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Despite of the numerous characteristics of the multirotor unmanned aircraft systems (UASs), they have been termed as less energy-efficient compared to fixed-wing and helicopter counterparts. The purpose of this paper is to explore a more efficient multirotor configuration and to provide the robust and stable control system for it.

A heterogeneous multirotor configuration is explored in this paper, which employs a large rotor at the centre to provide majority of lift and three small tilted booms rotors to provide the control. Design provides the combined characteristics of both quadcopters and helicopters in a single UAS configuration, providing endurance of helicopters keeping the manoeuvrability, simplicity and control of quadcopters. In this paper, rotational as well as translational dynamics of the multirotor are explored. Cascade control system is designed to provide an effective solution to control the attitude, altitude and position of the rotorcraft.

One of the challenging tasks towards successful flight of such a configuration is to design a stable and robust control system as it is an underactuated system possessing complex non-linearities and coupled dynamics. Cascaded proportional integral (PI) control approach has provided an efficient solution with stable control performance. A novel motor control loop is implemented to ensure enhanced disturbance rejection, which is also validated through Dryden turbulence model and 1-cosine gust model.

Robustness and stability of the proposed control structure for such a dynamically complex UAS configuration is demonstrated with stable attitude and position performance, reference tracking and enhanced disturbance rejection.

The purpose of this study was to evaluate the psychosocial impact during the current epidemic situation of COVID-19 in Pakistan.

A total of 1,149 respondents were recruited in the study. Mental health status and psychological impact of COVID-19 outbreak were measured by impact of events scale–revised (IES-R) instrument and depression, anxiety and stress scales (DASS-21), respectively.

Results of IES-R revealed moderate or severe psychological impact in 13.05% respondents (score > 33). DAAS score revealed that severe and extremely severe depression (score: 21–42), anxiety (score: 15–42) and stress (score: 27–42) were reported in 6.35%, 6.87% and 2.78% respondents, respectively. Higher levels of stress, anxiety and depression were recorded in female gender, student, medical professionals, farmer and daily wages employed, exhibiting significant (p < 0.05) association with psychological impact of the COVID-19 outbreak. Majority of respondents received increased support, shared feeling and family care.

Mild to moderate psychological impact on mental health status was recorded in this study, which enables further planning and opportunities for health authorities to design psychological interventions for the improvement of negative psychological impact of COVID-19 epidemic in vulnerable groups.

The purpose of this study is to elaborate mixed convection impact in stratified nanofluid flow by convectively heated moving surface. Rheological relations of second-grade fluid are used for formulation. Magnetic field, heat absorption/generation and convective conditions are considered for modeling.

Convergent solutions are achieved using homotopy procedure.

The authors found opposing behavior for radiation and thermal stratification variables against thermal field.

No such analysis has yet been reported.

This paper aims to enhance the existing literature on adaptive market hypothesis (AMH) as this study first time links the month of Ramadan with AMH that permits the performance of well-known Ramadan effect to fluctuate over time.

To fulfill the purpose, the authors inspect the daily returns of 107 individual firms listed at Pakistan Stock Exchange over the period of 20 years. To explore the varying degree of return predictability during Ramadan, the authors use four different subsamples comprising equal length of observations of five years each. The authors use a GARCH (1,1) regression model which facilitates for time varying nature of volatility in equity returns. To facilitate the non-normal nature of stock return data, the authors use Kruskal–Wallis test statistic.

The authors find that behavior of Ramadan effect evolves over time, as performance of this effect varies from time to time and consistent with AMH. Finally, the paper proposes that AMH is well elucidation of behavior of Ramadan effect than traditional efficient market hypothesis.

First limitation is related to the choice of sub-sample as the study uses a sub-sample of five years. Second, the authors ignore transection cost (commissions, fee and taxes) as it is freely negotiated and varies between 4 and 10% (Khan, 2013). Due to such varying information we ignore the transaction cost. It is suggested that a sub-sample analysis of long period may be a more appropriate method to elucidate the idea of AMH in future research and suggest the current method could be adapted and helpful to examine other calendar and market anomalies in different equity markets.

