Experimental Performance Evaluation Research Articles

EXPERIMENTAL INVESTIGATION AND LIFE-CYCLE COST ANALYSIS OF A MULTI-PIPE ARRAY HEAT STORAGE SYSTEM USING PHASE-CHANGE MATERIALS FOR SOLAR GREENHOUSE HEATING

To simplify the structure of accumulator and enhance the utilization of phase-change materials (PCM), this paper presents the development, experimental investigation, and life-cycle cost of a novel phase-change heat storage system with multi-pipe array type for greenhouse heating. The platforms of single accumulator performance evaluation and multi-pipe array storage system performance evaluation were established in the paper, and the life-cycle cost analysis was also studied in contrast to the PCM wallboard storage system and coal-fired heating system. It was found from the experimental investigation that the blackened coating treatment of PVC pipe could improve the thermal storage capacity by 66.7% compared to the original surface after 6 h of sun exposure. The preferred package size in multi-pipe array system was 75 mm in diameter under an illumination time of 6 h and long-lasting heat release (> 10 h), which not only guaranteed higher thermal storage capacity and transformation ratio but also maintained long-term heat discharge. The PCM loading capacity of 1560 kg can raise the night temperature by 1.6°C in the multi-pipe array storage system performance evaluation experiments under ambient temperature range of -18°C-+5&#176C. Due to its cost-effectiveness in terms of both system operation and initial investment, the life-cycle costs of the multi-pipe array system were USD1606, which was only 63.2 and 31.3% that of the wallboard system and coal-fired heater, respectively.

Versatile Confocal Raman Imaging Microscope Built from Off-the-Shelf Opto-Mechanical Components.

Confocal Raman microscopic (CRM) imaging has evolved to become a key tool for spatially resolved, compositional analysis and imaging, down to the μm-scale, and nowadays one may choose between numerous commercial instruments. That notwithstanding, situations may arise which exclude the use of a commercial instrument, e.g., if the analysis involves toxic or radioactive samples/environments; one may not wish to render an expensive instrument unusable for other uses, due to contamination. Therefore, custom-designed CRM instrumentation-being adaptable to hazardous conditions and providing operational flexibility-may be beneficial. Here, we describe a CRM setup, which is constructed nearly in its entirety from off-the-shelf optomechanical and optical components. The original aim was to develop a CRM suitable for the investigation of samples exposed to tritium. For increased flexibility, the CRM system incorporates optical fiber coupling to both the Raman excitation laser and the spectrometer. Lateral raster scans and axial profiling of samples are facilitated by the use of a motorized xyz-translation assembly. Besides the description of the construction and alignment of the CRM system, we also provide (i) the experimental evaluation of system performance (such as, e.g., spatial resolution) and (ii) examples of Raman raster maps and axial profiles of selected thin-film samples (such as, e.g., graphene sheets).

Experimental Performance Evaluation of an Integrated, LCPV/T Membrane Distillation System for Electricity and Seawater Desalination

In this paper, an integrated system based on low-concentrated photovoltaic/thermal (LCPV/T) technology and efficient vacuum membrane distillation (VMD) seawater desalination utilizing the energy of solar is established. Through a theoretical analysis and a series of experiments, this paper explores the temperature change of a single VMD process, and the variation trend of single-day membrane flux with solar irradiation and temperature parameters. In addition, the changes in solar irradiation, temperatures of the integrated system, membrane flux, and thermoelectric properties in different seasons are also analyzed. A mathematical model was established to calculate the relationship between membrane flux and temperature difference. The experimental results show that the membrane flux of VMD is 2.73 L/(m2·h); the simulated seawater can achieve a desalination rate of 99.9%. After economic analysis, the operating incomes of the system under sunny weather conditions in different seasons were all positive.

