Kerosene Usage Research Articles

Drivers of Rural Households’ Choices and Intensity of Sustainable Energy Sources for Cooking and Lighting in Ondo State, Nigeria

Poverty reduction and the promotion of sustainable human development are fundamentally dependent on having access to modern energy services. Energy supplies that are dependable, reasonably priced, and sustainable are vital to modern societies. In achieving the sustainable development goals (SDG7) and access to clean energy supplies, this study, using cross-sectional data from 180 randomly sampled rural households, analyzed the key factors determining the choice and intensity of energy sources used for lighting and cooking in rural Nigeria. Both descriptive and inferential statistics (multivariate probit (MVP) and zero-truncated Poisson (ZTP models)) were employed for the analyses. The result showed that there is evidence of fuel stacking in their choice of cooking and lighting energy, and it increases with rising income levels but is more pronounced for lighting than cooking. The result also revealed that reliable access to clean energy (9% of sampled households for LPG and 23% of the households for grid electricity) is very low, as these households still rely on fuelwood (70%) for cooking, but the predominant usage of kerosene (39%) for lighting, as reported in the literature, has drastically changed to dry cell battery (51%). The results using a multivariate probit model to capture the multiple fuel usage phenomenon among rural households show that access to clean energy, improvement in rural poverty, usage of indoor kitchens, household size, and an increase in the education of household heads’ spouses significantly influence the use of clean energy in the rural areas. In the same vein, the result of the ZTP model showed that income, access to energy sources, and occupation of the household head were the drivers of the intensity of cooking and lighting energy sources. Thus, it is recommended that any policy interventions that are targeted at encouraging rural households to use clean energy should start by improving rural access to these clean energy sources, improving their poverty status while also increasing the level of education and awareness of rural women concerning the risks of using dirty energy sources.

Aviation fuels of the future − A techno-economic assessment of distribution, fueling and utilizing electricity-based LH2, LCH4 and kerosene (SAF)

This paper investigates the techno-economic implications on air travel when fossil-based kerosene is phased out of the market, specifically focusing on the comparison between liquid hydrogen, liquid methane and renewable kerosene for ten exemplary flight routes to estimate the cost of air travel per passenger and 100 km distance travelled €2020PAX100km for every fuel type. By considering the entire supply chain, including hydrogen production from renewable sources, synthesis, oversea transport, domestic distribution, and utilization, this study addresses the overarching question of whether it is more economical to change the fuel source or the fuel itself to reduce fossil kerosene usage in the aviation industry. It is demonstrated that aircraft acquisition costs play a minor role compared to fuel supply costs and specific fuel demand. The study shows that for electricity-based fuels, liquid hydrogen is the most economic option, even with a potential energy penalty, followed by liquid methane and renewable kerosene. The results for an aircraft with a capacity 180 passengers are 3.08, 4.57 and 5.11 €PAX100km for liquid hydrogen, liquid methane and renewable kerosene, respectively. Challenges regarding storage and isolation requirements for cryogenic fuels in aviation are discussed, with assumptions made that these obstacles can be overcome to realize economic benefits. Additionally, the study suggests potential shifts in aircraft size selection by airlines to mitigate rising fuel prices in the future. The study advocates for the aviation industry's openness to new fuels like liquid hydrogen and liquid methane to alleviate the cost increase associated with phasing out fossil kerosene.

Reducing energy poverty, carbon footprint, human health risk and achieving the sustainable development goals, by use of solar lamps at Indian Sundarbans

Energy poverty is one of the major hindrances in achieving the UN SDG goals. This article highlights a socio-environmental interventions at the Indian Sundarban where 1220 families received solar lamps in 2017 towards achieving the global target of SDG 7 (Affordable and Clean Energy). A survey on 1000 beneficiaries and human health risk assessment revealed that the interventions have played a significant role in addressing the issue of energy poverty and helped to achieve SDG-3. Health risk assessment infers that maximum exposure (high flame kerosene wick lighting) of PM2.5, would have resulted in very high Hazard Quotient (HQ) 32, 60 and 136 for adult (≥ 20 years), children (1-5 years), and infant (≤ 1 year) respectively. Cost benefit analysis revealed that each beneficiary was saving 2.61€ per month on kerosene usage and as a result, within approximately nine months the cost of the solar lamp can be recovered. The use of solar lamps has resulted in reduced emission equivalent of around 803 kg of CO2/person/year.

Investigating household sector's non-renewables, biomass energy consumption and carbon emissions for Pakistan.

