Academic literature on the topic 'Metallic split-block'

A field experiment was conducted in the experimental field of the Crop Sciences Department at the College of Agricultural Engineering Sciences - University of Baghdad during fall seasons of 2021 and 2022. The aim of this study was to investigate the role of nano and metallic boron foliar nutrition on yield, components, water use efficiency, and water consumption under water stress for sweet corn (Zea mays L.). Randomized Complete Block Design was used within split -plot arrangement with three replicates, where the main plots included three levels of water stress (irrigation at 40, 60, and 80% of available water) coded as W1, W2, and W3, respectively. The nano and metallic boron spray concentrations represented 5, 10, 20, and 40 mg L-1 coded as N1, N2, M1, and M2, respectively. Results showed that nano and metallic boron concentrations significantly affected all the studied traits. The concentration of 5 mg L-1 of nano boron N1 significantly exceeded other concentrations under study in increasing ear length, number of rows per ear, number of grains per row, and weight of 500 grains, which positively reflected on improving grain yield of 5.93 and 5.96 t ha-1. The interaction between water stress treatments and nano and metallic boron concentrations was significant for all the studied traits except for ear length.

Splinting of the mobile teeth is a critical part of periodontal management to improve the prognosis and longevity of stable results of periodontally compromised teeth with increased mobility. Different types of splints are used in the dental field based on their mechanical and physical properties.The objective of the current in vitro study was to evaluate the flexure strength and flexural modulus of different types of splinting materials, such as: composite block, ligature wire, Ribbond®, InFibra®, and F-splint-Aid® bonded utilizing Flowable composites resin material. Seventy-five bar specimens were prepared with the dimensions of 25 × 4 × 2 mm, utilizing split metallic mold. Specimens were divided equally (n = 15) into five groups (one control group, four test groups). Different layers of splinting material were placed in between the layers of composite before curing. All the specimens were subjected to a three-point bending test by using a universal testing machine to calculate the flexural strength and flexural modulus. The entire data was subjected to statistical tests to evaluate the significance. Specimens from composite block groups showed the least mean value for flexural strength (89.15 ± 9.70 MPa) and flexural modulus (4.310 ± 0.912 GPa). Whereas, the highest mean value for flexural strength (168.04 ± 45.95 MPa) and flexural modulus (5.861 ± 0.501 GPa) were recorded by Ribbond® specimens. Inter group comparison of flexural strength showed statistically significant differences (P-value < 0.05), whereas comparison of flexural modulus showed non-significant difference among the groups (P-value > 0.05). Within the limitation of the present study, it was concluded that the Ribbond® exhibits maximum flexural strength and flexural modulus, whereas the composite blocks recorded the least values. Still, the decision making depends on the clinical scenario and the unique characteristic of each splint material.

Abstract. The origin and evolution of metal melts in the Earth's mantle and their role in the formation of diamond are the subject of active discussion. It is widely accepted that portions of metal melts in the form of pockets can be a suitable medium for diamond growth. This raises questions about the role of silicate minerals that form the walls of these pockets and are present in the volume of the metal melt during the growth of diamonds. The aim of the present work was to study the crystallization of diamond in a complex heterogeneous system: metal-melt–basalt–carbon. The experiments were performed using a multianvil high-pressure apparatus of split-sphere type (BARS) at a pressure of 5.5 GPa and a temperature of 1500 ∘C. The results demonstrated crystallization of diamond in metal melt together with garnet and clinopyroxene, whose chemical compositions are similar to those of eclogitic inclusions in natural diamond. We show that the presence of silicates in the crystallization medium does not reduce the chemical ability of metal melts to catalyze the conversion of graphite into diamond, and, morphologically, diamond crystallizes mainly in the form of a cuboctahedron. When the content of the silicate material in the system exceeds 5 wt %, diamond forms parallel-growth aggregates, but 15 wt % of silicate phases block the crystallization chamber, preventing the penetration of metallic melt into them, thus interrupting the growth of diamond. We infer that the studied mechanism of diamond crystallization can occur at lower-mantle conditions but could also have taken place in the ancient continental mantle of the Earth, under reducing conditions that allowed the stability of Fe–Ni melts.

