Iron Roof Research Articles

Examination of Housing Quality in The Peri-Urban Areas of Akure, Nigeria

Rapid urban population expansion, high living costs, and a need for affordable housing all encourage migration to Akure’s peri-urban districts. This drive has led to increased land utilization for housing development in peri-urban areas. This study evaluated housing quality in the peri-urban areas of Oba-Ile, Oda, and Ibule-Soro in Akure. Households were the unit of analysis, with one household head per building selected for questionnaire administration. Based on an average household size of five people per family and five households per building in Ondo State, the total number of households in the three locations was 47,110. From the 47,110 households, 800 households (1.7%) were randomly selected for the questionnaire administration. Data from the field survey were subjected to statistical analysis. The results revealed that some buildings were structurally unsound; most buildings had corrugated iron roofs and lacked sanitation infrastructure; and open defecation was commonplace, particularly in Ibule-Soro. These findings call for better urban planning and investment in basic amenities to improve housing quality and living standards in peri-urban areas.

Steel Production Process in CV. Tiga Putra Jaya Sejahtra

The construction services business is an activity in the economic, social and cultural fields which has an important role in achieving various targets to support the realization of national development goals. CV. Tiga Putra Jaya Sejahtra is a company engaged in the steel construction industry which provides the manufacture of fences, trellises, balconies, canopies, stair railings, rolling doors, children's toys, folding doors, light steel, galvalume, water towers, iron roofs. The purpose of this The implementation of this activity is to observe the production process of making hollow fences and the result of this activity is to find out how long it takes to make hollow fences, the costs that will be needed and the preparation of the BOM for hollow fences.

ANALYSIS OF THE IMPACT OF CAMEROUN ZINC, STONE-COATED TILES, ASBESTOS, CORRUGATED IRON ROOFS AND GALVANIZED IRON TANK ON HARVESTED RAINWATER IN SOUTH-SOUTH, RIVERS STATE, NIGERIA USING WATER QUALITY INDEX

Harvested rainwater has shown lots of benefits in the universe including providing water in remote areas for their approximately safe usage and it also supports the global water demands due to inadequate amount of water supply for utilization. This present study was aimed at analyzing the impact of various roofing materials, galvanized iron tank and industrial activity on rainwater quality by determining the physicochemical characteristics, bacteriological properties and the metal composition of the roof types and storage medium. Rainwater was harvested from Cameroun zinc, stone-coated tiles, asbestos, corrugated iron roofs run-offs, and stored rainwater in galvanized iron tank and directly from the sky (control) in the urban and rural areas of Rivers State between the months of April-July, 2018. The results will be compared with the standards (NAFDAC, USEPA, WHO and NSDWQ) for drinking water quality and Water Quality Index (WQI) ratings since there is no standard for rainwater quality. Roofs ages from <5, 5-10, 15-20, and >25 years in service conditions and stored rainwater in storage vessels for the duration of one year and above were considered. Heavy metals were analyzed using Flame-AAS; other parameters were analyzed using standard methods. The WQI ratings were calculated using the weighted arithmetic method. Results obtained in both areas gave mean values ranging from 6.10-6.90 for pH, Temp., (20.00-28.00 oC), EC (17.00-132.00 µ?/cm), E. coli (no detection). Other results (mg/L) were; TDS (15.50-71.67), TSS (19.00- 84.67), Pb (0.00-0.23), Cr (0.00-0.12), Zn (0.01-0.03), Fe (0.01-0.22) and Al (0.00-1.61).The WQI ratings gave excellent water to unfit for drinking water quality in both areas. Generally, harvested rainwater is not free of contaminations because of its catchment/storage systems due to atmospheric pollution and leaching of the roofing material; hence, it should be treated before being used for domestic and potable usages.

Building Paper arrives in New Zealand

Building paper, invented in Beloit, Wisconsin in 1869, arrived in New Zealand in the late 1880s. In 1891 it was used under the corrugated iron roof and walls in the four-bed Tasman Glacier Hut where it would have provided relief from condensation on the inside of the corrugated iron as well as reducing the ability of the wind to blow through the hut. Building paper quickly became common place, with advertising from English and American manufacturers appearing daily newspapers as well as trade journals. The paper traces the first decades of building paper use in New Zealand as it evolved from a novelty to a common building product – hidden under the cladding but improving on the comfort of the occupants. It ends with a brief foray into the twentieth century, with examples of its use and eventual inclusion in building controls starting with NZSS 95 Part IX: Light Timber Construction:1944.

