轻质碳酸钙生产节能探讨

本文从轻质碳酸钙厂的碳化、脱水、烘干过程，如何挖掘节能潜力，提高经济效益，列出较详细的各种不同工艺参数，并绘制出不同工艺参数与能耗关系曲线图，进行耗能与经济效益对比分析。     

带式振动浓缩压榨一体化脱水机理的研究

带式浓缩压榨脱水是近几年新发展起来的一种经济高效连续固液分离技术。作者在多年从事该技术研究工作的基础上，提出了一种脱水效率更好的“带式振动浓缩压榨一体化脱水技术”。该技术利用振动方式分别对重力脱水和压榨脱水过程进行作用，使重力脱水过程由静态滤饼过滤变为悬浮动态过滤，压榨脱水过程由静态压滤变为动态压滤，从而提高了整个脱水效率。并通过实验研究，对参数进行了优化，为该技术的推广应用奠定了理论与实验基础。     

油水界面检测仪表的应用探讨

文章阐述了原油脱水原理，准确检测控制油水界面的必要性，简述了油田常用的几类油水界面检测仪表的工作原理、技术特点，分别分析了实用性并提出了选用原则。     

Some experiences in the use of a polymeric cryoprotectant in the freezing of plant tissue

Recently it has been suggested that polymeric cryoprotectants might be usefully employed for reducing ice crystal size during ultrastructural and analytical studies of frozen biological tissues. Furthermore, it was reported that they have little physiological effect and cause negligible structural changes in the tissue. Our experiences with one such polymer, polyvinyl pyrrolidone (PVP), in the cryopreservation of mature plant roots prepared for electron microscopy, have led us to conclude that preservation deep into the structure of this tissue is not improved. Even short periods of exposure of tissue to polymer cause rapid withdrawal of water from vacuolated cells of plant roots, resulting in shrinkage and collapse. Low temperature techniques have confirmed that little if any improvement in the reduction of ice crystal size results if the root is first treated with PVP.     

Effects of different osmo‐dehydrofreezing treatments on the volatile compounds,phenolic compounds and physicochemical properties in mango (Mangifera indica L.)

The influences of different osmotic solution pretreatments (sucrose, glucose and maltose with concentration of 45%) on the volatile compounds, phenolic compounds and other physicochemical parameters in frozen mangoes were studied. Volatile and phenolic compounds were measured using SPME/GC‐MS and HPLC method, respectively. The results revealed that compared with untreated frozen mango, some volatile compounds (e.g. alcohols, aldehydes and some terpenes and esters) increased significantly and there were more compounds identified in osmo‐dehydrofrozen samples. These changes positively affected mango aroma and resulted in higher sensory scores for osmo‐dehydrofrozen samples. In addition, data on phenolic compounds showed that dehydrofrozen samples pretreated in glucose and sucrose had higher ρ‐hydroxybenzoic acid and quercetin contents, respectively, while samples pretreated in maltose showed higher ρ‐coumaric acid and sinapic acid contents compared with untreated frozen samples. The current work indicates that osmo‐dehydrofreezing can improve the retention of phenolic and aromatic compounds in frozen mango.     

Osmotic dehydration pretreatment for improving the quality attributes of frozen mango: effects of different osmotic solutes and concentrations on the samples

The effect of osmotic dehydration pretreatment on the quality attributes (e.g. colour, hardness, drip loss, vitamin C content and pH) of frozen mango cuboids in different osmotic solutions (sucrose, glucose and maltose) and concentrations (30, 45 and 60% (wt/wt)) was investigated. Results revealed that melting temperature of mango cuboids was affected by both solute type and solid mass fraction. In addition, the dehydrofrozen samples pretreated in maltose had higher quality in vitamin C content (increasing by 23.5–73.0%), colour (colour change reducing by 2.6–39.2%) and drip loss (reducing by 0.7–9.7%) than those pretreated in other osmotic solutions. The cuboids pretreated in glucose displayed higher hardness (increasing by 16.4–36.2%). Based on principal component analysis and group distance, osmotic dehydration in 45% maltose was proposed as the most favourable freezing conditions with the highest sensory score (6.8). The current work indicates osmotic dehydration significantly improves frozen mango quality.     

The hurdle effect of osmotic pretreatment and high‐pressure cold pasteurisation on the shelf‐life extension of fresh‐cut tomatoes

Tomatoes are perishable products due to the activity of microorganisms and endogenous enzymes. The objective was to produce cut tomatoes with extended shelf life, using the combined hurdle effect of osmotic pretreatment (OD) and high pressure (HP), instead of a conventional one‐step thermal process. Samples were processed in a multicomponent osmotic solution at 35 °C, subsequently cold‐pasteurised in pack at 600 MPa and stored at 5–15 °C. Quality deterioration during isothermal and nonisothermal storage was kinetically modelled. Both OD process and OD‐HP combined process caused an increase in lycopene content that was well retained. Texture, colour and flavour of treated samples were evaluated as similar to fresh, with OD‐HP samples showing better retention during storage. Being microbiologically stable, shelf life of OD‐HP samples was limited by sensory deterioration, whereas OD samples were rejected due to eventual microbial growth. Shelf life of OD and OD‐HP samples was estimated at 77 and 181 days, respectively, at 5 °C.     

Highly selective CuO/γ–Al2O3 catalyst promoted with hematite for efficient methanol dehydration to dimethyl ether

A recent alternative for replacing traditional hydrocarbons like gasoline, diesel, and natural gas, is the use of dimethyl ether (DME), which is more environmentally friendly. One of the ongoing challenges is to catalyze methanol dehydration for selectively producing the DME (2CH₃OH → CH₃OCH₃ + H₂O). It is established that the CuO catalyst over alumina performs the methanol dehydration, but the formation of by-products is the main drawback. For these reasons, we synthesized a CuO/γ–Al₂O₃ catalyst promoted with hematite aiming to enhance the activity toward DME at atmospheric conditions. The resulting bimetallic catalyst (CuO-Fe₂O₃/Al₂O₃) performed a 70% conversion at 290 °C, which is similar to other catalysts recently reported in the literature but done in harsh conditions. In addition, this bimetallic catalyst exhibited a 100% in selectivity toward the DME production. XPS spectra of the fresh and used catalyst suggested that the chemical oxidation states of Cu and Fe remain without change. After regenerating the catalyst at 600 °C for 2 h in air, it performed at a similar catalytic conversion, confirming the reusability of the as-synthesized material and reducing the environmental impact.