Optimization of bonding parameters of laminated wood using a novel bio-based RPF adhesive

Adhesive is the key component and factor for the manufacture of glulam, affected both the properties and cost of glulam product. Bio-based resorcinol-phenol-formaldehyde (BRPF) resin was developed by partly replacing the expensive resorcinol and phenol with the cheap biomass derived pyrolysis oil. The press process parameters and the dosage of adhesive and corresponding curing agent were selected as the factors and extensively studied. BRPF resin was successfully used to bond the laminas to produce glulam, and the optimized process parameters for the cold-pressing adhesion of BRPF resin with pine wood were obtained as follows: the cold-pressing pressure 1.4 MPa, the cold-pressing time 9 h, the amount of adhesive coating 320 g/m2, and the proportion of curing agent (poly-formaldehyde) 17%. The mechanical performances of laminated wood bonding with BRPF resin under the optimal condition were further verified. It is believed that the results obtained here will promote the use of bio-based resin in the bonding of laminated wood, and then contribute to the green manufacturing of glulam with lower cost

Trust Index Based Fault Tolerant Multiple Event Localization Algorithm for WSNs

This paper investigates the use of wireless sensor networks for multiple event source localization using binary information from the sensor nodes. The events could continually emit signals whose strength is attenuated inversely proportional to the distance from the source. In this context, faults occur due to various reasons and are manifested when a node reports a wrong decision. In order to reduce the impact of node faults on the accuracy of multiple event localization, we introduce a trust index model to evaluate the fidelity of information which the nodes report and use in the event detection process, and propose the Trust Index based Subtract on Negative Add on Positive (TISNAP) localization algorithm, which reduces the impact of faulty nodes on the event localization by decreasing their trust index, to improve the accuracy of event localization and performance of fault tolerance for multiple event source localization. The algorithm includes three phases: first, the sink identifies the cluster nodes to determine the number of events occurred in the entire region by analyzing the binary data reported by all nodes; then, it constructs the likelihood matrix related to the cluster nodes and estimates the location of all events according to the alarmed status and trust index of the nodes around the cluster nodes. Finally, the sink updates the trust index of all nodes according to the fidelity of their information in the previous reporting cycle. The algorithm improves the accuracy of localization and performance of fault tolerance in multiple event source localization. The experiment results show that when the probability of node fault is close to 50%, the algorithm can still accurately determine the number of the events and have better accuracy of localization compared with other algorithms

Mutual fund managers' prior work experience and their investment skills

This paper examines the relationship between mutual fund managers’ past professional backgrounds and their portfolio performance, using Chinese mutual fund data from 2003 to 2016. We focus on managers with prior work experience either as industry analysts or as macro analysts, the two most common career paths for Chinese fund managers. We hypothesize that managers who worked as industry analysts exhibit superior stock-picking skills, while managers with a background as macro analysts are more skillful in timing the market. These hypotheses are supported by the data, even after controlling for observable fund and manager characteristics. Bootstrap analyses suggest that the significant difference in performance between these two types of managers cannot be attributed purely to luck

Mutual fund managers’ prior work experience and their investment skills

This paper examines the relationship between mutual fund managers’ past professional backgrounds and their portfolio performance, using Chinese mutual fund data from 2003 to\ud 2016. We focus on managers with prior work experience either as industry analysts or as macro analysts, the two most common career paths for Chinese fund managers. We\ud hypothesize that managers who worked as industry analysts exhibit superior stock-picking skills, while managers with a background as macro analysts are more skillful in timing the market. These hypotheses are supported by the data, even after controlling for observable fund and manager characteristics. Bootstrap analyses suggest that the significant difference in performance between these two types of managers cannot be attributed purely to luck

Optimization of bonding parameters of laminated wood using a novel bio-based RPF adhesive