DETERMINATION OF THE LEACHING TENDENCIES OF VARIOUS ROOFING SHEETS MODELLED AS RAIN WATER HARVESTERS IN IMO STATE NIGERIA

Runoff rain water from roofing materials is a predominant channel for obtaining drinking water for most inhabitants in Imo State Nigeria as such water is even kept in storage tanks for later usage.. Analysis of four different roofing materials used in the area- Zinc, Aluminum Metro tiles and Galvanized iron roofing sheets (Zinc) was carried out to determine their chemical content and leaching abilities. 5gms of each sheet was separately ground to powder and elemental analysis using a compact multi-element bench top Energy Dispersive X-ray Fluorescent (EDXRF) EDX3600B by Skyray Instrument (precision: 0.0% deviation; detection limit: 0.0001% (1ppm) - 99.99%) was carried out. The research showed the metro tile roofing sheet contains toxic metals like lead; Pb(0.0962 mg/kg), Al (2.1380 mg/kg), Cr (0.1988 mg/kg) and Mn(0.2163 mg/kg) unlike the rest which roughly contain Al (1.0407 mg/kg), Zn (0.9000 mg/kg), Mn(0.1057 mg/kg) and Fe (1.0008 mg/kg). Leaching capability of the four sheets was determined.Rainwater was harvested into clean plastic container previously washed and rinsed severally. Simple leaching experiment was carried out. The sheets were cut into sizes of (4 by 4)cm and the surface areas measured. Each was introduced into a separate beaker with 150ml rainwater (mentioned) for 24 hours. The sheets were then removed from the rainwater and their surface areas re-measured. The resultant waters and the unused rainwater- the control, were analysed using Agilent 240 AA Atomic Absorption Spectrophotometer. The result detected that the metro tile roofing sheet decreased by 0.01cm in its surface area and was observed to have leached out Al (0.028mg/kg) and Pb(0.0060mg/kg) into the water. This can be hazardous by accumulation if proven.More work on this is still in the pipeline.

Hygiene Practices, Water Supply, Sanitation, and Childhood Diarrhoea in Resource-Poor Settings of Rural Central Tanzania: A Mixed-Method Study

Diarrhoeal diseases are associated with high morbidity and mortality, especially in children less than five years of age in many low- and middle-income countries (LMICs). This cross-sectional convergence mixed-method study explored water, sanitation and hygiene challenges as the important contributors to childhood diarrhoea in rural Tanzania. The study involved questionnaire survey (N=340), key informant interviews (KII) (n=10) and eight focus group discussions (FDG) (n=61). Prevalence of diarrhoea was 22.2% and 18.7% in Sanza and Iwondo Wards, of Manyoni and Mpwapwa Districts respectively. Improved houses (iron roof and baked brick walls) were more common in Sanza, while 80% of the houses in both wards had earth floor. Water sources in dry period and frequency of sharing water sources with animal were significantly different between wards (P<.001). Boiling drinking water was uncommon, practised by only 5.2% and 8.6% of the households in Sanza and Iwondo, respectively. More than 95% of the households in both wards used traditional pit latrines, and latrine sharing was more common in Iwondo than in Sanza (P=.035). The themes from KII and FGD were: knowledge of occurrence and causes of diarrhoea, water safety, hand-washing, availability of improved sanitation services, keeping chickens inside the house overnight, health effects associated with keeping chickens inside the house and knowledge of occurrence and causes of diarrhoea. Mixed methods analysis through merging data sets revealed poor community knowledge on the causes of childhood diarrhoea, ineffective hand washing, seasonal variation of drinking water sources and high human-chicken interactions. Prevention and control of gastrointestinal infections in resource-poor settings should promote the use of cheap and locally available resources and feasible practices in response to the existing challenges related to water and sanitation services, financial constraints, economic activities, and cultural practices.

