Low Collection Efficiency Research Articles

Effects of asymmetric cost information on collection outsourcing of used products for remanufacturing

Due to environmental and economic benefits from remanufacturing as well as an existing or potential take-back regulation, a manufacturer often implements remanufacturing, but it often delegates a third-party (3P) to collect used products. However, the collection efficiency is the 3P’s private information while the prior distribution of the 3P’s collection efficiency is possessed by the manufacturer. To maximize its expected profit, the manufacturer can design nonlinear pricing contracts to stimulate the 3P to select one that corresponds to its true type, where the nonlinear pricing contracts consist of the wholesale price and the collecting quantity. Specifically, our modeling analysis reveals that asymmetric information can result in the downward distortion of quantities collected by the 3P with low collection efficiency, whereas the quantities collected by the 3P with high collection efficiency remain unchanged. Besides, faced with information asymmetry and collection outsourcing, the manufacturer may also bring the new product quantity down if the 3P has low collection efficiency. Moreover, the take-back regulation will indirectly reduce consumer surplus, and this negative effect will be amplified by asymmetric information.

Point cloud registration method for maize plants based on conical surface fitting\u2014ICP

Reconstructing three-dimensional (3D) point cloud model of maize plants can provide reliable data for its growth observation and agricultural machinery research. The existing data collection systems and registration methods have low collection efficiency and poor registration accuracy. A point cloud registration method for maize plants based on conical surface fitting—iterative closest point (ICP) with automatic point cloud collection platform was proposed in this paper. Firstly, a Kinect V2 was selected to cooperate with an automatic point cloud collection platform to collect multi-angle point clouds. Then, the conical surface fitting algorithm was employed to fit the point clouds of the flowerpot wall to acquire the fitted rotation axis for coarse registration. Finally, the interval ICP registration algorithm was used for precise registration, and the Delaunay triangle meshing algorithm was chosen to triangulate the point clouds of maize plants. The maize plant at the flowering and kernel stage was selected for reconstruction experiments, the results show that: the full-angle registration takes 57.32 s, and the registration mean distance error is 1.98 mm. The measured value’s relative errors between the reconstructed model and the material object of maize plant are controlled within 5%, the reconstructed model can replace maize plants for research.

A sheathed virtual impactor – Microseparator for improved separation of sub- and supercritical sized particles

In the separation process of airborne microbial particles, a typical virtual impactor with sheath flow is effective to lower the critical diameter and minimize wall loss. However, a considerable fraction of undesired subcritical particles smaller than the critical diameter are gathered in the minor flow. To address this issue, this article presents a novel microseparator to reduce subcritical particle content while preserving the typical virtual impactor's advantages. The microseparator made of a microfluidic chip adopts a core-aerosol-sheath configuration in which the core and sheath flows raised from clean airflow confine the distribution of microparticles in the aerosol flow towards the core region of the microchannel but away from the center axis. Such configuration effectively decreases the subcritical particle content in the minor flow. The improvement of the proposed microseparator is quantified by comparing the performance with the typical virtual impactor numerically and experimentally at the same critical diameter. At the critical diameters of 0.35 μm, 0.42 μm, 0.52 μm, and 0.6 μm, we find that, firstly, the ratios of subcritical particle content to total particle content (Csp) of our device are 5.24%, 4.74%, 12.34%, and 7.76% smaller than those of typical virtual impactor, respectively. Secondly, the corresponding reduction ratios of subcritical particle (Rsp) of our device are 25.87%, 21.20%, 40.31%, and 33.92%. Lastly, the maximum wall loss of the proposed microseparator in the collection probe is slightly smaller than the typical one, while the operation range of minor flow is enlarged with the premise of maintaining low subcritical particle collection efficiency.

