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Effects of strain and inter-pass time on the restoration behavior of 436 stainless steels
(Springer, 2025-11) Salojee, Muhammed Yusuf; Siyasiya, Charles Witness; Annan, Kofi Ahomkah; Moema, Joseph S.; u13271050@tuks.co.za
Ferritic stainless steels (FSSs) are viable alternatives to nickel containing austenitic stainless steels. The AISI 436 FSS grade is fully ferritic at all temperature ranges, and therefore, grain refinement can only be achieved through controlling inclusions during solidification and/or recrystallization. In this work, the effects of strain and inter-pass time on the restoration behavior of 436 were systematically investigated using the Gleeble 1500 thermomechanical processing simulator. The aim of the study was to promote the accumulation of strain by delaying recrystallization during roughing rolling simulation to improve the driving force for recrystallization during finishing rolling simulation at lower temperature. Three roughing rolling schedules were designed, i.e., the first simulated the existing industry practice (Control), the second with increased inter-pass time (INT) and the last with both increased inter-pass time and strain per pass (INT + S). Roughing and finishing were each simulated in three-passes, amounting to a total of six-passes. The SEM-EBSD results revealed that the Control and INT schedules resulted in higher strain localization, particularly around particles. On the contrary, the increased inter-pass times and strains (INT + S) led to less strain accumulation. Annealing after roughing rolling simulation led to the nucleation of fine grains in the Control, which suggests that delaying finishing rolling would promote recrystallization and the breakdown of the cast structure.
Microstructure and mechanical properties evaluation of high Ti-V microalloyed steel after coiling process at different temperatures in a hot strip rolling simulation process
(Springer, 2025-08) Jafarpour Rezaei, Seyed Reza; Siyasiya, Charles Witness; Tang, Zhenghua; Moema, Joseph
Today, reducing greenhouse gas emissions is a crucial concern, making the development of steel alloys with optimal desired properties and reduced weight an urgent priority, especially in automotive industries, as it leads to decreased fuel consumption, hence the continued interest in developing high-strength low-alloy steels (HSLA). In this research, the impact of coiling temperature on the final microstructure and mechanical properties of Ti-V HSLA microalloyed steel was investigated. The Gleeble 1500 was used to simulate the hot rolling and coiling processes. The results indicated that reducing coiling temperatures led to a transition in microstructures from polygonal ferrite and pearlite to acicular ferrite and bainite. The optimal coiling temperature for achieving high diffusion rates of microalloying elements and optimal precipitation kinetics to form nanosized precipitates was determined to be 650 °C, where the smallest precipitates were observed of 30 nm. However, the specimen subjected to a lower coiling temperature of 550 °C exhibited the highest yield stress (781 MPa), ultimate tensile strength (971 MPa), and hardness (324 HV), which were attributed to microstructural characteristics such as high dislocation density and a finer grain size of 3 µm compared to 6 µm at 700 °C.
Tuning optoelectronic properties of CsPbI2Br perovskite films via octadecyl ammonium iodide substitution
(Springer, 2025-11) Thubane, Sandile Job; Nombona, Nolwazi; Diale, M. (Mmantsae Moche); mmantsae.diale@up.ac.za
Please read abstract in the article.
Biosecurity practices and their determining factors in commercial layer chickens in selected regions of Tanzania
(BioMed Central, 2025-10) Mdemu, Siha; Matondo, Augustine B.; Christensen, Jens Peter; Amasha, Ahmed E.; Ngowi, Helena Aminiel; Westwood, Erica; Ochai, Sunday Ochonu; Nonga, Hezron Emmanuel; Osbjer, Kristina; Mdegela, Robinson Hammerthon
INTRODUCTION : Biosecurity measures are crucial for controlling infectious diseases in poultry farms. It involves all measures aiming at preventing disease-causing agents from entering the farm (external biosecurity) and those measures practiced with the aim of preventing the spread of disease-causing organisms within the farm (internal biosecurity). However, their implementation is often limited in low-income countries due to various factors such as socioeconomic challenges, farming practices and limited resources. The aim of this study was to explore the current biosecurity levels and their related factors in commercial layer chicken farms.
