胺改性磺化酚醛树脂降滤失剂SCP

以苯酚、甲醛、焦亚硫酸钠、无水亚硫酸钠和有机胺为原料，合成了改性磺化酚醛树脂降滤失剂ＳＣＰ。本文简要介绍了ＳＣＰ的合成工艺条件，初步评价了ＳＣＰ在泥浆中的性能。ＳＣＰ的降滤失性能优于磺化酚醛树脂，有较强的抗盐、抗温及抑制页岩水化分散的能力。     

改性磺化酚醛树脂性能的室内评价

高聚物降滤失剂改性磺化酚醛树脂是由磺化酚醛树脂与腐殖酸在一定条件下磺化共聚制成。对改性磺化酚醛树脂在淡水、盐水钻井液中的抗盐性、抗温性及降滤失性进行了评价。改性磺化酚醛树脂的最优加量为5％,它与其它增粘剂配合使用,抗盐达15％。改性磺化酚醛树脂抗温达200℃,随温度升高降滤失能力增强,温度为150℃时改性磺化酚醛树脂的降滤失效果最佳,改性磺化酚醛树脂的降滤失性能优于SLSP,高温时其钻井液形成的滤饼薄而致密。     

用花生壳提取物制备钻井液降滤失剂

用花生壳提取物与苯酚、甲醛、亚硫酸盐等经浓缩聚集、磺化工艺制得了一种钻井液降滤失剂。初步评价了合成产物与钻井液配伍的降滤失性能。结果表明，这种降滤失剂具有良好的抗温、抗盐及高温高压降滤失效果。     

两性磺化酚醛树脂ASP-1的研制及性能评价

制备了一种两性磺化酚醛树脂ASP-1，对其钻井液性能进行了评价。结果表明，两性磺化酚醛树脂ASP-1比磺化酚醛树脂SMP-1具有更好的降滤失性、防塌性、水溶性和抗温抗盐，而且与SMP-1成本相当，是一种较好的高温防塌降滤失剂。     

磺化栲胶-酚醛树脂降滤失剂的合成

用栲胶替代部分苯酚合成了磺化栲胶-酚醛树脂钻井液降滤失剂,并探讨了影响合成产物性能的主要因素及产物对钻井液性能的影响。试验结果表明,这种降滤失剂具有良好的高温高压降滤失效果及较强的抗盐、抗酸能力。     

两性磺化酚醛树脂降滤失剂APR的研制

以苯酚、甲醛、亚硫酸钠、二甲胺和１－溴丁为原料,合成了两性磺化酚醛树脂降滤失剂ＡＰＲ。通过红外光谱对其结构进行了表征,考察了ＡＰＲ的抗高温盐降滤失性能、抑制性及其与两性聚合物重泥浆的配伍性。从研究ＡＰＲ在膨润土上的吸附入手,对其作用是进行了简要分析。     

对磺化酚醛树脂生产应用的认识

以实验数据为基础,讨论了磺化酚醛树脂在生产、应用中及其改性产品出现的问题,提出磺化酚醛树脂的发展方向应该是改变磺化酚醛树脂分子结构,使磺化酚醛树脂在淡水钻井液中高温老化后不增粘,单剂在盐含量高、高温老化后就具有良好降滤失效果,在盐含量低、老化温度低时也有良好的降滤失效果。     

天然多元酚制备磺化酚醛树脂降滤失剂的研究

介绍了用橡菀、落叶松树皮和花生壳等提取物替代部分苯酚制备磺化酚醛树脂泥浆降滤失剂的方法 ,并对产物的泥浆性能进行了初步评价。结果表明 ,用天然多元酚化合物替代部分苯酚制备钻井液用降滤失剂磺化酚醛树脂是可行的     