Concerns over the observed rising trend towards carbon emissions and the resulting adverse effects of climate change on human activities are the main challenges facing human beings. This study examines household sector's non-renewables and biomass energy consumption magnitude and how much carbon is emitted from non-renewable and biomass energy in Pakistan by using the PSLM 2018-2019 survey. In addition, using STIRPAT model, this study investigates the effect of income, household size, and clean energy on non-renewables and biomass energy choices of the household sector. The results show that 77% of households rely on the consumption of biomass energy. An average household uses firewood at the largest magnitude of 142.06 kg month-1 and kerosene usage at the smallest magnitude of 4.08 kg month-1 among non-renewables and biomass energy choices. The largest contributor to carbon on average is dang cake and its magnitude of carbon emissions is 0.87 tons household-1 year-1 followed by coal with a magnitude of 0.76 tons household-1 year-1. LPG is the lowest contributor to carbon and its carbon emission magnitude is 0.04 tons household-1 year-1. The income impact finding indicates that LPG, kerosene, firewood, and dang cake are necessities, whereas coal is an inferior commodity. The coefficient of household size indicates that large household uses firewood and dang cake, and small one uses LPG and kerosene. As such, households prefer to reduce non-renewable and biomass consumption by increasing clean energy. Therefore, the study suggests that to reduce non-renewable and biomass energy consumption and follow clean energy provision at household level without compromising on environmental quality. The rise in household income and reducing household size could also be a valid policy option for reducing the non-renewable and biomass energy consumption.

Effect of kerosene and biomass fuel as cooking medium on pulmonary function of adult nontobacco addict homemaker women residing in slums of Ahmedabad City, Gujarat.

Combustion of kerosene and biomass fuel in the kitchen as cooking medium is one of the major sources of indoor air pollution. Such contaminated indoor air quality adversely affects the respiratory health of exposed individuals over a period of time. Homemaker women especially residing in slum areas are always vulnerable to indoor air-pollution-related health hazards. The objective is to assess the relationship between various socio-demographic factors and usage patterns of cooking fuel; and to determine the effect of cooking medium namely biomass, kerosene on pulmonary function parameters. A cross-sectional observational study was carried out during April 2012 - April 2016 among 531 nontobacco addicted adult primary homemaker women residing in slums of Ahmedabad city of Gujarat. Basic information-related socio-demographic parameters were collected on a pretested questionnaire. Pulmonary function test (PFT) parameters were evaluated with standard techniques. The statistical analysis was carried out with SPSS software (version 17.0). Statistical tests of significance between groups and mean along with multivariate linear regression analysis were applied. Predominant cooking medium for nearly 40% of slum households were kerosene and biomass. Mean value of forced expiratory volume in the 1st s (FEV1) and FEV1/forced vital capacity (FVC) were significantly lower among Kerosene and biomass users compared to LPG users. Multivariate regression analysis with involvement of PFT parameters, cooking medium, and environmental tobacco smoke exposure (ETS) shows, deprivation of both FEV1 and FEV1/FVC were significantly related with the usage of kerosene and biomass; whereas no relation found with ETS. Reduction of pulmonary function parameters among the study participants were related with kerosene and biomass fuel usage in the kitchen.

Knowledge, Attitude and Practice Towards Burn Patients Admitted in Madina Hospital Mogadishu Somalia

Background : Burns are among the most devastating forms of trauma, and also the most common typesof injury affecting children in home environment. There are a major cause of morbidity and mortality all over the world for both children and adults,especiallyfor developing countries like Somalia because of inadequate medical treatment.Objective: The main objective is to gain knowledge, attitude andpractice towards burn patients admitted to Madina Hospital between October 2017 and October 2018.Methods: Throughout the study,researchers utilized both quantitative and qualitativemethods of data collection which were achieved from patients included in the study. A briefintroduction was made to the respondents before distributing the questionnaires with the explanation about thesignificance of the study.Results: 404 participants had been included in the study of which were divided into two groups such as ‘case’ (n=202) and ‘control’ (n=202) groups of each having equal number of patients. Burn injuries had beenfound most frequent in children less than 4 years of age (42.6%), and secondlyingadults between 20 and 40 years of age (38.6%). The male-female ratio had been found similar. Significant risk factors regarding burn injuries were such as; low level of education (OR=2.32, 95% CI: 1.28- 4.22, p<0.005),kerosene usage for cooking (OR=1.935; 95% CI:1.303–2.874, p<0.005) and lack of knowledgeconsideringprevention andsafety (OR=1.885, 5% CI:1.559-2.279, p<0.005).Conclusion: Ways of tackling the hazards posed by fire and othercauses of burns in homes, institutions and all work places should be taught in primary, secondary and tertiary levels of education. Low level of education as a risk factor for burns is a complex issue involving communities, non-governmental organizations and government. Theministry of education should incorporatehealth education in the curriculum of primary and secondary schools.International Journal of Human and Health Sciences Vol. 03 No. 04 October’19 Page : 218-222

