Low Dwellings Research Articles

Microstructural Effects on Thermal-Mechanical Alleviation of Cold Dwell Fatigue in Titanium Alloys

Cold dwell fatigue is a well-known problem in the titanium components of aircraft engines. The high temperature and low dwell stress of in-service conditions have been reported to give rise to dwell fatigue resistance through a thermal-mechanical alleviation process. Here, dwell fatigue tests at room temperature and the component operating temperature were performed on IMI834 titanium alloy to assess the microstructural effects on thermal-mechanical alleviation of cold dwell fatigue while eliminating the effect of chemical composition. The ratcheting strain rates under different loading conditions were quantitatively investigated to aid the understanding of thermal-mechanical alleviation.

Dwelling Affordability from Theory to Practice: The Use of Earth as Indigenous Building Material for Sustainable Development Amidst Post Covid-19 Situation in Nigeria

Driven by urbanization and demographic growth in Nigeria, the estimated cost for low cost dwelling unit is very expensive, because of high cost of conventional building material. Indigenous building materials abound in our various locations and communities in our nation, in the olden days dwelling place were never an issue as man could make or create a dwelling place for himself and his family with available indigenous resources. He uses local materials such as earth, timber, bamboo, stone, thatch, bush rope, etc with one or two assistant and able to put together a dwelling to accommodate his activities. The paper examined earth as indigenous building materials and assessing local building cultures with earth for resilience and sustainable development for dwelling affordability in Nigeria. Also, it generates a practical guide for community-based assessment of earth material fortification without compromising the durability. The sustainability solution of earth as building material were discussed which include local employment opportunity for socio economic development among others. The paper then concludes on some sustainability strategies known with the earth over the year as productive and effective building material.

‘We would like this place to be a town’: The benefits and challenges of rural development near protected areas

The degree to which African small town development poses a challenge to conservation near protected areas remains understudied. Low levels of economic development limit the ability to investigate and theorize how rural populations alter the built environment as incomes rise. This studyexamined the spatial and temporal dynamics of dwelling construction in two Mozambican villages located near Limpopo National Park where rhino poaching has financed rapid rural development. We analyzed 495 photographs of the built environment and 110 semi-structured interviews occurring over a six-year period (2009–2015) corresponding with increased rhino poaching. We find a rapid and exponential increase in dwellings rebuilt or renovated exclusively with finished construction materials, a process we refer to as upgrading. Exposure to upgraded dwellings corresponds with positive assessments of community-wide development, even for individuals not living in these dwellings. Residents of neighborhoods with the least upgrading were most likely to discuss low quality dwellings as diminishing human dignity. Taken together, these findings suggest growing acceptance of illegal activity as a development strategy in rural communities.

Social exclusion of the Roma population in Slovakia (selected characteristics of habitation)

Primarily, the objective of this paper is to assess the basic infrastructure like the existence of water, electricity, and gas mains and the sewage in Roma settlements. A comparatively lower dwelling level has been observed above all in segregated Roma settlements. Five categories of Roma settlements have been classified by using of the point method. Comparison of infrastructure available to the majority in concerned municipalities is important and illustrative for the exclusion of the Roma population. Roma settlements seem to be marginalized and it is precisely where the exclusion is obvious not only in terms of the dwelling level but also in terms of working opportunities, education and health care.

Practical Investigation of a MIMO radar system capabilities for small drones detection

The latest progress of the multiple-input multiple-output (MIMO) radar system developed for small drones detection at Beijing Institute of Technology is presented herein. A low-cost S-band MIMO scanning radar system is designed for the detection of small drones. A practical design optimisation and implementation of a sparse array covering the whole airspace, and a target-based MIMO radar array calibration method to improve the signal-to-noise ratio of the target are proposed. An experiment in the microwave chamber was conducted to verify the designed sparse-array beam-pattern, and measurement campaigns for small drones were performed to test the system performance where the radar achieved detection and tracking of a small DJI-Phantom 4 drone at a range of up to 5 km. Target features, including micro-Doppler and radar cross-section signatures were extracted to assist target classification. The experimental results indicate that the system has promising capability in small drones detection and tracking, despite the challenges of low dwell time on targets due to the scanning nature of the system.

