLBFS is simple yet robust, where a fractional method is applied to split the FSI process into a predictor step and a corrector step. The RLBFS is applied in the predictor step to predict the intermediate flow field, while the EIB is invoked in the corrector step to impose the no-slip boundary conditions within the flow field, thereby, correcting the predicted flow field to satisfy the no-slip boundary conditions. The proposed approach (EIB-RLBFS) has been tested and evaluated extensively in terms of accuracy and efficiency on several benchmark cases such as, a 2D self-propelled unconstrained flapping/undulatory foil, a 2D filament, a 3D streamwise rotating sphere, and a 3D flapping flag. Results obtained using the proposed approach are in good agreement with previous studies, substantiating the capability and flexibility of EIB-RLBFS for solving FSI problems.

VOXELISATION AND VOXEL MANAGEMENT OPTIONS IN UNITY3D

Abstract. Voxels have been used in various application domains successfully for the last several decades. Their main advantage is the underlying discrete data structure allowing to reliably work with surrounding voxels all the time. In this paper, capabilities of the Unity game engine for voxels management and geometry voxelisation are assessed, where 4 native solutions and 7 open-source projects written for Unity are investigated. Although many voxel-based options exist in Unity, they only deal with one part related to voxels. Therefore, the available capabilities to voxelise, visualise, structure and export voxels are combined and extended with the goal of successfully processing large 3D models and geometries. Many voxel visualisation techniques are investigated including mesh, VFX, point clouds and SVO, which have distinctive benefits in various aspects. Possibilities to structure voxels for effective management in simulations and other tasks are shown. Also, it is enabled to export voxels as point clouds and to the Postgres database for further processing, spatial analysis and distribution. One of the main conclusions is the lack of support for state-of-the-art voxel data structures, where the presented platform can easily be extended to support any. This platform can be used by people who deal with 3D discrete data, require voxelising 3D data, visualise voxels in different ways and technologies, as well as manage more efficiently sparsely occupied voxels.

Nickel-Based High-Bandwidth Nanostructured Metamaterial Absorber for Visible and Infrared Spectrum.

The efficient control of optical light at the nanoscale level attracts marvelous applications, including thermal imaging, energy harvesting, thermal photovoltaics, etc. These applications demand a high-bandwidth, thermally robust, angularly stable, and miniaturized absorber, which is a key challenge to be addressed. So, in this study, the simple and cost-effective solution to attain a high-bandwidth nanostructured absorber is demonstrated. The designed nanoscale absorber is composed of a simple and plain circular ring of nickel metal, which possesses many interesting features, including a miniaturized geometry, easily fabricable design, large operational bandwidth, and polarization insensitivity, over the previously presented absorbers. The proposed nanoscale absorber manifests an average absorption of 93% over a broad optical window from 400 to 2800 nm. Moreover, the detailed analysis of the absorption characteristics is also performed by exciting the optical light’s various incident and polarization angles. From the examined outcome, it is concluded that the nanostructured absorber maintains its average absorption of 80% at oblique incident angles in a broad wavelength range from 400 to 2800 nm. Owing to its appealing functionalities, such as the large bandwidth, simple geometry, low cost, polarization insensitivity, and thermal robustness of the constituting metal, nickel (Ni), this nano-absorber is made as an alternative for the applications of energy harvesting, thermal photovoltaics, and emission.

Ductile Tearing or Plastic Collapse?

Abstract Ductile fracture is characterized by a large amount of deformation. Two mechanisms may lead to ductile failure: local tearing may appear in front of a stress concentration region like a crack front or large geometry changes in a weak part of the structure can induce global collapse of the structure. For large cracks such as those considered in Leak Before Break studies, tearing analyses and net-section collapse criteria have been used. The present paper examines the link between these two mechanisms for a through-wall cracked pipe under bending and concludes that the transition from ductile tearing to collapse depends not only on material properties but also on geometrical parameters. The reference stress approach is a promising approach for predicting the transition, provided the transferability issue of j-resistance curve has been solved.

