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Methanol/high reactivity fuel (HRF) dual fuel combustion cannot further extend methanol energy ratio (MER) at medium and low loads. Polyoxymethylene dimethyl ether (PODE) as a biofuel with high cetane number is well suited for HRF. This paper explored the effect of spark ignition (SI) on energy conversion and MER extension for methanol/PODE under medium and low loads. The results show that SI triggers the exothermic processes of SI and dual fuel spark-assisted compression ignition (D-SACI). SI raised MER from 30 %, 40 %, 46 % to 40 %, 60 %, 90 % for brake mean effective pressure (BMEP) of 0.2, 0.4, 0.6 MPa, respectively. SI and D-SACI combustion can partially or completely replace premixed compression ignition (CI). Diffusion combustion and one or more exothermic processes of SI, D-SACI and premixed CI make up two-stage or three-stage exotherm. D-SACI is easily triggered when spark timing approaches PODE injection timing, otherwise, SI exotherm is easily triggered; at BMEP of 0.6 MPa, the exothermic energy of premixed CI is gradually converted into the exothermic energy of D-SACI and SI as MER increases. By optimizing, maximum brake thermal efficiency for BMEP of 0.4 and 0.6 MPa are 37.75 % and 42.82 %, respectively, corresponding to the MER of 50 % and 80 %, respectively. • The effect of spark ignition (SI) on methanol/PODE combustion was studied. • SI made SI and dual fuel spark-assisted compression ignition (D-SACI) combustion. • SI and D-SACI partially or completely replaced premixed compression ignition. • SI raised methanol energy ratio and thermal efficiency of dual fuel combustion. [ABSTRACT FROM AUTHOR]

• A novel dynamic graph attention network is proposed for EEG emotion recognition. • The high accuracy can be obtained from the DGAT model in EEG emotion recognition. • The channel connectivity can reflect the synergistic relationships within the brain. Deep learning classification models based on electroencephalogram (EEG) emotion recognition have demonstrated considerable proficiency in the categorization of emotional states. However, these models have limitations in their capability to analyze the active states and cooperative relationships among distinct brain regions. This study proposes a dynamic graph attention network (DGAT) for EEG emotion recognition, which learns the features of each channel and leverages multiple-head self-attention mechanisms to capture non-Euclidean relationships between channels. Then, we use differential entropy features of emotions signals on the SJTU emotion EEG dataset (SEED). The DGAT model achieved improved subject-dependent and cross-subject classification accuracy compared to previous models. Moreover, ablation studies show that the channel weight matrix(CWM) and appropriate hyper-parameters can improve the performance of the DGAT model significantly. Furthermore, by conducting interpretable analysis of the new connections and electrode weights learned by the model, we find that these connection weight relationships reflect a certain degree of coordination within the brain for EEG-based emotion recognition. These findings provide a new method for EEG emotion recognition and highlights the potential for using deep learning models to analyze the active state and synergistic relationships among brain regions. [ABSTRACT FROM AUTHOR]

There have been no studies on laparoscopic anatomical hemihepatectomy guided by the middle hepatic vein combined with transhepatic duct lithotripsy for the treatment of complex hemihepatolithiasis. This study aimed to investigate the safety and efficacy of laparoscopic anatomical hemihepatectomy guided by the middle hepatic vein combined with transhepatic duct lithotomy to treat complex hemihepatolithiasis. The clinical data for patients who underwent laparoscopic anatomical hemihepatectomy for complex intrahepatic bile duct stones with or without common bile duct stones from January 2016 to June 2020 were prospectively collected. Patients were divided into 2 groups according to surgical approach: laparoscopic anatomical hemihepatectomy guided by the middle hepatic vein (middle hepatic vein group) or laparoscopic anatomical hemihepatectomy not guided by the middle hepatic vein (nonmiddle hepatic vein group). The safety and short-term and long-term efficacy outcomes of the 2 groups were compared with 1:1 propensity score matching. With only a slightly longer operative time (P =.006), the initial and final stone residual rates in the middle hepatic vein group (n = 70) were significantly lower than those in the nonmiddle hepatic vein group (n = 70) (P =.002, P =.009). The bile leakage rate and stone recurrence rate were also significantly lower (P =.001, P =.001). Laparoscopic anatomical hemihepatectomy guided by the middle hepatic vein is safe and effective for treating intrahepatic bile duct stones and can decrease the stone residual rate, reduce the bile leakage rate and stone recurrence rate, and accelerate early recovery. However, owing to the complicated technical requirements for surgeons and anesthesiologists, use of the procedure is limited to large and experienced medical centers. [ABSTRACT FROM AUTHOR]

