Effects of process variables on the reactivity of slaked lime produced from Shuk quicklime

This is a research report of the effects of process variables on the reactivity of slaked lime produced from Shuk quicklime. It involved the calcination (at temperature of 1000 0C, particle size of 90 µm and time of 3 hrs) of Shuk limestone and subsequent slaking of its quicklime. The quicklime was characterized by x-ray diffractometer (XRD) and scanning electron microscopy (SEM) respectively to determine its mineral content and surface morphology respectively. Effects of process variables (quicklime/water ratio, particle size and time) on the reactivity of the slaked lime were determined. The reactivity was optimized using response surface methodology (RSM). The XRD analysis revealed calcite as the type mineral of the Shuk quicklime. The surface morphology of the quicklime sample showed that the particles are packed together in powdered form with visible pores that will allow passage of water. Reactivity of the lime was influenced by the quicklime/water ratio, particle size and time. Quadratic model appropriately explained the relationship between reactivity and considered slaking factors of quicklime/water ratio, particle size and time. The optimum reactivity value of the slaked lime was obtained as 59.3 oC at quicklime/water ratio of 0.24 g/ml, particle size of 88.2 µm and time of 15.1 minutes.

Processing of Yandev quicklime for potential amelioration of acidic soil

This study focused on processing of Yandev quicklime for potential amelioration of acidic soil. It involved production of quicklime from the Yandev limestone, characterization and slaking of the quicklime. In a batch process, 10g of the limestone (90mm particle size) was calcined for 3hrs to produce the quicklime. Mineralogical composition of the quicklime was determined by X-ray Diffractometer (XRD), while scanning electron microscope (SEM) was used to examine its surface morphology. The CaO was hydrated for the production of slaked lime (Ca (OH) 2). The slaking process was carried out by digesting CaO in distilled water. During the slaking/hydration process, values of reactivity (rise in temperature) were recorded. Central composite design (CCD) tool of Design Expert Software 11 was used to design the experiment of the slaking process. Quicklime/water ratio, particle size and time were the considered slaking variables, while reactivity was considered as the response. Analysis of the results quicklime is made up of pure calcite with visible pores. Quadratic model adequately described the relationship between reactivity and the considered slaking factors of quicklime/water ratio, particle size and time. Optimum reactivity was obtained as 58.4 0C with the corresponding optimal factors of quicklime/water ratio (0.26 g/ml), particle size (93.0 µm) and time (16.4 minutes). Properties of the slaked lime showed that it is suitable for acidic soil amelioration.

Size effect at testing strength properties of concrete

Various strength characteristics of concrete are considered as fracture parameters. The compressive strength of concrete is of paramount importance when designing concrete structures, whereas tensile strength of concrete is the basic property when estimating cracking resistance of a structure and analysing fracture processes in concrete. When testing the compressive strength of concrete, the results are dependent on the shape and dimensions of used specimens. Some findings reported in the literature suggest that size effect exists also when testing such fracture properties of concrete as tensile strength. Unfortunately this problem is much less recognized and described compared to size effect in compressive test results. In this paper, the experimental investigation is presented on how the length of cylindrical specimens influences the tensile splitting strength of concrete obtained by means of the Brazilian method. Additional variable parameters were: type of aggregate (natural gravel and crushed granite) and cement-water ratio (C/W = 1.8 and C/W = 2.6). In conducted laboratory experiments a higher splitting tensile strength of concrete was noted for all specimens with nominal dimensions of 150×150 mm, compared to specimens 150×300 mm in size, regardless of type of aggregate or cement-water ratio.

Optimization of antimicrobial efficiency of silver nanoparticles against three oral microorganisms in irreversible hydrocolloid impressions

Background and Objectives: Silver nanoparticles (Ag-NPs) are potent antimicrobial agents, which have recently been used in dentistry. The aim of the current study was to optimize antimicrobial activity of Ag-NPs used in preparing irre- versible hydrocolloid impressions against three microorganisms of Escherichia coli, Streptococcus mutans and Candida albicans. Materials and Methods: After assessing antimicrobial activity of the compound using disk diffusion method, three parame- ters of concentration of Ag-NPs (250-1000 ppm), ratio of hydrocolloid impression material powder to water (0.30-0.50) and time of mixing (20.0-60.0 s), affecting antimicrobial activity of irreversible hydrocolloid impression materials against the three microorganisms, were optimized. This combined process was successfully modeled and optimized using Box-Behnken design with response surface methodology (RSM). Decreases in colony number of E. coli, S. mutans and C. albicans were proposed as responses. Results: Qualitative antimicrobial assessments respectively showed average zone of inhibition (ZOI) of 3.7 mm for E. coli, 3.5 mm for S. mutans and 4 mm for C. albicans. For all responses, when the mixing duration and powder-to-water ratio increased, the circumstances (mixing duration of 59.38 s, powder-to-water ratio of 0.4 and Ag-NP concentration of 992 response) increased. Results showed that in optimum ppm, the proportion of decreases in colony numbers was maximum (89.03% for E. coli, 87.08% for S. mutans and 74.54% for C. albicans). Regression analysis illustrated a good fit of the ex- perimental data to the predicted model as high correlation coefficients validated that the predicted model was well fitted with data. Values of R2Adj with R2Pred were associated to the accuracy of this model in all responses. Conclusion: Disinfection efficiency dramatically increased with increasing of Ag-NP concentration, powder-to-water ratio and mixing time.

