Search results

The purpose of this paper is to design a compact, light and relatively inexpensive navigation and guidance system capable of providing the required navigation performance (RNP) in all phases of flight of small unmanned aircrafts (UA), with a special focus on precision approach and landing.

Two multi-sensor architectures for navigation and guidance of small UA are proposed and compared in this paper. These architectures are based, respectively, on a standard extended Kalman filter (EKF) approach and a more advanced unscented Kalman filter (UKF) approach for data fusion of global navigation satellite systems (GNSS), micro-electro-mechanical system (MEMS)-based inertial measurement unit (IMU) and vision-based navigation (VBN) sensors.

The EKF-based VBN-IMU-GNSS-aircraft dynamics model (ADM) (VIGA) system and the UKF-based system (VIGA+) performances are compared in a small UA integration scheme (i.e. AEROSONDE UA platform) exploring a representative cross-section of this UA operational flight envelope, including high-dynamics manoeuvres and CAT-I to CAT-III precision approach tasks. The comparison shows that the position and attitude accuracy of the proposed VIGA and VIGA+ systems are compatible with the RNP specified in the various UA flight profiles, including precision approach down to CAT-II.

The novelty aspect is the augmentation by ADM in both architectures to compensate for the MEMS-IMU sensor shortcomings in high-dynamics attitude determination tasks. Additionally, the ADM measurements are pre-filtered by an UKF with the purpose of increasing the ADM attitude solution stability time in the UKF-based system.

The goal of this research is to create a conceptual model that identifies the relationship between organizational learning and green human resource management practices and its contribution to the circular economy. The focus of this research is to identify the organizational learning and green human resource factors that lead to a more circular economic transformation.

The importance of the interaction of factors benefiting both individuals and organizations has been comprehensively explained by combining two well-known theories: resource-based view theory and organizational learning theory. As learning entails change, a climate of organizational learning combined with green human resource practices will efficiently help firms transition to a circular economy. The authors establish a conceptual model in this study, which they then apply to the small- and medium-sized manufacturing industry and report on in the second paper.

This study concentrates on the factors of organizational learning and green human resource management practices that help to create a circular economy after conducting a thorough literature analysis and consulting with experts.

The conceptual model can be applied to organizations in any industry. In the second part, the authors would investigate the interaction of the indicated factors and build their structural hierarchy using the total interpretive structural modelling method for the small- and medium-sized industries and then present the findings.

The proposed framework might facilitate decision-makers, practitioners and academicians to comprehend the relationship between organizational learning and green human resource management factors and their influence on organizations’ transition into a circular economy. The study’s findings will help HR managers clarify the significant organizational learning and green human resource management factors that play a vital role in transitioning organizations into a circular economy.

This research adds to our understanding of the intricate interactions between organizational learning and green human resource management as they relate to the circular economy. To the best of the authors’ knowledge, the conceptual model illustrating the inter-relationship between organizational learning and green human resource management is the first of its type, and it is a novel notion because no previous research has looked into it.

Aircraft assembly is the crucial part of aircraft manufacturing, and to meet the high-precision and high-efficiency requirements, cooperative measurement consisting of multiple measurement instruments and automatic assisted devices is being adopted. To achieve the complete data of all assembly features, measurement devices need to be placed at different positions, and the flexible and efficient transfer relies on Automated Guided Vehicles (AGVs) and robots in the large-size space and close range. This paper aims to improve the automatic station transfer in accuracy and flexibility.

A transferring system with Light Detection and Ranging (LiDAR) and markers is established. The map coupling for navigation is optimized. Markers are distributed according to the accumulated uncertainties. The path planning method applied to the collaborative measurement is proposed for better accuracy. The motion planning method is optimized for better positioning accuracy.

A transferring system is constructed and the system is verified in the laboratory. Experimental results show that the proposed system effectively improves positioning accuracy and efficiency, which improves the station transfer for the cooperative measurement.

A Transferring system for collaborative measurement is proposed. The optimized navigation method extends the application of visual markers. With this system, AGV is capable of the cooperative measurement of large aircraft structural parts.