This study aimed to find a distributed renewable power system with hydrogen generation and storage to meet the current Isle of Rum's energy demands. Five different systems (Case 2–6) were evaluated compared to the current power system (Case 1), with the inclusion of a hydrogen generation and storage subsystem acting as an energy storage medium in Case 3, 4, 5 and 6. Case 2 exhibited a 96.2% reduction in diesel consumption. Case 3 and 4 achieved a fully renewable generation mix through the addition of a hydrogen subsystem comprised of a 28 kW PEM electrolyser, 120 kg compressed storage and modified gen-set. Case 5 and 6 also achieved a fully renewable generation mix, meeting the domestic heating and full heating demands of the island respectively through the integration of heat pumps. Economic analysis showed that Case 2 exhibited the lowest cost, with a LCOE of £3.02/kWh, a 43% reduction from Case 1. Both Case 3 and Case 4 also had a lower LCOE than Case 1 of £5.02/kWh and £4.37/kWh respectively. This shows that the hydrogen subsystem designed can be an economically viable option despite its currently high CAPEX. Both Case 5 and 6 had the highest CAPEX of all systems, due to the additional generation technology required to meet the additional heating demand. However, they achieved the lowest LCOE at £1.86/kWh and £0.76/kWh, due to the high efficiency exhibited by the heat pumps used for the heating load. [ABSTRACT FROM AUTHOR]

We introduce a framework to efficiently capture and identify the defects on the subway tunnel surfaces. Specifically, we design a high-speed multi-camera-synchronous acquisition system for scanning the tunnel surfaces and capturing the cracks from images. We propose an Improved Cascade Region-Based Convolutional Neural Network (R-CNN) method to locate and classify defects, with the crack being refined by image processing algorithms. The methodology is tested by on-site experiments carried out in an operational subway. The mAP value reaches 0.827, with a specific AP value of 0.625 and a newly proposed measure identification rate of 0.942 for crack objects. Notably, by training on bounding box labels, our overall algorithm exhibits the lowest Error Rate (ER) and the highest Intersection over Union (IoU) across all test images, surpassing the performance of classical semantic segmentation networks trained on pixel-level labels. [ABSTRACT FROM AUTHOR]

• The tension of Cu/Nb nanolayered composites is simulated by atomic simulations. • The normal sample with ordinary interfaces is subject to severe strain localization. • The addition of amorphous interfacial layer gives an enhanced strain delocalization. • Strong strain delocalization is further gained by composition gradient in interface. • The delocalization results from nanotwinning and vortex flow of interfacial layers. Nanostructured metals and alloys possess ultrahigh strength but suffer from severe shear instability (strain localization). Recent experiments have shown that the strength and strain delocalization capability of some novel nanostructured alloys and nanolayered composites can be enhanced simultaneously by introducing nanoscale amorphous interfacial layers. However, the study on the underlying mechanism is still in an embryonic stage due to the ignorance of the complicated elemental composition of the interfacial layers, especially the compositional gradient along the interface thickness. Here, the atomic mechanisms of the tensile deformation of Cu/Nb nanolayered composites with amorphous interfacial layers are systematically investigated by molecular dynamics simulations. Depending on whether the composition of the interfacial layers is invariable or has a gradient distribution along the interface thickness, these samples are classified as amorphous or gradient samples, respectively. The simulations of normal Cu/Nb nanolayered composites with ordinary incoherent Cu‒Nb interfaces are also included for comparison, the results of which show that strain localization occurs due to the inhomogeneous plastic deformation between soft and hard grains in the Cu and Nb layers. The strain localization is inhibited in the amorphous samples mainly through the activation of deformation twinning in the Cu and Nb layers that produces a co-deformation between grains. Intriguingly, the gradient arrangement of the elemental composition of the amorphous interfacial layers gives a further stronger strain delocalization by further promoting the co-deformation between grains through stimulating more nanotwins in Cu layers and hindering twin growth in Nb layers, and by producing a much more uniform von Mises strain distribution in the interfacial layers. In addition, a better strain delocalization capability can be obtained when the thickness of the interfacial layers is closer to that of the crystalline ones in the amorphous sample or the range of gradient composition is larger in the gradient one. [ABSTRACT FROM AUTHOR]

