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This paper presents a novel Continuous Variable Transmission (CVT) design. CVT is highly beneficial for actuators with rotary output as it can improve the energy efficiency of the actuators by providing an optimum transmission ratio. This property of CVT is highly beneficial for fossil-fuel-based vehicles, electric vehicles, wind turbines, industrial robots, etc. With the exception of Spherical CVT and DH CVT, all known CVTs like push belt CVTs, toroidal CVTs, Milner CVTs, etc., require additional gear sets and clutches for direction reversal and neutral gear ratio. However, Spherical CVT and DH CVT have low torque capacity due to a single traction point constraint. Foregoing in view, a new CVT named CAD CVT has been developed. The paper presents the design conception, the operating principle, the transmission ratio, the torque capacity, frictional losses, and experimental verification of the basic functionality by manufacturing a Proof of Concept (PoC). The proposed CVT is the only CVT capable of independent direction reversal and high torque capacity as it can transmit torque through multiple traction points. The new CVT will significantly impact high-torque applications in different engineering applications, especially land transport consisting of heavy vehicles like trucks, buses, and trailers. [ABSTRACT FROM AUTHOR]

In the paper, a back swept impeller of centrifugal compressor is experimentally studied and numerically validated and modified to increase its pressure ratio and improve efficiency, as well as to analyse the effect of splitter blade location between two main blades. The back swept multi splitter blade impeller was designed with a big splitter positioned close to the main blade suction surface and a smaller splitter close to the pressure surface. Adding this multi splitter improves the overall performance of the modified impeller due to less intensive flow separation and smaller pressure loss. In particular, the total pressure ratio was observed to increase from 4.1 to 4.4, with one percent increase in efficiency.

Fiber-reinforced polymer (FRP) composite bridges are usually constructed for rapid installation. The durability of the bridge is increased by stiffness, strength to weight ratio, and corrosion resistance. The main factors on which the design of the composite sandwiched bridge considerably depends are ply layers, material system, alignment of ply angles, and thickness of the core. In this work, a parametric design study for a bridge using finite element analysis (FEA) is presented. Two types of composite materials—carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP)—were used as the sandwich structure's skin, and three different types of woods were used as a core. Different design configurations were acquired based on material and instability constraints by using Euro-codes. Failure criterion of Tsai-Hill, Tsai-Wu, MS, equivalent stress, and maximum shear stress were implemented to analyze the overall failure of the bridge deck under Ultimate Limit State (ULS) conditions. The total deformation was examined under Serviceability Limit State (SLS) conditions, and the results were compared and verified by the previous study. The core was also examined using the core-factor and increasing the thickness of the core through parametric modeling. [ABSTRACT FROM AUTHOR]

The performance of zero ozone depletion potential refrigerants is investigated when retrofitted in R22 based air conditioning system. The options evaluated are R407C, R417A, R422D, R427A, and R438A. In order to arrive at most suitable alternative(s) to R22, energy and exergy performance of candidate refrigerants is carried out and compared against that of R22. The COP and exergy efficiencies showed that none of selected refrigerant is as efficient as R22 however their values suggests that each may be considered as potential substitute for retrofitting. Having comparable COP to others but low cooling capacity of R417A makes it less attractive. With comparatively reduced COP, lowest exergy efficiency and highest mass-flow rate, makes R422D the least desirable option. The R407C, R427A, and R438A emerged as most attractive substitutes. The lower discharge temperatures of substitutes will enhance the compressor life. Further, for substitutes there may be a possible change out of expansion valve. [ABSTRACT FROM AUTHOR]

Global increased need for energy, reduction of conventional fossil-fuel, and critical environmental concerns are navigating the researchers towards renewable energy sources. Energy sources such as oil, coal, and gas are being quickly exhausted or have scarce reserves for future demands. Since the world today is experiencing a great shortage of energy, it should be captured, stored, conditioned, and utilized by alternative techniques. Ocean energy is one of these promising energy resources. The renewable energy source of ocean mainly is contained in waves, ocean current and offshore solar energy. The advantage of using this source is the availability of forecast for waves, which can help in designing the right elements. Moreover, improved computational techniques for modelling and simulation have made the studies of wave climatology and ocean energy converters more promising in future. A considerable research and execution of various projects has already been undertaken globally in this field. Many countries which include UK, Scotland, Ireland, USA, China, Portugal and India have launched various Wave Energy Conversion (WEC) models/projects and rapidly progressing towards cost effective solutions. Pakistan, with its geographical location has a great potential of extracting various energy resources, remains undersupplied and currently facing crisis with energy management. The most important factors are the slow progress towards research and adaptation to renewable energy resources in the country. Though, amongst renewable energy resources, the technology for Wind and Solar energy has generally been focused and has come a long way. In Pakistan, with a 170 km available creek system of Indus delta, ocean wave energy harnessing can play a vital role in eradicating the energy crisis. However, very fewer efforts have been made to harness this reliable and predictable resource in Pakistan. This paper at first, presents the analysis of various Wave Energy Conversion techniques currently available and their advantages/disadvantages. In addition, major WEC models being employed globally by various companies, have been discussed in detail. Further, investigation of two novel concepts of on-shore and near shore wave energy extraction method, which are introduced by National University of Science and Technology, are also reviewed. In light of the existing energy crisis, the financial and technical restrictions in Pakistan, these methods are considered to be a cost effective solution and could turn into a viable project for adaptation by rural sector of Pakistan i.e. along the Sindh and Baluchistan coastlines. These concepts are designed for on-shore or near-shore application and are based upon total energy conservation, which utilizes both potential and kinetic energy of the waves. [ABSTRACT FROM AUTHOR]

Solar heating is one of the important utilities of solar energy both in domestic and industrial sectors. Evacuated tube heaters are a commonly used technology for domestic water heating. However, increasing cost of copper and nickel has resulted in huge initial cost for these types of heaters. Utilizing solar energy more economically for domestic use requires new concept which has low initial and operating costs together with ease of maintainability. As domestic heating requires only nominal heating temperature to the range of 60-90 °C, therefore replacing nickel coated copper pipes with any cheap alternate can drastically reduce the cost of solar heater. We have proposed a new concept which utilizes double slope triangular chamber with EPDM based synthetic rubber pipes. This has reduced the initial and operating costs substantially. A detailed analytical study was carried out to design a novel solar heater. On the basis of analytical design, a prototype was manufactured. Results obtained from the experiments were found to be in good agreement with the analytical study. A maximum error of 10% was recorded at noon. However, results show that error is less than 5% in early and late hours.