Thermal annealing of injection molded VHMW PLLA

Abstract In this study, DSC experiments were used to elaborate an annealing protocol for injection molded very high molecular weight (VHMW) PLLA with two molecular masses, 320,000 g/mol and 700,000 g/mol. The initial material obtained from the injection molding process was found to be highly amorphous and not in thermodynamic equilibrium state, as distinct cold crystallization and enthalpy relaxation were observed in DSC data. Thermal annealing to 85 °C for 60 - 90 min under controlled conditions using a DSC device showed to be sufficient to stabilize the polymer and increase the crystallinity to up to 50 %. Annealing did not result in any signs of thermal decomposition. The elaborated thermal treatment has been transferred to manual annealing of large specimen geometries for subsequent DMA analysis.

A state parameter-based scaling law for centrifuge modelling

When centrifuge modelling is applied to a prototype with large geometries that the centrifugal acceleration (Ng) could not fully recover the overburden stress of the prototype in the model, the generalized scaling law proposed by Iai (i.e., Iai's GSL) is often a promising choice. However, the scaling factor of shear strain is always larger than unity in Iai's GSL, which leads to the fact that the strain of the model soil is always smaller than that of the prototype. To address such a problem in Iai's GSL, a state parameter-based centrifuge scaling law securing the same shear strain between the model and the prototype is proposed in this paper. The proposed scaling law controls the model and the prototype to have the same initial state parameter by adjusting the void ratio of the model. The corresponding depth variation of the initial void ratio of the model is derived theoretically. To simplify the procedure of controlling the continuous change of void ratio through the model depth, a simplified approach is adopted for model preparation. The resultant effects of the proposed scaling law on soil density and permeability coefficient for different types of soils are also discussed. Finally, three centrifuge model tests of a submerged gently sloping ground of Ottawa F-65 sand with the same target geometry, state parameter and input motion at prototype scale have been conducted to validate the proposed scaling law, where the dynamic response and liquefaction-induced deformations were carefully monitored and analyzed. The applicability of the proposed scaling law is well confirmed by the centrifuge model test results.

Sound shielding simulation by coupled discontinuous Galerkin and fast boundary element methods

ABSTRACT A code coupling has been established for performing efficient fan tone shielding simulations of aerial vehicles with unconventional engine installations. In particular, the Fast Multipole Boundary Element Method (FM-BEM) which is formulated to solve a surface integral based on the Kirchhoff-Helmholtz wave equation for large geometries is combined with a volume resolving Discontinuous Galerkin (DG) method which is well suited for the compact region around a jet engine intake where strong mean flow gradients are present. The Möhring-Howe acoustic analogy is utilised during the backward data exchange process for derivation of acoustic velocities in presence of a mean flow. The method can help to overcome a major difficulty related to computational complexity when solving fan noise shilding and scattering problems for a complete aircraft geometry.

Flexible and high-intensity photoacoustic transducer with PDMS/CSNPs nanocomposite for inspecting thick structure using laser ultrasonics

Laser ultrasonic technique has been increasingly implemented for nondestructive testing and structural health monitoring. However, the poor signal-to-noise ratio (SNR) and low amplitude of laser generated ultrasonic signals under thermoelastic regime severely restrict its applications. In this paper, we propose a method for fabricating flexible, high-intensity and readily transplantable photoacoustic transducer (PAT) comprised of candle soot nanoparticles (CSNPs) and polydimethylsiloxane (PDMS), and utilize it to generate high SNR and amplitude ultrasonic signals for inspecting thick structures. A robotic-arm based layer-by-layer automatic scanning strategy is developed to realize candle soot nanoparticles (CSNPs) deposition with excellent homogeneity and thickness controllability, and the optimal thickness of PDMS/CSNPs nanocomposite layer to achieve high SNR and amplitude ultrasonic signal is obtained. In addition, a novel method for optimizing the PAT's structure to generate distinguishable and pure longitudinal ultrasonic signals is proposed, with amplitude over 100 times, and with center frequency (13.5 MHz) and −6 dB bandwidth (20.1 MHz) 29.8% and 35.8% higher than those generated without PAT. The optimized PAT is eventually combined with laser ultrasonic technique to successfully inspect and visualize the internal defects with various sizes (4, 2, 0.8 mm in diameter) of an aluminum component with thickness of 50 mm. With the merits of flexible and high-intensity nanocomposite PAT, the laser ultrasonics can be promisingly implemented for inspecting structure with large thickness and complex geometry under thermo-elastic mechanism.