The response to Nigeria's energy inadequacies and waste management issues is projected in this research to be achieved with hydrogen and methane co-produced from pretreated (PT) rice straw (RS) in a three-stage digestion process. This study also demonstrated a novel pretreatment (PTM) agent to improve biological energy recovery from RS. The objectives were accomplished using acidogenic and methanogenic procedures in batch, semi-continuous and continuous systems after pretreating RS with chemical/potash extract (PE) followed by a biological agent. At the same time, the energy assessments were done using data from the laboratory study and the literature. The research findings indicated that at the acidogenesis stage, specific hydrogen yield was insignificant when chemical agents and PE were employed alone. However, the daily H 2 production increased when the PT RS residues were enzymatically hydrolysed with NaOH-PT (114 NmL H 2 g−1 TS d−1) and PE-PT (103 NmL H 2 g−1 TS d−1) RS substrates having the highest values at steady states and raw RS producing the least (30 NmL H 2 g−1 TS d−1). In the methanogenesis phase, chemical/ PE PTM followed by enzymatic hydrolysis of RS improved the daily specific methane production by 18%, 31.7% and 41.5% for HCl, PE and NaOH-PT RS residues. The methane production efficiency was 80% for NaOH, 75% for PE, and 68% for HCl RS PT samples, while the raw RS was 48%. The total output energy expressed in electricity and thermal production using combined cooling, heat, and power (CCHP) showed that NaOH and PE-PT RS digesters gave the highest electricity (892.43 and 852.00 KWh elect. tonne-1 TS) and thermal (1194.10 and 1140 KWh therm. tonne-1 TS) yield respectively. Similarly, the cooling fluid in KWh cool produced per tonne of TS RS was 835.57, 798.00 and 741.66 for NaOH, PE and HCl PT RS samples. Finally, whereas the Firmicutes, especially the Clostridium , Ruminococcus and Thermoanaerobacterium, were the dominant microbial community in acidogenic digestates, the Euryarchaeota typified by Methanobacterium , Methanosarcina and Methanosaeta were the principal phyla for most methanogenic reactors. [Display omitted] • Co-production of H 2 and CH 2 from PT rice straw in a novel 3-stage digestion process. • Improving rice straw energy recovery via innovative potash extract pretreatment. • Daily H 2 and CH 4 yield from RS improved with chemical/PE and enzyme pretreatment. • NaOH and PE-PT RS digesters generated the highest electricity, thermal, and cooling fluid in CCHP. • Firmicutes and Euryarchaeota dominated acidogenic and methanogenic reactors, respectively. [ABSTRACT FROM AUTHOR]

We propose a new hybrid model algorithm that addresses the challenges of recognizing multiple objects. Specifically, objects are recognized from massive, large-scale, and complex tunnel images without repeated parameter adjustments and high-cost annotation datasets. Our algorithm utilizes a multi-scale, fusion-based encoder–decoder segmentation model to classify objects from high-resolution images of the tunnel surfaces. To enhance the accuracy of crack identification from complex backgrounds, we incorporate the Expanded Threshold Search (ETS) algorithm and the Local Window Extraction (LWE) algorithm. The acquisition device and the algorithm, implementing the multi-object dataset, have successfully tested, whereby it recognizes five objects and attains the highest Intersection over Union (39.3% for the crack object, 65.6% for the leakage object, and 75.7% for the rest). [Display omitted] • An image acquisition device is designed for tunnel. • A multi-object dataset of complex subway tunnel images is efficiently built. • An efficient and accurate hybrid model is proposed. • Comprehensive experimental results are provided. [ABSTRACT FROM AUTHOR]