Experimental investigation and performance evaluation of an oval tubular solar still with phase change material

The problem of freshwater scarcity is a major issue for people all over the world. Solar still is one of the most simplest and affordable ways to produce freshwater using solar energy which is available with no cost and eco-friendly. Recently, tubular solar stills (TSS) have gained popularity as one of the best solutions for acquiring pure water, especially in arid and coastal areas. The main objective of this paper is to enhance the productivity and efficiency of TSS by introducing a new form/shape, the oval tubular solar still (OTSS), integrated with cover cooling and phase change material (PCM). The OTSS is made of a transparent oval tube that is permeable to sunlight from all directions to maximize solar irradiance, and it is integrated with a black basin to improve absorption and water evaporation. It has an appropriate level of flexibility, durability, and low cost. Experiments were conducted out in the climatic conditions of Cairo, Egypt. This paper investigated different basin water depths and different water cover cooling flow rates to obtain their optimal values. Moreover, the effects of using PCM as a thermal management solution were studied in detail. In the case of no cooling, it is observed that the production rate decreases with increasing the water depth in the basin and the maximum production rate reached up to 5.21 L/m2/day at the optimal water depth of 0.5 cm. However, with cooling, the maximum production rate of 6.34 L/m2/day was achieved at the optimum water-cooling flow rate of 2 L/h. Using the PCM the maximum production rate of 6.78 L/m2/day was able to be achieved. The efficiency and productivity of the OTSS were enhanced by 41.26 % and 32.42 %, respectively, when using PCM. Furthermore, the daily thermal exergy efficiency of the OTSS was 3.46 %, 3.85 %, and 4.14 % for the cases no cooling, with cooling and with PCM, respectively. Economically, the cost per liter of desalinated water production was $0.020, $0.017, and $0.017 for the three cases, respectively.

Experimental Structural Performance Evaluation of Hybrid Damper Combining with High Damping Rubber and Steel Slit

Experimental Structural Performance Evaluation of Hybrid Damper Combining with High Damping Rubber and Steel Slit

Construction of novel Heat-conducting Cu-based MOF nanocomposite (HK-mBNNS/PVDF) film for highly efficient Ad-/desorption of toluene

Metal-organic frameworks (MOFs) modification and composite to chase high adsorption capacity and desorption efficiency for volatile organic compounds (VOCs) capture are a great challenge work. Seeking a suitable strategy to simultaneously promote the adsorption capacity and regeneration efficiency of MOFs is a significant practical challenge in this context. Herein, novel heat-conducting MOFs (HKUST-1) composite films were prepared for efficient and synchronous improvement of adsorption affinity and desorption efficiency. In our case, bulk Boron nitride (BN) was exfoliated into BN nano-sheets (BNNS), which were then spread as flakes on PVDF nanofibers to form a conductive network (BNNS/PVDF film, which was abbreviated as B/P film). With the aid of citric acid (CA) modification, HKUST-1 crystals were dispersed-grown on modified B/P (mB/P) film, resulting in the formation of a hierarchical pore structure in HK-mB/P film with a relatively high MOFs loading amount (45.8 wt%) and surface area (448 m2/g). Performance evaluation experiments showed that the toluene adsorption and desorption rates of the HK-mB0.4/P0.6 film were 5.5 and 5.3 times higher than those of the powder HKUST-1, respectively. The fast adsorption rate could be ascribed to the constructed heat-conducting network and porous stacked nanofibers. Furthermore, its adsorption capacity for toluene was significantly increased up to 4.69 mmol/g at low pressure (P/P0 = 0.01), which was approximately-two times higher than that of pure HKUST-1. This merit was mainly attributed to the newly formed interface between HKUST-1 and mBNNS, which could strengthen the adsorption affinity for toluene by the generated unsaturated metal sites of (BNNS-CA-O|Cu|O-ligand) and π-π attraction of B-N bonds. Besides, the HK-mB0.4/P0.6 film also displayed good cycling performance, with only a 3–4 % decrease in activity observed after five consecutive cycles.

µAl-based reactive materials with improved energy efficiency by using the fluorine-containing oxidizer perfluoropolyether as an interfacial layer

To enhance the reactivity of micro-sized aluminum (µAl) particles in the energetic materials, the fluorine-containing oxidizer perfluoropolyether (PFPE) was chosen as an interfacial layer based on the molecular dynamics simulation results to construct µAl-based reactive materials. It was determined that PFPE was uniformly distributed on the surface of the µAl particles by various characterization techniques, including scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). This characteristic microstructure could improve the interfacial contacts between fuels and oxidizers. Besides, the thermal analysis and combustion performance evaluation experiment indicated that fluorine-containing oxidizer PFPE participated in the oxidation and combustion of µAl particles. The burning rates of PFPE-functionalized µAl particles were 1.5 to 3.0 times higher than that of µAl particles. Experimental results revealed that the environmental resistance and the overall reactivity of µAl-based reactive materials was improved owing to the characteristic structure and synergistic effects of the components, respectively. This work provides a deeper understanding towards oxidation process and combustion properties.

