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.

Formulation of Non-Fired Bricks Made from Secondary Aluminum Ash

The secondary aluminum ash is the black slag left after the primary aluminum ash is extracted from the metal aluminum. To address the environmental pollution and resource waste caused by the accumulation and landfill of aluminum ash, this study fabricated non-fired bricks by using secondary aluminum ash as the principal raw material, which was supplemented by cement, slaked lime, gypsum and engineering sand. The effects of mix proportions of various admixtures on the mechanical properties of non-fired bricks were investigated, and on this basis, the hydration mechanism was analyzed. The results showed that the mix proportions were 68.3% aluminum ash, 11.4% cement, 6.4% slaked lime, 4.2% gypsum and 9.7% engineering sand. The compressive strength of the fabricated bricks reached 22.19 MPa, and their quality indicators were in line with the MU20 requirements for Non-fired Rubbish Gangue Bricks. Evident hydration reaction occurred inside the non-fired bricks, with main products being calcium silicate hydrate (CSH), calcium aluminate hydrate (CAH) and ettringite (AFt). Besides, a dense structure was formed, which enhanced the brick strength.

Activated Carbon Impregnated with Elementary Iodine: Applications against Virus- and Bacteria-Related Issues

An iodine-doped activated carbon (named IodAC) was developed by adsorbing molecular iodine (I2) on commercially available activated carbon (AC). Iodine was selected with the purpose to add its well-known antibacterial and antiviral properties to the AC and in order to produce an innovative material for environmental pathogens control and for healthcare-related applications. The impregnation method achieved the goal of strongly adsorbing iodine on the AC surface, since both volatility and water solubility resulted to be negligible, and therefore it did not affect the stability of the material. An antibacterial test (on Escherichia coli) and an antiviral test (on an avian influenza strain) were conducted, showing the effectiveness of IodAC against the pathogens. In addition, IodAC was also compared to slaked lime (a material widely used for disinfection of outdoor spaces and livestock farming areas). The data proved the performance of IodAC against virus and bacteria and also evidenced a more stable and long-lasting disinfecting power of IodAC compared to slaked lime, the later reacting with carbon dioxide and suffering a gradually decrease of its disinfectant power; such drawback does not affect IodAC. Overall, the presented results show that IodAC can be used for a wide range of applications, including as a granular disinfectant for public spaces, for water disinfection, zoonotic diseases countermeasures (e.g., as an animal feed additive for avian influenza control), post-harvest food storage, and sanitization. Its characteristics also indicate its potential to be used for medical treatments, such as for blood, intestinal (for HIV, sepsis, irritable syndrome, ulcerative colitis therapy), and medical supplies (antibacterial bandages, gauze, cotton, etc.) sterilization.

A Case Report on Acute Transient’s Psychotic Disorders

Background: Little is known about acute and transient psychotic disorders (ATPD), a diagnostic category introduced with ICD-10. Case Presentation: Acute transient psychotic disorder is a heterogeneous group of disorders characterised by the acute onset of psychotic symptoms such as delusion, hallucination and perceptual disturbances, and by the severe disruption of ordinary behaviour. Patient history: The Male patient 48 year old who was apparently admitted in AVBRH on date 08/05/2021 with chief complaint was Abnormal behaviour( taking clothes off in public ), irritability, aggressive, muttering and smiling to self from 10 days back. His parents once locked him in a room as they fear he might hurt him. He was taken to a faith healer in Pandarkawda twice by his parents. The Baba gave him some mysterious beats like bracelet to wear which eventually decreased his symptoms for 3 days but the symptoms persisted from the fourth day. This time, the Baba mixed a lemon juice, turmeric powder & kumkuma (a powder made from dried turmeric with a bit of slaked lime) and applied all over him eyes which severely inflamed & burnt his eyes. His eye injury elevated his psychotic symptoms which is why his parents took him to psychiatric OPD in AVBRH. Past History: Patient was apparently asymptomatic 2 yrs back. He was married to a woman of his parent’s choice. His marriage life was stressful and unhealthy. He was underestimated by his wife due to his low qualification and health problem. Clinical Finding: The patient has been undergone with various investigations like culture, blood tests, Physical examination and mental status examination symptomatically with antipsychotic agent and anticonvulsant such as Tab Olanzapine 10mg- HS, Tab Clonazepam 0.5mg – SOS. Medical Management: Antibiotic eye drop homatropine and eye ointment ciprofloxacin. Nursing Management: Administered fluid replacement i.e DNS and RL, eye care was done with betadine and Normal Saline solutions, eye care by administering eye drops and monitored all vital signs hourly. Conclusion: Patient was admitted to hospital with the chief complaint of muttering to self, irritability and eye injury, blisters, pus discharge from eyes and his condition was very critical and patient was admitted in AVBR Hospital ,immediate treatment was started by health team member and all possible treatment were given and now the patient condition is satisfactory.

