Research Progress in Techniques for Postharvest Preservation of Green Sweet Peppers

Green sweat peppers are rich in nutrients and diverse in shape and color. Apart from being eaten as a vegetable, it is widely used as seasoning and side dishes. Due to respiration and infection by harmful microorganisms, postharvest green peppers are prone to water loss, wilting and even rot. Appropriate preservation technology can maximize the preservation of nutrients and extend the storage period of green peppers. This paper introduces the techniques used for postharvest preservation of green sweet peppers: physical preservation methods such as refrigeration and packaging, biological preservatives such as microbial, plant and animal extracts, and chemical preservatives such as calcium agents and 1-methylcyclopropene (1-MCP), and compares the advantages and disadvantages of these preservation techniques. It elaborates the effect of chitosan or konjac glucomannan-based composite coatings on preserving the quality of green sweet peppers. Our intention is to provide a reference and guidance for the storage and preservation of postharvest green peppers

Shape-Controlled Synthesis of ZnS Nanostructures: A Simple and Rapid Method for One-Dimensional Materials by Plasma

In this paper, ZnS one-dimensional (1D) nanostructures including tetrapods, nanorods, nanobelts, and nanoslices were selectively synthesized by using RF thermal plasma in a wall-free way. The feeding rate and the cooling flow rate were the critical experimental parameters for defining the morphology of the final products. The detailed structures of synthesized ZnS nanostructures were studied through transmission electron microscope, X-ray diffraction, and high-resolution transmission electron microscope. A collision-controlled growth mechanism was proposed to explain the growth process that occurred exclusively in the gas current by a flowing way, and the whole process was completed in several seconds. In conclusion, the present synthetic route provides a facile way to synthesize ZnS and other hexagonal-structured 1D nanostructures in a rapid and scalable way

Synthesis of Hierarchical Hollow MnO2 Microspheres and Potential Application in Abatement of VOCs

Hierarchical hollow MnO2 microspheres have been synthesized by a facile hydrothermal method based on the decomposition of KMnO4 precursor in nitric acid solution in the presence of Ce3+ ions. The hierarchical hollow microspheres consisted of discuslike nanoplatelets and nanorods. The BrunauerEmmetTeller (BET) specific surface area and the pore volume of the hierarchical hollow microspheres are 29.2 m(2) g(1) and 0.30 cm(3) g(1), respectively. A possible formation mechanism of hierarchical hollow microspheres is proposed. Ce3+ ions play a crucial role in controlling the morphology and crystalline structure of MnO2. The concentration of Ce3+ ions is a key factor for the formation of the hierarchical hollow microspheres. The as-prepared hierarchical hollow MnO2 microspheres exhibit high catalytic ability for the oxidation of benzene

Catalytic removal of gaseous benzene over Pt/SBA-15 catalyst: the effect of the preparation method

Porous SBA-15 silica with high surface area was used as a support for loading active Pt with low content of 0.5 wt% through a deposition-reduction or impregnation method and further applied for deep oxidation of benzene. These materials were characterized by X-ray diffraction, nitrogen adsorption-desorption, transmission electron microscopy, inductively coupled plasma optical emission spectrometer and X-ray photoelectron spectroscopy techniques. The porous SBA-15 support with high surface area provides a sufficient room for dispersion of Pt nanoparticles. The synthesis routes have a great influence on the chemical-physical properties and catalytic performances of the Pt/SBA-15 catalysts. The catalysts reduced by NaBH4 and H-2 exhibited higher activities than that on air-treated and sodium citrate-reduced samples because of their smaller crystallite size, higher dispersion and negatively charged metallic introduced with a strong metal-support interaction. Complete benzene conversion to CO2 has been achieved at about 145 A degrees C over the best NaBH4-derived Pt/SBA-15 catalyst which was 82 A degrees C lower than that on the catalyst prepared by sodium citrate reduction approach.</p

Co-templating synthesis of mesoporous hollow silica spheres and their application in catalytic oxidation with low Pt loading

Mesoporous hollow silica spheres (MHSS) with uniform size were successfully prepared by introducing monodispersed polystyrene (PS) spheres as hard template and selected surfactant as soft template in acid condition. With assistance of different surfactants, a series of mesoporous shells were created and the used surfactants have a significant effect on the structural properties of MHSS. The highest surface area was 690.3 m(2) g(-1) on the MHSS which was achieved by using P123 as a soft template. The MHSS was further used for loading active Pt through the reaction between chloroplatinic acid or and sodium borohydride. The as -prepared Pt/MHSS catalyst exhibited high activity for VOCs&#39; deep oxidation. (C) 2016 Elsevier B.V. All rights reserved

Mater. Lett.