Imbibition mechanisms of high temperature resistant microemulsion system in ultra-low permeability and tight reservoirs

Lower-phase microemulsions with core-shell structure were prepared by microemulsion dilution method. The high temperature resistant systems were screened and the performance evaluation experiments were conducted to clarify the spontaneous imbibition mechanisms in ultra-low permeability and tight oil reservoirs, and to direct the field microfracture huff and puff test of oil well. The microemulsion system (O-ME) with cationic-nonionic surfactant as hydrophilic shell, No.3 white oil as oil phase core has the highest imbibition recovery; its spontaneous imbibition mechanisms include: the ultra-low interfacial tension and wettability reversal significantly reduce oil adhesion work to improve oil displacement efficiency, the nanoscale “core-shell structure” formed can easily enter micro-nano pores and throats to expand the swept volume, in addition, the remarkable effect of dispersing and solubilizing crude oil can improve the mobility of crude oil. Based on the experimental results, a microfracture huff and puff test of O-ME was carried out in Well YBD43-X506 of Shengli Oilfield. After being treated, the well had a significant increase of daily fluid production to 5 tons from 1.4 tons, and an increase of daily oil production to 2.7 tons from 1.0 ton before treatment.

Experimental Evaluation of the Fatigue Performance and Self-Healing Behavior of Nanomodified Porous Asphalt Mixtures Containing RAP Materials under the Aging Condition and Freeze–Thaw Cycle

Experimental Evaluation of the Fatigue Performance and Self-Healing Behavior of Nanomodified Porous Asphalt Mixtures Containing RAP Materials under the Aging Condition and Freeze–Thaw Cycle

LoRa-based IoT applications on campus: experimental demonstrations and performance evaluation

Lora technology is widely used in solving many IoT problems because of its long-range capability and low-cost. However, the model which works in the 2.4GHz frequency and without regional limitations is a novelty and its full capabilities are unknown. In this research the device is test for its transmission capabilities on a university campus because this is the conditions with high 2.4GHz interference from Wi-Fi, Bluetooth, etc. The authors also try to find the packet delivery rate and define at what distance LoRa end-node starts to lose connection with its gateway. Along the way receiving signal strength indicator is registered in order to understand the device power level. All of it is done by placing the gateway in the middle of the campus so that it equally reaches the furthermost points, connecting it with a LoRa-based end-node and testing this connection by placing the end-node device in different spots within the area and analysing the connection. LoRa 2.4GHz has shown lower effectiveness in terms of distance in comparison with its sub-GHz counterparts. Receiving signal strength indicator also demonstrated a lower power level in comparison with the mentioned device specifications. However, the LoRa technology still provides bigger distance than Wi-Fi or Bluetooth and is cheaper than other protocols used in IoT. Higher results can be achieved by using a better antenna and by eliminating physical obstacles.

Design and Optimization of a Multimode Amphibious Robot With Propeller-Leg

This article describes the design, optimization, and performance evaluation of a novel multimode motion robot named SHOALBOT, which with multimode operations depends on only one type of propulsion device and can work flexibly in the amphibious environment including running on beaches, grasslands, seabed, and swimming in the water. Robots that work in water need to minimize the number of drive components to improve reliability and reduce communication pressure, our unique design enables the robot to rely on a kind of propulsion device named propeller-leg to have the ability to run rapidly in the seaside and seabed, and swim with multi-degrees-of-freedom in the water (such a propulsion system contains only four driving elements), and it can make the robot complete more work content and improve its adaptability to the environment. Running is more stable than swimming and will not disturb the animals in the water, but when the robot encounters a high obstacle with a large area coverage, switching the motion mode to the swimming mode can pass directly over obstacles instead of detouring or giving up work, this can improve work efficiency. We analyzed and optimized propeller-leg by simulation combined with the open water test, the propeller-leg's thrust in the water before and after optimization differs by 400% according to the test results. We optimized the minimum difference between the forward and reverse thrust of the propeller-leg to improve the stability of the robot movement process and optimized the difference from 25% to 3%. This article provides sufficient technical details and completeness, and through a series of performance evaluation experiments validated that the SHOALBOT has excellent movement ability in the amphibious environment compared with other published amphibious robots of the same size.