AN IMPROVED METHOD FOR THE PREPARATION OF PHLOROGLUCINOL FROM 1,3,5-TRINITROBENZENE

Статья посвящена способу получения флороглюцина, представляющего интерес в качестве основы для конструирования лекарственных средств, полимеров различного назначения и малочувствительного взрывчатого вещества 1,3,5-триамино-2,4,6-тринитробензола. Современным и наиболее экологичным методом получения флороглюцина является каталитическое гидрирование 1,3,5-тринитробензола на палладиевом катализаторе до 1,3,5-триаминобензола и его последующий гидролиз. Использование палладиевых катализаторов позволяет проводить восстановление в мягких условиях, но их высокая стоимость обуславливает потребность в поиске путей снижения расхода палладия и, соответственно, себестоимости процесса. В данном исследовании показано, что использование 1 %-го Pd/сибунит (50 % к массе субстрата) в сочетании с водно-ацетоновым раствором в качестве среды при проведении гидрирования способствует более длительному сохранению активности катализатора. Установлено, что оптимальное соотношение ацетона и воды находится в диапазоне от 4:1 до 7:1. В этом случае может быть проведено до 20 циклов гидрирования без добавления свежего катализатора, за счет чего удается снизить расход палладия в три раза по сравнению с другими известными методиками. Кроме того, подход позволяет исключить из схемы синтеза токсичный растворитель метанол. Триаминобензол, полученный в ходе гидрирования, без выделения подвергается гидролизу в присутствии серной кислоты с образованием флороглюцина. Изучена зависимость выхода флороглюцина от мольного соотношения серной кислоты и тринитробензола. Установлено, что оптимальное соотношение серная кислота : тринитробензол составляет 2,0-2,4 моль/моль. Суммарный выход флороглюцина составляет 76 % в пересчете на тринитробензол. The study is concerned with a synthetic method for phloroglucinol that is of great concern as a scaffold for designing medicinal drugs, different-purpose polymers and the insensitive explosive 1,3,5-triamino-2,4,6-trinitrobenzene. The current and most eco-benign method for the synthesis of phloroglucinol is through catalytic hydrogenation of 1,3,5-trinitrobenzene over the Pd catalyst to 1,3,5-triaminobenzene followed by its hydrolysis. The use of Pd catalysts allows the reduction under mild conditions, but their high cost necessitates the need to find ways how to spare the Pd usage and, consequently, the process cost. Here we demonstrated that the use of 1% Pd/Sibunite (50% to substrate weight) combined with a water-acetone solution as the medium in hydrogenation allows the catalyst to keep active longer. The optimum acetone-to-water ratio was found to be between 4:1 and 7:1. In this case, as many as 20 hydrogenation runs can be done without a fresh catalyst added whereby the Pd usage can be lowered threefold when compared to the other common methods in use. Besides, this approach allows the toxic solvent methanol to be expelled from the synthetic protocol. Triaminobenzene resulting from the hydrogenation without isolation undergoes hydrolysis in the presence of sulfuric acid to furnish phloroglucinol. The relationship between the phloroglucinol yield and the molar ratio of sulfuric acid and trinitrobenzene was also explored. The optimum sulfuric acid-to-trinitrobenzene ratio was found to be 2.0-2.4 mol/mol. The overall yield of phloroglucinol was 76% on a trinitrobenzene basis.