AMPS/AM/VAC共聚物钻井液降滤失剂合成

采用氧化－还原引发体系合成了２－丙烯酸胺基－２－甲基丙碳酸－丙烯酰胺－醋酸乙烯酯（ＡＭＰＳ／ＡＭ／ＶＡＣ）三元共聚物钻井液降滤失剂,室内研究表明：ＡＭＰＳ／ＡＭ／ＶＡＣ三元共聚钻井液降滤失荆,抗温、抗盐能力强,在淡水钻井液、饱和盐水钻井液和人工海水钻井液中均有较强的降滤失作用。评价了三元共聚物对钻井液性能的影响,选择了合适的配方,探讨了影响三元共聚物降滤失能力的因素和引发剂、ＡＭＰＳ的用量对三元共聚物降滤失性能的影响。     

钻井液降滤失剂PAMS601的合成与性能

采用氧化－还原引发体系合成了２－丙烯酰胺基－２－甲基丙磺酸（ＡＭＰＳ）－丙烯酰胺ＡＭ）二元共聚物钻井液降滤失剂ＰＡＭＳ６０１,借助红外光谱和ＤＴＡ－ＴＧ研究了共聚物的结构和热稳定性,并对其泥浆性能进行了室内评价。结果表明,本文合成的ＰＡＭＳ６０１降滤失剂热稳定性好,降滤失能力和抗浊抗盐能力强。     

Microwave moisture meter for in-shell peanut kernels

A microwave moisture meter built with off-the-shelf components was developed, calibrated and tested in the laboratory and in the field for nondestructive and instantaneous in-shell peanut kernel moisture content determination from dielectric properties measurements on unshelled peanut pod samples. The meter operates at a single frequency of 5.8 GHz and uses free-space transmission measurement principles for determining the dielectric properties of the peanut pods. From these properties, a dielectric-based algorithm provides peanut kernel moisture content from measurements on pods. Field tests at a peanut buying station showed that moisture content of peanut kernels can be determined with a standard error of performance of 0.82% when compared to the official moisture meter which required the pods to be shelled before kernel moisture content can be determined. When performance of both the microwave moisture meter and the official meter were compared to the oven-drying standard method, values of the standard errors of performance were 0.53% for the microwave moisture meter and 0.87% for the official moisture meter.     

Occurrence and factors associated with aflatoxin contamination of raw peanuts from Lusaka district's markets,Zambia

Peanuts, one of the most susceptible crops to aflatoxin (AF) contamination, are widely produced and consumed in Zambia. This cross-sectional study was designed to determine the levels of AFs in raw peanuts sold in Lusaka district's markets as well as identify factors associated with increased AF presence. Raw peanut samples were collected from open markets and supermarkets and analyzed for aflatoxin contamination using high performance liquid chromatography (HPLC). A questionnaire was also administered to the peanut vendors to investigate factors contributing to increased levels of AFs in peanuts. Of the 92 samples, 51 (55.4%; 95% CI: 44.9–65.4) tested positive for presence of AFs. The overall median and geometric mean ± standard deviation (SD) concentration for AF were 0.23 ppb (range: 0.014–48.67 ppb) and 0.43 ± 9.77 ppb, respectively. The association between market types and presence of AFs was not statistically significant (Pearson Χ² = 0.0587, p = 0.809). Of 51 samples that tested positive to AF, 6.5% and 12% were above the maximum permissible limits (MPLs) set by the Codex Alimentarius Commission and European Union standards, respectively. There was a significant difference in the levels of AF between Chalimbana and Kadononga (p<0.0001), and also Chalimbana and Makulu red (p<0.0001). Chalimbana was the most at risk of AF contamination, when compared to other peanut varieties. The high level of AFs in raw peanuts from both supermarkets and open markets samples constitutes a health hazard for the population of Lusaka district. Therefore, intervention strategies that reduce the levels of AF contamination in peanuts should be given priority.     