AbstractPrevalent PET imaging reconstructs 2γ-photon pairs emitted after an annihilation from para-positronium (p-Ps) and rejects 3γ events from ortho-positronium (o-Ps) as noises. The 3γ/2γ decay ratio is ~ 3/7 in human body theoretically but in fact significantly lower due to pick-off process, hence PET imaging quality is well controlled. In a PET-MR hybrid unit, the MR magnetic field alters positronium decay patterns through magnetic quenching: all o-Ps and excited p-Ps states are split into finer quantum states under strong magnetic field, thus transitions between some triplet and singlet finer states (mz = 0) were no longer forbidden, thus some o-Ps converts to p-Ps spontaneously by emitting hyperfine split (HFS) photons, which also drops 3γ/2γ ratio hence helps PET imaging quality. However, inverse magnetic quenching might also occur if any external source of HFS frequencies is nearby, thus many p-Ps convert to o-Ps by absorbing those HFS photons (induced HFS transitions). This will dramatically increase 3γ/2γ ratio and hence degrade PET imaging quality instantaneously. The HFS spectrum lies in a broad range of microwaves, from 0.02 to 200 GHz. To prevent inverse magnetic quenching, it is necessary to block external microwave sources outside the hybrid vault, by adding a thin metal layer at all directions of the vault. This could be achieved by adopting the metallic Faraday Cage, which was originally for MR shielding, with possible amendment if necessary. The frequencies of excitation pulses in MR imaging overlap with HFS spectrum, however, the chance for mutual interference during hybrid imaging is small, hence there seems no need to veto each other during hybrid scans.

Aujourd'hui, le nombre d'appareils électroniques connectés fait face à une croissance exponentiel motivé par la demande constante d'utilisateurs pour plus de mobilité, donnant lieu à une croissance du trafic de débit de données global. C'est pourquoi l'amélioration de la connectivité sans-fils est cruciale pour appuyer les débits de donnés nécessaires pour les applications émergentes. En conséquence, le standard IEEE 802.15.3d a fixé une bande continue entre 253-321 GHz pour supporter la future technologie 6G, en attendant des transmissions de débits de donnés élevés à faible consommation par l'utilisation de modulations peu complexes. Par rapport à l'état de l'art, les architectures de réception préférées au-delà de 200 GHz sont basées sur des mélangeurs sous-harmoniques (SHMs) à diode Schottky en technologie III-V grâce aux bonnes performances électriques. Cependant, ces solutions sont couteuses, en rendant difficile le déploiement massif requis pour la technologie 6G. En conséquence, dans cette thèse la technologie silicium et la mise en boitier associée est évaluée afin de proposer des SHMs à diode Schottky en technologie Silicium à 268 GHz. Des pertes de conversion de ~ 11.7 dB et pertes de circuit passif de ~5.1 dB (substrat silicium à faible résistivité) ont été achevés en simulation sur une mise en boitier hybride en utilisant du substrat organique intégré dans un module split-block métallique. Ces résultats donnent des bonnes perspectives pour proposer des alternatives peu couteuses aux SHMs conventionnels. Dans un cas pratique, une liaison sans fils de 15Gb/s utilisant modulation OOK et 30 Gb/s utilisant PAM-4 peuvent être atteints avec le circuit développé
Nowadays, the number of connected electronic devices is facing an exponential growth which is driven by the never-ending demand of users for more mobility, resulting in an increase of global mobile data traffic. In this logic, the improvement of wireless connectivity is crucial to support the forecasted data rate required for emerging applications. Therefore, the IEEE 802.15.3d standard has defined a continuous frequency band between 252-321 GHz to support the future 6G technology, achieving high-data rate transmission in a power-efficient way by using low-complexity modulations. Concerning the literature, above 200 GHz most receiver architectures are based on III-V Schottky diode Sub-Harmonic Mixers (SHMs), thanks to outstanding electrical performances. However, these solutions are pricy, going in contradiction with required mass-deployment of future 6G technology. Therefore, in this thesis we evaluate silicon (Si) based BiCMOS and innovative packaging technologies to enable cost-effective Si-based Schottky diode SHM solutions at 268 GHz. Simulated diode conversion loss of ~11.7 dB and passive circuit losses of ~5.1 dB (low resistivity silicon substrate) have been achieved by following an innovative hybrid packaging solution with organic substrate and metallic split-block module, showing promising perspectives to enable cost-effective SHM alternatives. In a practical case, a real-time wireless links of 15 Gb/s using OOK modulation and 30 Gb/s using PAM-4 could be achieved with the proposed circuit