Degradable preformed particle gel as temporary plugging agent for low-temperature unconventional petroleum reservoirs: Effect of molecular weight of the cross-linking agent

The development of unconventional petroleum resources has gradually become an important succession for increasing oil production. However, the efficient development of this type of reservoir is paying more and more attention to the application of temporary plugging agents. The use of temporary plugging agents can further expand the stimulated reservoir volume (SRV) and facilitate the flow of oil and gas to the bottom of the well. Particle-gels used as temporary plugging agents have the characteristics of the simple injection process, good deformation, high plugging strength, and complete self-degradation performance, which has been widely applied in recent years. In this paper, five samples of DPPG polymerized by different molecular weights of cross-linking agents were prepared. In addition, infrared spectroscopy analysis, differential calorimetry scanning (DSC) analysis, static particle gel swelling and degradation performance evaluation experiments, and dynamic temporary plugging performance experiments in cores were used to study the influence mechanism of the cross-linking agent molecular weight ( M w ) of the DPPG molecule on its temporary plugging performance. Results show that as the molecular weight of the cross-linking agent (at 0.01 g) in the DPPG molecule decreases from 1000 to 200 Daltons, the fewer cross-linking sites of DPPG, the looser the microscopic three-dimensional mesh structure formed, and the swelling ratio is increased from seven to 33 times. However, the complete degradation time increases from 40 to 210 min. Moreover, the DSC scanning results confirmed that the larger the molecular weight of the cross-linking agent, the worse it is chemical stability and the more prone it to self-degradation. The DPPG particle samples have good temporary plugging performance in reservoir cores. The DPPG prepared by the cross-linking agent with smaller molecular weight has a smaller expansion ratio, higher gel strength, and greater plugging strength in the core. Moreover, the degraded DPPG is less damaging to the cores. However, its slower degradation rate takes a slightly longer time to reach complete degradation. The results of this paper can provide new ideas and a theoretical basis for the development of particle gel-based temporary plugging agents (TPA) with controllable degradation time in low-temperature reservoirs. It can help to expand further the application range of existing DPPG reservoir conditions.

An experimental and statistical evaluation of flexural performance of single and double notched glass/epoxy composite

The existence of a notch in a composite structure is inevitable. However, its presence automatically changes the stress distribution pattern in the component. The present work analyses the flexural performance of glass/epoxy composite with single and pair holes in different locations and sizes. In paired holes (2 mm diameter), stress concentrations were placed at a distance of 10, 20 and 30 mm. In single hole specimens, the notch locations were at 4, 8 and 12 mm distance with hole diameter of 2, 4 and 6 mm. The work suggests a significant drop (30.21%) of flexural strength with a hole placed at 10 mm, which eventually reduced up to 14 ± 1% with the hole moving further away in a paired configuration. Although, the optimum performance was at 20 mm location with improvement in flexural modulus by 12.27%. The single hole arrangement reiterates the significance of hole location and reports that flexural strength decreases significantly as it moves away from the support end (42.44%). However, this drop is never linear, suggesting a fall between mid-location. The notch size appears as an important element in flexural performance for it changes the stress distribution around the hole and the associated damage propagation. The above analysis supported Weibull statistics and found good agreement with experimental results.

Life performance of 40-year-old RC beams with different concrete covers and bar diameters in natural corrosion environments

This study entailed an experimental evaluation of the life performance of 40-year-old reinforced concrete (RC) beams with different concrete cover depths and tensile bar diameters. Beams that were naturally corroded in a marine environment were used in this study, and no artificial process was employed to accelerate the corrosion. Most existing evaluations of beams employ electrical acceleration, admixture, or exposure to designed chloride environments to aid corrosion. Given the paucity of studies on naturally corroded beams, this study is of significance regarding the design, service, and life assessment of RC structures. Two-point load bending test was employed to examine the residual mechanical performance. The corroded bars were extracted to assess the corrosion properties, while the mechanical properties were evaluated via a tensile test. The focus of this study was on evaluating the progress of deterioration and capacity loss in naturally aged beams. The results indicated that a concrete cover of 50 mm satisfies the requirements of a design service life of 50 years. Furthermore, the cross-sectional loss–ultimate capacity loss relationship is consistently linear for the RC beams. Thus, the estimation of ultimate capacity loss based on cross-sectional loss is acceptable in case of natural corrosion of the RC beams. Hence, the findings can contribute to the prediction of the life performance and maintenance of existing structures as well as to designing new structures.

