Addis Ababa Science and Technology University

ABSTRACT This study aims to assess the geological challenges associated with potash solution mining in the active rift of the Dallol Depression and to propose an optimised borehole design for Circum Minerals Limited. An integrated approach combining satellite image interpretation, field observations, borehole data, and seismic images was utilised to produce detailed geological and structural maps and to characterise subsurface evaporite sequences. The seismic images and borehole logs acquired by the company were interpreted to demarcate subsurface features, whereas three‐dimensional models derived from multiple well logs and fence diagrams enhanced stratigraphic interpretation. The nearest neighbour polygon method was used to estimate the total potash deposits of the concession area. The high‐resolution seismic data were interpreted in conjunction with the subsurface geological map generated from borehole data using Rockworks 15 software. The borehole data indicated that the stratigraphic sequences of the evaporite deposits (salt deposits and muddy salt) consist of clastic materials, upper halite, marker beds, sylvinitite member, upper carnallitite member, bischofitite member, lower carnallitite, kainitite member, lower halite unit, and a basal clastic unit. The evaporite sequence in general, and the upper halite and bischofitite members in particular, show two distinct thickening trends: towards the rift‐axis and towards the rift center. The total potash resource is estimated at approximately 18.81 billion tons, of which 3.57 billion tons remain unexploited due to the effects of fault confinements. The existing borehole designs limit the company's total extraction capacity. To improve recovery both from intact and fault‐bounded potash deposits, this study recommends the addition of 16 systematically located boreholes, considering the deposit geometry and resource distributions, to enhance potash recovery and promote sustainable mining practises.

Hybrid polymer composites are immensely beneficial in a range of industries, including aerospace, automotive, marine and construction, due to their versatility and adaptability. Therefore, this study examined the thermo-mechanical properties of hybrid polymer composites reinforced with glass and hemp fibers using two different 2D fillers, MXene and graphene. For this purpose, hybrid composites with various layup configuration such as Glass/Hemp (G/H) fiber, Glass/Hemp (G/H) fiber with Graphene filler (G/H-G), and Glass/Hemp fiber with MXene filler (G/H-M) reinforced with epoxy LY 556 with hardener HY951, were used and tested. The composites were fabricated using vacuum bag assisted hand lay-up technique. Dynamic mechanical analysis (DMA) was then performed to evaluate the significant viscoelastic parameters, including storage modulus E', loss modulus E'' and damping (Tan δ). In addition, thermogravimetric analysis (TGA) was performed to find the residual mass %. The results show that hybrid composites using 2D filler materials exhibited superior dynamic mechanical characteristics and thermal stability compared to pure Glass/Hemp composites. The G/H-M hybrid composite showed the highest storage modulus value. The incorporation of graphene and MXene into the glass-hemp hybrid composites exhibits an identical degradation pattern, resulting in a residual mass increase of up to 44% at temperatures up to 600 °C. The G/H-G hybrid composite demonstrated remarkable thermal stability at elevated temperatures, as well as resistance to deformation.

Abstract Subclinical rheumatic valvular disease is a significant yet underdiagnosed contributor to the global rheumatic heart disease (RHD) burden. Early detection through population screening is essential to prevent its progression to severe RHD. Rhythm changes and prolongations of PR and QTc intervals in the ECG are described in the advanced RHD cases. However, these parameters were not yet studied in asymptomatic RHD. We aimed to investigate the potential of ECG biomarkers for screening RHD in asymptomatic schoolchildren. ECG tracings from 611 schoolchildren aged 10 to 20 years were selected from a cohort screened for RHD in four schools in an RHD-endemic region. Confirmatory diagnoses were based on echocardiographic findings, where 564 (F=326, M=238) were healthy, and 47 (F=28, M=19) were positive for RHD (24 borderline RHD and 23 definite RHD). Independent, blinded reviewers manually annotated the ECGs and PR interval (PR), P-wave dispersion (PWd), and the ratio between the P-wave duration and PR interval (Pw/PR) were analyzed. The mean age of the study cohort at diagnosis was 16.1 ± 2.5 years, and 58% of the participants were females. Atrial fibrillation was seen in 8% (n=4), and prolonged PR in 2% (n=1) of RHD-positive cases. The mean ± std for normals vs RHD is (PR, 138±19 vs 150±19), (Pw/PR, 0.75±0.06 vs 0.71±0.07), and (PWd, 49±14 vs 56±17). The PR (p<0.001), Pw/PR (p<0.001), and PWd (p=0.008) showed a significant difference between healthy and RHD-positive subjects. The PR was increased consistently with severity across age groups above and below 16 years. The PR, PWd, and Pw/PR can serve as non-invasive biomarkers for the screening of RHD in at-risk schoolchildren. Monitoring alterations in these markers at an early stage of RHD is crucial for enabling prompt management and follow-up. It is thus evident that ECG can support an intermittent ambulatory RHD screening in resource-limited settings.