Abstract Food and drink processing industries are extremely large consumers of thermal energy as well as bio-wastes producers. The utilisation of bio-wastes for energy recovery appears to be a good opportunity to improve the overall efficiency of process industries. In this study, waste generation, management and energy auditing of a micro-brewery located in the north east of England is investigated. Fermented grains and hops are disposed as organic wastes after the production process. Hence, this study focuses on recovery of energy from these wastes through anaerobic digestion process. Experimental work was carried out in the laboratory for the wastes characterisation. The waste samples are then anaerobically digested at 55 ⁰C and 35 ⁰C with a 5L laboratory scale continuous stirred reactor using 5 gVSL-1 and 25 days organic loading rates and hydraulic retention times respectively. Further to the experimental work, simulations were completed to evaluate the feasibility of the process. ASPEN plus simulation software was used to carry out the simulations using a novel approach for AD which is based on the ADM1 model. The experimental results showed that biogas can be produced at mesophilic and thermophilic conditions: 3.0 and 2.6 litres per day respectively. At thermophilic conditions, the methane content is 65 % while at mesophilic conditions, it is 55%. It is also found that the values of the final biogas production from the simulation were similar to the ones obtained in the experiments (-6.85%). However, the model would need further modifications to be able to accurately predict the biogas compositions. The result shows that the thermophilic process is able to fuel 126.01 kW boiler while mesophilic process can power 76.48kW boiler. [ABSTRACT FROM AUTHOR]

Abstract This study investigated the thermal and indoor environmental performance of an office building in the northeast of England. The building was built using natural stone and glass; internally the large floor plates are bordered and penetrated by open voids that ventilate the building and provide exceptional day lighting. A computational model for this building was set up using Design Builder software. The model is validated using on-site monitoring data and then it is used to predict and evaluate the performance of the building. It is found that the U-value of glass and natural stone is relatively high that caused high energy consumption. To achieve the performance recommended by passive house standard, two scenarios are proposed and simulated. It is found that when the window size is reduced and low U-value wall materials used, the energy consumption for heating can be reduced by 33.9% for Scenario 1 and 45.7% for Scenario 2 in a year. [ABSTRACT FROM AUTHOR]

• Propose a GASF-LDA feature enhancement method for sEMG feature processing. • This method uses GASF to expand features and dig deeper into potential feature information. • The adaptive principle is proposed to effectively improve the convergence and search ability of ABC algorithm. • This method uses improved ABC algorithm optimizing SVM, improves the accuracy of sEMG-based gesture recognition. The surface EMG signal (sEMG) is the potential signal produced by human muscle movement, which is closely related to the movement pattern of the limb and widely used in the field of gesture recognition. However, most of existing methods suffer from insufficient adaptability and low recognition accuracy, in order to achieve rapid and accurate gesture recognition from sEMG signals, a novel sEMG-based gesture recognition method is proposed involving feature enhancement based on gramian angular summation field-linear discriminant analysis (GASF-LDA) and improved support vector machine. Specially, feature enhancement is implemented for the extracted features by GASF-LDA algorithm. Additionally, an adaptive principle based on the artificial bee colony algorithm is proposed to optimize the support vector machine for sEMG-based gesture recognition. As a result, for the eight-classification study of sEMG signals, the combination of feature enhancement and classifier optimization achieved an average accuracy of 97.54 ± 1.03 %. The experimental results show that the method has high classification accuracy and stability. [ABSTRACT FROM AUTHOR]

The objective of the study has been to determine the river discharge by measuring the river flow velocity using two different measurement methods together with the area method and compare the accuracy of the results. Two river flow velocity measurement methods were used, the floating method and the use of current meter. In floating method a floating object was used to determine the water flow velocity on the surface by allow a float to move a distance of 1 m along the river and record the time it takes to travel that distance in seconds. Ten readings were taken and manually recorded and the flow velocity was determined by taking the distance travel by the float (1 m) divide by the time taken by the float (in seconds). On the other hand, the current meter method measure directly the average flow velocity across the river depth, twenty readings were taken and recorded manually and the average velocity were calculated. The use of current meter display flow velocity directly without the need of calculations. The result shows that both methods produce very close value, but the floating method have displayed higher value of around + 2% than current meter method which is a good value, despite the fact that floating method measures the surface velocity and the use of calculation. Many literature highlighted the accuracy of flow velocity measurement using current meter due to the fact that it measures the average velocity across the river, but from the findings when the floating method flow velocity measurement is properly applied it will produce as accurate results as the current meter with a fraction of cost in terms of instrument cost and expertise requirement in measurements. The floating method flow velocity measurement method could be applicable as alternative to current meter in micro hydropower projects river flow measurements in rural areas of developing countries with limited funding and local expertise. [ABSTRACT FROM AUTHOR]

