Computer model for the characterisation of the size distribution of spheroidal graphite in ductile cast iron

A computer model was developed to establish the relationship between the two-dimensional (2D) and the three-dimensional (3D) parameters, specifically the number of particles and particle size distribution. The computer experiments were performed for both monodispersed and lognormally polydispersed systems. The model was based on a random distribution of a number of spherical grains in a cubic unit, with no intersection between the grains. The cubic unit was cut by a random plane and the number of particles which appeared in the section and the area fraction were measured. This procedure was repeated until the average number of particles and the average area fraction became constant. Finally, the 2D size distribution of the particles over all sections was obtained.

It was concluded that the volume fraction is equal to the area fraction, irrespective of the particle size distribution, providing that the total number of measured 2D particles is large enough. As for the number of particles, an equation was found to calculate the number of 3D particles in a monodispersed system from the number of 2D particles and the volume fraction. However, in lognormally polydispersed systems the number of 3D particles could be calculated using the 3D mean and standard deviation, estimated from the 2D mean and standard deviation by a method specifically developed for the purpose.

Finally, the method was applied to two ductile cast iron specimens and the applicability of the present model was verified.     

Heterogeneous Cubic Multidimensional Integrated Circuit for Water and Food Security in Fish Farming Ponds

Among major food production sectors, world aquaculture shows the highest growth rate, providing more than 50% of the global seafood market. However, water pollution in fish farming ponds is regarded as the leading cause of fish death and financial losses in the market. Here, an Internet of Things system based on a cubic multidimensional integration of circuit (MD‐IC) is demonstrated for water and food security applications in fish farming ponds. Both faces of the silicon substrate are used for thin‐film‐based device fabrication. The devices are interconnected via through‐silicon‐vias, resulting in a bifacial complementary metal‐oxide‐semiconductor‐compatible electronics system. The demonstrated cubic MD‐IC is a complete, small, and lightweight system that can be easily deployed by farmers with no need for specialists. The system integrates on its outer sides simultaneous air and water quality monitoring devices (temperature, electrical conductivity, ammonia, and pH sensors), solar cells for energy‐harvesting, and antenna for real‐time data‐transfer, while data‐management circuitry and a solid‐state battery are integrated on its internal faces. Microfluidic cooling technology is used for thermal management in the MD‐IC. Finally, a biofriendly polymeric encapsulation is used to waterproof the embedded electronics, improve the mechanical robustness, and allow the system to float on the surface of the water.     

Microscale characterization of damage accumulation in CMCs

The developing roles of damage mechanisms in the failure response of SiC/SiC minicomposites was investigated by the characterization of microscale damage accumulation with respect to microstructure. A multi-modal approach combining spatially resolved acoustic emission (AE) with tensile testing in-SEM (scanning electron microscope) was used to simultaneously examine surface (observed in-SEM) and bulk damage (monitored via AE). Strong agreement was shown between the evolving crack density estimated by AE and in-SEM measurements. The following were observed: (i) in-plane matrix content and distribution impacted crack growth; (ii) spatially-distributed matrix cracks generated varying stress-dependent AE; and (iii) certain individual cracks became more probable failure locations due to unique combinations of damage mechanisms that drove their growth. This approach enabled characterizing potential failure determinants and suggests that early damage behavior is related to certain microstructural features (e.g. surface flaws), while subsequent damage behavior is coupled to interactions of local mechanisms evolving with stress.     

Assessment of shock resistance of barium ferrite at dynamic shocked conditions

Journal of Materials Science: Materials in Electronics - This research work probes into the crystallographic and magnetic structural stability of barium ferrite nanoparticles (BaFe2O4 NPs) at...     

Prognostic significance of postoperative empyema in lung cancer

OBJECTIVE: To evaluate the safety and feasibility of laparoscopic choledocholithotomy via choledochotomy for the treatment of choledocholithiasis. DESIGN: A prospective series of 1332 consecutive patients who underwent laparoscopic cholecystectomies, with a mean follow-up of 21.2 months. SETTING: University-affiliated referral center. Patients: Forty-three patients (3%) with documented common bile duct stones from January 1991 to February 1995. INTERVENTIONS: Laparoscopic choledocholithotomy with choledochotomy and T tube drainage were performed in 40 patients. Postoperative endoscopic sphincterotomy after laparoscopic cholecystectomy was performed in three patients. MAIN OUTCOME MEASURES: Documented removal of common bile duct stones and procedure-related complications. RESULTS: Laparoscopic choledocholithotomy via choledochotomy was successful in 35 (88%) of 40 patients in whom this procedure was attempted. The mean (+/- SD) operation time was 191.3 +/- 75.4 minutes, and the mean (+/- SD) length of postoperative stay was 10.4 +/- 2.7 days. Seven complications (18%) were recorded, including three major complications (8%) and two retained stones (5%). CONCLUSIONS: Laparoscopic choledocholithotomy via choledochotomy can be performed safely, without increasing the morbidity rate as compared with that of open choledocholithotomy. Thus, some of the advantages of minimally invasive surgery are preserved.     