Nanoprecipitation of Biocompatible Poly(malic acid) Derivative, Its Ability to Encapsulate a Molecular Photothermal Agent and Photothermal Properties of the Resulting Nanoparticles

Biocompatible nanoparticles (NPs) of hydrophobic poly(benzyl malate) (PMLABe) were prepared by nanoprecipitation. The influence of nanoprecipitation parameters (initial PMLABe, addition rate, organic solvent/water ratio and stirring speed) were studied to optimize the resulting formulations in terms of hydrodynamic diameter (Dh) and dispersity (PDI). PMLABe NPs with a Dh of 160 nm and a PDI of 0.11 were isolated using the optimized nanoprecipitation conditions. A hydrophobic near infra-red (NIR) photothermally active nickel-bis(dithiolene) complex (Ni8C12) was then encapsulated into PMLABe NPs using the optimized nanoprecipitation conditions. The size and encapsulation efficiency of the NPs were measured, revealing that up to 50 weight percent (wt%) of Ni8C12 complex can efficiently be encapsulated with a slight increase in Dh of the corresponding Ni8C12-loaded NPs. Moreover, we have shown that NP encapsulating Ni8C12 were stable under storage conditions (4 °C) for at least 10 days. Finally, the photothermal properties of Ni8C12-loaded NPs were evaluated and a high photothermal efficiency (62.7 ± 6.0%) waswas measured with NPs incorporating 10 wt% of the Ni8C12 complex.

A Novel Mathematical Model for Fracturing Effect Evaluation Based on Early Flowback Data in Shale Oil Reservoirs

For shale oil reservoirs, the horizontal well multistage fracturing technique is mostly used to reform the reservoir in order to achieve economic and effective development. The size of the reservoir reconstruction volume and the quantitative characterization of the fracture system are of great significance to accurately predict the productivity of shale oil wells. There are few flowback models for shale oil reservoirs. To solve this problem, first, a physical model of the simultaneous production of oil, gas, and water in the early flowback stage of shale oil development is established using the material balance equation for a fracture system. Second, the physical model of the underground fracture system is simplified, which is approximately regarded as a thin cylindrical body with a circular section. The flow of the fluid in the fracture system is approximately regarded as radial flow. In this model, the expansion of the fluid and the closure of the fracture are defined as integrated storage coefficients to characterize the storage capacity of the fracture system. Then, the curves illustrating the relationships between the oil-water ratio and the cumulative oil production and between the gas-water ratio and the cumulative gas production are drawn, and the curves are used to divide the flowback stage into an early stage and a late stage because the flowback process of shale oil wells exhibits obvious stage characteristics. Finally, the reservoir reconstruction volume and the related hydraulic fracture parameters are estimated based on the material balance method, and the rationality of the model is verified via numerical simulation. The interpretation results of this novel model are more accurate, making it an effective way to evaluate the hydraulic fracture parameters and transformation effect, and it has guiding significance for the evaluation of the hydraulic fracturing effect in the field.

Organoleptic Evaluation for Accessing Sensory Attributes of Lycopene Containing Tomato Purees and its Overall Acceptability

A study on organoleptic evaluation for accessing sensory attributes of lycopene containing tomato purees & its overall acceptance was conducted at Food Science Analysis Laboratory, School of Home Science, B.B.A.U, Lucknow, Uttar Pradesh, India, during July 2020 to May 2021. Different treatments under the investigation were prepared using dried tomato (Lycopersicum esculentum), tomato pulp and water to find out most appropriate treatment having significantly higher sensory attributes and overall acceptability. Five different types of treatments/purees viz. Dried tomato powder without food additives (T1), Mixture of tomato powder and water (ratio 1:10) without heating (T2), Mixture of tomato powder and water (ratio 1:10) heating at 60-70 ᴼC for 5 minutes (T3), Fresh tomato pulp (T4) & Tomato pulp cooked at 60-70 ᴼC for 35 minutes (T5) were used in the investigation. The effect of these treatments was distinguished as reflected on sensory characters like appearance, aroma, texture & overall acceptance. The highest overall acceptance of 8.20±0.7 on hedonic scale was obtained from tomato pulp cooked at 60-70 ᴼC for 35 minutes (T5) followed by dried tomato powder without food additives (T1) ie. 7.90±1.0. These results appeared highly promising depending on the appearance, aroma & texture.