This research experimentally investigated the impact of adding Carbon Coated Nickel and Carbon Coated Aluminium on the sorption performance of conventional Strontium Chloride-Natural Expanded Graphite (SrCl 2 -NEG) chemisorption composite. In order to evenly distribute Nano particles into the material, manufacture methodology is developed and reported. In this study, experiments were set for testing the sorption performance of applying novel Ni/Al-additive adsorbent with the working fluid of ammonia. Compared with that of SrCl 2 -NEG, Ni-additive adsorbent improves the comprehensive heat and mass transfer performance as it reacted faster in both adsorption tests and low temperature desorption tests. By adopting Carbon coated Ni into the chemisorption composite, the overall sorption cycle time and require relatively lower energy for sorption cycles. While Al-additive adsorbent only improves the reaction speed in low temperature desorption tests, and may be applied in negative catalyser for its bad behaviour in adsorption performance tests. This paper reveals that adding Carbon Coated Nickel into conventional chemisorption composite would provide a potential way for improving the overall efficiency of an adsorption system and reducing the overall sorption cycle time. [ABSTRACT FROM AUTHOR]

ORC (organic Rankine cycle) technology is promising in industry for utilizing low-grade heat to generate electricity. It is acknowledged that in an internal combustion engine, only a small amount of primary fuel energy can be effectively used for the power generation, and the other part of the energy lost through exhaust gas, cooling of elements and overcoming friction. The heat in exhaust gas and cooling system (jacket water) can be used as a heat source to drive ORC units for power generation. In this way, the energy lost can be recovered to generate extra power. In this study, Ricardo Wave software was used to investigate the amount of waste heat available from a 1-cylinder diesel engine and THERMOLIB toolbox in SIMULINK was used to simulate and evaluate the performance of a small ORC unit designed for the application. The simulation results from the engine and ORC models were validated against experimental data from other researchers. Two different heating methods to the ORC were used: a) directly driven by the exhaust gas and jacket water (EG-JW); b) thermal oil (TO) was used to collect the waste heat from the engine exhaust gas; the heated thermal oil together with jacket water were then used to drive the ORC. It was found that the performance of the ORC was improved and it was more stable when using TO under different engine running conditions than that directly driven by EG-JW. [ABSTRACT FROM AUTHOR]

Buildings consumed 40% of the world’s primary energy consumption. In hot climate countries, more than 50% of building’s energy was spent on the cooling system. Aimed to reduce building’s cooling load in a tropical country, this study compares building’s construction configuration for two types of air-conditioned rooms in a high-rise office building. The two types of air-conditioned rooms are: (a) air conditioned rooms operating during office hours and (b) IT rooms and data centre with 24hours cooling. Six scenarios were compared using four building’s configurations (baseline, adding insulation, adding phase change material (PCM), and adding both insulation and phase change material) to evaluate the most efficient construction and cooling settings for both room types. It was found that for air conditioned rooms operating during office hours, adding PCM with melting point 29°C and force night time ventilation is the most effective in reducing cooling load. Meanwhile, for a room with 24hours cooling load, adding insulation material is the most efficient. PCM was only fully effective when night time ventilation was introduced which allows the PCM to discharge. High thermal conductivity walls have the potential to create a mould problem in the building (due to differences in moisture pressure at night time between the internal and external of the building) which can be eradicated by using night time ventilation or adding insulation to the wall. PCM installation reduced the sensible cooling load but not the latent cooling load. Hence, mechanical cooling or dehumidifier is still required. [ABSTRACT FROM AUTHOR]

