Inspection of chicken wings and legs for animal welfare monitoring using X-ray computed tomography, visual examination, and histopathology.

In broiler chickens, fractures of wings and legs are recorded at poultry slaughterhouses based on the time of occurrence. Prekilling (PRE) fractures occur before the death of animal, so the chicken was still able to experience pain and distress associated with the injury (an animal welfare issue). Postkilling (POST) fractures occur when the chickens are deceased and fully bled-out and consequently unable to feel pain (not an animal welfare issue). Current practice dictates that fractures are recognized visually and recorded by the animal welfare officers as mandated by European Union and/or national regulations. However, new potential monitoring solutions are desired since human inspection suffers from some significant limitations including subjectivism and fatigue. One possible solution in detecting injuries is X-ray computed tomography (CT) scanning and in this study we aim to evaluate the potential of CT scanning and visual inspection in detecting limb fractures and their causes. Eighty-three chicken wings and 60 chicken legs (n = 143) were collected from a single slaughterhouse and classified by an animal welfare officer as PRE, POST or healthy (HEAL). Samples were photographed and CT scanned at a veterinary hospital. The interpretation of CT scans along with photographs took place in 3 rounds (1. CT scans only, 2. CT scans + photographs, 3. photographs only) and was performed independently by 3 veterinarians. The consistency of the interpretation in 3 rounds was compared with the animal welfare officer's classification. Furthermore, selected samples were also analyzed by histopathological examination due to questionability of their classification (PRE/POST). In questionable samples, presence of hemorrhages was confirmed, thus they fit better as PRE. The highest consistency between raters was obtained in the 2nd round, indicating that interpretation accuracy was the highest when CT scans were combined with photographs. These results indicate that CT scanning in combination with visual inspection can be used in detecting limbs fracture and potentially applied as a tool to monitor animal welfare in poultry slaughterhouses in the future.

Visualizing defects and pore connectivity within metal-organic frameworks by X-ray transmission tomography.

Metal-Organic Frameworks (MOFs) have the potential to change the landscape of molecular separations in chemical processes owing to their ability of selectively binding molecules. Their molecular sorting properties generally rely on the micro- and meso-pore structure, as well as on the presence of coordinatively unsaturated sites that interact with the different chemical species present in the feed. In this work, we show a first-of-its-kind tomographic imaging of the crystal morphology of a metal-organic framework by means of transmission X-ray microscopy (TXM), including a detailed data reconstruction and processing approach. Corroboration with Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM) images shows the potential of this strategy for further (non-destructively) assessing the inner architecture of MOF crystals. By doing this, we have unraveled the presence of large voids in the internal structure of a MIL-47(V) crystal, which are typically thought of as rather homogeneous lattices. This challenges the established opinion that hydrothermal syntheses yield relatively defect-free material and sheds further light on the internal morphology of crystals.

Heterogeneity in the Fragmentation of Ziegler Catalyst Particles during Ethylene Polymerization Quantified by X-ray Nanotomography.

Ziegler-type catalysts are the grand old workhorse of the polyolefin industry, yet their hierarchically complex nature complicates polymerization activity-catalyst structure relationships. In this work, the degree of catalyst framework fragmentation of a high-density polyethylene (HDPE) Ziegler-type catalyst was studied using ptychography X-ray-computed nanotomography (PXCT) in the early stages of ethylene polymerization under mild reaction conditions. An ensemble consisting of 434 fully reconstructed ethylene prepolymerized Ziegler catalyst particles prepared at a polymer yield of 3.4 g HDPE/g catalyst was imaged. This enabled a statistical route to study the heterogeneity in the degree of particle fragmentation and therefore local polymerization activity at an achieved 3-D spatial resolution of 74 nm without requiring invasive imaging tools. To study the degree of catalyst fragmentation within the ensemble, a fragmentation parameter was constructed based on a k-means clustering algorithm that relates the quantity of polyethylene formed to the average size of the spatially resolved catalyst fragments. With this classification method, we have identified particles that exhibit weak, moderate, and strong degrees of catalyst fragmentation, showing that there is a strong heterogeneity in the overall catalyst particle fragmentation and thus polymerization activity within the entire ensemble. This hints toward local mass transfer limitations or other deactivation phenomena. The methodology used here can be applied to all polyolefin catalysts, including metallocene and the Phillips catalysts to gain statistically relevant fundamental insights in the fragmentation behavior of an ensemble of catalyst particles.

Correlated X-ray Ptychography and Fluorescence Nano-Tomography on the Fragmentation Behavior of an Individual Catalyst Particle during the Early Stages of Olefin Polymerization.

A combination of X-ray ptychography and X-ray fluorescence tomography (XRF) has been used to study the fragmentation behavior of an individual Ziegler-Natta catalyst particle, ∼40 µm in diameter, in the early stages of propylene polymerization with submicron spatial resolution. The electron density signal obtained from X-ray ptychography gives the composite phases of the Ziegler-Natta catalyst particle fragments and isotactic polypropylene, while 3-D XRF visualizes multiple isolated clusters, rich in Ti, of several microns in size. The radial distribution of Ti species throughout the polymer-catalyst composite particle shows that the continuous bisection fragmentation model is the main contributor to the fragmentation pathway of the catalyst particle as a whole. Furthermore, within the largest Ti clusters the fragmentation pathway was found to occur through both the continuous bisection and layer-by-layer models. The fragmentation behavior of polyolefin catalysts was for the first time visualized in 3-D by directly imaging and correlating the distribution of the Ti species to the polymer-catalyst composite phase.