Pakistan's energy sector—from a power outage to sustainable supply. Examining the role of China–Pakistan economic corridor

The industrial development alongside inadequate planning in the energy sector put demand-side pressure on Pakistan's energy demand. Similarly, the excessive dependency on fossil fuels has an ecological footprint. Moreover, the abuse of energy tariff subsidies and deficits had a detrimental effect on department earnings, limiting the sector's emergence and intensifying its crisis. This research examines the electric demand and supply imbalance in the context of the China–Pakistan economic corridor investments using the system dynamics modeling approach, highlights the renewable resources, and discusses the hurdles in the way of green conversion. Moreover, the study forecasts the production capacity, electric demand, and supply up to 2040. The results show that China–Pakistan economic corridor investments will uplift the production capacity up to 12.9%, whereas the average production will reach 15.8%, variables that were 5% and 4.8% before China–Pakistan economic corridor. As a result, the energy sector will be able to meet the energy demand after 2021. However, the current investment in the renewable industry will not help in achieving policy targets. The study provides targeted implications to overcome potential barriers to the green path.

Responding to Digital Repression

This chapter discusses strategies civil society groups can use to raise the costs of repression associated with the dictator’s digital dilemma. It examines specific approaches activists can pursue to counter state repression, such as using reputational, economic, political, and supply-side pressure to reverse regime advantages. Turning to the private sector, it describes companies’ roles and responsibilities in relation to digital repression. It contends that democracies should consider advancing a stronger normative framework that will set clearer guidelines about responsible corporate behavior related to digital technology. Such steps will help companies push back on political demands from nondemocratic states. Finally, it proposes strategies that democracies and civil society can adopt to counter the proliferation of digital repression equipment and services provided by authoritarian states like China and Russia, and it discusses policy implications of the COVID-19 pandemic in relation to digital technology.

Performance calculation and configuration optimization of annular radiator by heat transfer unit simulation and a multi-objective genetic algorithm

A performance calculation method based on heat transfer unit (HTU) simulation is proposed to calculate heat transfer capacity and air-side pressure drop of Annular radiator (AR), which can avoid the problem of a huge amount of grids, and at the same time, ensure the calculation accuracy. Calculation results are compared with experimental data, and the average errors of heat transfer capacity and air-side pressure drop are 11.5%, and 5.9%, respectively, which effectively validates the effectiveness and the reliability of this method. Besides, based on HTU simulation knowledge database, a configuration optimization method of AR using Non-dominated Sorted Genetic Algorithm-II (NSGA-II) is introduced. Number of fins in circumferential direction, number of fins in axial direction, and fin height are chosen as design parameters, and two conflicting optimization objectives include heat transfer capacity maximization and air-side pressure drop minimization. Three optimal structures of AR are obtained, and the optimal results indicate that the heat transfer capacity of the optimal configurations increases by 34.31% on average compared with the original one, while the air-side pressure drop decreases by 24.00% on average, which indicates that this method is feasible and valid and can provide significant guidance for structural design of AR.

Final proof Starling’s law wrong and G tube hydrodynamic is the correct replacement: New results and critical analytical criticisms of landmark articles

Substantial evidence demonstrating Starling’s law is wrong currently exists. This article presents the final definitive proof that Starling’s law is wrong, and the correct replacement is the hydrodynamic of the G tube. The presented evidence is based on reported and new results of the G tube hydrodynamic and critical analytical criticism of landmark and contemporary impactful articles. The objectives of this article are to affirm applicability to capillary; crossing the editors’ barrier to convince the hardest of critics that the new theory is correct. The new results presented here further affirm this and the critical analytical criticisms reveal many errors that has misled authors into reporting erroneous results and conclusions affirming Starling’s law and its equations are wrong. The new results show the difference between the hydrostatic pressure and the two components of dynamic pressure: Flow and Side pressures. The side pressure is a negative pressure gradient exerted on the wall of G tube built on a scale to capillary ultrastructure of precapillary sphincter and the wide intercellular cleft pores in its wall. This affirms Starling’s law and its equation are wrong and its correct replacement is the magnetic field like phenomenon of the G tube that explain the fast capillary interstitial fluid transfer necessary for viability of cells at rest and during strenuous exercise.