This study investigates the effects on engine performance and exhaust emissions using carbon coated aluminium (Al@C) nanoparticles as additives in palm oil methyl ester biodiesel. The nanoparticles were blended with the biodiesel fuel in the mass fractions of 30 ppm under ultrasonic mixing. A series of experimental tests have been conducted using a heavy-duty diesel engine test bench provided by Cummins. The influences of three kinds of biofuel, including biodiesel, biodiesel with ethanol, and biodiesel with ethanol and nanoparticles, have been studied in detail. The results show clearly that adding Al@C nanoparticles can reduce brake specific fuel consumption (BSFC) remarkably with average of 10%. NOx and CO emission reduce significantly in nanoparticles fuel blends cases at about 12% and 9% respectively, comparing with neat biodiesel. However, total hydrocarbon compounds (THC) emission and emitted particle numbers increase with adding nanoparticles. [ABSTRACT FROM AUTHOR]

The macroscopic characteristics of Hydrotreated vegetable oil (HVO), a renewable biodiesel, were investigated by both experimental and numerical approaches in this paper. The experiment on spray of 0.6ms injection duration was conducted in a constant volume vessel (CVV) at 1800 bar common rail pressure, 70 bar ambient pressure and 100℃ ambient temperature, and the numerical work with the Wave breakup model and RNG k-ε turbulence model was done on a corresponding 2D geometric model at the same condition. The results indicated that the spray tip penetration grew with a decreasing tip velocity and the cone angle increased gradually after a dramatic growth and slight drop. Moreover, the prediction of numerical method, when used in conjunction with experimental studies, was proven effective in elucidating the macroscopic characteristics of HVO spray. The error between the predicted spray tip penetration and the experimental one was no more than 4% except that within 0.2ms flow time after SOI. In addition, the predicted cone angle was in similar trend to the experimental one and the error was within 10% after 0.2 ms. [ABSTRACT FROM AUTHOR]

Novel composite sorbents are developed. Strontium chloride (SrCl 2 ) is selected whereas expanded natural graphite and nanoparticle i.e. carbon coated nickel are integrated as the additive with different densities for the better heat transfer and sorption performance. Thermal properties such as thermal diffusivity and conductivity are investigated by the laser flash method. The sorption performance is tested by the unit which is especially designed. It is indicated that the highest thermal diffusivity could reach 2.242 mm 2 ·s -1 when the density is 1000 kg·m -3 and testing temperature is 20 °C. For different testing temperature and density, the thermal diffusivity range from 1.3 mm 2 ·s -1 to 2.242 mm 2 ·s -1 . Also worth noting that the highest thermal conductivity could reach 2.5 mm 2 ·s -1 for the environmental temperature. One paramount factor i.e. the global conversion rate of the novel composite SrCl 2 is compared and analyzed under different working conditions. It can be found that the higher desorption temperature results in the faster variation of the global conversion rate. In addition, It takes about 15 minutes and 40 minutes to finish the reaction SrCl 2 8-1 and 1-0 when the desorption temperature is 180 °C and 130 °C, respectively. For sorption process, it is indicated that the global conversion rate varies faster with the increase of the sorption temperature. When the global conversion is 0.7, it takes about 14 to 28 minutes when sorption temperature range from -5 °C to 15 °C. [ABSTRACT FROM AUTHOR]

One third of the global food production ends up in the bins such that food waste now ranks third when placed amongst the world’s CO 2 emitters. Bulk of food waste occurs at the early stage of food value chain in the developing countries where many people ironically suffer from food insecurity. To reduce this trend, a biogas driven tri-generation system which synchronizes power generation with food drying and cold room storage is designed and analyzed in context of the current renewable energy policy of the Nigerian government. Using Aspen Plus simulator, market wastes from a rural community is analyzed for biogas generation. The biogas is subsequently used to fuel a 72kWe internal combustion engine which drives a generator to generate electricity. The recovered heat from the engine’s exhaust is used for drying and cooling of agricultural products while heat from the cooling jacket is used to maintain the anaerobic digestion process. The results from this study show that the system’s efficiency increases from 25.66% to 76.02% for electricity only and tri-generation respectively. The results also indicate that the system is able to provide electricity, drying energy requirements and postharvest cold storage for 322, 56, and 922 farming households respectively. This amounts to drying of 20.35MT, 2.313MT and 3.75MT of cassava tubers, maize and tomato respectively per household per year while 3.75MT of tomato is also cold stored. The results equally demonstrate that with the current electricity tariffs for remote areas being charged at USD 13.1/MWh and Feed-in Tariffs (FITs) of USD 122.48/MWh, the Net Present Value is positive regardless of FITs availability and the current banks’ lending rates. However, the payback period is sensitive to FITs and lending rates and varies between 2.1years to 7.19 years depending on the lending rates. [ABSTRACT FROM AUTHOR]