Since the 1980s agricultural biotech investments by the public sector have increased substantially in both China and India. In the last two decades there has also been a dramatic increase in private section investment in agricultural biotechnology particularly in India. The promise of major benefits of Bt cotton identified in early socioeconomic studies of Bt cotton has proven to be true. Bt cotton has spread to at least 66% and 85% of total cotton areas of China and India, respectively – wherever bollworm is a major problem. Bt cotton continues to control bollworm in both countries, and farmers continue as major beneficiaries rather than biotech or seed companies. The major impacts have been yield increases in India and reduced pesticides consumption in China. In China, evidence also suggests that Bt cotton has suppressed the bollworm population so that non-Bt cotton growers and producers of other crops that are susceptible to bollworm are also benefitting.

The chapter also provides evidence that in the near future Bt rice and Bt eggplant could have major positive impacts by reducing pesticide use and farmers’ exposure to chemical pesticides and increasing yields. Both crops were approved for commercial production by government biosafety regulators, but are not yet available for commercial cultivation.

The issue of foreign aid has continued to gain renewed economic cum political attention in the early years of the twenty-first century. At a summit, popularly known as the Millennium Summit, which took place in 2000, there was an agreement by the international community concerning some goals known as the Millennium Development Goals which were targeted to be reached by the year 2015 but have now been replaced by the Sustainable Development Goals. Against this background, it becomes pertinent to ascertain the contributions and impact of foreign aid in the form of Overseas Development Assistance (ODA) on capital formation in Nigeria. This is an area of foreign aid studies that has been ignored by many researchers. Most studies are seen delving into analyzing the aid-growth nexus without evaluating the transmission link through which foreign aid transmits to affect economic growth. There is paucity of studies on the aid-capital nexus. The paper aims to discuss these issues.

The empirical method used was autoregressive distributed lag (ARDL) model.

The empirical results from the ARDL model estimations show that foreign aid, which is proxied by ODA, has a positive and significant impact on capital formation in Nigeria for the years under analysis. The result of the Granger causality test shows that a bi-directional granger causality exists between foreign aid and gross fixed capital formation (GFCF).

Empirical results from the ARDL model estimations show that foreign aid, which is proxied by ODA, has a positive and significant impact on capital formation in Nigeria for the years under analysis. The result of the Granger causality test shows that a bi-directional Granger causality exists between foreign aid and GFCF. It is therefore recommended that government should make serious efforts toward the implementation and effective utilization of foreign aid. Appropriate policy measures that would monitor the maximum and effective utilization of foreign aid are also required.

A widespread focus on the plant-based antimicrobial cotton fabric finishes has been accomplished with notable importance in recent times. The antimicrobials prevent microbial dwelling in fabrics, which causes severe infections to the fabric users. Chemical disinfectants were conventionally used in fabrics to address this challenge; however, they were found to be toxic to humans. Thus, the present study aims to deal with the utilization of phytochemical extracts from different parts of Pongamia pinnata as antimicrobial coatings in cotton fabrics.

The root, bark and stem were collected and washed several times using tap water. Then, the leaves were dried at room temperature and the root and bark were dried using an oven at 40ºC. After drying, they were ground into fine powder and extracted with ethanol using the Soxhlet apparatus. After that the extract was coated on the fabric tested for antimicrobial studies.

The results reported that the leaf extract of P. pinnata-coated fabric exhibited enhanced antibacterial property towards gram-negative Escherichia coli bacteria, followed by root, bark and stem. The wash durability test in the extract-coated fabric samples revealed that dip-coating retained antibacterial activity until five washes. Thus, the current study clearly suggests that the leaf extract from P. pinnata is highly useful to develop antibacterial cotton fabrics as health-care textiles.

The novelty of the present work is to obtain the crude extract from the leaves, bark, root and stem of P. pinnata and evaluate their antibacterial activity against E. coli, upon being coated on cotton fibres. In addition, the extracts were subjected to wash durability analysis to study the coating efficiency of the phytochemicals in cotton fabrics and a probable mechanism for the antibacterial activity of P. pinnata extracts was also presented.