Experimental and modeling evaluation of siphon-type subsurface drainage performance in flooding and waterlogging removal

Agricultural subsurface drainage is necessary for crop production in humid, poorly drained regions with frequent rainfall. Flooding and waterlogging have become more widespread and frequent in recent years, and effective measures should be adopted to increase the subsurface drainage capacity and alleviate flooding and waterlogging disasters after short-term heavy rainfall. However, subsurface drainage focused on the layout parameters (drain depth, drain spacing, etc.) in previous studies, and these measures were limited and cumbersome in the improvement of the flow rate of subsurface drainage. Thus, we aimed to alleviate the flooding and waterlogging threats to farmland and innovatively proposed a new method to increase the flow rate of subsurface drainage, namely siphon-type subsurface drainage. The paper evaluated the performance of the siphon-type subsurface drainage by the indoor sand tank test and the HYDRUS-2D model. Three factors were considered during the experiments: conventional and improved subsurface drainage; shallow, medium, and deep drain depth; and the outlet elevation, including the outlet elevation of the drain pipe under the non-siphon drainage and the outlet elevation of the siphon pipe under the siphon drainage. The results indicated that the siphon-type subsurface drainage performed better under the conditions of steady-state ponding and ponding subsided. The flow rate of the siphon-type subsurface drainage was 27.1–45.7%, 41.8–89.8%, and 39.3–50.5% higher than that of conventional, thin-improved, and thick-improved subsurface drainage with non-siphon drainage under steady-state ponding, respectively. It also had a significant advantage when the outlet elevation was the same. The siphon-type subsurface drainage could increase the flow rate during ponding subsided and reduce the flow rate attenuation degree before the ponding disappears. The flooding removal effect of the siphon-type subsurface drainage was significantly better than that of non-siphon subsurface drainage. The water head and flow rate were used to calibrate and validate the HYDRUS-2D model. The results indicated that the simulated values of flow rate matched well with the measured ones and the relative errors were less than 10%. The influence range and absolute values of the negative water head increased with the decrease of outlet elevation, and the increase effect of flow rate increased with the decrease of the water head. The siphon-type subsurface drainage has more control distance than the non-siphon. The advantages of siphon-type subsurface drainage are not only prominent in quart sand but also applicable to field soil. The results of this study could provide technical support for the application of flooding and waterlogging removal in areas where waterlogging is prone to occur and could improve the ability of agricultural production to address waterlogging disasters.

Experimental evaluation of performance and emission characteristics of different blends of ecofriendly Hibiscus and Coconut oil mixture on CRDI engine

Present work deals with the study of hybrid biodiesel which is a mixture of Hibiscus and Coconut oil biodiesel. Various blends of the hybrid mixture along with diesel are used in CRDI engine to study different engine performance and emission parameters. This study is carried out at different engine load conditions at compression ratios of 18 and 16. The fuels used in the engine are pure diesel, 5%, 10%, 15%, 20%, and 25% hybrid biodiesel and diesel by volume blends denoted as BD00, BD05, BD10, BD15, BD20, and BD25 respectively. The outcome of the experimentation are presented in terms of performance indicative parameters like brake-specific fuel consumption, brake thermal efficiency, air-fuel ratio, and emission parameters like CO2, NOx, smoke, HC, and CO from the engine. It is revelaed that the B20 blend has shown highest thermal efficiency of 28%. BD20 has relatively lower HC and CO emissions at CR16 as well as CR18. Therefore, B20 blend can be used to power diesel engines.

