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Peri-implant debris certainly lead to osteolysis, necrosis, pseudotumor formation, tissue granulation, fibrous capsule contractions, and even implant failure. For the three-dimensional (3D) printed cage, impaction during cage insertion is one of the most potential sources of fracture debris. A finite-element study was carried out to reduce the impact-induced debris of the 3D-printed cage. This study focused on the design strategy of solid and cellular structures along the load-transferring path. Using the finite-element method, the cellular structure of the transforaminal lumbar interbody fusion (TLIF) cage was systematically modified in the following four variations: a noncellular cage (NC), a fully cellular (FC) cage, a solid cage with a cellular structure in the middle concave (MC) zone, and a strengthened cage (SC) in the MC zone. Three comparison indices were considered: the stresses at the cage-instrument interfaces, in the MC zone, and along the specific load-transferring path. The NC and FC were the least and most highly stressed variations at the cage-instrument interfaces and in the MC zone, respectively. Along the entirely load-transferring path, the FC was still the most highly stressed variation. It showed a higher risk of stress fracture for the FC cage. For the MC and SC, the MC zone was consistently more stressed than the directly impacted zone. The further strengthened design of the SC had a lower peak stress (approximately 29.2%) in the MC zone compared with the MC. Prior to 3D printing, the load-transferring path from the cage-instrument interfaces to the cage-tissue interfaces should be determined. The cage-instrument interfaces should be printed as a solid structure to avoid impact-induced fracture. The other stress-concentrated zones should be cautiously designed to optimize the coexistence strategy of the solid and cellular structures.

The present research was focussed to investigate the influence of liquid-gaseous dielectric on debris formation in magnetic field-assisted electrical discharge machining. The air and argon gas were used to make two-phase dielectric fluids such as liquid-air and liquid-argon gas, respectively. Experimentation was conducted to compare the effect of different liquid-gaseous dielectric environments on debris formation. The morphology and diameter distribution of debris were analyzed. In addition, the effect on elemental analysis, phase transformation and magnetic property of debris was investigated. The experimental results showed the exothermic reaction due to air from liquid–air dielectric, and inert property of argon gas from liquid-gaseous dielectric affected the formation of debris. The XRD results confirmed the formation of oxides in the debris produced using liquid-air mixed dielectric. The oxide-free debris formed while using the argon gas. Low saturation of magnetization was found in the debris, formed in the liquid–air dielectric which showed the weak attraction toward magnet when compared with that in the liquid–argon gas mixed dielectric.

Debris in high-volume, high velocity flows, such as tsunamis, storm surges, and dam breaks, cause widespread damage to coastal communities. Evaluating the motion of the debris within the flow is difficult due to the variety of variables that can affect the motion, therefore techniques must be developed to quickly and accurately track the motion of the debris within the flow. This paper presents an optical tracking technique to track the motion of debris over a horizontal bottom under laboratory conditions. The debris consisted of scaled-down shipping containers, made of polyethylene (PE), placed on a dry, raised, flat section of the basin floor. Container movement was measured using two overhead cameras and a novel object tracking and detection algorithm implemented in MATLAB. The algorithm was developed to be able to quickly and accurately track uniform containers throughout an experimental run. The algorithm combines image-processing techniques such as Color Thresholding and Blob Analysis with tracking methods such as the Kalman Filter and Hungarian (Munkres) Algorithm. The algorithm was evaluated by comparing the results to those from a manual tracking method. For experiments with one, three, and six containers, the algorithm showed good agreement with the results of the manual method. However, with nine containers, the increase in the amount of container–container collisions and the agglomeration of the containers resulted in poor results compared to the manual method. While the algorithm is only evaluated here to track the motion of the shipping containers, there is potential for its use in many other fields of hydraulic and coastal engineering.

Climate change poses one of the most tangible security challenges of our times. The effort to securitize the issue has sped up since the last decade owing to its increasing existential threats. In spite of this growing realization and development of international regime complex for climate change (Jervis 2020:21), the issue still suffers from what is called a “Climate Change Securitisation Paradox” (Lucke et al. 2020). On the one hand are several securitization efforts by activists, government, and trans-governmental actors revving up a national security debate around it, but on the other hand there remains lack of consensus to undertake much needed extraordinary measures to tackle this inordinate threat. This disjunct between narratives and praxis is even more glaring in outer space where major players have been expanding their futuristic power maximization capabilities. What makes research on climate governance in space daunting and yet indispensable is the inevitability of the space age in human life. It is indeed no exaggeration to state that whoever controls space, will control the future. However, we must manage the spillovers from the space race, most notably in how they could potentially alter climate considerations that may threaten human life back on Earth. This chapter examines two most prominent factors where competitive spacefaring behavior has complicated the already complex and highly debated issue of climate change. First is the problem of space debris polluting and cluttering the Lower Earth Orbit (LEO), and second is the phenomenon of space drag which is directly related with the greenhouse emission produced on Earth which also adds to space cluttering. The chapter analyzes key events and patterns that have led to the increase in space debris and space drag. It highlights the lack of a strong regime complex to control the repercussions of the irresponsible spacefaring behavior of countries like China. It concludes by proposing ways to strengthen the Regime Complex for Climate Change by delving in the concept of Space 2.0 that emphasizes on techniques of augmentation and reconstitution to make spacefaring more cost effective, reusable, and transparent and thereby lessening the problem of space cluttering.