Interpreting chemistry and technology of lime binders and implementing it in the conservation field _ Interpretação da química e da tecnologia de ligantes à base de cal e sua implementação no campo da conservação

The objective of the paper is the compilation, review and dissemination of updated scientific knowledge on lime theory and technology in the field of heritage conservation.The strong evidence of the last decade’s research on the positive effect of the-not demonstrable by a chemical equation-‘key’ missing link of the maturation process is highlighted. It is demonstrated that the exceptional performance characteristics of durable lime based mortars predominately rely on the capacity for rapid, efficient and extensive carbona-tion of the air-hardening phase of limes, in particular when matured (nanoparticle wet slaked) lime putties are used; and on the chemical and mechanical stability of the strength components (principally CSHs) of the hydraulic phase of limes, which is higher in their more crystalline forms of historical lime-pozzolan mixtures than in their amorphous forms of modern cements. Hence, physicochemical adhesion and cohesion bonds both at the lime matrix and at the binder/aggregate interfaces are ensured imparting minimization of cracks and durability to lime based mortars and historic masonries.The comprehensive documentation of the former leads to optimal materials and procedures to preserve our cultural heritage. Resumo O objectivo do presente artigo é a compilação, revisão e disseminação do actual conhecimento científico sobre teoria e tecnologia da cal no campo da conservação do património. Com base na investigação da última década, são destacados os fortes indícios do efeito positivo-não demonstrável por equação química-do elo perdido ‘chave’, o processo de maturação. É demonstrado que as excepcionais características de desempenho das argamassas à base de cal mais duráveis dependem predominantemente das suas capacidades para uma rápida, eficiente e extensa carbonatação da fase de presa aérea da cal, em particular quando é usada cal em pasta com maior tempo de maturação (extinção húmida ao nível das nanopartículas); e da estabilidade química e mecânica dos com-ponentes de resistência (principalmente silicatos de cálcio hidratados (CSHs)) da fase hidráulica da cal, que é mais elevada nas for-mas mais cristalinas das misturas históricas de cal e pozolana do que nas formas amorfas dos cimentos modernos. Deste modo são asseguradas as ligações fisico-químicas por adesão e por coesão, quer na matriz de cal, quer nas interfaces ligante/agregado, conferindo minimização de fissuras e durabilidade a argamassas à base de cal e alvenarias históricas. Uma abrangente documentação destes proces-sos permitirá a obtenção de materiais e procedimentos progressivamente mais adequados à preservação do nosso património cultural. Palavras-chave Maturação; Cal em pasta; Argamassa de cal; Componentes de resistência; Estabilidade estrutural.

Combined Effect of Different Flower Stem Features on the Visiting Frequency of the Generalist Ant Lasius niger: An Experimental Study

In order to understand the effects of the morphology and surface texture of flower stems in Smyrnium rotundifolium on the visiting frequency of generalist ants, we conducted experiments with Lasius niger ants running on dry wooden sticks mimicking different types of stems: (1) intact (grooved) sticks; (2) sticks painted with slaked (hydrated) lime (calcium carbonate coverage) imitating plant epicuticular wax coverage; (3) intact sticks with smooth polyester plate-shaped cuffs imitating upper leaves; and (4) intact sticks bearing cuffs painted with slaked lime. Ants were attracted by the sweet sugar syrup droplets placed on a stick tip, and the number of ants visiting the drops was counted. Our data showed significant differences in the visiting frequencies between the different types of stem-mimicking samples. The number of recorded ants progressively decreased in the following order of samples: intact sticks—painted sticks—sticks with intact cuffs—sticks with painted cuffs. These results clearly demonstrated that micro/nanoscopic surface coverages and macroscopic physical barriers, especially if combined, have a negative impact on the attractiveness of stems to ants. This study provides further evidence for the hypothesis that having a diversity of plant stems in the field, generalist ants prefer substrates where their locomotion is less hindered by obstacles and/or surface slipperiness.