Differences in anchoring strategy underlie differences in coordination in novice jugglers

The learning process of ball juggling is characterized by considerable individual differences in acquired coordination patterns. Previous research has shown that the coordination patterns observed in novice jugglers can be roughly divided into two classes: the high ratio pattern, in which the ball is held for a relatively long time, and the low ratio pattern, in which the ball is held for a relatively short time. To account for these differences in coordination patterns, we examined the anchoring strategies employed by novice jugglers for controlling the juggling movements. Analyses of the correlation between coordination patterns and selected spatiotemporal variabilities revealed that the coordination patterns with a high dwell ratio had lower temporal variability than patterns with a low dwell ratio, which in turn had lower variability of spatial variables than patterns with a high dwell ratio. These findings indicate that individual differences in the coordination patterns adopted by novice jugglers, and hence their learning paths, result from differences in the control strategies employed.

Predictors of institutional delivery service utilization among women of reproductive age in Senegal: a population-based study

BackgroundIn Senegal, sub-Saharan Africa, many women continue to die from pregnancy and childbirth complications. Even though health facility delivery is a key intervention to reducing maternal death, utilization is low. There is a dearth of evidence on determinants of health facility delivery in Senegal. Therefore, this study investigated the predictors of health facility-based delivery utilization in Senegal.MethodsData from the 2017 Senegal Continuous Survey were extracted for this study, and approximately 11,487 ever-married women aged 15–49 years participated. Chi-square test was used to select significant variables and multivariable logistic regression analysis was performed to identify statistically significant predictors at a 95% confidence interval with a 0.05 p-value using Stata version 14 software.ResultsFacility-based delivery utilization was 77.7% and the main predictors were maternal educational status (primary school Adjusted Odds Ratio [aOR] = 1.44, 95% CI; 1.14–1.83; secondary school aOR = 1.62, 95% CI; 1.17–2.25), husband’s educational status (primary school aOR = 1.65, 95% CI; 1.24–2.20, secondary school aOR = 2.17, 95% CI; 1.52–3.10), maternal occupation (agricultural-self-employed aOR = 0.77, 95% CI; 0.62–0.96), ethnicity (Poular aOR = 0.74, 95% CI; 0.56–0.97), place of residence (rural aOR = 0.57, 95% CI; 0.43, 0.74), media exposure (yes aOR = 1.26, 95% CI; 1.02–1.57), economic status (richest aOR = 5.27, 95% CI; 2.85–9.73), parity (seven and above aOR =0.46, 95% CI; 0.34–0.62), wife beating attitude (refuse aOR =1.23, 95% CI; 1.05–1.44) and skilled antenatal care (ANC) (yes aOR = 4.34, 95% CI; 3.10–6.08).ConclusionUptake of health facility delivery services was seen among women who were educated, exposed to media, wealthy, against wife-beating, attended ANC by skilled attendants and had educated husbands. On the other hand, women from ethnic groups like Poular, those working in agricultural activities, living in rural setting, and those who had more delivery history were less likely to deliver at a health facility. Therefore, there is the need to empower women by encouraging them to use skilled ANC services in order for them to gain the requisite knowledge they need to enhance their utilization of health facility delivery, whiles at the same time, removing socio-economic barriers to access to health facility delivery that occur from low education, poverty and rural dwelling.

The applicability of nearly/net zero energy residential buildings in Brazil – A study of a low standard dwelling in three different Brazilian climate zones

Buildings account for 34% of world energy consumption and about half of electricity consumption. The nearly/Net Zero Energy Building (nZEB/NZEB) concepts are regarded as solutions for minimizing this problem. The countries of Southern Europe, which included the nZEB concept recently in their regulatory requirements, have both heating and cooling needs, which adds complexity to the problem. Brazil may benefit from their experience since most of the Brazilian climate zones present significant similarities to the Southern European climate. Brazil recently presented a household energy consumption increase, and a growing trend in the use of air conditioning is predicted for the coming decades. Simulations with various wall and roof solutions following the Brazilian Performance Standard were carried out in a low standard single-family house in three different climate zones in order to evaluate thermal comfort conditions and energy needs. Results show that in milder climate zones, achieving thermal comfort with a low energy consumption is possible, and there is a great potential to achieve a net zero-energy balance. In the extreme hot climate zone, a high cooling energy consumption is needed to provide thermal comfort, and the implementation of a nearly zero-energy balance may be more feasible.