Substitution of Soybean Meal with Fermented Kapok Seeds and its Effect on the Growth Performance and Nutrient Digestibility of Sheep Raised in Stall with Palm Leaf and Galvanized Iron Roofs

Substitution of Soybean Meal with Fermented Kapok Seeds and its Effect on the Growth Performance and Nutrient Digestibility of Sheep Raised in Stall with Palm Leaf and Galvanized Iron Roofs

Application of encapsulated and immobilized nano zero-valent iron for iron removal from roof-harvested rainwater

Abstract Rainwater harvesting is a viable option for dealing with the global challenge of increasing water scarcity, but heavy metal contamination often prevents it from being widely used for drinking water purposes. Harvested rainwater collected from galvanized iron (GI) and tile roofs containing iron concentration of 0.46 and 0.38 mg/L respectively, were treated by two nano sorbents, CaCO3-nZVI and PUF/CaCO3-nZVI with the intention of making the iron concentration conform to drinking quality standards. The nano sorbents were synthesized and characterized using BET (Brunauer-–Emmett–Teller surface area), SEM-EDX (Scanning Electron Microscopy-Energy-Dispersive X-ray spectroscopy, and FTIR (Fourier Transform Infrared Spectroscopy). CaCO3-nZVI achieved iron removal efficacy of 88.69% and 89.21% for harvested rainwater from GI sheet roof and tiled roof respectively and the efficiency increased to 95.65% and 95.78% when treated with PUF/CaCO3-nZVI. In addition, the nano sorbents were found to have appreciable removal efficiency for other metals (Pb, Mn, Zn, Cu, Cd and Cr) present in the collected rainwater. The use of FTIR and EDX to characterise spent nano sorbents divulged that the iron was removed through sorption process. This study thus explored the potential of CaCO3-nZVI and PUF/CaCO3-nZVI for treating heavy metal contamination in roof-harvested rainwater.

Performance of Bombyx mori and Samia cynthia ricini silkworms under controlled environmental conditions in Uasin Gishu County

The domesticated silkworm Bombyx mori and Eri worm (Samia cynthia ricini) are bivoltine and multivoltine, feeding exclusively on mulberry and castor leaves, respectively. The domestication of silkworms has made them highly sensitive to fluctuations in temperature and relative humidity. The research determined the performance of silkworm reared inside pre-constructed structures with equal dimensions (4 m x 4 m x 3 m height), with iron roof; timber walled (L1) and mud walled (L2). Greenhouses with four flaps open (L3), three sides open (L4), two sides open (L5), one side open (L6) and completely enclosed (L7), and concrete walled (L0) were used. The survival percentage, larval duration and cocoon quality and quantity were tested and compared. The temperature and relative humidity were recorded. The mean temperature of structures during rearing ranged between 22.73 °C±1.86 (L0) and 31.63 °C±0.81 (L7) during the wet season with a similar trend in the dry season, the mean relative humidity of 33.26%±7.29 (L1) and 43.18%±9.53 (L0) during the wet season and 33.11%±7.27 (L1) and 42.16%±7.38 (L7). Larval duration was longest in L2 for both B. mori and Eri during the wet season. Larval survival was highest in L2 (76.73±4.20%) and L0 (78.70%) during the wet and dry season respectively. A similar trend obtained in L2 (77.00%) and L0 (80.10%) for Eri in wet and dry season respectively. The cocoon weight was highest in structure L2 (0.86±0.03) during the dry season, L5 (2.78±4.30) during the wet season. Eri cocoon weight was highest in L0 (2.35±0.49) during the wet season and highest in L3 (2.44±0.34) in the dry season. The longest significantly different Filament length for B. mori was in L2 (1377.80±150.17 m). During the dry season L3 (1382.80±117.23m) was the longest. For the Eri the longest filament length was from L2 (437.6±32.26). The seasons did not influence average survival, filament length and weights from the tested structures.