Given the widespread consumption of dairy products, adding fruit and vegetable processing pomace to them would contribute to the achievement of SDGs 2, 11, and 12, which are, respectively, about zero hunger with enhanced nutrition, sustainability, and environmental preservation through zero waste. Valorization of industrial pomaces could promote a circular economy in addition to successfully reducing or preventing diseases linked to the nutritional deficiencies. Because they possess nutritious and bioactive qualities, fruits and vegetables pomace are becoming great sources for enhancing dairy products. Therefore, the objective of this review is to comprehensively summarize and critically analyze the recent research findings dealing the inclusion of fruits and vegetables processing pomaces in the dairy products. Moreover, the impact of adding fruit and vegetable pomace on the rheological, physicochemical, nutritional, bioactive, antioxidant, and other quality characteristics of dairy products, such as cheeses, ice creams, butters, fermented milk, and yoghurts, is thoroughly reviewed in this work. From the findings, it has been discovered that adding fruits and vegetable pomaces to dairy products alters their physicochemical, textural, and sensory qualities. As a result, a notable increase in the dairy products' vitamins, minerals, carotenoids, fibers, polyphenols, and numerous other bioactive compounds has been observed. In conclusion, adding fruit and vegetable pomaces to cheese, butter, ice cream, whey, kefir, and yogurts not only increases their market share because of the high demand for food products that are rich in biologically beneficial and antioxidant-active compounds for an improved diet, but it also helps to manage the useful food industry waste.

Biochar, a low-cost, and carbon-rich product of the thermal decomposition of biomass under oxygen-limited conditions and at relatively low temperatures, has recently been identified as a promising porous material with a wide range of industrial applications. In the present study, a comprehensive analysis of proximate, ultimate, nutrient profile, structural, and textural properties of a biochar derived from two Ethiopian indigenous Brassica carinata cultivars was conducted. The characterization of the biochar was achieved by employing a variety of well-established methods, including proximate analysis (moisture, volatile matter, ash content, and fixed carbon), ultimate analysis (C, S, and O content), atomic oxygen to carbon ratio (O/C), morphological and elemental composition analysis through scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). Furthermore, a combination of mercury intrusion porosimetry (MIP), dynamic vapor sorption (DVS), and gas adsorption methods such as nitrogen and krypton gas adsorption, were used for an in-depth study of the porous structure. SEM morphological characterization showed that the biochar surfaces showed multiple pores of diverse sizes and shapes. EDS elemental composition analysis revealed that sodium, aluminium, and silicon were not detected, but potassium, calcium, magnesium, and iron were all present in noticeable amounts. Furthermore, ultimate analysis showed that the most prevalent elements were carbon (86 wt.%) and oxygen (10.41‒9.77 wt.%), while sulphur was present in negligible concentrations. MIP analysis demonstrated that the porosities of the biochars varied from 62.68 to 69.99 wt.%, with the Holetta-1 biochar showing the highest porosity. The superior porosity of Holetta-1, as confirmed via MIP analysis, yielded higher values for bulk volume (2.36 mL g− 1), skeletal volume (1.65 mL g− 1), and total intrusion volume (1.65 mL g− 1) compared to the Yellow Dodolla. The most frequent pore diameters were 172.46 μm for Yellow Dodolla and 111.42 μm for Holetta-1. The MIP log differential pore diameter distributions were observed to vary from 18 to 411 μm and 10 to 411 μm, respectively, for Yellow Dodolla and Holetta-1. Despite the biochars’ low specific surface areas (0.17–0.21 m² g⁻¹), krypton sorption was a suitable technique for its characterization compared to DVS and nitrogen sorption methods. In conclusion, the characterization studies confirmed that this carbon-rich porous material possesses unique and valuable properties, with these attributes position it as a promising alternative for diverse industrial applications, contributing to the development of a bio-based circular economy.

Klebsiella pneumoniae is a common pathogen responsible for various infections, with multidrug-resistant (MDR) strains increasingly complicating treatment. Phage therapy has shown significant potential in treating difficult bacterial infections; however, research specifically focused on phages targeting this bacterium remains limited. This study aimed to isolate and characterize lytic bacteriophages that target multidrug-resistant K. pneumoniae. Phages were isolated from 66 environmental samples through spot assays conducted on 10 multidrug-resistant strains. Phages were isolated via spot assays and purified via streak plating. Characterization included PCR-based identification and classification, determination of the latent period, efficiency of plating, burst size, stability testing, and evaluation of in vitro bactericidal activity. From a total of 660 spots tested against 10 multidrug-resistant (MDR) isolates, 102 phages were successfully isolated. These phages demonstrated individual lytic activity ranging from 8% (4/46) to 63% (29/46). PCR-based classification of the 60 bacteriophages identified six distinct virulent phage genera, with Taipeivirus being the most prevalent at 18.3% (11/60) and Webervirus the least common at 10.0% (6 out of 60). Stability assessments of pH and temperature demonstrated optimal activity between pH 5 and 9 and at temperatures up to 50 °C. These results endorse phage therapy as a viable alternative for treating MDR and hypervirulent K. pneumoniae infections. The data offer critical insights into local bacteriophage diversity and underscore its potential for developing targeted therapeutic agents. Genome sequencing, in vivo studies, and clinical trials are required to validate the efficacy and safety of these phages.