METHODS : We conducted a cross-sectional survey of 203 randomly selected commercial layer farms with ≥ 200 birds across Dar es Salaam (n = 154), Morogoro (n = 28), and Unguja (n = 21) regions from March-June 2023. Biosecurity practices were scored using an adapted Biocheck.UGent™ tool (0-100 scale). One-way Analysis of Variance (ANOVA) and t-tests were used for comparing biosecurity scores across groups when data met normality assumptions, while the non-parametric Kruskal-Wallis (K-W) H test and Mann-Whitney (M-W) test served as alternatives when the normality assumption was not met. Further, we used multiple linear regression to identify factors associated with biosecurity implementation; with results reported as standardized beta coefficients (β) and 95% confidence intervals.
RESULTS : Mean biosecurity scores were significantly (p < .001) below global benchmarks with overall biosecurity 58.2 ± 8.6, external biosecurity (preventing disease entry) at 60.5 ± 8.7 and internal biosecurity (preventing disease spread within the farm) at 52.9 ± 14.5 compared to global averages of 72%, 67% and 77% respectively. The average external biosecurity scores was significantly lower in farms supervised by farmers with primary education (57.8 ± 7.9) than both those under farmers with secondary education (61.3 ± 9.3, p = .042) and tertiary education (62.1 ± 8.2, p = .019). Farm experience of > 2 years significantly improved internal biosecurity practices (55.0 ± 14.6 vs. 47.0 ± 12.9, p = .002). Further, large-scale operations demonstrated superior internal biosecurity compared to small-scale farms (63.1 ± 16.4 vs. 51.5 ± 12.8, p = .002). Multiple regression analysis (F₇,₁₉₅=2.279, p = .030, R²=0.076) revealed that secondary education (β = 0.224, 95% CI: 1.03–6.73, p = .007) and tertiary education (β = 0.209, 95% CI: 0.82–7.20, p = .014) were independently associated with higher biosecurity scores compared to primary education.
CONCLUSION : This paper provides the first assessment of biosecurity implementation in commercial layer farms in Tanzania comparing it with global benchmarks. Biosecurity implementations were largely influenced by three key factors; education level, scale of production, and farming experience. These findings indicate that tailored interventions and evidenced-based policies are essential for strengthening biosecurity practices, and potentially enhancing poultry health and productivity in layer farms.
Molecular characterisation of tick-borne pathogens in cattle in Kenya : insights from blood, ticks, and skin swab analyses
(BioMed Central, 2025-10) Getange, Dennis; Mukaratirwa, Samson; Bargul, Joel L.; Khogali, Rua Khogali Ibrahim; Ng'iela, John; Kabii, James; Masiga, Daniel K.; Villinger, Jandouwe
BACKGROUND : Ticks pose a major threat to livestock and human health in sub-Saharan Africa, with climate change and pastoral movements fueling their spread. Few studies have integrated multiple sample types to characterize tick-borne pathogens (TBPs) in cattle in Kenya. This knowledge gap hinders the development of effective surveillance and control strategies, leaving vulnerable populations and their livestock susceptible to these persistent threats.
METHODS : We screened 280 bovine blood samples, 589 tick pools, and 284 non-invasive skin swabs from cattle in northern (Marsabit) and southern (Kajiado) Kenya by high-resolution melting analysis and Sanger sequencing of PCR products.
RESULTS : Rhipicephalus spp. (47.1%), Hyalomma spp. (30.8%), and Amblyomma spp. (22.1%) were prevalent, with Rhipicephalus evertsi only found in Kajiado and Rhipicephalus camicasi in Marsabit. In blood, Anaplasma spp. (62.9%; A. marginale, A. platys, A. ovis) and Theileria spp. (34.6%; T. velifera, T. mutans) were dominant. Tick pools harbored Coxiella burnetii, Rickettsia africae, Rickettsia aeschlimannii, Anaplasma marginale, Theileria velifera, T. ovis, and Babesia occultans, and for the first time two co-circulating Ehrlichia ruminantium strains (Welgevonden and Kumm2). Notably, C. burnetii and T. ovis were detected only in Marsabit, and T. mutans only in Kajiado. Skin swabs from tick predilection sites (ears, anal region) yielded R. africae, R. aeschlimannii, and T. velifera at low positivity, while nose swabs were negative.
CONCLUSIONS : Detection of zoonotic pathogens such as C. burnetii and R. africae underscores critical public health risks, and co-infections in cattle reinforce the need for robust, integrated surveillance. Although skin swabs demonstrated limited diagnostic yield, they remain a promising non-invasive sampling approach. These findings highlight the value of targeted acarological research and coordinated control programs under a One Health framework.