Probing the Electronic Structure and Bond Dissociation of SO3 and SO3- Using High-Resolution Cryogenic Photoelectron Imaging.

The SO3 molecule and its radical anion SO3- are important chemical species atmospherically. However, their thermodynamic properties and electronic structures are not well known experimentally. Using cryogenically cooled anions, we have obtained high-resolution photoelectron images of SO3- and determined accurately the electron affinity (EA) of SO3 and the bond dissociation energy of SO3- → SO2 + O- for the first time. Because of the large geometry changes from the C3v SO3- to the D3h SO3, there is a negligible Franck-Condon factor (FCF) for the 0-0 detachment transition, that defines the EA of SO3. By fitting the high-resolution photoelectron spectra with computed FCFs using structures from high-level ab initio calculations, we have determined the EA of SO3 to be 2.126(6) eV. By monitoring the appearance of the O- signal in the photoelectron images at different photon energies, we are able to measure directly the bond dissociation energy of SO3-(X2A1) → SO2(X1A1) + O-(2P) to be 4.259 ± 0.006 eV, which also allow us to derive the dissociation energy for the spin-forbidden SO3(X1A1') → SO2(X1A1) + O(3P) to be 3.594(6) eV. The excited states of SO3- are calculated using high-level ab initio calculations, which are valuable in aiding the interpretation of autodetachment processes observed at various photon energies. The current study provides valuable information about the fundamental molecular properties of SO3, as well as the radical anion SO3-, which is known in redox reactions involving SO32- and may also play a role in the chemistry of SO2 in the atmosphere.

Effects of phase aberration on transabdominal focusing for a large aperture, low f-number histotripsy transducer

Objective. Soft tissue phase aberration may be particularly severe for histotripsy due to large aperture and low f-number transducer geometries. This study investigated how phase aberration from human abdominal tissue affects focusing of a large, strongly curved histotripsy transducer. Approach. A computational model (k-Wave) was experimentally validated with ex vivo porcine abdominal tissue and used to simulate focusing a histotripsy transducer (radius: 14.2 cm, f-number: 0.62, central frequency f c: 750 kHz) through the human abdomen. Abdominal computed tomography images from 10 human subjects were segmented to create three-dimensional acoustic property maps. Simulations were performed focusing at 3 target locations in the liver of each subject with ideal phase correction, without phase correction, and after separately matching the sound speed of water and fat to non-fat soft tissue. Main results. Experimental validation in porcine abdominal tissue showed that simulated and measured arrival time differences agreed well (average error, ∼0.10 acoustic cycles at f c). In simulations with human tissue, aberration created arrival time differences of 0.65 μs (∼0.5 cycles) at the target and shifted the focus from the target by 6.8 mm (6.4 mm pre-focally along depth direction), on average. Ideal phase correction increased maximum pressure amplitude by 95%, on average. Matching the sound speed of water and fat to non-fat soft tissue decreased the average pre-focal shift by 3.6 and 0.5 mm and increased pressure amplitude by 2% and 69%, respectively. Significance. Soft tissue phase aberration of large aperture, low f-number histotripsy transducers is substantial despite low therapeutic frequencies. Phase correction could potentially recover substantial pressure amplitude for transabdominal histotripsy. Additionally, different heterogeneity sources distinctly affect focusing quality. The water path strongly affects the focal shift, while irregular tissue boundaries (e.g. fat) dominate pressure loss.