The building performance monitored over one year of a Conventional House and a Passive House in North East England is presented in this paper. These two houses which differ in building fabric, the type of ventilation and thermal storage, the use of different energy and residents’ occupancy result in distinct building energy performance and indoor air quality. According to the measurement data, the primary energy demand of the Conventional House and Passive House were 169.85 kWh/(m 2 a) and 64.11 kWh/(m 2 a) while the annual average indoor temperature of the two properties maintained at 17.7°C and 22.0°C, respectively. A simulation study was conducted by DesignBuilder software to improve the Conventional House’s energy and indoor environmental performance using passive retrofitting methods, aiming to reduce the primary energy demand, the space heating demand of the property and enhance its general indoor air environmental performance. The DesignBuilder models were validated by monitored data and used to predict the performance of the Conventional House after retrofitting, and then compared it with the Passive House. The results indicate the reduction of space heating demand is by about 80% compared to its current status. The findings showed that there was a huge potential for conventional house retrofitting using passive energy saving methods in northern England. [ABSTRACT FROM AUTHOR]

Free-piston engine is a kind of linear internal combustion engine, and shows advantages on simple mechanical structure, low frictional losses, high thermal efficiency and operational flexibility. In this research, an experimental test rig of a dual-piston air-driven free-piston linear expander (FPLE) is established using the FPE concept. A linear generator is used to convert the mechanical work of the pistons into electricity during the expansion process. The piston dynamics, the output voltage of the generator, and the expander operation frequency, as well as the system energy conversion efficiency are identified. It is observed that the piston displacement profile is similar with a sinusoidal wave. The piston is found to run at relative high speed during the middle stroke, and peak velocity is usually achieved when the piston approaches the middle stroke. The output voltage of the generator is sensitive with the piston velocity. With higher driven pressure, the expander frequency is higher. The energy conversion efficiency increases with higher driven pressure and can reach up to 55% with a driven pressure of 3.75 bar. This research presents a fundamental analysis of a FPLE prototype, which can be used as a guidance for the future design of this FPLE type. [ABSTRACT FROM AUTHOR]

In this paper, we establish a model to analyze the light scattering properties of material surface considering the specific morphology information based on small element scattering hypothesis and analysis of receiving flux components. Aluminum micro-structure material is chosen as an example, its surface scattering characteristics are simulated and analyzed using this model. Results show that the scattering distribution on the surface of the material is mainly dependent on the information of the surface topography, when the size and distance of the surface of the material do not cause obvious diffraction effect, and the incident light energy is not enough to cause obvious Compton effect. The research of this paper can provide an effective method for the study of scattering characteristics of new materials and new surface structure, which is the theoretical foundation of the complex scattering analysis and the target detection based on the light scattering characteristics. [ABSTRACT FROM AUTHOR]

Laser conduction limited heating finds wide application in surface processing industry. Modeling of the laser heating can give an insight into the physical processes. In this paper, repetitive long pulse laser heating of solid materials is considered, and an analytical solution for two-dimensional modeling of the temperature distribution is obtained using the method of separation of variables combining with Laplace transformation. It is found that the results obtained from the analytical solution agree well with the existing finite element method. Temperature distributions for different radial locations, axial locations, duty cycles and repetitive frequencies are calculated, and effects of these parameters on temperature distributions are analyzed. The results of this study can give some theoretical basis for revealing the mechanism of laser heating and provide some guidance for experiments of repetitive long pulse laser heating materials in the next work. [ABSTRACT FROM AUTHOR]