Catalyst and reaction conditions are the main affecting factors for the yield and quality of carbon nanotubes (CNTs) produced by the chemical vapor deposition (CVD) method. In this paper a ternary component catalyst based on Fe-Ni-Mo/MgO was explored using methane as precursor. The influences of temperature and methane concentration were investigated, and the as-produced CNTs were characterized by SEM, HRTEM, XRD and TGA. The diameter of the CNTs is in the range of 20-30 nm and the maximum carbon yield can reach up to 80 times of the catalyst under the selected condition, The purity of the as-prepared CNTs is over 93%. Our results indicated that this novel tercomponent catalyst presented a good catalytic activity for manufacturing high quality and quantity of CNTs. (C) 2008 Elsevier B.V. All rights reserved.Catalyst and reaction conditions are the main affecting factors for the yield and quality of carbon nanotubes (CNTs) produced by the chemical vapor deposition (CVD) method. In this paper a ternary component catalyst based on Fe-Ni-Mo/MgO was explored using methane as precursor. The influences of temperature and methane concentration were investigated, and the as-produced CNTs were characterized by SEM, HRTEM, XRD and TGA. The diameter of the CNTs is in the range of 20-30 nm and the maximum carbon yield can reach up to 80 times of the catalyst under the selected condition, The purity of the as-prepared CNTs is over 93%. Our results indicated that this novel tercomponent catalyst presented a good catalytic activity for manufacturing high quality and quantity of CNTs. (C) 2008 Elsevier B.V. All rights reserved

Indoor Environmental Comfort Assessment of Traditional Folk Houses: A Case Study in Southern Anhui, China

Due to the unique geographical location and historical culture, the traditional houses in the southern region of Anhui Province, China (South Anhui) have different indoor environments. In summer and winter, this study adopted a field survey, questionnaire survey, and statistical analysis to carry out a comprehensive field survey on Xixinan Village in South Anhui, and selected a typical traditional residence in the village to evaluate its indoor environment status. The final results show that the overall indoor environment of the traditional houses in South Anhui was awful, including the indoor thermal environment, with high temperature and humidity in summer and cold and humidity in winter. Additionally, the indoor light environment with dim light still had much room for improvement, while the indoor air quality and sound environment were relatively excellent. In addition, this study determined that the neutral temperatures of residents are 15.5 °C and 28.7 °C in winter and summer, respectively, and the comfort range of indoor light intensity is 752.6–1252.5 lx, which determines the adjustment range of indoor environmental parameters for residents’ comfort needs. This paper’s research methods and results provide a reference for the study of residential indoor environments in other regions with similar climatic conditions as South Anhui, and a theoretical basis for architects and engineers to enhance the indoor environment of traditional houses in this region

Fire Risk Assessment of Heritage Villages: A Case Study on Chengkan Village in China

Fire risk assessment is important in heritage-village risk management and cultural relics protection. This study aims to establish a fire risk assessment system and model to assess fire safety for heritage villages. Given the complexity and openness of the heritage village system, the nonlinearity of the driving factors, and the dual attributes of residence and tourism, this paper constructs an index system of three aspects: cultural relic value sensitivity, village fire hazard, and evacuation accessibility. Based on ANP and the Bayes algorithm, a hybrid intelligent model is developed, and the index is weighted by combining subjective expert scoring and objective fact statistics. Finally, ArcGIS buffer and network analysis functions are used for grid processing to quantify and evaluate the difference in fire risk distribution in spatial units of heritage villages. We apply this assessment method to Chengkan Village, a national critical cultural relic protection unit. The results reveal that the cluster settlement layout pattern of the ancestral temple buildings plays a decisive role in the fire risk distribution in Chengkan Village; furthermore, the main factors leading to fire risk were analyzed. In Chengkan Village’s core area, the focus of the local government should be on strengthening active fire prevention measures to reduce the probability of fire. In contrast, in the northern and southern areas, it should focus on enhancing passive fire prevention measures to reduce the possibility of significant fires

Ecologic shift and aridification in the northern Tibetan Plateau revealed by leaf wax n-alkane δ\u3csup\u3e2\u3c/sup\u3eH and δ\u3csup\u3e13\u3c/sup\u3eC records

Two competing factors, the global cooling and the uplift of Tibetan Plateau, have been proposed to drive the central Asian aridification, but their relative role has seldom been discriminated in paleoclimate and paleoenvironment records. Here, we reconstruct a 14-million-year-long record of paleohydrology and paleoecology in the western Qaidam Basin by applying the compound-specific hydrogen (δ H) and carbon (δ C) isotope analyses to terrestrial leaf wax long-chain n-alkanes. The δ H values are low during the interval of 14.6 to 13.0 Ma. Then the δ H increases from 13.0 to 12.2 Ma and maintains high values from 12.2 to 3.2 Ma with a peak high value of −156.1‰ at 8.0 Ma. After 3.2 Ma, the δ H values are low and vary larger than 30‰. The δ C values decrease from 14.6 to 13.0 Ma and are low from 13.0 to 3.2 Ma except a high value at 3.8 Ma. Then they decrease slightly after 3.2 Ma. Low δ H values indicate relatively wet climate between 14.6 and 13.0 Ma. The decreasing δ C values during the same time period support the ecologic shift with the decline of warm component of conifers after the Mid-Miocene Climatic Optimum. High δ H values since 13.0 Ma are synchronous with the uplift of northern Tibetan Plateau, implying tectonics-driven aridity. Large-amplitude variation in δ H values since ca. 3.2 Ma seen in East and West Qaidam and lower δ C values reveal the climatic cyclic responses to the Northern Hemisphere Glaciation. 2 13 2 2 2 13 2 13 2 2 1