This study investigates the effect of exchange-correlation on the electronic properties of hybridized hetero-structured nanomaterials, called single-walled carbon boron nitride nanotubes (SWCBNNT). A first principles (ab initio) method implemented in Quantum ESPRESSO codes, together with different parametrizations (local density approximation (LDA) formulated by Perdew Zunga (PZ) and the generalized gradient approximation (GGA) proposed by Perdew–Burke–Ernzerhof (PBE) and Perdew–Wang 91 (PW91)), were used in this study. It has been observed that the disappearance of interface states in the band gap was due to the discontinuity of the π–π bonds in some segments of SWCNT, which resulted in the asymmetric distribution in the two segments. This work has successfully created a band gap in SWCBNNT, where the PBE exchange-correlation functional provides a well-agreed band gap value of 1.8713 eV. Effects of orbitals on electronic properties have also been studied elaborately. It has been identified that the Py orbital gives the largest contribution to the electrical properties of our new hybrid SWCBNNT nanostructures. This study may open a new avenue for tailoring bandgap in the hybrid heterostructured nanomaterials towards practical applications with next-generation optoelectronic devices, especially in LED nanoscience and nanotechnology.

Due to greater demand to use 1D semiconducting chips to replace semiconductors made from bulk structures We studied the structural and electronic properties of free (7, 0) metallic oxides and non-metallic carbide nanotubes. SWMgONT, SWZnONT and SWSiCNT were chosen as the representative model. All the quantum simulation studies were done within DFT ab’initio implemented in quantum ESPRESSO. Results obtained for structural properties revealed that the most stable bond lengths of MgONT, ZnONT and SiCNT are 1.80 Å, 1.82 Å and 1.42 Å respectively. The results obtained revealed 2.8 eV band gap for SWMgONT, 0.5 eV for SWZnONT and 0.8 eV for SWSiCNT respectively. Furthermore SWMgONT and SWZnONT are regarded as direct band gap semiconductors while SWSiCNT is regarded as an indirect semiconductor with narrow band gap. The narrow band gap of all the three systems obtained demonstrates their potential in the optoelectronic application in the next generations’ sustainability science and technology. Recent studies showed that explorations were conducted on oxide nanotubes such SiO2NT, however to the best of our knowledge, studies of the oxide nanotubes of Mg, Zn and Si have not been reported, hence few literature are available.

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In this study, the optical refractive constants of the (5, 5) SWBNNT and (5, 5) SWCNT systems were calculated in both parallel and perpendicular directions of the tube axis by using Quantum ESPRESSO and YAMBO code. It also extended the optical behaviors of (5, 5) SWCNT and (5, 5) SWBNNT to both perpendicular and parallel directions instead of the parallel directions reported in the literature. It also looked at the effects of the diameter of the nanotube on the optical properties instead of chiral angles. From our results, the best optical reflection was found for (5, 5) SWBNNT, while the best optical refraction was found with (5, 5) SWCNT. It was observed that the SWCNT demonstrates refraction in both parallel and perpendicular directions, while (5, 5) SWBNNT shows perfect absorption in perpendicular direction. These new features that appeared for both nanotubes in perpendicular directions were due to new optical band gaps, which appear in the perpendicular directions to both nanotubes’ axis. The electron energy loss (EEL) spectrum of SWBNNT revealed the prominent π- and π + δ- Plasmon peaks, which demonstrates themselves in the reflectivity spectrum. Furthermore, little effect of diameter was observed for the perpendicular direction to both nanotubes’ axis; as such, the combined properties of (5, 5) SWBNNT and (5, 5) SWCNT materials/systems for transmitting light offer great potential for applications in mobile phone touch screens and mobile network antennas. In addition, the studies of optical properties in the perpendicular axis will help bring ultra-small nanotubes such as SWCNT and SWBNNT to the applications of next-generation nanotechnology.

Investigation of the effects of oxygen absorption on the two types of single walled silicon carbide nanotubes (SWSiCNTs) with different chiral angles were done. Our calculations were performed using density functional theory with quantum ESPRESSO and YAMBO codes. Changes in electrical and optical properties were analyzed after introducing two molecules of oxygen as absorbing gas to both armchair and zigzag nanotubes. Results demonstrated a new future by SWSiCNT in which oxygen absorption significantly closes the band gap which transformed the materials from semiconducting to metallic. This future revealed its potential for application as automobile gas switches for air conditioners. Results from optical calculations revealed that zigzag SiCNT is not optically potential above 20 eV, generally, the (6, 6) SWSiCNT demonstrate higher transmission with and without oxygen absorption in the ultraviolet region. The first absorption peaks appeared within the range of 1 eV to 3.4 eV for all systems, there is higher absorption by the oxygen absorbed (6, 6) SWSiCNT than the oxygen absorbed (6, 0) SWZSiCNT. This demonstrates that armchair form of SWSiCNT absorbs gases more than the zigzag form. The absorption peaks can be seen to fall above 3.5 eV and then rise again up to 10 eV, this behavior justifies the nanotubes potential in automobile day light sensors.

NiTi is categorized as a Shape Memory Alloy (SMA) that has been commercially studied and used in biomedical industry due to two main unique properties, Pseudoelastic (PE) and Shape Memory Effect (SME). Combined with biomimetic properties to human bone, NiTi has the potential to be applied as implants by engineered manufacturing process. The common manufacturing by casting has some challenges in order to obtain intrinsic and miscellaneous design of NiTi parts leash to explore more using powder metallurgy (PM) method that expected to get the porous structure. This paper aims to provide an overview of processing NiTi by conventional PM method which could contribute in focusing porous part that suits for biomedical and implants.

Lime has been investigated as a ground improvement material for soils, particularly for road construction, as an alternative to soil cement stabilisation. However, the effect of lime on lateritic soil compaction characteristics is not completely defined. In this article, soil samples from Universiti Teknologi Malaysia (UTM), Skudai, Johor were subjected to a variety of engineering tests, including specific gravity, sieve analysis, Atterberg’s limit, and compaction. According to the results of Atterberg’s Limit, lateritic soil has a plasticity index (PI), a plastic limit (PL), and a liquid limit (LL) of 19, 46, and 65, respectively. The obtained specific gravity value is 2.79. Compaction tests were conducted on untreated and lime-treated soils with lime additions of 3%, 5%, 7%, and 9%, respectively, using an automatic compactor. The OMC and MDD values for untreated laterite are 28% and 1.46 g/cm3, respectively. However, as the lime content increases, the OMC increases slightly while the MDD decreases. The dry density of lime-laterite soil decreases from 1.47 to 1.38 g/cm3, but the moisture content increases slightly from 27% to 31%. The MDD of soil treated with 5% lime is lower than that of lateritic soil in its natural state.