Trigeneration produces power, heat and cooling simultaneously. It utilises the waste heat from generator for heating and generating cooling. From previous studies, it is found that some part of the waste heat recovered by the trigeneration is not being used when it is in operation. It is therefore necessary to find a way to utilise the heat. Integrating an ORC (organic Rankine cycle) system into a micro trigeneration system is studied. The waste heat recovered by the trigeneration system is utilised by the ORC system to generate electrical power. An ORC model is set up in Matlab and a micro trigeneration system based a diesel engine generator in the laboratory at Newcastle University is used as the case study. R245fa is used as the working fluid. The result showed that the ORC system may generate 0.737 kW electrical power with 9.25% efficiency at the generator full-load operation point. [ABSTRACT FROM AUTHOR]

A dual-source chemisorption power generation system using scroll expander is proposed and studied to recover dual heat sources under various working conditions. The chemisorption power generation system mainly composes of two adsorption beds and two expansion machines for the purpose of recovering low grade heat energy such as solar energy and industrial waste heat into electricity. The performance evaluation of the system with Six Metal Chlorides-Ammonia working pairs and scroll expander as the expansion device has been conducted to identify the optimal operational conditions of the system. Results indicate MnCl 2 -SrCl 2 is the optimal working pair while the first heat source temperature is from 90 o C to 220 o C. NiCl 2 -SrCl 2 is suitable to be used when the first heat source temperature is higher than 220 o C. Considering about the specific energy and operational condition of the scroll expander, the optimal working pair of the system is achieved by MnCl 2 -SrCl 2 while the first heat source temperature from 180 to 200 o C and the second heat source temperature from 80 to 90 o C. The average specific energy of the system under the suggested conditions can be as high as 102 kJ/kg salts for Mode 1 and 85 kJ/kg salts for Mode 2 with the overall average thermal efficiency at 10%. [ABSTRACT FROM AUTHOR]

A simulation study to improve energy and indoor environmental performance of a rural house by retrofitting in Beijing of China is presented in this paper. This dwelling was retrofitted using passive energy saving methods and it aims to reduce the annual energy consumption, especially the energy used for household heating demands and to improve the indoor air temperature during the winter. Two main retrofitting methods were used for this case study: insulation was added to the envelope of the house, and the single glazing windows had been replaced by double glazing. The model of this rural house simulated by DesignBuilder software is validated by the actual energy consumption. The validated model is then used to evaluate and predict the future performance of this house. The findings of this study indicate the advantages of retrofitting a rural house by using passive methods: annual energy saving for heating is about 60% and the indoor temperature of the house can be improved dramatically compared to its original status. Moreover, the environmental impacts cause by the heating fuel source has been mitigated. The results showed the potential for rural house retrofitting using passive energy saving methods in northern China. [ABSTRACT FROM AUTHOR]

This paper reports the design and investigation of a small scale Organic Rankine cycle using a targeted scroll expander to recover both coolant and exhaust energy from a diesel fuelled internal combustion engine. The designed system could potentially be used to recover both the heat source energy into electricity using simple control of the mass flow rate of the working fluid. Results indicated that under the optimal conditions this ORC system can generate 1 kW power under the full load operational condition of a 6.5 kW engine. Moreover, the corresponding rotation speed of the scroll expander is about 4000 rpm, which means the expander could be adapted with conventional generator to produce electricity at relatively reasonable cost. [ABSTRACT FROM AUTHOR]

In this research, a smart grid using renewable energy and energy storage unit is studied. The system's storage units applies novel supercapacitor technologies to work with traditional batteries. This study aims at satisfying the dynamic demand of a household and evaluate the performance of the smart grid. The system design and the control strategy design is expressed in the paper combined with the discussion of the system's operation theory. The control panel of the system use SIEMENS S7-200 PLC as the core chipset. Digital software is an auxiliary tool for monitoring the system's operation process. The controlling method is divided into two situations, with renewable energy source and without renewable energy source, and both the operation processes are presented in detail in the results discussion part. After analysing the operation details of the system, the controlling strategy is proven to be useful for the operation of the smart grid system. Future work for the system is combining the electrical smart grid with other energy source. This system is potentially to be developed as electrical part of a multi energy system. [ABSTRACT FROM AUTHOR]