This paper aims to prepare a new donor–π–acceptor (D–π–A) and acceptor–π– D–π–A (A–π–D–π–A) phenothiazine (PTZ) in conjugation with vinyl isophorone (PTZ-1 and PTZ-2) were designed and their molecular shape, electrical structures and characteristics have been explored using the density functional theory (DFT). The results satisfactorily explain that the higher conjugative effect resulted in a smaller high occupied molecular orbital–lowest unoccupied molecular orbital gap (Eg). Both compounds show intramolecular charge transfer (ICT) transitions in the ultraviolet (UV)–visible range, with a bathochromic shift and higher absorption oscillator strength, as determined by DFT calculations.

The produced PTZ-1 and PTZ-2 sensors were characterized using various spectroscopic methods, including Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy (¹H/¹³CNMR). UV–visible absorbance spectra of the generated D–π–A PTZ-1 and A–π–D–π–A PTZ-2 dyes were explored in different solvents of changeable polarities to illustrate positive solvatochromism correlated to intramolecular charge transfer.

The emission spectra of PTZ-1 and PTZ-2 showed strong solvent-dependent band intensity and wavelength. Stokes shifts were monitored to increase with the increase of the solvent polarity up to 4122 cm⁻¹ for the most polar solvent. Linear energy-solvation relationship was applied to inspect solvent-dependent Stokes shifting. Quantum yield (ф) of PTZ-1 and PTZ-2 was also explored. The maximum UV–visible absorbance wavelengths were detected at 417 and 419 nm, whereas the fluorescence intensity was monitored at 586 and 588 nm.

The PTZ-1 and PTZ-2 dyes leading to colorimetric and emission spectral changes together with a color shift from yellow to red.

The purpose of this research is to evaluate construction and industrial waste materials in concrete using different additives.

The experimental study investigated the effect of waste foundry sand (WFS), waste glass (GW) as partial substituent to natural sand and addition of waste glass fibers (GFs) and silica fume (SF) in natural/construction waste aggregate concrete on mechanical properties, durability and microstructure using.

The results reveal significant strength enhancement on using two admixtures, the maximum increase in compressive strength was obtained on using 20% WFS and 0.75% GF for both natural (75% increment) and construction waste (72% increment) coarse aggregates. Using three admixtures simultaneously, the maximum enhancement in compressive strength was found for (WFS(20%) + GW(10%) + GF(0.75%)) for both natural aggregates (122% increment) and construction waste (114% increment) coarse aggregates as compared to control mix. The 28 days split tensile and flexural strength of natural/construction waste aggregate concrete improve with age appreciably for optimal contents of single, two or three admixtures and the maximum tensile and flexural strength increment was 135 and 97% for mix (WFS(20%) + GW(10%) + GF(0.75%)) with natural aggregates as compared to control mix. The microstructural analysis results indicate improved microstructure upon partial substitution of sand with WFS, GW and SF along with addition of waste GFs.

The use of construction and industrial waste as a substituent to natural aggregate/sand will provide far reaching benefits for the green construction and the environment at large.

Interorganizational dependence is considered as a liability for each firm and needs to be managed properly. Rather than exploring the opportunistic outcome of dependence, the authors focus on the moderating role of supply chain boundary spanners' guanxi. This study tends to uncover the way and the conditions under which boundary spanners' guanxi influences dependence-opportunism relationships.

Using a survey of 380 buyer–supplier exchanges in China, this study first examines the relationship between dependence and opportunism, then assesses the contingent role of boundary spanners' guanxi and further tests how unfairness perception and legal inefficiency alter the role of guanxi in managing dependence.

This study finds that buyer dependence increases supplier opportunism while supplier dependence lowers supplier opportunism. Boundary spanners' guanxi weakens the opportunism-facilitating impact of buyer dependence and mitigates the opportunism-restricting effect of supplier dependence. However, unfairness perception would attenuate the value of guanxi in restricting depended sides' opportunism but strengthen the value of guanxi in motivating depending sides' opportunism; legal inefficiency would amplify the value of guanxi in facilitating depending suppliers' opportunism.

First, the study enriches supply chain dependence studies by incorporating interpersonal guanxi into the investigation of dependence-opportunism relationships. Second, the study adds to the supply chain management literature by uncovering a contrasting role of guanxi in influencing the dependence-opportunism relationship. Third, the study incorporates an agency view to uncover two boundary conditions under which guanxi is mobilized for personal interest seeking or for organizational purposes.