Framing the context of energy poverty in Croatia: A case-study from Zagreb

Like many other European countries, Croatia is also missing a systematic and adequate policy framework to tackle the problem of energy poverty. Currently, there is no distinction between energy and general poverty in Croatian legislation, and direct payments of utility bills are the only measure of help to (energy) poor households. Local and national authorities are lacking validated facts to make informed investments that would make a long-term impact on lowering energy demand, but also improving living conditions and quality of life of energy poor. To collect relevant data, 102 energy poor households in the City of Zagreb were visited and surveyed. Data analysis revealed a significant share of citizens living in low energy-efficient dwellings reducing heating during winter and with draught and mould problems. Wall retrofitting investment was investigated more closely by calculating a simple payback period and proving to be a cost-effective measure with many positive direct and indirect implications. The higher share of rented apartments in the group of the most energy-intensive dwellings presents a potential obstacle in conducting energy-efficiency measures and should anticipate the adoption of stricter renting regulations.

Healthy movement behaviours in children and youth during the COVID-19 pandemic: Exploring the role of the neighbourhood environment.

This paper explores patterns of increased/ decreased physical activity, sedentary and sleep behaviours among Canadian children and youth aged 5-17 years during the COVID-19 pandemic, and examines how these changes are associated with the built environment near residential locations. A cluster analysis identified two groups who were primarily distinguished by the changes in outdoor activities. Compliance to 24-hour movement guidelines was low among both groups. For children, houses (versus apartments) was correlated with increased outdoor activities; proximity to major roads was a barrier. For youth, low dwelling density, and access to parks in high-density neighbourhoods, increased the odds of increased outdoor activities during the pandemic. Our findings can inform future urban and health crisis planning practices by providing new insights into the desirable public health messaging and characteristics of healthy and resilient communities.

Influence of Thermal Processing Factors, Linked to the Destabilisation of Austenite, on the Microstructural Variation of a White Cast Iron Containing 25% Cr and 0.6% Mo

Hypoeutectic white cast irons containing 25% Cr are used in ore-processing industries due to their high resistance to erosive wear. Applying a Design of Experiments (DoE), the aim of this study is to analyse the influence of thermal processing factors on the microstructural variation of a white cast iron containing 25% Cr and 0.6% Mo. The carbides present in the as-cast state are of the M7C3, M2C, and M3C types. M2C carbides precipitate on the eutectic M7C3 carbides favoured by heterogeneous nucleation conditions. Two kinetics compete during the destabilisation of austenite. One dissolves those eutectic carbides precipitated as a result of non-equilibrium solidification (M7C3 and M2C), while the other enables the precipitation of secondary M7C3 and M23C6 carbides. The M7C3 carbides begin to precipitate first. Low destabilisation temperatures and short dwell times are insufficient to dissolve the precipitated eutectic carbides from non-equilibrium conditions, thus favouring the presence of M2C carbides, which are associated with Mo. The factor that has the greatest influence on hardness is the tempering temperature. The optimal tempering temperature is found to be 500 °C. Short tempering times maintain the distortion of the ferrite unit cell. The precipitation of Cr carbides during tempering requires a temperature of 500 °C and the prior dissolution of the carbon precipitated during the initial stages of said tempering. With short tempering times, the Cr atoms still remain dissolved in the ferrite, distorting its unit cell and increasing the hardness of the matrix constituent of the alloy.

Relationship between distance to overhead power lines and calculated fields in two studies

There is some evidence that both distance from transmission lines and measured or calculated magnetic fields are associated with childhood leukemia. Because distance is a key component when calculating the magnetic field generated by power lines, distance from lines and calculated fields based on lines tend to be highly correlated. Socioeconomic status (SES) and dwelling type are also associated with magnetic field exposure. We used exposure data from two large studies of childhood leukemia and other cancers, in the US and the UK, to describe a relationship between distance and magnetic fields across the population within 100 meters (m) of power lines as a whole and evaluate potential modifiers such as SES and type of dwelling. There were 387 subjects living within 100 m of an overhead power line. There was no significant difference in mean calculated fields or distance to 200+ kV lines within 100 m by study. Within the range where the power-line field is expected to be significant compared to other sources, which we take as 100 m, distance to high-voltage lines predicted magnetic field (MF) variation in both studies better than other functions of distance tested in both linear and logistic regression. There were no differences between high and low SES or dwelling types (single-family home versus other). In conclusion, we found that calculated fields do appear to diminish linearly with increasing distance from overhead power lines, up to 100 m, particularly those 200+ kV and above. These results are stronger in the UK study. Within 100 m, distance to high-voltage lines continues to be highly correlated with calculated MFs and each can be a proxy for the other.