Effects of high pressure processing on immunoreactivity and microbiological safety of crushed peanuts

Peanuts are a common economical food source consumed worldwide but exist health concern of food allergy and are particularly susceptible to infection by the mold fungus Aspergillus flavus during storage, accumulating highly toxic substance aflatoxin. In this study, the effect of high pressure treatments on peanut immunoreactivity, peanut amino acid composition, A. flavus growth and aflatoxin contents on crushed peanuts was evaluated. Results showed that immunoreactivity of peanuts treated with 600 MPa and 800 MPa for 10 min was significantly lower (P < 0.05) than those of the control group by 69.2 ± 5.3% and 73.3 ± 1.9%, respectively. High pressure treatment at 800 MPa decreased total essential amino acid content as well as two nutritional indexes, the chemical score and the essential amino acid index, by 32.4 ± 2.1% and 31.1 ± 3.2%, respectively. The growth of aflatoxigenic fungi was inhibited in peanuts with aflatoxin accumulation that were subjected to different levels of pressure treatments during 30 days of storage. Peanuts treated with 600 MPa and 800 MPa had considerably lower aflatoxin levels, 0.26 μg/g and 0.22 μg/g in wet basis, respectively, than the control peanut aflatoxin level (9.08 μg/g) on day 30. Results were demonstrated that high pressure treatment had a significant inhibitory effect on A. flavus growth in peanuts and this contributes to reduction of aflatoxin production and accumulation instead of directly destroy aflatoxin. Taken together, the findings of this study indicated that high pressure treatment could preserve peanut quality by reducing food immunoreactivity and by eliminating A. flavus in peanuts.     

Comparative study of thermal inactivation kinetics of Salmonella spp. in peanut butter and peanut butter spread

Peanut butter has been implicated in multi-state outbreaks of salmonellosis in recent years. Studies have shown that Salmonella exhibited increased thermal resistance in peanut butter. However, little is known about the effect of product formulation on the kinetics of survival of Salmonella during thermal treatment. Therefore, the objective of this research was to compare the thermal resistance of Salmonella in four commercially available peanut butter and spread products, and evaluate the effect of product formulation on the survival of this pathogen during heating.Four peanut butter and spread samples, including Omega 3 (A), regular fat (B), reduced sugar (C), and reduced fat (D), inoculated with a 6-strain cocktail of Salmonella spp., were heated at 70, 75, 80, 85, and 90 °C. Experimental results showed that the highest thermal resistance of Salmonella was found in the samples with reduced fat, while the least in the samples with Omega 3 formulation. No significant difference in the bacterial thermal resistance was observed in the regular fat and reduced sugar formulations. The Weibull survival model was used to describe the survival curves. Results showed that the average exponent (shape factor) of the model ranged from 0.38 to 0.662, suggesting progressively decreased rate of inactivation during heating. The scale (rate) coefficients of the model increased linearly with temperature. The calculated minimum lethal temperature for Salmonella was 54.8, 59.8, 59.5, and 63.9 °C in samples A, B, C, and D, respectively. No tail effect was observed. The results of this study suggest that proper formulation of peanut butter and spread may enhance thermal inactivation of Salmonella.     

A MOLECULAR MECHANICS-DENSITY FUNCTIONAL STUDY OF THE ADSORPTION OF FRAGMENTS OF ASPHALTENES AND RESINS ON THE (001) SURFACE OF Fe2O3

A combination of Molecular Mechanics and Density Functional Theory allowed the calculation of the charge distribution and the adsorption energy on the (001) surface of hematite (α—Fe₂O₃) of a set of twelve molecules that represent fragments of resins and asphaltenes. The results showed that no covalent bond was formed with the inorganic surface upon adsorption, which indicates that physisorption instead of chemisorption takes place. In aromatic hydrocarbons, the adsorption energy was found to be proportional to the molecular surface, which indicates the main role, played for the van der Waals forces in the adsorption of these molecules. For 2-substituted naphthalenes, the energy decreased with the increase in the length of the alkyl chain. This decrease was related to the gain in deformation energy of the alkyl chain that was required by the adsorption process. The aromaticity and the H/C ratios were found to be good indicators of the ability of the molecules to be adsorbed on the hematite surface. In particular, molecules with high aromaticity and low H/C ratio show high adsorption energy. This result can explain the experimental finding of a high content of high aromatic and low hydrogen content molecules found in asphaltenic deposits extracted from wells. Substitution of the central ─CH₂─ group by N─H, O or S at the five-member ring in fluorene produced complex changes in the adsorption energies. In some these molecules, the atoms protruding from the molecular plane produced reduced adsorption energies.     

