Mechanical Transformation of Fly Ash toward Its Utilization in Cemented Paste Backfill

Fly ash (FA) showed low reactivity when being used to prepare the binder for cemented paste backfill (CPB). In the present work, wet-grinding treatment was used to increase the pozzolanic reactivity of FA and promote its sustainable utilization. The results showed that wet-grinding could be a suitable and efficient technology for FA pretreatment. Wet-grinding strongly modified the structure of FA by decreasing the crystalline phase content and the binding energy of Si 2p and Al 2p, contributing to the increase in pozzolanic reactivity of FA. The performance of CPB samples prepared by wet-ground FA was then optimized. This was reflected by the acceleration in the sample setting and increase in the strength development. The compressive strength of the CPB samples prepared by wet-ground FA for 120 min was increased by around 40% after curing for 28 d compared with the control samples.

At the origins of Pompeii: the plant landscape of the Sarno River floodplain from the first millennium bc to the ad 79 eruption

The ad 79 eruption of the Vesuvius severely affected the floodplain surrounding the ancient city of Pompeii, i.e. the Sarno River floodplain. The landscape was covered with volcaniclastic materials that destroyed the ecosystem but, at the same time, preserved the traces of former environmental conditions. This study provides—for the first time—a pollen sequence reconstructing the environmental evolution and the plant landscape of the Sarno floodplain between 900 and 750 cal bc and ad 79, i.e. before and during the foundation of the city, and during its life phases. Previous geomorphological studies revealed that the portion of the Sarno floodplain under the “Pompeii hill” was a freshwater backswamp with patchy inundated and dry areas. Palynology depicts a thin forest cover since the Early Iron Age, suggesting an open environment with a mosaic of vegetation types. The local presence of Mediterranean coastal shrubland, hygrophilous riverine forest and mesophilous plain forest is combined with the regional contribution of mountain vegetation through the sequence. Oscillations between inundated and wet ground characterized the studied area until the ad 79 eruption. Such a natural environment shows anthropogenic traits since pre-Roman times: pasturelands, cultivated fields and olive groves, which probably occupied drier soils. The most important change in the land use system was the introduction of cabbage cultivation in the fourth century bc and its intensification from the second century bc, when Roman influence grew. The presence of tree crops and of ornamental trees reveals the opulence of the Imperial age until the catastrophic eruption.

Numerical Analysis of the Effect of Ground Dampness on Heat Transfer between Greenhouse and Ground

This paper deals with the problem of the influence of ground dampness on heat exchange between greenhouse and ground. The effect of humidity on the distribution of ground temperature fields was analyzed. The analysis was performed based on the analytical numerical method in the WUFI®plus software. The computational tool was used after a validation process. Research and simulations were conducted on the example of a real single-span greenhouse located in Southern Poland. The results of indoor and outdoor air temperature measurements were used to determine the boundary conditions, while the measured ground temperatures were used to compare with the results of theoretical calculations. Three variants were used for calculation analysis, assuming different levels of ground dampness. Analysis of the test results showed that during the summer period, dry ground provides 8% more thermal energy to the interior of the greenhouse than the damp ground, and provides 30% more thermal energy than wet ground. In the transition period (autumn/spring), the ground temperature fields are arranged parallel to the floor level, while the heat flux is directed from the ground to the interior of the greenhouse, regardless of the ground dampness level. During this period, the ground temperature ranges from 4.0 °C to 13.0 °C. Beneficial effect of dry ground, which contributes to maintaining an almost constant temperature under the greenhouse floor, was found in winter.

Characterisation and comparative analysis of metallic inclusions in dry, paste and wet ground maize (zea mays) forms and its health implication on human