Adhesive is the key component and factor for the manufacture of glulam, affected both the properties and cost of glulam product. Bio-based resorcinol-phenol-formaldehyde (BRPF) resin was developed by partly replacing the expensive resorcinol and phenol with the cheap biomass derived pyrolysis oil. The press process parameters and the dosage of adhesive and corresponding curing agent were selected as the factors and extensively studied. BRPF resin was successfully used to bond the laminas to produce glulam, and the optimized process parameters for the cold-pressing adhesion of BRPF resin with pine wood were obtained as follows: the cold-pressing pressure 1.4 MPa, the cold-pressing time 9 h, the amount of adhesive coating 320 g/m2, and the proportion of curing agent (poly-formaldehyde) 17%. The mechanical performances of laminated wood bonding with BRPF resin under the optimal condition were further verified. It is believed that the results obtained here will promote the use of bio-based resin in the bonding of laminated wood, and then contribute to the green manufacturing of glulam with lower cost

Annual Precipitation Fluctuation and Spatial Differentiation Characteristics of the Horqin Region

Precipitation is the main water source for vegetation survival in arid and semi-arid areas. However, previous studies always focus on the effects of precipitation in different time scales, but ignore the effects of precipitation in different spatial scales. To further study the effects of precipitation fluctuation in different spatial scales, we used the wavelet analysis method to analyze its temporal and spatial change based on data from eighteen meteorological stations during 1961–2015 in Horqin region. Results showed that: (1) from the overall tendency of precipitation changes, the precipitation inter-annual variations in Horqin region had the tendency of gradually decreasing from the southeast (District IV) to the northwest; (2) the precipitation anomalies of District I–IV between 1960 and 1980 were small and approximate to the normal value; (3) in the time scale of 23–32 years, the cyclical fluctuations were very significant and the annual precipitation underwent two cyclical fluctuations from a period of low precipitation to a period of high precipitation; and (4) as results of analyzing the spatial wavelet variance of sub-region, the main cycle of precipitation in District I, District II and District III was between 10 and 11 years, while the main cycle of precipitation in District IV was 25 years. The main conclusions include the following. (1) This region tended to be arid, and the precipitation gradually decreased from the southeast (District IV) to northwest (District I). (2) The influence of spatial differentiation characteristics on precipitation fluctuation in this region was cyclical fluctuation, which gradually decreased from the southeast to the northwest. The length of the cyclical change period gradually shortened. In the first main cycle, whose annual precipitation changes were most significant, the changing characteristic was District IV and District I decreased from 25 years to 10 years. (3) Predicated from the cyclical changing law that the annual precipitation decreases from high to low, the Horqin region will remain in a period of low precipitation between 2016 and 2020

Petroleum Geology and Exploration of Deep-Seated Volcanic Condensate Gas Reservoir around the Penyijingxi Sag in the Junggar Basin

Many types of volcanic rock oil and gas reservoirs have been found in China, showing great petroleum exploration potential. Volcanic reservoir also is one of the key fields of exploration in the Junggar Basin and mainly concentrated in the middle and shallow layers, while the deep volcanic rock and natural gas fields have not been broken through. Based on comprehensive analysis of core observation, single well analysis, reservoir description, source rocks evaluation, combined with seismic data and time-frequency electromagnetic technology, multiple volcanic rock exploration targets were identified, and industrial oil and gas flow was obtained in the well SX 16 of the Penyijingxi Sag, western Junggar Basin. It is believed that the deep Permian source rocks have relatively higher natural gas generation potential and volcanic breccia usually have large reservoir space. And the mudstone of the Upper Wuerhe Formation played as the role of caprock. The success of exploration well SX16 has achieved a major breakthrough in natural gas exploration in the Penyijingxi Sag, which has essential guiding significance for the exploration of deep volcanic rocks and large-scale gas exploration in the Junggar Basin

Métamatériaux pour la Génération de Vapeur par Energie Solaire

International audienceNous présentons dans cet article une nouvelle classe de métamatériaux optimisés pour améliorer les performances de systèmes de génération de vapeur par énergie solaire. Le matériau proposé consiste en un réseau de micropores disposés en 2D et percés sur du silicium noir. L'optimisation de la conception de ce métamatériau est effectuée à l’aide d’un modèle numérique multiphysique. L'évaluation expérimentale de ce nouveau métamatériau sous un rayonnement incident d’un soleil montre un taux d'évaporation de 1,34 kg/(h.m2) correspondant à une efficacité de conversion de 89 %. Une alternative bas coût réalisable par impression 3D est également présentée et montre des performances comparables