The Metaverse: Survey, Trends, Novel Pipeline Ecosystem & Future Directions

The Metaverse offers a second world beyond reality, where boundaries are non-existent, and possibilities are endless through engagement and immersive experiences using the virtual reality (VR) technology. Many disciplines can benefit from the advancement of the Metaverse when accurately developed, including the fields of technology, gaming, education, art, and culture. Nevertheless, developing the Metaverse environment to its full potential is an ambiguous task that needs proper guidance and directions. Existing surveys on the Metaverse focus only on a specific aspect and discipline of the Metaverse and lack a holistic view of the entire process. To this end, a more holistic, multi-disciplinary, in-depth, and academic and industry-oriented review is required to provide a thorough study of the Metaverse development pipeline. To address these issues, we present in this survey a novel multi-layered pipeline ecosystem composed of (1) the Metaverse computing, networking, communications and hardware infrastructure, (2) environment digitization, and (3) user interactions. For every layer, we discuss the components that detail the steps of its development. Also, for each of these components, we examine the impact of a set of enabling technologies and empowering domains (e.g., Artificial Intelligence, Security & Privacy, Blockchain, Business, Ethics, and Social) on its advancement. In addition, we explain the importance of these technologies to support decentralization, interoperability, user experiences, interactions, and monetization. Our presented study highlights the existing challenges for each component, followed by research directions and potential solutions. To the best of our knowledge, this survey is the most comprehensive and allows users, scholars, and entrepreneurs to get an in-depth understanding of the Metaverse ecosystem to find their opportunities and potentials for contribution

Combined percutaneous ethanol injection and mitoxantrone versus radiofrequency ablation in the treatment of hepatocellular carcinoma

New therapeutic choices have been developed for hepatocellular carcinoma, including percutaneous ablation therapy, transarterial chemoembolization, radiation therapy and molecular target therapy. Ablation of liver tumors is currently the main alternative to liver resection. This work aimed at comparing percutaneous combined local injection of ethanol and mitoxantrone versus percutaneous radiofrequency ablation in the treatment of Hepatocellular Carcinoma. This study included 124 patients with hepatocellular carcinoma, they were randomly divided into two groups; group I (64 patients) treated with local injection of ethanol plus mitoxantrone. Group II (60 patients) treated with radiofrequency ablation. Clinical assessment, laboratory evaluation and CT studies were performed to all patients prior to treatment and at 1, 3, 6, and 12 months' post treatment. The percentage of ablation in both groups at 1, 3, 6 and 12 months were 81.3%, 81.3%,76.6 and 71.9% in group I respectively versus 88.3%, 88.3, 85%% and 81.7% in group II respectively with no statistical significant difference between the two groups. Percentage of ablation in small tumors is higher than large tumors in both groups. Side effects and complications are statistically higher in group II than group I. Combination of percutaneous local injection of ethanol and mitoxantrone is comparable to radiofrequency ablation with less frequent complications in the treatment of Hepatocellular Carcinoma when surgical resection or liver transplantation is not amenable or available. [Med-Science 2016; 5(4.000): 948-56

Evaluation of plasma produced by first and second harmonic nano-second laser for enhancing the capability of laser induced breakdown spectroscopy technique

Evaluation of plasmas produced and optimized for improving the capability of convenential laser induced breakdown spectroscopy (LIBS) for analytical purposes of solid samples is the main goal of the present work. The plasma produced in the present study was generated by focusing a single nano-second Nd:YAG laser at the fundamental wavelength of 1064 nm and at the second harmonic wavelength of 532 nm on an Al target in air at atmospheric pressure. The emission spectrum was recorded time resolved over the whole UV-NIR (200–1000 nm) spectral range. This work describes an extension of previously reported studies and focuses now on the determination of the plasma parameters at the optimum condition – highest signal-to-noise ratio (SNR) and minimum limit of detection (LOD) – of the LIBS technique, which is now widely applied to the elemental analysis of materials in atmospheric air. Parameters of the produced plasma in the time interval from 0 to 10 μs are determined for to further understanding the LIBS plasma dynamics. O I and Mn I spectral lines are used in the present work as thermometric lines for the determination of the plasma temperature based on Boltzmann plots. Stark broadening of lines yields the electron density. The widths of the Hα-line at 656.27 nm, of the O I line at 844.65 nm, of Al II lines at 281.65 nm and 466.30 nm and of the Si I line at 288.15 nm has been utilized for that. The plasma temperature ranged from 0.73 eV to around 1 eV for the different laser energies with both laser wavelengths for the optimized plasma used for LIBS analysis. This temperature is very close to that well known for the other spectrochemical analytical techniques or in excitation sources such as inductively coupled plasma-optical emission spectrometry (ICP-OES)

Lubricant Additives Based on Carbon Nanotubes Produced from Carbon-Rich Fly Ash

<p>Carbon-rich fly ash has been reported to be a suitable precursor and catalyst for carbon nanotube (CNT) growth. In this work, CNTs grown from carbon-rich fly ash were evaluated as a lubricant oil additive to reduce the friction coefficient of metallic surfaces using a ball-on-disk tribometer. Different concentrations of the as-grown CNTs in the range 0.005–0.5 wt% were dispersed in a base sunflower oil. The value of the friction coefficient was also investigated as a function of load. Excellent results were obtained for the value of the friction coefficient, where it drastically decreased to around 58% of its original value without additives. This was achieved at a very low concentration of CNTs; that is, 0.1 wt%. The obtained result was compared with that of a commercial multiwalled CNT at the same concentration and found to be superior. This superiority of CNTs produced from fly ash could be attributed to the existence of active radical sites on their side wall. Moreover, the friction coefficient value was observed to decrease with increasing load, which might be due to the formation of protective graphitic carbon layers on antagonist surfaces. The viscosity of pure and 0.1 wt% CNTs-impregnated base oil was also studied in the 25–100°C temperature range. No significant changes are observed in the viscosity of the CNTs-impregnated base oil. These results suggest that the low-cost CNTs produced from fly ash are excellent nanomaterials as additives for lubricant oil.</p