Development of Eco-Responsible Thermal Comfort Designs for the Valorization of the Traditional Malagasy House

This study aims to provide any assistance in the design of a green thermal comfort solution that is aware of the current climate change and considers sustainable development. This concept is helpful to the environment and offers a possibility of popular use. The process results are reproducible to a maximum of eventuality in the thermal building field, but in this article, we discussed the cases of Malagasy thatched cottage with envelope in mud and roof in thatch and the case of an ordinary house of the popular Malagasy mass, with fired clay brick envelope, cement coating, galvanized corrugated iron roof. The approach is as follows: locate the study area, analyze the scenarios of ecological thermal solutions, carry out the heat balances according to the scenarios, and classify the optimal solution. To do this, METEONORM is used for geographical location, the heat balance is carried out using the THERMEXCEL tool, and the multi-criteria analysis is made by the PROMETHEE tool in the educational version.

Investigation of the Effects of the Classification of Building Stock Geometries Determined Using Clustering Techniques on the Vulnerability of Galvanized Iron Roof Covers Against Severe Wind Loading

In the risk assessment of buildings against severe wind loading, the vulnerability component of risk is highly affected by the geometry of the structure. Parameters such as the height, width, length, aspect ratio, eaves length, and roof slope, affect the pressure distribution around the structure, which in turn affects the response of galvanized iron (GI) roof covers to wind loadings. In developing countries, there is a large variation in the building geometric parameters which poses a challenge in determining the archetypes that would best represent the building population for risk assessment. This paper aims to develop and propose a method in determining the building archetypes based on its geometry. The hierarchy for grouping of geometries started with the roof type. These were gable type roofs, mono-slope type roofs and hip type roofs. The building datasets per roofing type were then clustered using a two-stage approach involving Hierarchical and K-means clustering which were based on the aforementioned geometric parameters. These algorithms will aggregate buildings having similar sets of geometric parameters but the number of clusters must be specified. In order to determine the optimal number of clusters, this study employs various validation tools or measures namely – dendrograms, variation of the variance ratio criterion (VRC) across number of clusters, validity indices such as, Davies Bouldin, Silhouette and Calinski Harabasz, and the elbow method. Although guided by these validation methods, the final selection of the number of clusters were determined considering computational time and resources. To define an archetype, the mean values of each parameter per cluster were selected. Resulting to 5, 3, and 3, archetypes for gable, hip, and mono-slope roof buildings, respectively. The selection of the archetype was further evaluated by investigating its effects on the vulnerability of GI roof covers in order to see how distinct each archetype would behave. A Kruskal Wallis test on the vulnerability curves of the different building archetypes showed that there is a significant difference between vulnerability curves under a roof shape category, which reinforces the distinction between the selected building archetypes.

Characterization of women and youth smallholder agricultural entrepreneur’s in rural irrigation schemes in Vhembe district, South Africa

The purpose of the study was to characterize irrigated smallholder agricultural enterprises (ISAEs) in selected areas of Vhembe District, Limpopo Province. The characterization focused on the geophysical environment and on participants in ISAEs. Precipitation was at most 460mmpa for villages along Madimbo Corridor and 701-1380mmpa for those along Mutale Valley, and temperatures were 38.1℃-44.0℃ (Madimbo) and 30.0℃-40.0℃ (Mutale). Groundwater supplemented surface water and was utilized more at Madimbo Corridor compared to Mutale Valley. The study area was characterized as semi-arid to sub-humid, hence technologies for efficient irrigation should be promoted. Participants in ISAEs were female (94.9%), and adult (52.72%) with low education levels (67.7% ≤ secondary education). The majority (88.65%) were not formally employed (54.61% self-employed, 34.04% full-time farmers). Participants experienced some level of poverty, 68.03 percent received low household incomes (R1001-R5000/month), 77 percent received social grants. Interestingly, the majority (65.31%) stayed in multiple-roomed houses, had cement brick walls, and corrugated iron roofs (54.42%), and all had electricity, a stove, and a fridge. Also, majority-owned radio (96.67%), DSTV (87.45%), vehicles (65.56%), and cellphones. Participants mostly provided adequate food supply (91.84%) with three meals/day (79.38%) except during hard times where 49.56 percent provided fewer meals mostly due to delayed readiness of farm produce. Strategies to empower ISAE participants to be more effective should consider their gender, age, education, and economic status estimated by income, asset ownership, and food security.

