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A range of optical fibre-based sensors for the measurement of ethanol, primarily in aqueous solution, have been developed and are reviewed here. The sensing approaches can be classified into four groups according to the measurement techniques used, namely absorption (or absorbance), external interferometric, internal fibre grating and plasmonic sensing. The sensors within these groupings can be compared in terms of their characteristic performance indicators, which include sensitivity, resolution and measurement range. Here, particular attention is paid to the potential application areas of these sensors as ethanol production is globally viewed as an important industrial activity. Potential industrial applications are highlighted in the context of the emergence of the internet of things (IoT), which is driving widespread utilization of these sensors in the commercially significant industrial and medical sectors. The review concludes with a summary of the current status and future prospects of optical fibre ethanol sensors for industrial use.

The energy crisis and increasing fossil fuel prices due to increasing demands, controlled supplies, and global political unrest have adversely affected agricultural productivity and farm profitability across the globe and Pakistan is not an exception. To cope with this issue of energy deficiency in agriculture, the best alternate strategy is to take advantage of biomass and solid waste potential. In low-income countries such as Pakistan, the greenhouse heating system mostly relies on fossil fuels such as diesel, gasoline, and LPG. Farmers are reluctant to adopt greenhouse farming due to the continuously rising prices of the fossil fuels. To reduce reliance on fossil fuel energy, the objective of this study was to utilize biomass from crop residues to develop an efficient and economical biomass furnace that could heat greenhouses to protect the crop from seasonal temperature effects. Modifications made to the biomass furnace, such as the incorporation of insulation around the walls of the furnace, providing turbulators in fire tubes, and a secondary heat exchanger (heat recovery system) in the chimney, have increased the thermal efficiency of the biomass furnace by about 21.7%. A drastic reduction in hazardous elements of flue gases was observed due to the addition of a water scrubber smoke filter in the exit line of the flue. The efficiency of the biomass furnace ranged from 50.42% to 54.18%, whereas the heating efficiency of the diesel-fired heater was 71.19%. On the basis of the equal heating value of the fuels, the unit material and operating costs of the biomass furnace for wood, cotton stalks, corn cobs, and cow dung were USD 2.04, 1.86, 1.78, and 2.00 respectively against USD 4.67/h for the diesel heater. The capital and operating costs of the biomass furnace were about 50% and 43.7% of the diesel heater respectively, resulting in a seasonal saving of about 1573 USD. The produced smoke was tested as environmental friendly under the prescribed limits of the National Environmental Quality Standards (NEQS), which shows potential for its large-scale adoption and wider applications.

Biogas production is a clean renewable energy source that can improve lives in developing countries. However, winter temperatures in some areas are too low to enable enough biogas production in small unheated digesters to meet the energy requirements of households. Low-cost, high yield reactors adapted to the local climate are needed in those situations. A decision-support model was developed to assist in the design of biogas reactors capable of meeting households’ year-round energy needs. Monthly biogas production relative to household energy needs was calculated for the scenario of suburban Hanoi, Vietnam. Calculations included pig number, slurry (manure water mixture) dilution, retention time and biogas/solar heating. Although using biogas to heat the digester increased biogas production, it did not lead to an energy surplus, particularly with the 1:9 slurry dilution rate commonly used on pig farms. However, at a 1:3 slurry dilution, the use of solar heating to provide 90% and biogas 10% of the heat required to heat the digester to 35 °C improved the biogas production by 50% compared to psychrophilic production. The energy needs of an average five-person family throughout the year required 17 fattening pigs. This model can establish the best solution for producing sufficient energy throughout the year.

The rapid growth of rooftop photovoltaic (PV) arrays installed in residential houses leads to serious voltage quality problems in low voltage distribution networks (LVDNs). In this paper, a combined method using the battery energy management of plug-in electric vehicles (PEVs) and the active power curtailment (APC) of PV arrays is proposed to regulate voltage in LVDNs with high penetration level of PV resources. A distributed control strategy composed of two consensus algorithms is used to reach an effective utilization of limited storage capacity of PEV battery considering its power/capacity and state of charge (SoC). A consensus control algorithm is also developed to fairly share the required power curtailment among PVs during overvoltage periods. The main objective is to mitigate the voltage rise due to the reverse power flow and to compensate the voltage drop resulting from the peak load. Overall, the proposed algorithm contributes to a coordinated charging/discharging control of PEVs battery which provides a maximum utilization of available storage capacity throughout the network. In addition, the coordinated operation minimizes the required active power which is going to be curtailed from PV arrays. The effectiveness of the proposed control scheme is investigated on a typical three-phase four-wire LVDN in presence of PV resources and PEVs.