Boosting the Efficiency of Kesterite Solar Cell: Use of Ag Mixed Cu2ZnSnS4Intermediate Thin Film Layer

Kesterite materials such as copper–zinc–tin–sulfide (CZTS) and copper–zinc–tin–selenide (CZTSe) are potential candidates for cost‐effective photovoltaic applications. However, the material suffers low carrier collection efficiency due to poor quality of thin film during deposition and in‐house defects. The use of Ag‐doped CZTS layer as an intermediate layer can save the device from such issues. Herein, the impact of ACZTS layer on solar cell performance is analyzed. Numerical investigation on the influence of different loss mechanisms such as radiative recombination and recombination through traps and defects on the performance of the device is presented. A remarkable efficiency is achieved in solar cell with the incorporation of intermediate ACZTS layer.

Experimental Research of Gaseous Emissions Impact on the Performance of New-Design Cylindrical Multi-Channel Cyclone with Adjustable Half-Rings

Cyclones are widely used for separating particles from gas in energy production objects. The efficiency of conventional centrifugal air cleaning devices ranges from 85 to 90%, but the weakness of many cyclones is the low collection efficiency of particles less than 10 μm in diameter. The novelty of this work is the research of the channel-type treatment device, with few levels adapted for precipitation of fine particulate matter, acting by a centrifugal and filtration principle. Many factors have an impact on cyclone efficiency—humidity, temperature, gas (air) composition, airflow velocity and etc. Many scientists evaluated only the effect of origin and size of PM on cyclone efficiency. The effect of gas (air) composition and temperature, and humidity on the multi-channel cyclone-separator efficiency still demands contributions. Complex theoretical and experimental research on air flow parameters and the efficiency of a cylindrical eight-channel system with adjustable half-rings for removing fine-dispersive particles (<20 μm) was carried out. The impact of air humidity and temperature on air flow, and gaseous smoke components on the removal of wood ashes was analyzed. The dusty gas flow was regulated. During the experiment, the average velocity of the cyclone was 16 m/s, and the temperature was 20–50 °C. The current paper presents experimental research results of wood ash removal in an eight-channel cyclone and theoretical methodology for the calculation of airflow parameters and cyclone effectiveness.

Налогообложение и регулирование табачной и инновационной никотинсодержащей продукции в России: новые проблемы и решения

Introduction: despite the progress in smoking reduction achieved over the past 10 years Russia is still among the leaders of the global anti-rating. the progress in reducing smoking achieved over the past 10 years Russia is still among the leaders of the global anti-rating. The effectiveness of the excise policy as the main instrument begins to decline from the illicit trade, which is expanding due to the inconsistency of the tax policy in the Eurasian Economic Union (EEU) countries. At the same time, the innovative nicotine delivery system market has been expanding, regulation of which is characterized by serious gaps. Objectives: to identify opportunities for improving regulation of traditional tobacco and innovative nicotinecontaining products markets to increase the collection of excises and achieve public health goals. Methods: comparative analysis, retrospective and counterfactual analysis, econometric estimations. Results: for the first time, econometric estimates for the Russian market were obtained on the aggregate regional (panel) data based on the simultaneous equations model using specially generated database “Addictive products in Russian regions”. The estimates show that, ceteris paribus, an increase of 1 p.p. the distance adjusted excise tax difference to the living cost ratio (DATDLC) leads to a reduction in the legal market by an average of 0.16 %. Price elasticity estimate of the legal aggregate demand is (-0.7), income elasticity is 0,8 and price elasticity of supply is 1,5. The analysis of budgetary and market statistics showed a low collection efficiency of excise taxes on ENDS; the problem of fiscal forestalling in this segment has been discovered. Conclusions: the results of the analysis allowed to propose several effective and feasible measures including the creation of an IT-system within the EEU for the exchange of information on excisable goods, the transfer of part of excise revenue to regional budgets, controlled legalization of nicotine pouches, anti-forestalling regulation in ENDS, etc.