Old age is associated with decreased wealth in rural villages in Mtwara, Tanzania: findings from a cross-sectional survey.

ObjectiveIn many countries, housing is used for wealth accumulation and provides financial security in old age. We tested the hypothesis that household wealth, measured by housing quality and ownership of durable assets, would increase with age of the household head.MethodsWe conducted a survey of household heads in 68 villages surrounding Mtwara town, Tanzania and recorded relevant demographic, housing and social characteristics for each household. The primary analysis assessed the relationship between age of the household head, quality of the house structure and socio‐economic score (SES) using multivariate analysis. Principal Components Analysis (PCA) was used as a data reduction tool to estimate the social‐economic status of subjects based on relevant variables that are considered as proxy for SES.ResultsOf 13 250 household heads were surveyed of whom 49% were male. Those at least 50 years old were more likely to live in homes with an earth floor (86%) compared to younger household heads (80%; P < 0.0001), wattle and daub walls (94% vs. 90%; P < 0.0001) and corrugated iron roofs (56% vs. 52%; P < 0.0001). Wealth accumulation in the villages included in the study tends to be an inverted V‐relationship with age. Housing quality and SES rose to a peak by 50 years and then rapidly decreased. Households with a large number of members were more likely to have better housing than smaller households.ConclusionsHousing plays a critical role in wealth accumulation and socio‐economic status of a household in rural villages in Tanzania. Households with a head under 50 years were more likely to live in improved housing and enjoyed a higher SES, than households with older heads. Larger families may provide protection against old age poverty in rural areas. Assuring financial security in old age, specifically robust and appropriate housing would have wide‐ranging benefits.

Parametric strategy on passive design affordances in cool-humid climate zones of North-East India

Buildings often have fixed function spaces that are complimentary or incompatible with thermal comfort (18–28 °C). Synergetic relationships ameliorates energy shortage and affords comfort. Galvanized iron roof two-storey houses of North-East India were studied to develop a theory-and-strategy to optimize design process and energy conservation. Methods include affordance theory criticism, surveys, simulations, synergy analysis. Parametric strategy on passive design affordances examines human comfort and temperature on diurnal time scales: Daytime (08–17 h), Evening (17–22 h), Night (22–08 h) in various seasons. Under flexible ventilation, living-dining space (S1) shows optimum temperature ranges: 20–28 °C in autumn (M1), 17–22 °C in winter (M2), and 20–31 °C in summer (M3) due to the complementary combination of passive design elements and can function as bedroom, living-room, kitchen, and social space in most seasons. In the attic-space flexible ventilation shows peak temperatures of 42 °C (autumn) and 48 °C (summer) due to low thermal mass but high thermal conductivity envelopes, and low air-changes rate (0.5 ACR) above 28 °C. Normal ventilations with 30 ACR in autumn, and a combination of 30 ACR (night) and 0.5 ACR (day) in summer reduced maximum temperature to ≤35 °C in autumn, and ≤41 °C in summer. Attic-space (S2) shows ≤29 °C in winter daytime and ≥20 °C in summer nights due to the envelope’s high heat emissivity (0.8) and function as day space in winter and summer bedroom. Shaded veranda (S3) shows low temperature (18–28 °C) in summer evening and afternoon and can function as shaded space for light work and enjoying fresh air. Passive design connotes responsiveness of spaces to the climate, and affordance theory’s complementarity lifestyle adds novelty, and it is critical to energy and space efficiency. Climate analysis affords perceptions of space and climate relationship. Parametric strategy straddles differences between space, climate, and functions to ameliorate energy needs and optimize design process.

Honor among Chiefs: An Experiment on Monitoring and Diversion Among Traditional Leaders in Malawi

Traditional, hereditary chiefs are an integral part of the development infrastructure in many African countries. To capture chiefs’ behaviour as agents of development and understand the accountability mechanisms they face, we conduct a field experiment with 200 Malawian village chiefs, documenting how they distribute a valuable development good – iron roofing sheets – as we sequentially add monitoring by donors, subjects, and the state. We find evidence that even in the absence of formal accountability institutions, chiefs are responsive to monitoring by all principals. However, principals have competing demands: while most principals prefer allocations based on need as classified by the local community, a subset of the chief’s subjects – his relatives – prefer to receive sheets themselves, regardless of need. When subjects are informed about the availability of sheets, relatives are able to capture allocations, overriding other principals and causing discontent. Altogether, diversion is minimised when chiefs are monitored by the donor, and only the donor. When chiefs are monitored by all their principals simultaneously, diversion is not significantly lower (compared to control), but dissatisfaction among subjects is greater. This study adds to the literature on chieftaincy and highlights the role of common agency in the design and analysis of development interventions.