Source shot noise mitigation in focused ion beam microscopy by time-resolved measurement

Focused ion beam microscopy suffers from source shot noise – random variation in the number of incident ions in any fixed dwell time – along with random variation in the number of detected secondary electrons per incident ion. This multiplicity of sources of randomness increases the variance of the measurements and thus worsens the trade-off between incident ion dose and image accuracy. Repeated measurement with low dwell time, without changing the total ion dose, is a way to introduce time resolution to this form of microscopy. Through theoretical analyses and Monte Carlo simulations, we show that three ways to process time-resolved measurements result in mean-squared error (MSE) improvements compared to the conventional method of having no time resolution. In particular, maximum likelihood estimation provides reduction in MSE or reduction in required dose by a multiplicative factor approximately equal to the secondary electron yield. This improvement factor is similar to complete mitigation of source shot noise. Experiments with a helium ion microscope are consistent with the analyses and suggest accuracy improvement for a fixed source dose by a factor of about 4.

Transferring the index of vulnerable homes: Application at the local-scale in England to assess fuel poverty vulnerability

Fuel poverty, or energy poverty, has traditionally been associated with households that cannot afford to keep their homes adequately warm and/or cool due to low income and energy inefficient dwellings. Recent studies show a need for a good understanding of levels of vulnerability and how they are shaped by poor quality housing and economic circumstances. This work, which examines the current level of vulnerability to fuel poverty in a neighbourhood in the Broughton ward of Salford using quantitative data, provides a comprehensive tool to assess fuel poverty vulnerability at a local scale in England, the Index of Vulnerable Homes (IVH), which evaluates the identification of households in or at risk of fuel poverty. The IVH results lead to an evaluation of current fuel poverty indicators in terms of their ability to assess fuel poverty vulnerability in England, providing a fuller understanding of the variety of fuel poverty situations, as well as recognizing the high prevalence of hidden fuel poverty. Additionally, having used the IVH in both England and Spain, it makes possible reflections upon how vulnerability to fuel poverty may differ in these countries, leading to relevant recommendations for policymakers to develop effective fuel poverty measures.

AA5052 sheets welded by protrusion friction stir spot welding: High mechanical performance with considering sheets thickness at low dwelling time and tool rotation speed

In the present work, AA5052 sheets with thickness of 1 mm were successfully welded by protrusion friction stir spot welding as a low cost single-step method with a simple design that produces the no-keyhole joints with special mechanical properties at short dwell time and low tool rotation speed. By using suitable process parameters, the process is able to produce welds with superior mechanical performance in items of peak load and energy absorption compared to other techniques. The plunging depth and dwell time in this method were set as 0.2 mm and 6 s, respectively. The tool rotation speed was changed as 500, 800, 1250, and 1600 r/min to determine the optimum condition based on the microstructural and mechanical properties. Welds strength produced by the protrusion friction stir spot welding was directly related to the joint thickness, and the effective thickness of the upper sheet was maximum at 500 r/min. Protrusion friction stir spot welding joints presented circumferential failure mode after tensile shear testing. Regarding the sheets thickness used in this study, the joints produced by the current work presented high load bearing ability at dwell time of 6 s and tool rotation speed of 500 r/min compared to other techniques.

Analysis and Application of Log-Linear and Quantile Regression Models to Predict Bus Dwell Times

Understanding the key factors that contribute to transit travel times and travel-time variability is an essential part of transit planning and research. Delay that occurs when buses service bus stops, dwell time, is one of the main sources of travel-time variability and has therefore been the subject of ongoing research to identify and quantify its determinants. Previous research has focused on testing new variables using linear regressions that may be added to models to improve predictions. An important assumption of linear regression models used in past research efforts is homoscedasticity or the equal distribution of the residuals across all values of the predicted dwell times. The homoscedasticity assumption is usually violated in linear regression models of dwell time and this can lead to inconsistent and inefficient estimations of the independent variable coefficients. Log-linear models can sometimes correct for the lack of homoscedasticity, that is, for heteroscedasticity in the residual distribution. Quantile regressions, which predict the conditional quantiles, rather than the conditional mean, are non-parametric and therefore more robust estimators in the presence of heteroscedasticity. This research furthers the understanding of established dwell determinants using these novel approaches to estimate dwell and provides a relatively simple approach to improve existing models at bus stops with low average dwell times.

The modality of choice, manual or automated, for urgent start peritoneal dialysis.