Data fusion based wireless temperature monitoring system applied to intelligent greenhouse

In intelligent greenhouses, wireless sensor networks with uneven temperature distribution and low collection efficiency may lead to poor monitoring effects in real time. To improve the performance of the temperature monitoring system in intelligent greenhouses, a real-time fusion strategy for a hierarchical wireless sensor network (WSN) is proposed. The designed WSN has three layers. In the bottom, sensors collect and preprocess the temperature data of the greenhouse by an improved unscented Kalman filter. In the middle layer, each cluster-head sensor, as a local fusion center, is used to fuse the data collected from the bottom sensors by a parallel inverse covariance intersection fusion algorithm. In the top, a global fusion center is utilized to fuse the temperature data from the middle layer to reflect the global temperature of the greenhouse by an improved extreme learning machine algorithm. The designed algorithm applied in each layer ensures the efficiency and accuracy of data fusion in real time. Simulation results show that the designed fusion strategy effectively improves the fusion accuracy and realizes the real-time fusion. The performance of the designed temperature monitoring system is greatly improved.

Microbial Air Samplers for Meaningful Cleanroom Environmental Monitoring

Airborne microbiological concentrations within pharmaceutical cleanrooms are determined by sampling and to maximise the detection of any airborne microbes, it is essential that the sampling is undertaken in locations where there is greatest contamination risk using air samplers that have a verified and appropriate performance. Sampler performance can be assessed by review of both the physical and biological collection efficiencies that are determined by testing. The physical collection efficiency is the ability to collect particles of various sizes and the biological collection efficiency assesses the collection of viable microbes that includes the losses caused by the physical collection efficiency and the detrimental effect that the sampling has on the viability of the captured microbes. Due to the limitations of the established biological collection efficiency test method, this efficiency is only determined for microbes of sub-micron size which are not representative of the larger microbe-carrying particles typically present with cleanrooms. Samplers with a low physical collection efficiency for sub-micron particles are likely to have a poor performance when this test method is utilised and in an attempt to remove this bias from the testing the ‘biological efficiency’, is often reported. This is a measure of the likelihood that any captured microbes would survive, but is often mistaken for the biological collection efficiency and samplers may be utilised in the false belief that they have an appropriate performance. This article provides information regarding air sampler performance testing and reviews the test results reported by the same independent specialist testing company, therefore negating issues resulting from different testing methods, for three different air samplers. The results that are used to determine the ‘biological efficiency’ are examined to provide information relating to the biological collection efficiency of each sampler and to also provide additional information relating to the physical collection efficiency. Improvements to enhance the air sampler testing procedures, to enable a better direct comparison of the performance of different samplers, are suggested.

Infrared erbium photoluminescence enhancement in silicon carbide nano-pillars

Color centers that emit light at telecommunication wavelengths are promising candidates for future quantum technologies. A pressing challenge for the broad use of these color centers is the typically low collection efficiency from bulk samples. Here, we demonstrate enhancements of the emission collection efficiency for Er3+ incorporated into 4H-SiC surface nano-pillars fabricated using a scalable top-down approach. Optimal Er ion implantation and annealing strategies are investigated in detail. The substitutional fraction of Er atoms in the SiC lattice is closely correlated with the peak photoluminescence intensity. This intensity is further enhanced via spatial wave-guiding once the surface is patterned with nano-pillars. These results have broad applicability for use with other color centers in SiC and also demonstrate a step toward a scalable protocol for fabricating photonic quantum devices with enhanced emission characteristics.

Recombination and localization: Unfolding the pathways behind conductivity losses in Cs2AgBiBr6 thin films

Cs2AgBiBr6 (CABB) has been proposed as a promising nontoxic alternative to lead halide perovskites. However, low charge carrier collection efficiencies remain an obstacle for the incorporation of this material in optoelectronic applications. In this work, we study the optoelectronic properties of CABB thin films using steady state and transient absorption and reflectance spectroscopy. We find that optical measurements on such thin films are distorted as a consequence of multiple reflections within the film. Moreover, we discuss the pathways behind conductivity loss in these thin films, using a combination of microsecond transient absorption spectroscopy and time-resolved microwave conductivity measurements. We demonstrate that a combined effect of carrier loss and localization results in the conductivity loss in CABB thin films. Moreover, we find that the charge carrier diffusion length and grain size are of the same order of magnitude. This suggests that the material's surface is an important contributor to charge-carrier loss.