The extent and structure of pig rearing system in urban and peri-urban areas of Guwahati

ABSTRACT Livestock is common in Indian cities and contribute to food security as well as livelihoods. Urban livestock keeping has been neglected, and in India, little is known about the topic. Therefore, urban and peri-urban pig farms of Guwahati, Assam, India, were surveyed in order to understand more about the pig rearing systems and risks of diseases. A total of 34 urban and 66 peri-urbanpig farms were selected randomly. All reared cross-bred pigs. Free-range pig rearing was common in both urban (58.8%) and peri-urban (45.45%) farms. Artificial insemination was used by around half of the pig farmers. Disinfection in pig farms was practiced in 26.5% of urban and 28.8% of peri-urban farms. More urban pig farms were observed to be moderately clean in (82.4%) compared to peri-urban (69.7%). However, more urban (67.7%) than peri-urban farms (57.6%) reported ahighrodent burden. Pig sheds were mostly basic, with bricked floors in 18.2% farms in peri-urban areas, and more than 80% had corrugated iron roofing sheets. In conclusion, free-roaming pigs in both urban and peri-urban areas of Guwahati can contribute to disease transmission, and the low standard of hygiene and buildings may further increase the risk of diseases.

Arsenic contamination in rainwater harvesting tanks around Lake Poopó in Oruro, Bolivia: An unrecognized health risk

Drinking water sources used by largely rural and indigenous communities around Lake Poopó in the Bolivian Altiplano are impacted by drought and a combination of natural and anthropogenic mining-related contaminants putting the long-term health and sustainability of these communities at risk. As an alternative drinking water source, 18 rainwater harvesting tanks connected to corrugated iron roofs, each with a first-flush system, were installed in 5 communities around the lake. The water quality of these tanks was monitored over 22 months and compared to alternative unprotected surface and groundwater sources the communities previously relied upon. The rainwater quality was found to be within the Bolivian and World Health Organization (WHO) limits, except for elevated arsenic concentrations two times the recommended health limit (0.01 mg/L). Tracing arsenic concentrations through the rainwater flow-path showed that the elevated arsenic concentrations result from mineral dust particles entering the system when rainwater interacts with the roof catchment, with arsenic leaching out. A leaching test showed that 24 h of contact time between 200 mL of water and <1 g of roof dust is enough to raise the arsenic levels of the water above the Bolivian and WHO limit. Currently, no other research exists evaluating the quality of harvested rainwater in the Bolivian Altiplano for human consumption or the source of arsenic in harvested water. This represents a significant knowledge gap for future development practitioners and programs addressing water security around Lake Poopó and the wider region. As a result, it is strongly recommended to include arsenic as a standard parameter in water quality monitoring of rainwater harvesting projects, especially in active mining regions, and to optimize strategies to minimize roof dust from entering the collection system.

Effects of roofing materials on harvested rain water quality

The effects of roof materials (corrugated iron, aluminum and asbestos) on the quality of harvested rainwater were evaluated in this study. The physical, chemical and bacteriological characteristics of rainwater collected from the different roof materials were analyzed and the results compared with WHO standard for potable water. The results of the physical analysis revealed that the colour, turbidity, total solids and total dissolved solids fell within WHO acceptable standards for potable water. Also, the calcium and magnesium hardness as well as nitrate and sulphate content of the sampled water fell within WHO permissible limits. The results, however, showed that harvested rain water within the study area is slightly acidic with average pH values of 6.13, 6.25 and 6.15 respectively for the corrugated iron, aluminum and asbestos roof materials respectively. The water samples analyzed had traces of Lead and Iron with average values of 0.605mg/L and 0.715mg/L of Lead as well as 0.38mg/L and 0.52mg/L of Iron for the corrugated and asbestos roof materials respectively. These values exceeded the WHO permissible limits of 0.01mg/L and 0.3mg/L for Lead and Iron respectively. The microbiological indicators assessed showed no detection for E. coli , while the total heterotrophic plate and total coliform counts fell within permissible limits. However, the presence of heavy metals (iron and Lead) in the rainwater samples in concentrations that exceed WHO permissible limits is an indication of high contamination of the water samples, hence, it is recommended that the rainwater samples should be suitably treated before human consumption. Keywords: roof materials, harvested rainwater, permissible limits, human consumption