This study investigates metallic inclusions in ground maize forms of dry, paste and wet using domestic grinding machine and its health implications to human. With progressive maize processing using the grinding machine, metals are introduced as contaminants into ground maize due to wear and tear of the grinding discs and other machine parts. Maize samples of 1 kg each were grinded in wet, paste, and dry forms. The metallic inclusions were extracted from the ground maize forms using magnetisation, sedimentation and decantation. The extractions were quantified using an Electronic weighing balance and were characterised using, Scanning Electron Microscopy, Optical Emission Microscopy and Energy Dispersive Spectroscopy. Iron fillings were discovered to be the dominant metallic inclusion present in the various food forms and also in the grinding disc with 88.48% by weight in the grinding disc. The extracted metallic inclusions is 0.157g/kg, 0.196g/kg and 0.268 g/kg for dry, paste and wet ground maize forms which exceeded the World Health Organisation limit of 15 mg/kg. The EDS result show that the wet form has the highest amount of metallic inclusions of 95.97 at. %, the paste form with 91.39 at. % and dry form with 83.35 at. %. From the SEM analysis of particle size, the dry, paste and wet ground maize had 17μm, 27μm and 36μm particle sizes respectively. When in excess the Iron filling metallic inclusions from the ground maize accumulates in body organs since there is no physiological mechanism to eliminate excess iron thereby leading to health complications. The accumulated iron in the heart causes increased risk of cardiovascular diseases, siderosis and hemochromatosis in the liver leading to hepatoma-the primary cause of cancer of the liver among others. Elevated levels of free iron also predisposed individuals to high risk of bacterial and viral infections leading to death.

STUDIES ON THE MORPHO-ANATOMICAL PARTICULARITIES OF LYSIMACHIA NUMMULARIA L.

"The objective of the study was the histo-anatomical analysis of the root, stem and leaf belonging to the species Lysimachia nummularia L. from the Primulaceae family. The plant is native to Europe, but has been introduced to North America, where it is considered an invasive species in some areas. It aggressively spreads in favourable conditions, such as low wet ground or near ponds. It is moderately difficult to remove by hand pulling. Any tiny piece left behind will regrow. The research results led to the following assessments: root with primary structure and beginning of secondary structure, the presence of calcium oxalate druze in the bark, endoderm and primary type conducting bundles. The results of the study also demonstrated the existence of the stem with four prominent ribs, a meatic-type bark with small secretory channels and a central cylinder with a secondary structure. Another element studied from a histo-anatomical point of view; leaf with dorsi-ventral bifacial structure, with heterogeneous asymmetrical structure, collateral free-woody bundle, without periectors. From the morpho-anatomical data described, it can be concluded that the species Lysimachia nummularia L. belongs to the family Primulaceae and is related to other species of the genus Lysimachia."

ثنائية البعل والمرأة من خلال قصة إبراهيم عليه السلام في القرآن الكريم: دراسة دلالية اجتماعية

The research aims to study the social significance in the conjunction of the word (woman) with (Baal) in one context, therefore, the linguistic meanings of these two terms are investigated, and what can be derived from their root of vocabulary, and subsequently this is applied to the story of Ibrahim, peace be upon him, with his wife Sarah. The Study concluded that the concept of Baal and what is derived from it means: what grows in a place where water does not reach from a place higher than it, but only by what comes from the clouds, even if it intensifies and is solid and its roots reach the layers of the wet ground till it needs no more water, it takes it as much as needed, then it is distinguished with its fruit which is between wet and dry. Describing the female as (the woman) indicates that her nature is based on her need to others, and that she has the ability to adapt to it, and this has been mentioned in the Holy Qur’an, or that the female is referred to as the original innocence, or that she has reached the summit of feminist perfection, especially in the context of overcoming crises, and what is related to marital life has emerged through the dualism of Ibrahim, peace be upon him, and his wife Sarah.

Utilization of Carbide Slag by Wet Grinding as an Accelerator in Calcium Sulfoaluminate Cement

In this study, wet-ground carbide slag (i.e., WGCS) was utilized as an accelerator in calcium sulfoaluminate cement (CSA) for obtaining considerably faster setting processes for some special engineering processes such as plugging projects and rapid repair engineering. The WGCS–CSA system was designed, in which the replacement ratio of CSA by carbide slag was chosen as 4%, 8% and 12%. The setting time and compressive strength were measured, and the mechanism of the system hydration was studied in detail by means of calorimetry, XRD, thermogravimetry (TG) and SEM. The results showed that WGCS shortened the setting time of cement and significantly augmented the early strength. The addition of 8% of WGCS contributed to increasing the 2-h compressive strength from 4.2 MPa to 32.9 MPa. The decrease in the setting time and the increase in the initial strength were mainly attributed to the high initial pH value of the liquid phase and the high content of calcium ions in WGCS. Both these factors contributed to the ettringite formation and, at the same time, to the transformation of the morphology at a later time. Such results testify that WGCS can be used as an accelerator in the CSA system and also that it provides a novel approach to the reutilization of carbide slag.