Over the last decade, urgent start peritoneal dialysis (USPD), defined as initiation of peritoneal dialysis (PD) before the traditionally recommended break-in period of 2–4 weeks, has increasingly been seen as a viable option for late-presenting end-stage renal disease patients, obviating the need for haemodialysis via central venous catheter. Different prescriptions and protocols involving both manual and automated exchanges have been published, but there is no head-to-head comparison of the two modalities and no consensus on the most suitable modality exists. Evaluation of the available evidence suggests that PD can be initiated urgently using either or both options without much difference in the outcome. The two most critical aspects dictating the success of a USPD programme are using low dwell volumes and keeping patients in a strict supine position during the dialysis exchanges in the first couple of weeks of the therapy. These measures are crucial in keeping the intraperitoneal pressure to a minimum and reduce the risk of mechanical complications, including catheter leaks and malpositioning.

Hybrid microwave sintering of blended elemental Ti alloys

Powder metallurgy, and in particular the blending elemental approach, is a recognised way to reduce the processing cost of titanium-based materials for their wider industrial uptake. Microwave sintering is claimed to be a faster sintering process that could contribute to the cost reduction. In this study hybrid microwave sintering was used to consolidate cold pressed blended elemental alpha + beta (i.e. Ti-6Al-4V and the low-cost Ti-5Fe), metastable beta Ti-5Al-5Mo-5V-3Cr titanium alloys as well as hydride-dehydride Ti. It is found that densification is achieved at low sintering temperatures and short dwell time but proportionally higher temperatures and longer sintering times are required for the homogenisation of the chemical composition of more heavily alloyed materials. Similarly to vacuum sintering, for most of the materials relative density around 94–95% are obtained, but no faster sintering at maximum temperature was perceived. The mechanical properties increase along with the sintering parameter obtaining values comparable to the respective wrought and/or powder metallurgy counterparts.

New Ecological Paradigm of Architectural Development of the Energy Efficient Affordable Low Dwelling

The problems of the planet’s ecology and the degradation of the environment are taking a dangerous turn. Uncontrolled growth of global greenhouse gas emissions has continued, the planet’s temperature rises. The construction industry is harmful to the environment. Therefore, it is necessary to apply “green construction”, especially developing the direction of energy-efficient low-rise housing. Designing low dwelling housing, focused on low energy consumption, it is necessary to take care not only about the heat, but also about the architecture of the building, ecology and internal comfort. It is necessary to suggest the construction of a building in which sunlight, the heat of the earth worked for the tenants. The considered ecological problems of the development of low dwelling architecture, adapting to the changing people’s needs, applying the principles of architectural and planning organization and developing construction technologies, move from the conceptual aspect to the actual one. In connection with this, it is necessary to use prefabricated buildings. It will require the erection of plants for the production of serial houses and the production of inexpensive building materials. There was a need to create buildings that would have maximum factory readiness, transportability, minimum volume, rapid erection and high comfort. There was a need to develop a project base and development of construction production for the low-rise housing industry. A wide application of prefabricated volumetric modular technologies for house building. Implementation of sustainable construction using only environmental materials. Analysis of the current situation for the development of low dwelling housing architecture showed that the main prerequisites for the formation of low dwelling housing are certain conditions. This is the impact of special natural and climatic factors, the choice of new land for construction, requiring minimum costs. A functional-spatial model of a low dwelling has been developed and proposed, an assessment of the comfort of a dwelling, the possibility of resource saving and expansion with an increase in the family. Energy saving and energy efficiency, they will be achieved in the form of increasing the heat-shielding properties of enclosing structures. Living in multistoried buildings leads to a progressive deterioration in the health of people, both physical and mental - this is the path to nowhere. Therefore, in the long term, an ecological low dwelling housing has no alternative. The sooner we start building them, the less our losses will be.

Strength Characteristics of Bamboo Reinforced Slabs

The construction industry consumes large quantities of composite materials, such as steel, cement and other binding materials. This process emits enormous volume of carbon dioxide leading to global warming and other environmental degradation. As an alternative to steel, bamboo, rattan cane and other agricultural products have been used as reinforcement in different parts of world. However, the application of this non fossil-fuel products has not been exploited to greater extent. In the present study the use of bamboo (bambusa vulgaris) has been adopted as an alternative to steel in fabricating slabs of dimension 1500 mm x 500 mm x 75 mm (length x breadth x thickness). M25 grade with water cement ratio as 0.5 was used. The slabs were tested using Non-Destructive Tests to determine the quality of concrete adopted. Subsequently, destructive tests were carried using a loading frame of capacity 1000 kN. The non-destructive tests and destructive tests were repeated on steel reinforced slabs and control slabs (without any reinforcement). The results indicate that the bamboo reinforced slabs comparatively weaker with respect to steel reinforced slabs and stronger with respect to control slabs. Therefore, it is recommended to adopt BRC slabs for low cost dwellings.