Hidden Above Church Vaults: The Design Evolution of Early Iron Roof Trusses in Mid-Nineteenth-Century Belgium

ABSTRACTThis article sets out to assess the first phase of iron roof construction in Belgian churches, from the 1840s to the 1860s, and the evolution of iron roof structures in this period, through an in-depth analysis of four case studies, located in Brussels, Antwerp, and Ghent. The article is based on fieldwork as well as archival and literature research. The cases are contextualized within the architectural, technical, political-economic, and intellectual environment of the time when structural iron was introduced in Belgium: a country that industrialized at an early date, with an iron industry that developed rapidly. The Belgian findings are put into an international perspective. By providing new insights into the early use of iron and the evolution of new construction principles in churches, this study seeks to encourage researchers, architects, and heritage assessors to climb above the vaults of churches and consider the hidden roof structures with greater care.

Dramatic decreases of malaria transmission intensities in Ifakara, south-eastern Tanzania since early 2000s

BackgroundOngoing epidemiological transitions across Africa are particularly evident in fast-growing towns, such as Ifakara in the Kilombero valley, south-eastern Tanzania. This town and its environs (population ~ 70,000) historically experienced moderate to high malaria transmission, mediated mostly by Anopheles gambiae and Anopheles funestus. In early 2000s, malaria transmission [Plasmodium falciparum entomological inoculation rate (PfEIR)] was estimated at ~ 30 infectious bites/person/year (ib/p/yr). This study assessed the PfEIR after 15 years, during which there had been rapid urbanization and expanded use of insecticide-treated nets (ITNs).MethodsRandomly-selected 110 households were sampled across Ifakara town and four adjacent wards. Mosquitoes were trapped nightly or monthly (June.2015–May.2016) using CDC-light-traps indoors, Suna® traps outdoors and human landing catches (HLC) indoors and outdoors. All Anopheles mosquitoes were morphologically identified and analysed by ELISA for Plasmodium circumsporozoite proteins. Mosquito blood meals were identified using ELISA, and sub-samples of An. gambiae and An. funestus examined by PCR to distinguish morphologically-similar siblings. Insecticide resistance was assessed using WHO-susceptibility assays, and some Anopheles were dissected to examine ovariole tracheoles for parity.ResultsAfter 3572 trap-nights, one Plasmodium-infected Anopheles was found (an An. funestus caught outdoors in Katindiuka-ward by HLC), resulting in overall PfEIR of 0.102 ib/p/yr. Nearly 80% of malaria vectors were from Katindiuka and Mlabani wards. Anopheles gambiae densities were higher outdoors (64%) than indoors (36%), but no such difference was observed for An. funestus. All An. funestus and 75% of An. gambiae dissected were parous. Anopheles gambiae complex consisted entirely of Anopheles arabiensis, while An. funestus included 84.2% An. funestus s.s., 4.5% Anopheles rivulorum, 1.4% Anopheles leesoni and 9.9% with unamplified-DNA. Anopheles gambiae were susceptible to bendiocarb and malathion, but resistant to pyrethroids, DDT and pirimiphos-methyl. Most houses had brick walls and/or iron roofs (> 90%), and 52% had screened windows.ConclusionMalaria transmission in Ifakara has decreased by > 99% since early-2000s, reaching levels nearly undetectable with current entomological methods. These declines are likely associated with ITNs use, urbanization and improved housing. Remaining risk is now mostly in peri-urban wards, but concerted efforts could further decrease local transmission. Parasitological surveys are required to assess actual prevalence, incidence and importation rates.