The majority of local respondents in a large-scale survey were in favour of planned local wind farms on the Danish coast, despite these wind farm plans being the source of wider public and political contestation and opposition. Here we discuss results from the open-ended questions in the survey, specifically focusing on comments expressing how some respondents felt split in their views of these wind farms, accepting the need for renewable energy while at the same time being concerned about the potential local impact of the wind farms. Building on previous theoretical propositions relating to energy infrastructure opposition, here we apply the concept of cognitive polyphasia in some depth, providing a socio-cognitive account of the internal contradiction of being positively disposed to renewable energy in principle, but concerned about or opposed to specific de­velopments in localities. We distinguish a cognitive polyphasic account of such mixed feelings from cognitive dissonance accounts, and we identify several types of polyphasic representations, providing a basis for further work in other cases. The majority of local respondents in a large-scale survey were in favour of planned local wind farms on theDanish coast, despite these wind farm plans being the source of wider public and political contestation andopposition. Here we discuss results from the open-ended questions in the survey, specifically focusing oncommentsexpressinghowsomerespondentsfeltsplitintheirviewsofthesewindfarms,acceptingtheneedforrenewableenergywhileatthesametimebeingconcernedaboutthepotentiallocalimpactofthewindfarms.Building on previous theoretical propositions relating to energy infrastructure opposition, here we apply theconceptofcognitivepolyphasiainsomedepth,providingasocio-cognitiveaccountoftheinternalcontradictionof being positively disposed to renewable energy in principle, but concerned about or opposed to specific de-velopments in localities. We distinguish a cognitive polyphasic account of such mixed feelings from cognitivedissonanceaccounts,andweidentify severaltypesofpolyphasicrepresentations,providingabasisforfurtherworkinothercases

This paper presents a comprehensive review of various techniques employed to enhance the low voltage ride through (LVRT) capability of the fixed-speed induction generators (FSIGs)-based wind turbines (WTs), which has a non-negligible 20% contribution of the existing wind energy in the world. As the FSIG-based WT system is directly connected to the grid with no power electronic interfaces, terminal voltage or reactive power output may not be precisely controlled. Thus, various LVRT strategies based on installation of the additional supporting technologies have been proposed in the literature. Although the various individual technologies are well documented, a comparative study of existing approaches has not been reported so far. This paper attempts to fill this void by providing a comprehensive analysis of these LVRT methods for FSIG-based WTs in terms of dynamic performance, controller complexity, and economic feasibility. A novel feature of this paper is to categorize LVRT capability enhancement approaches into three main groups depending on the connection configuration: series, shunt, and series-shunt (hybrid) connections and then discuss their advantages and limitations in detail. For verification purposes, several simulations are presented in MATLAB software to demonstrate and compare the reviewed LVRT schemes. Based on the simulated results, series connection dynamic voltage restorer (DVR) and shunt connection static synchronous compensators (STATCOM) are the highly efficient LVRT capability enhancement approaches.

The synthesis of biodiesel from Jatropha curcas by transesterification is kinetically controlled. It depends on the molar ratio, reaction time, and temperature, as well as the catalyst nature and quantity. The aim of this study was to explore the transesterification of low-cost, inedible J. curcas seed oil utilizing both homogenous (potassium hydroxide; KOH) and heterogenous (calcium oxide; CaO) catalysis. In this effort, two steps were used. First, free fatty acids in J. curcas oil were reduced from 12.4 to less than 1 wt.% with sulfuric acid-catalyzed pretreatment. Transesterification subsequently converted the oil to biodiesel. The yield of fatty acid methyl esters was optimized by varying the reaction time, catalyst load, and methanol-to-oil molar ratio. A maximum yield of 96% was obtained from CaO nanoparticles at a reaction time of 5.5 h with 4 wt.% of the catalyst and an 18:1 methanol-to-oil molar ratio. The optimum conditions for KOH were a molar ratio of methanol to oil of 9:1, 5 wt.% of the catalyst, and a reaction time of 3.5 h, and this returned a yield of 92%. The fuel properties of the optimized biodiesel were within the limits specified in ASTM D6751, the American biodiesel standard. In addition, the 5% blends in petroleum diesel were within the ranges prescribed in ASTM D975, the American diesel fuel standard.