Experimental investigation on steam/nitrogen condensation characteristics inside horizontal enhanced condensation channels

In order to investigate heat transfer characteristics of steam/nitrogen condensation inside horizontal enhanced condensation channels (HECCs), experiments have been performed, respectively, inside HECC and horizontal circular channel (HCC). HECC is formed by inserting different reinforcers into HCC including horizontal multi-start straight channels (HMSSCs) and horizontal spiral channels (HSCs). Effects of nitrogen mass fractions on average condensation heat transfer coefficients (CHTCs), average outlet condensate mass flowrates (CMFRs), and average steam-side pressure drops (SSPDs) are analyzed, respectively. The results indicate that HECC has better condensation performance than HCC under the same conditions, while average SSPDs of HECC will increase slightly. Then, HMSSC is compared against HCC, and enhancement factors of average CHTCs and average outlet CMFRs are about 1.45 and 1.12, respectively, while the enlargement factor of average SSPDs is about 1.16. Similarly, HSC is compared against HCC, and enhancement factors of average CHTCs and average outlet CMFRs are about 1.25 and 1.05, respectively, while the enlargement factor of average SSPDs is about 1.12.

Experimental and Numerical Study of Array Jet Impingement Cooling on a Leading-Edge Curved Surface

Aerothermal performance of an asymmetrical-profile, leading-edge jet impingement array is studied using numerical and experimental techniques. This array consists of a single row of 9 jets impinging on a leading edge of diameter ratio D/d = 2, and a distinct suction side/pressure side akin to that of an actual turbine blade. Two different jet-to-target heights are tested, while the jet spacing of 4 jet diameters is kept constant. A range of jet-averaged Reynolds numbers between 20k – 80k are tested. The mean flow field of the mid-jet plane is quantified experimentally, through a non-intrusive experimental method of Particle Image Velocimetry (PIV), while area-averaged heat transfer is measured by the constant temperature copper block technique. The target surface is divided into several copper blocks to investigate the area-averaged heat transfer at each jet. The numerical portion of the presented work serves to investigate the fidelity of the Reynolds Averaged Navier-Stokes (RANS) k-ω turbulence model and how well it can predict the flow field within the geometrical domain of the leading edge.

An analytical method for spiral-wound heat exchanger: design and cost estimation considering temperature-dependent fluid properties

Purpose Spiral-wound heat exchangers (SWHEs) are widely used in different industries. In special applications, such as cryogenic (HEs), fluid properties may significantly depend on fluid temperature. This paper aims to present an analytical method for design and rating of SWHEs considering variable fluid properties with consistent shell geometry and single-phase fluid. Design/methodology/approach To consider variations of fluid properties, the HE is divided into identical segments, and the fluid properties are assumed to be constant in each segment. Validation of the analytical method is accomplished by using three-dimensional numerical simulation with shear stress transport k-ω model, and the numerical model is verified by using the experimental data. Moreover, the HE cost is selected as the main criterion in obtaining the proper design, and the most affordable geometry is selected as the proper design. Findings The accuracy of different heat transfer and pressure drop correlations is investigated by comparing the analytical and numerical results. The average errors in the calculation of effectiveness, shell-side pressure drop and tube-side pressure drop using the analytical method are 2.1%, 13.9% and 13.3%, respectively. Moreover, the effect of five main geometrical parameters on the SWHE cost is investigated. The results indicate that the effect of longitudinal pitch ratio on the SWHE cost can be neglected, whereas other geometrical parameters have a significant impact on the total cost of the SWHE. Originality/value This work contains a versatile and low-cost analytical method to design and rating the SWHEs considering the variable fluid property with consistent shell geometry. The previous studies have introduced complex methods and have not considered the consistency of shell geometry.