Feasibility of a finite-difference time-domain model in large-scale acoustic simulations.

Wave-based techniques for room acoustics simulations are commonly applied to low frequency analysis and small-sized simplified environments. The constraints are generally the inherent computational cost and the challenging implementation of proper complex boundary conditions. Nevertheless, the application field of wave-based simulation methods has been extended in the latest research decades. With the aim of testing this potential, this work investigates the feasibility of a finite-difference time-domain (FDTD) code simulating large non-trivial geometries in wide frequency ranges. A representative sample of large coupled-volume opera houses allowed demonstration of the capability of the selected FDTD model to tackle such composite geometries up to 4 kHz. For such a demanding task, efficient calculation schemes and frequency-dependent boundary admittances are implemented in the simulation framework. The results of in situ acoustic measurements were used as benchmarks during the calibration process of three-dimensional virtual models. In parallel, acoustic simulations performed on the same halls through standard ray-tracing techniques enabled a systematic comparison between the two numerical approaches highlighting significant differences in terms of input data. The ability of the FDTD code to detect the typical acoustic scenarios occurring in coupled-volume halls is confirmed through multi-slope decay analysis and impulse responses' spectral content.

A mesoscale approach to simulate residual deformations in complex laser welding processes

Laser welding can be characterized by very small radii of beam, in the order of tenths of a millimeter, and very short high power inputs (more kW in few ms), and thus, it can be certainly classified as a microscale process with a high level of physical complexity. This is clearly incompatible, due to the high computational costs, with the analysis of macroscale processes related to large geometries and non-uniform welding patterns. In order to overcome this issue, a simplified finite element method (FEM)–based thermo-elastoplastic model is presented to simulate heat transfer and residual deformations due to thermal expansion and material plasticity. The idea is to substitute the microscale analysis with a mesoscale approach that renounces to describe in detail all the physical phenomena occurring in the heated zone and focuses attention on the correct prediction of the keyhole depth and weld pool size, that are the most important parameters to describe the mechanical characteristics of the welded joint. The concept of passive element, based on the numerical adjustment of the material properties in order to take into account the orthotropic behavior during the keyhole formation, is introduced. In particular, the new approach has been tested on the pulsed laser welding process of two overlapping DC04 steel plates with thickness of 0.5 mm (so-called sandwich) and validated through experimental tests involving different input parameters, such as power, pulse duration and frequency, speed, and geometrical pattern.

Large genus asymptotic geometry of random square-tiled surfaces and of random multicurves

We study the combinatorial geometry of a random closed multicurve on a surface of large genus g and of a random square-tiled surface of large genus g. We prove that primitive components $$\gamma _1, \dots ,\gamma _k$$ of a random multicurve $$m_1\gamma _1+\dots +m_k\gamma _k$$ represent linearly independent homology cycles with asymptotic probability 1 and that all its weights $$m_i$$ are equal to 1 with asymptotic probability $$\sqrt{2}/2$$ . We prove analogous properties for random square-tiled surfaces. In particular, we show that all conical singularities of a random square-tiled surface belong to the same leaf of the horizontal foliation and to the same leaf of the vertical foliation with asymptotic probability 1. We show that the number of components of a random multicurve and the number of maximal horizontal cylinders of a random square-tiled surface of genus g are both very well approximated by the number of cycles of a random permutation for an explicit non-uniform measure on the symmetric group of $$3g-3$$ elements. In particular, we prove that the expected value of these quantities has asymptotics $$(\log (6g-6) + \gamma )/2 + \log 2$$ as $$g\rightarrow \infty $$ , where $$\gamma $$ is the Euler–Mascheroni constant. These results are based on our formula for the Masur–Veech volume $${\text {Vol}}{\mathcal {Q}}_g$$ of the moduli space of holomorphic quadratic differentials combined with deep large genus asymptotic analysis of this formula performed by A. Aggarwal and with the uniform asymptotic formula for intersection numbers of $$\psi $$ -classes on $${\overline{{\mathcal {M}}}}_{g,n}$$ for large g proved by A. Aggarwal in 2020.