The paper includes implications for investors to choose a better model for investment. Investors can exploit greater returns in future month of Ramadan periods. Furthermore, the researchers can easily extend the methodology used in the study to address multiple issues like adaptive behavior of returns from bonds, real estate investment trusts, cryptocurrencies and trading rules of strategies.

Study confirms from sample t-test and GARCH (1,1) model that Ramadan effect is present in the full and in certain sub-samples; therefore, based on these discrepancies investors can earn abnormal returns by developing specific investment strategies as investors usually make investments in share according to the religious context of Islamic Calendar. The results provide good references for suitable time of investment in stock market. The findings of this study will be helpful to investors and brokers as well as portfolio managers to capture favorable returns across the Islamic calendar.

The paper identified need to study why behavior of Ramadan effect varies over time. The data set comprises daily returns of 107 individual companies over the period of 20 years to better investigate the varying nature of anomalous effect of month of Ramadan. The findings are valuable for international investors and portfolio managers.

Economic ties and formation of trade blocks escalates the movement of goods among the participants and bring different economic and structural changes. Therefore, the current research emphasises on the distribution of market structure and industrial value added among the participant countries of China–Pakistan economic corridor project while focussing on pre and post FTA status.

This study utilises the footloose capital model for analysing whether China or Pakistan is more suitable for attracting factors of production to increase their share of industrial value added. For econometric analyses the current research utilises data from 1995 to 2018 and maximum likelihood effect method to assess factors that affect regional value-added distribution.

Results show that both countries owe different level of economic developments. Effect of capital is, comparatively, similar for both countries while Pakistan supports trade openness which points towards the fact of positive utilisation of abundant labour resources in Pakistan by establishing industrial structure either through domestic capital formation or foreign investment. Whereas, share of labour and trade openness of China positively affect value added production of China.

This is one of the unique studies that studies the regional economic treaties usefulness for any developing country across Asia. Where this study uses the footloose capital model and maximum likelihood method for its analysis which is not previously done, while for detailed analyses the study further divides the timeframe into two parts as pre-FTA ranges from 1995 to 2006, post-FTA from 2007 to 2018 while overall results consist of whole-time frame.

The purpose of this study is to analyze the two-dimensional blood flow in the artery slant from the axis at an angle with mild stenosis under the joint effects of the electro-osmotic, magnetic field, chemical reaction and porosity using a new analytical method. In addition, the mathematical model presented by the researchers Tripathi and Sharma (2018c) was successfully developed by adding the effect of electro-osmosis and studying the impact of the new addition in the developed model on blood flow.

A new analytical method was used to find the analytical approximate solutions of two-dimensional blood flow in artery slant from the axis at an angle with mild stenosis. This technique is based on integrating the Akbari-Ganji and the homotopy perturbation methods.

The results of axial velocity, concentration, temperature and the wall shear stress for blood flow were analyzed in the cases of the absence and presence of electro-osmosis. Furthermore, in these two states of electro-osmosis, a contour plot was created to show the difference in the profile of velocity to the flow of blood when the magnetic field was increased and the altitude of stenosis was increased. The results showed that the new technique is effective and has high accuracy to determine the analytical approximate solutions of two-dimensional blood flow in artery slant from the axis at an angle with mild stenosis. The validity, utility and necessity of the new method were illustrated from the graphs of the new solutions; in addition, there is an excellent agreement with the results of previous studies.

This paper focuses on developing the mathematical model which was presented by the researchers Tripathi and Sharma (2018c), by adding the effect of the electro-osmosis to it, which has been successfully developed. According to the authors’ modest information, the new system has not been studied before. This current problem is solved by using an innovative approach known as the Akbari-Ganji homotopy perturbation method (AGHPM) which has not been used before in two cases: the presence and absence of the effect of electro-osmosis. This new technique afford new with effective and has high accuracy results. Furthermore, the new study (i.e. adding effect of electro-osmosis) with the applications of (variable viscosity, magnetic field, chemical reaction and porosity) illustrated the importance of applying electro-osmosis and how doctors can benefit from it during surgeries through proper use.