A Lightweight and Anonymous Authentication and Key Agreement Protocol for Wireless Body Area Networks

As a major building block of Healthcare 4.0, wireless body area networks (WBANs) play an important role in collecting patient’s real-time physical phenomena through small wearable or implantable intelligent medical devices and communicating with remote medical experts using short-range wireless communication techniques. However, the challenges of securing information access are partly evidenced by the difficulty in designing secure and efficient security protocols. For example, existing authentication and key agreement schemes have either potential security vulnerabilities or high communication and computation overhead. In this article, we propose a lightweight and anonymous authentication and key agreement protocol, also called liteAuth, for WBANs. In our approach, mutual authentication and session key agreement are achieved using the Tinkerbell map-based random shuffling, physical unclonable function, one-way hash function, and bitwise exclusive OR operation. The security of liteAuth is first verified using the AVISPA tool, and then its cyber resilience is analyzed. In addition, we develop a real-world testbed, implement liteAuth and two existing schemes (i.e., PSLAP and HARCI), and conduct experiments for performance evaluation and analysis. Experimental results indicate that liteAuth can improve the performance of communication overhead and computation time as well as reduce energy consumption, while meeting all security requirements.

Development and Experimental Performance Evaluation of a Multifunctional Refrigerator for Food Preservation

Development and Experimental Performance Evaluation of a Multifunctional Refrigerator for Food Preservation

Development of XYZ stage-type display robot system for stock and disposal tasks in convenience stores

ABSTRACT In recent years, the automation of stocking and disposal operations in convenience stores has attracted great attention. However, these operations have not yet been completely automated. This study describes the development of an XYZ stage-type display robot system that can automatically perform stocking and disposal operations in convenience stores. In the proposed approach, the robot moves along the backyard of the store and performs the stocking and disposal operations from behind the display case. The robot is equipped with an XYZ stage to move the robot hand in three-dimensional space, a stage lifting mechanism to move the XYZ stage vertically, and a shelf drawing mechanism to pull the shelf out. Furthermore, the robot can automatically perform tasks according to the list of operating procedures input in advance. A performance evaluation experiment was conducted using 20 product mock ups of six different types of products available at convenience stores. A robot equipped with 8 new products worked on a display case with 12 products placed randomly. During the operation, robot (I) retrieved the discarded products from the shelf board, (II) placed the new products on the shelf board, and (III) placed the products faceup. The average success rate was 74% and the average time required to complete the operation was 9 min and 54 s. We registered the developed robot with the World Robot Summit 2020 Future Convenience Store Challenge and were ranked the second best.

Experimental and numerical evaluation of the structural performance of corroded reinforced concrete beams under different corrosion schemes

The effect of steel corrosion on the structural performance of reinforced concrete (RC) beams is a complex phenomenon concerning all types of reinforcing steel (tension, compression, and shear reinforcement) which has not been fully investigated experimentally or through modelling. The parameters used in models have not been fully employed in the non-uniform corrosion of steel bar, the buckling effect of corroded compression reinforcement or bond slip at the steel to concrete interface due to the combined effects of longitudinal and shear reinforcement corrosion. The objectives of this paper are i) to experimentally investigate the effect of three corrosion schemes (tension reinforcement corrosion; tension and compression reinforcement corrosion; tension, compression and shear reinforcement corrosion) on the structural performance of RC beams through the investigation nine beams, each with dimension of 150 mm width, 200 mm height and 2100 mm length ii) to employ a finite element method (FEM) to model both the control and corroded RC beams in which non-uniform corrosion of steel bars has been modelled by varying the bar diameters and the locations of corrosion pits including the buckling effect of compressive reinforcing steel bar, iii) to propose a modified bond slip model at the longitudinal steel–concrete interface due to the combined effect of longitudinal and shear reinforcement corrosion. The experimental results show that the yield and ultimate strength of the RC beams reduced under the three corrosion schemes. The yield strength of corroded RC beams is affected by the tension reinforcement corrosion while the ultimate strength is influenced by both the tension and compression reinforcement corrosion. Shear reinforcement corrosion contributes to the reduction in flexural strength of the RC beams due to the reduction in confinement of concrete. The failure modes and the ductility of the corroded RC beams are influenced by the non-uniformed corrosion and its distribution along the steel bars. The proposed FEM demonstrates good correlation with the experimental results, with the difference in ultimate flexural strength from the FEM and the experimental test in the range of 0.1 % to about 4 % for small pitting corrosion beams and up to 10 % for critical pitting corrosion beams.