Band and interface engineering for quantum dot solar cells

<p indent=0mm>Semiconductor quantum dots (QDs) have received tremendous attention for solar cells owing to their excellent physical and chemical properties. In quantum dot solar cells (QDSCs), the low charge separation efficiency and low charge collection efficiency are two critical factors that greatly restrict their photovoltaic performance. Band engineering and interface engineering are of great significance for accelerating the separation of photogenerated electron-hole pairs and improving the efficiency of carrier collection to improve the performance of QDSCs. This article reviews the applications of band engineering and interfaces engineering for performance optimization from the perspectives of materials, films, and devices. Firstly, the features of QDs and the working principle and device structure of QDSCs are introduced. Secondly, based on the latest research progress of QDSCs, we overview the specific strategies of the band and interface engineering as well as their positive roles in improving the device performance. Finally, the correlation between band and interface issues and the further research direction of the band and interface engineering for QDSCs prospects are discussed.

Forest Biomass Collection from Systematic Mulching on Post-Fire Pine Regeneration with BioBaler WB55: Productivity, Cost and Comparison with a Conventional Treatment

Post-wildfire regenerated Mediterranean pine stands have a high risk of wildfire recurrence. Preventive clearings are frequently applied in a mix of systematic and selective ways, being a potential biomass source using technologies such as the collector-bundler BioBaler WB55. Our research aimed to compare the BioBaler with a chain mulcher performing systematic mulching of 50% vs. 67% of stand surface over 11.4 ha dominated by Pinus pinaster Ait. regenerated after a severe wildfire. Time studies included the machinery GPS follow-up and the weighing of each produced bale. Environmental aspects were also assessed. A regression curve related BioBaler weight productivity (odt·Workh−1) to pine biovolume (cover (%) average tree height, m). Surface productivity (stand ha·Workh−1) was greater for both technologies when a lower percentage of the total surface was cleared, but less than theoretically predicted. The BioBaler’s economic balance, including the cost of further selective clearing and the income from biomass selling, was costlier than that of the mulcher—in the most representative strata, 475 EUR·ha−1 vs. 350 EUR·ha−1. Under the studied conditions, BioBaler was not economically competitive with the conventional treatment, its main constraint being low collection efficiency (31% of the standing biomass in the cleared surface, 5.33 out of 17.1 fresh tonnes·ha−1).

Comparison of models to predict the collection efficiency of an axial cyclone with a spindle vane

An axial cyclone separator with a spindle vane has the advantages of low pressure drop and high collection efficiency. Collection efficiency is an important parameter for assessing the performance of a cyclone separator. Previous studies have shown that as the number of turns of a spindle vane increases or the pitch of the spindle vane decreases, the collection efficiency of the axial cyclone separator increases. There are two models for predicting the collection efficiency of an axial flow cyclone. One model by Hsiao et al. (2011) can predict the collection efficiency if the primary dimensions and inlet flow conditions of the cyclone are given. But the other model by Hsu et al. (2005) additionally requires a fitting constant to determine the collection efficiency. Because the accuracy of the model of Hsu et al. (2005) is limited by the fitting constant, it is necessary to find a fitting constant systematically. In the present study, we developed a method to determine the fitting constant for the model of Hsu et al. (2005) through experimental, numerical, and analytical investigation. It was found that the fitting constant is the function of flow transit time in the vane section. Finally, we compared the two existing prediction models with each other. Both model predictions agreed well with the experimental data.