Mid-infrared spectroscopy for discrimination and classification of Aspergillus spp. contamination in peanuts

In this study, Aspergillus spp., common colonists in peanut, were characterized, classified and quantified using FTIR coupled with ATR accessory. FTIR-ATR spectral data of infected peanut samples were preprocessed (mean-centering, smoothing the 1st derivative), and used for the PLS regression analysis for quantitative results. Very high R² values (96.20–99.98%) together with low error of RMSEC values (0.014–0.153 Log CFU/g of peanut) were obtained. Even, the spectrum of peanut matrix was dominant at early stages of invasion (≤2.5 Log CFU/g peanut), resulting in section separation (Nigri from Flavi) and at higher population (>4 Log CFU/g, species level separation (Aspergillus alliaceus, Aspergillus caelatus, Aspergillus flavus, Aspergillus parasiticus, and Aspergillus tamari) was observed. The accuracy of correct classification increased proportionally with fungal invasion level and 100% correct classification was reached when the cell level was Log CFU/g = 4.5–5. Samples with similar secondary metabolites (toxin producers) grouped close-by in PC score diagrams for all levels of fungal growth. Results highlight the possible implementation of FTIR-ATR model to detect infected peanuts even at early stages of invasion; besides, to prove the potential separation capability in terms of species and their secondary metabolites.     

Development of a direct sampling method for verifying the cleanliness of equipment shared with peanut products

A direct sampling method was developed to verify the cleanliness of stainless steel equipment used to produce peanut products. The protocol consisted of sampling the product-contact area with two Critical Swab^® flat zapped-head foam swabs pre-moistened with 20 mM phosphate, pH 7.2 (PBS), mixing each swab in PBS for 1 h, and analyzing the extract for peanut residues. Quantitation of peanut residues was accomplished with a non-specific assay while SDS–PAGE was used to ensure the recovery of the allergen, Ara h 1. This sampling approach was able to recover 90–95% of the peanut proteins at sub-microgram levels and Ara h 1 at low nanogram levels directly from a stainless steel surface.     

落叶松改性栲胶溶液及凝胶性质研究

本文报道落叶松改性栲胶溶液及凝胶性质的研究结果。磺化改性栲胶比未改性栲胶有较好的水溶性和耐盐能力，配成的堵剂溶液粘度较低，成胶时间主要受温度、pH值和缓凝剂浓度的影响。改性栲胶堵剂溶液的耐盐能力有限（NaCl浓度超过8％时便沉淀分相），但形成的凝胶可耐20％NaCl＋1.5％CaCl2盐水的侵蚀，且具有很高的强度。     

A Bayesian network to optimise sample size for food allergen monitoring

Generally, sampling size is optimised considering a single specific constraint. However, for financial reasons, only one sample is usually defined and used to satisfy several objectives. It is therefore crucial to choose a sample that meets all the required objectives.This paper proposes an original method for optimising a sample plan to monitor allergen traces in products consumed by allergy sufferers. The proposed method, based on a Bayesian network, enables several different constraints to be considered within a single model and the integration of literature data on concentration levels of allergen traces in food. Moreover, the construction of a three-stage sampling plan took into account the consumption preferences of peanut allergy sufferers between products with or without labels on the presence of allergen traces, and between the categories and subcategories of products. This method was applied to data from the MIRABEL project which aims to assess risks related to peanut traces for French allergy sufferers.The results show how the model used all the available information and constraints to balance the total number of samples set at 900 for food categories/subcategories and labelling types. As required, the model favoured the most consumed product categories and subcategories. At the same time, it increased the number of samples when peanut concentration is low. This helps reduce the uncertainty on peanut concentrations in these products and consequently on risk estimation.In conclusion, the proposed method is a useful tool for public administrations, risk assessors and risk managers to improve sampling plans for monitoring allergen traces or other health hazards in food.