Blending Lime with Sugarcane Bagasse Ash for Stabilizing Expansive Clay Soils in Subgrade

Expansive soils constitute one of the most frequently encountered and challenging soils to geotechnical engineers. This study assessed the possibility of utilizing sugarcane bagasse ash (SCBA) by partially replacing slaked lime to stabilize expansive clay soils. The soil samples were picked from Muduuma area, Mpigi district, Central Uganda. Experimental tests of linear shrinkage (LS), plasticity index (PI), and California Bearing Ratio (CBR) were conducted on both unstabilized soil and SCBA-lime treated samples. The SCBA-lime mixture was prepared by partially replacing 5% lime with SCBA at 2, 4, 6, 8, and 10% by weight. Hence, SCBA was used in proportions of 0.1, 0.2, 0.3, 0.4, and 0.5% by dry weight of the soil. The addition of lime greatly lowered the PI and LS, which later increased with the addition of the SCBA. The maximum dry density was generally lowered with the addition of lime and SCBA, from 1.87 g/cm3 to 1.58%. The CBR increased with SCBA-lime addition from 12% for unstabilized soil up to 48% at 6% SCBA replacement. The optimum lime replacement was established as 6% SCBA lime replacement based on CBR criteria. At the 6% optimum, the optimum moisture content (OMC) was 1.7 Mg/m3, LS was 10%, and PI was 20%. This study demonstrated the potentiality of SCBA as a novel construction material, specifically by partially reducing the usage of the unsustainable, non-environmentally friendly lime. It is also expected to enable using currently unsuitable clays from the region.

Influence of Lime for Enhancing Characteristics of Expansive Soils in Road Works

Expansive soils are found in black cotton soils, which swell or shrink in volume when presented to changes in moisture content. Lime treatment is exhaustively used to increment the properties of sensitive and fragile soils. One of the hugest clarifications behind using lime is to decline the developing presentation of the earth soil. The arrangement of extra safeguards improves the reaction of quicklime (CaO) with water, structures hydrated (slaked) lime (Ca (OH)2), and thus earth characteristics. The vast inadequacy of employing lime is growing the deficiency of lime offset earth. Following that, the goal of this study is to see how re-establishing time affects the geotechnical qualities of settled Black cotton soils with lime. These discoveries recommend that adding Lime as a stabilizer works on the strength of black cotton soil. Some of the characteristics of the soil likely to be increased by using stabilizer in this work are UCS (Unconfined Compressive Strength) at different curing periods (7,14,28 and 56 days), CBR (California Bearing Ratio) value at unsoaked and soaked and MDD (Maximum Dry Density) decrease at different lime percentages(%) like 2.4.6.8 and 10. The result showed here untreated soil got stabilized by using the stabilizer in certain extent In this adjustment various rates of cementitious material is added to black cotton soil and directed tests like plasticity, compaction, swell pressure, free swell index(FSI), Coefficient of permeability (k) and CBR(soaked and unsoaked) at various conditions like OMC,OMC+2% water and OMC+5% water, UCS (Unconfined Compressive Strength) was performed. From the test results, it is identified that the stabilization agent decreases plasticity and improves strength characteristics. Addition of stabilizing agent makes the black cotton soil to non-plastic, non-swelling and attains increase CBR values which are greater than 25% for a dosage of 10% lime at OMC but remaining OMC+2%water & OMC+5%water CBR values are not various much difference as per test results. With the addition of lime, the black cotton soil becomes non-plastic, non-swelling, and has high strengths. Treated soils are used as a development material, for example, a subgrade layer in the development of adaptable asphalt pavements for roads.