A staggered 3-layer DOI PET detector using BaSO4 reflector for enhanced crystal identification and inter-crystal scattering event discrimination capability

The spatial resolution of small animal positron emission tomography (PET) scanners can be improved by the use of crystals with fine pitch and rejection of inter-crystal scattering (ICS) events, which leads to a better quantification of radiopharmaceuticals. On the other hand, depth-of-interaction (DOI) information is essential to preserve the spatial resolution at the PET field-of-view (FOV) periphery while keeping the sensitivity. In this study we proposed a novel staggered 3-layer DOI detector using BaSO4 reflector material for an enhanced crystal identification performance as well as ICS event rejection capability over those of ESR reflector based DOI detectors. The proposed staggered 3-layer DOI detector had 3-layer staggered LYSO crystal arrays (crystal pitch = 1 mm), an acrylic light guide, and a 4 × 4 SiPM array. The 16 SiPM anode signals were read out by using a resistive network to encode the crystal position and energy information while the timing signal was extracted from the common cathode. The crystal map quality was substantially enhanced by using the BaSO4 reflector material as compared to that of the ESR reflector due to the low optical crosstalk between the LYSO crystals. The ICS events can be rejected with BaSO4 by using simple pulse height discrimination thanks to the light collection efficiency difference that depends on the crystal layers. As a result, the total number of events was decreased around 26% with BaSO4 as compared to that of ESR. The overall energy resolution and coincidence timing resolution with BaSO4 were 19.7 ± 5.6% and 591 ± 160 ps, respectively which were significantly worse than 10.9 ± 2.2% and 308 ± 23 ps values of ESR because of the relatively low light collection efficiency with BaSO4 (1057 ± 308 ADC) compared to that of ESR (1808 ± 118 ADC). In conclusion, we found the proposed staggered 3-layer DOI detector using the BaSO4 reflector material with ICS event rejection capability can be a cost-effective solution for realizing high resolution and highly sensitive small animal PET scanners while minimizing the complexity of the SiPM readout circuit.

Experimental and computational study on the separation performance of an electrostatic precipitator with curved transvers collecting plates

Aiming at the problems of low collection efficiency of fine particulate matter and large area occupied by existing electrostatic precipitators (ESP), a new type of horizontal electrode ESP is proposed. It has the advantages of accelerating turbulent coalescence, increasing the effective dust collecting area and increasing the particle driving speed. The performance of the new type of ESP is systematic studied through simulation and experiment at the same time, and the results matches well. By comparing the dust removal effect of the horizontal electrode ESP and the conventional ESP, it can be concluded that the horizontal electrode ESP has a better dust removal efficiency, and can still maintain a better dust removal effect under high air velocity. The dust removal efficiency of new ESP can reach above 98% under the experimental conditions.

Improvement of Snow Gauge Collection Efficiency through a Knowledge of Solid Precipitation Fall Speed

AbstractThe collection efficiency of a typical precipitation gauge-shield configuration decreases with increasing wind speed, with a high scatter for a given wind speed. The high scatter in the collection efficiency for a given wind speed arises in part from the variability in the characteristics of falling snow and atmospheric turbulence. This study uses weighing gauge data collected at the Marshall Field Site near Boulder, Colorado, during the WMO Solid Precipitation Intercomparison Experiment (SPICE). Particle diameter and fall speed data from a laser disdrometer were used to show that the scatter in the collection efficiency can be reduced by considering the fall speed of solid precipitation particles. The collection efficiency was divided into two classes depending on the measured mean-event particle fall speed during precipitation events. Slower-falling particles were associated with a lower collection efficiency. A new transfer function (i.e., the relationship between collection efficiency and other meteorological variables, such as wind speed or air temperature) that includes the fall speed of the hydrometeors was developed. The root-mean-square error of the adjusted precipitation with the new transfer function with respect to a weighing gauge placed in a double fence intercomparison reference was lower than using previously developed transfer functions that only consider wind speed and air temperature. This shows that the measured fall speed of solid precipitation with a laser disdrometer accounts for a large amount of the observed scatter in weighing gauge collection efficiency.