Effect of Substrate/Water Ratio on Biogas Production from the Mixture Substrate of Rice Straw and Salvinia molesta

The substrate/water (S/W) ratio is one of the affecting parameters in anaerobic digestion (AD) since it affects the concentration of total solids (TS) in the biogas feedstocks. The appropriate S/W ratio has to be found to result in a high biogas yield. The goal of this study was to look into the influence of S/W ratio on biogas production from mixture substrate of rice straw and Salvinia molesta. Ratio of S/W was varied to be 1/7 w/v (TS 9.67%w/w), 1/10 w/v (TS 7.52%w/w), 1/13 w/v (TS 6.15%w/w), 1/16 w/v (TS 5.20%w/w). The results showed that S/W of 1/7, 1/10, 1/13, 1/16 resulted a total biogas yield of 22.86, 38.67, 42.71, 43.69 mL/g TS respectively. Decreasing TS from 9.67 %w/w (S/W of 1/7) until 6.15%w/w (S/W of 1/13) could increase the TS removal from 31.03% until 55.66%. However, at TS 5.20%w/w (S/W of 1/16), the TS removal was lower than that at TS 6.15%w/w (S/W of 1/13). The modified Gompertz (R2 = 0.94 – 0.98) can predict evolution of biogas production with higher precision than the first order kinetic (R2 = 0.91 – 0.98). The optimum TS was successfully predicted to become 5.40%w/w.

Substantiation of the method of primary processing of Japanese kelp for food production

Химический состав и свойства морских водорослей позволяют с успехом применять их для профилактических и лечебных целей, для приготовления различных пищевых продуктов. В Японском море найдено более 310 представителей зеленых, бурых и красных водорослей. Из бурых водорослей преобладают многочисленные виды ламинариевых (Laminariaceae), наиболее ценной в промысловом отношении является ламинария японская (Laminaria japonica). Первичная обработка свежих водорослей предусматривает их тщательную мойку и вымачивание, но и после этого ее ткани содержат все еще высокие концентрации минеральных веществ, не позволяющие ее дальнейшее использование без дополнительной обработки. Поэтому при обработке ламинарии предусматривают ее варку, которая позволяет улучшить вкус, запах, цвет и консистенцию, а также повысить усвояемость водоросли организмом. Однако при варке в отвар переходит значительное количество водорастворимых солей и органических веществ. Поэтому выбор правильных режимов первичной обработки водорослей, при которых происходят минимальные потери физиологически ценных компонентов и обеспечиваются высокие органолептические показатели, будет способствовать производству широкого ассортимента пищевой продукции на их основе. Целью научно-исследовательской работы является обоснование способа первичной обработки ламинарии для производства пищевой продукции. Предложен способ обработки ламинарии, включающий в себя предварительную выдержку ламинарии в воде при температуре 10…15 °С в соотношении ламинария:вода - 1:2 в течение 20 мин и двукратную варку при температуре 40…50 °С при соотношении ламинария:вода 1:2 в течение 15-20 мин. Установлено, что внесение органических кислот на первом этапе варки способствует улучшению органолептических показателей водорослей. Исчезают специфические вкус и аромат водорослей, консистенция становится менее жесткой. Определены концентрации органических кислот в составе варочных вод: уксусной кислоты 1-3 %, лимонной кислоты 1-2 %. Полученный полуфабрикат при обработке ламинарии предложенным способом можно использовать при производстве разных видов пищевой продукции (сушеной, кулинарии, пресервов и др.). The chemical composition and properties of seaweed make it possible to successfully use them for prophylactic and therapeutic purposes, for the preparation of various food products. More than 310 representatives of green, brown and red algae have been found in the Sea of Japan. Numerous species of kelp (Laminariceae) prevail among brown algae, the most valuable commercially is Japanese kelp (Laminaria japonica). The primary processing of fresh algae involves their thorough washing and soaking, but even after that, its tissues still contain high concentrations of minerals, which do not allow its further use without additional processing. Therefore, when processing kelp, boil it is provided, which allows you to improve the taste, smell, color and consistency, as well as increase the digestibility of the algae by the body. However, during cooking, a significant amount of water-soluble salts and organic matter passes into the broth. Therefore, the choice of the correct modes of primary processing of algae, in which minimal losses of physiologically valuable components occur and high organoleptic characteristics are provided, will contribute to the production of a wide range of food products based on them. The purpose of the research work is to substantiate the method of primary processing of kelp for the production of food products. A method for processing kelp is proposed, which includes preliminary exposure of kelp in water at a temperature of 10…15 °C in a kelp: water ratio of 1:2 for 20 minutes and double cooking at a temperature of 40…50 °C at a kelp: water ratio of 1:2 within 15-20 minutes. It was found that the introduction of organic acids at the first stage of cooking contributes to the improvement of the organoleptic characteristics of algae. The specific taste and aroma of algae disappears, the consistency becomes less rigid. The concentration of organic acids in the composition of the cooking water has been determined: acetic acid 1-3 %; citric acid 1-2 %. The resulting semi-finished product when processing kelp by the proposed method can be used in the production of various types of food products (dried, cookery, preserves, etc.).