This study aims to examine the direct and indirect effects of supply chain resilience enablers on supply chain disruption orientation per supply chain resilience. It conjointly examined the moderation of supply chain complexity on resilience enablers and supply chain resilience. It further detailed the conditional indirect effects of supply chain resilience enablers on supply chain disruption orientations via supply chain resilience at varying levels of supply chain complexity.

This study employed a time-lagged design (three-wave) and self-administered surveys to collect data from the supply chain managers of fast-moving consumer goods firms. A sample of 214 responses was used to test the hypothesized relationships.

The results showed that supply chain resilience significantly mediated on the relationship between supply chain resilience enablers and supply chain disruption orientation. Further, supply chain complexity positively moderated on supply chain resilience enablers and supply chain resilience. The results also supported the moderated mediated hypothesis.

This study contributes to prevalent theory and practices in the wake of recent disruptions faced by the firms. It persuades the managers to emphasize on structuring resilient supply chain system to recover from the disruptions and accumulate and incorporate learning gained from the disruptions to strengthen the firm's response management system.

This study attempted to explore the underlying antecedents and consequences of supply chain resilience in Pakistan and established boundary condition effects of supply chain complexity on the proposed relationships. This research complemented and extended the conceits of resource-based and contingent resource-based views.

The present study aims to investigate the effect of radiation on the unsteady magnetohydrodynamic (MHD) flow of a viscous, electrically conducting Newtonian fluid over rotating disk moving upward/downward immersed in a porous medium, considering the Hall effect. The study is motivated by the various applications in the context of solar power technology, electric power generation, Hall accelerators, MHDs generators and other industrial areas when the fluid flow is subjected to the previously mentioned effects such as MHD, Hall effect and thermal radiation.

Suitable similarity transformations are employed to reduce the governing nonlinear partial differential equations into the nonlinear ordinary ones. The solutions of the reduced system are numerically obtained using the boundary value problem (BVP) Midrich scheme in Maple. The results are presented graphically for vertical disk movement, magnetic parameter, Hall current, Darcy parameter, thermal radiation and Schmidt number. Skin frictions, mass and heat transfer rates are numerically tabulated.

It is revealed that the vertical motion of the disk significantly boosts the radial and annular flows. Moreover, the Hall parameter has contrasting effects on velocity profiles for the range of magnetic field but temperature field is oblivious of this behavior. It is observed that heat and mass transfer considerably enhance along vertical disk movement. Also magnetic field, temperature ratio and radiation parameter significantly enhance the temperature field, while reaction rate parameter and Schmidt number decrease the concentration profile. The current model is calibrated in its reduced form to an already published literature with good correlation to ensure the numerical scheme's validity.

This work is original within the best efforts of the authors.

Autonomous Vehicles (AVs) promise great benefits, including improving safety, reducing congestion, and providing mobility for elderly and the disabled; however, there are discussions on how they should be programmed to respond in an ethical dilemma where a choice has to be made between two or more courses of action resulting in loss of life. To explore this question, the authors examine the current academic literature where the application of the existing philosophical theories to ethics settings in AVs has been discussed, specifically the utilitarianism and the deontological ethics. These two theories are widely regarded as rivals, and are useful in demonstrating the complex ethical issues that must be addressed when programming AVs. We also look at the legal framework, specifically normative principles in criminal law used to regulate difficult choices in an emergency, which some have suggested as a plausible defence for manufacturers who seek to program AVs using a utilitarian framework. These include the doctrine of necessity, the sudden emergency doctrine, and the duty of care. The authors critique each theory, highlighting their benefits and limitations. The authors then make a case for programming AVs using a randomized decision system (RDS) and propose that it could be a viable solution in dealing with certain moral dilemmas. Finally using our assessment, the authors suggest certain objectives for manufacturers and regulators in designing and programming AVs that are technically viable, and would make them morally acceptable and fair.