Nephron ultrastructural alterations induced by zinc oxide nanoparticles: an electron microscopic study

Due to their unique properties, zinc oxide nanoparticles (ZnO NPs) are invested in many industries, commercial products, and nanomedicine with potential risk for human health and the environment. The present study aims to focus on alterations that might be induced by ZnO NPs in the nephron ultrastructure. Male Wister Albino rats were subjected to ZnO NPs at a daily dose of 2 mg/kg for 21 days. Kidney biopsies were processed to transmission electron microscopy (TEM) and ultrastructural pathology examinations. Exposure to ZnO NPs‐induced ultrastructural alterations in the proximal convoluted tubules (PCTs) and to lesser extent in the distal ones (DCTs), while the loops of Henle were almost not affected. The glomeruli demonstrated dilatation, partial mesangial cells loss, matrix ballooning, slits filtration widening, and basement membrane thickening. Moreover, PCT revealed cytoplasmic necrosis, vacuolation, erosion, and disorganisation of the apical microvilli together with mitochondrial swelling and cristae destruction. The nuclei of the renal cells exhibited nuclear deformity, heterochromatin accumulation, and apoptotic activities. The findings indicate that ZnO nanomaterial have the potential to affect the nephron ultrastructure suggesting alteration in the kidney functions. More work is needed for better understanding the toxicity and pathogenesis of ZnO oxide nanomaterial.Inspec keywords: electron microscopy, zinc compounds, transmission electron microscopy, nanomedicine, biochemistry, diseases, cellular biophysics, biomembranes, kidney, nanofabrication, molecular biophysics, nanoparticles, II‐VI semiconductors, biomedical optical imagingOther keywords: electron microscopic study, unique properties, zinc oxide nanoparticles, ZnO NPs, nephron ultrastructure, Male Wister Albino rats, ultrastructural pathology examinations, NPs‐induced ultrastructural alterations, partial mesangial cells loss, ZnO nonmaterial, ZnO oxide nonmaterial, nephron ultrastructural alterations, kidney biopsies, time 21.0 d, ZnO     

Recovery of free volume in PIM-1 membranes through alcohol vapor treatment

Physical aging is currently a major obstacle for the commercialization of PIM-1 membranes for gas separation applications. A well-known approach to reversing physical aging effects of PIM-1 membranes at laboratory scale is soaking them in lower alcohols, such as methanol and ethanol. However, this procedure does not seem applicable at industrial level, and other strategies must be investigated. In this work, a regeneration method with alcohol vapors (ethanol or methanol) was developed to recover permeability of aged PIM-1 membranes, in comparison with the conventional soaking-in-liquid approach. The gas permeability and separation performance, before and post the regeneration methods, were assessed using a binary mixture of CO₂ and CH₄ (1:1, v:v). Our results show that an 8-hour methanol vapor treatment was sufficient to recover the original gas permeability, reaching a CO₂ permeability>7000 barrer.     

Hyper Elliptic Curve Based Certificateless Signcryption Scheme for Secure IIoT Communications

Industrial internet of things (IIoT) is the usage of internet of things (IoT) devices and applications for the purpose of sensing, processing and communicating real-time events in the industrial system to reduce the unnecessary operational cost and enhance manufacturing and other industrial-related processes to attain more profits. However, such IoT based smart industries need internet connectivity and interoperability which makes them susceptible to numerous cyber-attacks due to the scarcity of computational resources of IoT devices and communication over insecure wireless channels. Therefore, this necessitates the design of an efficient security mechanism for IIoT environment. In this paper, we propose a hyperelliptic curve cryptography (HECC) based IIoT Certificateless Signcryption (IIoT-CS) scheme, with the aim of improving security while lowering computational and communication overhead in IIoT environment. HECC with 80-bit smaller key and parameters sizes offers similar security as elliptic curve cryptography (ECC) with 160-bit long key and parameters sizes. We assessed the IIoT-CS scheme security by applying formal and informal security evaluation techniques. We used Real or Random (RoR) model and the widely used automated validation of internet security protocols and applications (AVISPA) simulation tool for formal security analysis and proved that the IIoT-CS scheme provides resistance to various attacks. Our proposed IIoT-CS scheme is relatively less expensive compared to the current state-of-the-art in terms of computational cost and communication overhead. Furthermore, the IIoT-CS scheme is 31.25% and 51.31% more efficient in computational cost and communication overhead, respectively, compared to the most recent protocol.     

Novel processing,testing and characterization of copper/carbon nanotube (Cu/CNT) yarn composite conductor

Sustainable electrified aircraft propulsion (EAP) is likely to lead to an increase in the electrical wiring contained within a single aircraft. Since the electrical resistance and mass of copper (Cu) conductors are associated with power losses, it is desirable to design high-conductivity lightweight conductor materials, thus reducing the mass of components like motor windings, low-voltage signal cables, and transmission cables for data and power to improve the overall energy efficiency. This paper describes a unique framework for manufacturing metalized carbon nanotube (CNT) composite conductors, measuring their electrical conductivity and strength, and modeling the overall conductivity and current sharing within such composites. Tensile testing was conducted on the processed composite conductor cables with the use of acoustic emission and electrical resistivity to determine stress-dependent-failure mechanisms while monitoring the electrical conductivity. The average of measured electrical conductivities of annealed Cu/CNT samples from batch 5 was greater than theoretical predictions by 9.8 percent and was also greater than the conductivity of pure annealed Cu by 4.8 percent and had comparable ultimate tensile strengths. Additionally, those Cu/CNT samples provide a 13.5% weight saving over current state of the art copper wires. Theories explaining improved intrinsic conductivity are discussed.