Experimental and numerical identification of corrosion degradation of ageing structural components

The study presents experimental and numerical identification of corrosion degradation of thin-walled structural components employing guided wave propagation. The steel structural components are subjected to through-thickness varying corrosion degradation levels. The developed approach using the non-destructive guided wave-propagation quantifies the equivalent average corrosion degradation level by exploring a limited number of transducers. A group velocity dispersion curve reconstruction has been used to determine the corrosion-induced plate thickness reduction. Two case studies are used to examine experimentally the newly developed approach. In the first one, the dispersion curve and the assessment of the corrosion thickness reduction have been made using wave signals of various excitation frequencies. In the second one, the analysis was conducted only for two wave propagation signals and one excitation frequency which allowed for reconstructing the dispersion curve in a limited frequency range. A good agreement between the natural and estimated corrosion degradation levels was observed in both case studies. The present study develops a signal processing methodology, which can be used in the SHM systems. Several aspects still need to be further investigated before the developed approach can be applied to the complex ship hull structures' large size and complex geometry.

Modeling acoustic cavitation with inhomogeneous polydisperse bubble population on a large scale

A model for acoustic cavitation flows able to depict large geometries and time scales is proposed. It is based on the Euler–Lagrange approach incorporating a novel Helmholtz solver with a non-linear acoustic attenuation model. The method is able to depict a polydisperse bubble population, which may vary locally. The model is verified and analyzed in a setup with a large sonotrode. Influences of the initial void fraction and the population type are studied. The results show that the velocity is strongly influenced by these parameters. Furthermore, the largest bubbles determine the highest pressure amplitude reached in the domain, which corresponds to the Blake threshold of these bubbles. Additionally, a validation is performed with a small sonotrode. The model reproduces most of the experimentally observed phenomena. In the experiments, neighboring bubbles are found which move in different directions depending on their size. The numerical results show that the responsible mechanism here is the reversal of the primary Bjerknes force at a certain pressure amplitude.

In vitro degradation and erosion behavior of commercial PLGAs used for controlled drug delivery.

Copolymers of lactic (or lactide) and glycolic (or glycolide) acids (PLGAs) are among the most commonly used materials in biomedical applications, such as parenteral controlled drug delivery, due to their biocompatibility, predictable degradation rate, and ease of processing. Besides manufacturing variables of drug delivery vehicles, changes in PLGA raw material properties can affect product behavior. Accordingly, an in-depth understanding of polymer-related "critical quality attributes" can improve selection and predictability of PLGA performance. Here, we selected 19 different PLGAs from five manufacturers to form drug-free films, submillimeter implants, and microspheres and evaluated differences in their water uptake, degradation, and erosion during in vitro incubation as a function of L/G ratio, polymerization method, molecular weight, end-capping, and geometry. Uncapped PLGA 50/50 films from different manufacturers with similar molecular weights and higher glycolic unit blockiness and/or block length values showed faster initial degradation rates. Geometrically, larger implants of 75/25, uncapped PLGA showed higher water uptake and faster degradation rates in the first week compared to microspheres of the same polymers, likely due to enhanced effects of acid-catalyzed degradation from PLGA acidic byproducts unable to escape as efficiently from larger geometries. Manufacturer differences such as increased residual monomer appeared to increase water uptake and degradation in uncapped 50/50 PLGA films and poly(lactide) implants. This dataset of different polymer manufacturers could be useful in selecting desired PLGAs for controlled release applications or comparing differences in behavior during product development, and these techniques to further compare differences in less reported properties such as sequence distribution may be useful for future analyses of PLGA performance in drug delivery.