Removal of fine particles in coal fired power plant by chemical coagulation

The fine particle dust produced by coal-fired power plants is one of the important sources of air pollutants. Wet electrostatic precipitator (WESP) is one of the effective methods to remove fine particle dust. However, the traditional wet electrostatic precipitator still has low collection efficiency for the superfine particle dust. To improve the collection efficiency and the chemical coagulation method is applied to the wet electrostatic precipitator. Experiments are carried out by varying the chemical coagulation agent type, concentration, surfactant species. The results show that: Adding chemical coagulants can promote the coagulation effect of fine particles, and Xanthan gum (XTG) has the best coagulation effect; the concentration of chemical coagulant also affects the coagulation effect and collection efficiency of dust, the optimal concentration of XTG is 1.0×10−2 g/L; among the surfactants, dodecyl dimethyl benzyl ammonium chloride (1227) has the best effect, and the dust removal efficiency can reach 98.80%. Through experimental exploration, the chemical coagulation method has a good application prospect in wet electrostatic precipitators.

Adsorptive and responsive hybrid sponge of melamine foam and metal organic frameworks for rapid collection/removal and detection of mycotoxins

Mycotoxins have been regarded as one of the most severe threatens to food safety and environment, however, conventional detection methods are limited by low collection efficiency and tedious detection procedures. In this work, adsorptive and responsive hybrid sponge was prepared by integrating porous fluorescent Zr-LMOF (luminescent metal-organic framework) and robust melamine sponge for simultaneous collection/removal and detection of mycotoxins. The hybrid sponge achieved high load capacity of 15.8 mg g−1 within 10 min and worked well in a wide range of pH and temperatures. The fluorescence of the hybrid sponge was efficiently quenched by AFB1 in the aqueous water in 10 min due to the hierarchical pore structure enabled absorbent-target interaction. This simple, robust and low-cost dual functional hybrid sponge enabled the detection with relatively low LOD of 1.6 ppb and wide linear range of 31.2 ppb-15.6 ppm. Additionally, AFB1 in water was quickly absorbed by the Zr-LMOF crystals on the melamine microfibers with the removal efficiency reached as high as 90%. The removal efficiency towards other mycotoxins including aflatoxin B2, aflatoxin G1, aflatoxin G2, aflatoxin M1 and ochratoxin A also reached 80%. Overall, this low-cost, robust and elastic hybrid sponge has great potential in the construction of novel sensors for practical applications to ensure environmental and agricultural safety.

The fabrication of nanodiamond doped tellurite germanate glass with robust structure and its luminescence

AbstractFluorescence of negative‐charged nitrogen‐vacancy centers in nanodiamond allows applications in quantum metrology, nanoscale sensor, and bioimaging, of utmost relevance to domains from nanotechnologies to biosensing. However, the low color center content and collection efficiency of photons are crucial issues. Although, several studies about coupling nanodiamond into optical waveguides have already been proposed, the search for the most appropriate substance and simplest, most effective method are of keys. In this study, we present a novel nontraditional way to incorporate nanodiamond with increased negative‐charged nitrogen‐vacancy content to 75.48% into tellurite germanate glass. The hybrid glass is stable in structure with predominant TeO4 trigonal bipyramid. Moreover, the fluorescence intensity is enhanced in composite. Such robust nanodiamond in tellurite germanate glass optical system has the potential to be used for nanoparticle sensing and quantum metrology.

Development law of lateral displacement of deep soil mass in submerged breakwater

The 12.5m deep water channel project under Nanjing of the Yangtze River is a national key project. Based on the hechangzhou waterway section of the project, combined with the characteristics of water depth, strong wind, rapid flow and high wave, aiming at the problems such as short construction time, difficult instrument embedding, easy damage and low data collection efficiency, field monitoring test is carried out to monitor the foundation of submerged dike structure in the construction process The lateral displacement of deep soil mass, clear its development law, provide a strong guarantee for safe construction.