From fundamental study to practical application of kerosene in compression ignition engines: An experimental and modeling review

The use of kerosene in direct injection compression ignition engines is fundamentally due to the introduction of the Single Fuel Concept. As conventional direct injection compression ignition diesel engines are made specifically to use diesel fuel, the usage of kerosene will affect engine emissions and performance due to differences between the fuel properties of kerosene and diesel. As a result, in order for kerosene to be properly and efficiently used in diesel engines, it is needful for the scientific community to know the properties of kerosene, its autoignition and combustion characteristics, as well as its emissions formation behavior under diesel engine operating conditions. Moreover, it is desirable to know the progress made in the development of suitable kerosene surrogates for engine applications as it is a crucial step toward the development of reliable chemical reaction mechanisms for numerical simulations. Therefore, in this work, a comprehensive review is carried out systematically to better understand the characteristics and behavior of kerosene under direct injection compression ignition engine relevant conditions. In this review work, the fuel properties of kerosene are summarized and discussed. In addition, fundamental autoignition studies of kerosene in shock tube, rapid compression machine, fuel ignition tester, ignition quality tester, constant volume combustion chamber, and engine are compiled and evaluated. Furthermore, experimental studies of kerosene spray and combustion in constant volume combustion chambers are examined. Also, the experimental investigations of kerosene combustion and emissions in direct injection compression ignition engines are discussed. Moreover, the development of kerosene surrogates, their chemical reaction mechanisms, and the modeling of kerosene combustion in direct injection compression ignition engines are summarized and talked about. Finally, recommendations are also given to help researchers focus on the areas which are still severely lacking.

A survey availability of kerosene is the leading cause of suicidal burns-death of females in Salem district, Tamil Nadu, India

Background: Kerosene is the main culprit for the Burns, occupy 90% remaining 10% burns from other cause that to availability of kerosene at home /working place is the leading provocating cause for suicidal burns, For the past 7 years, we have followed 2645 burns admission (total) that too female burns, almost 98% of them are due to kerosene. In most of the case, suicide is due to some family problem. The remaining 10% burns are accidental burns to assess the burns due to kerosene usage and to analysis the mortality and morbidity among patients.Methods: This survey was conducted from 2010 to 2017. The number of burns patient admitted at our hospital is 2645/ female burns. cause of suicide attempting by self-immolation during 7 years 2010-2017 analyzed. A record sheet designed to extract data such as age, education, occupation, gender, residence, marital status, drug abuse, and extent of the burn injuries as a percent of burned total body surface area (TBSA).Results: A detailed survey conducted for the past 7 years female Burns are almost 90%. Due to suicide remaining 10% accidental. Accidental burns are minor/ moderate. We are able to save the life and reduce the mortality. But suicidal burns almost extensive/ major burns. We are not able to save the life with modern availability of treatment.Conclusions: Finding of the current study manifested a high rate of suicide by self-immolation among young, married, and low educated women in south India. It implies a social problem, and need to an arrangement of a cultural program aimed at improving health, psychological habits, and educational level.

The Effects of Kerosene Usage on Heavy Metals Uptake by some Vegetables in Khuzestan Province

The Effects of Kerosene Usage on Heavy Metals Uptake by some Vegetables in Khuzestan Province

Decisions of Scrapping the Subsidies in Kerosene Supply in India: How Will It Affect the Poor?

This research aims at exploring the impact of scrapping kerosene subsidy on the welfare of the poor. In India, still 31 % of households use kerosene fuel as an alternative source of energy to illuminate their house, especially in rural India. Kerosene along with the other social security goods has been disbursed at a highly subsidised rate for a long time. Off late, a new policy vows at scrapping such subsidies as a strategy to reform and restructure the energy sector. Keeping these things in consideration, the study views scrapping policy as having an adverse impact on people. The present study employs the latest census record (2011) on household energy consumption—source of lighting—for the analysis. The results bring to light a wide divide at various spatial levels of evaluation with regard to usage of kerosene and electricity for lighting purposes within the household. Apart from the gap at rural, urban, national, state and district level, the districts of the Empowered Action Group (EAG) states which are traditionally lagging behind in all the development indicators form a cluster of the major consumers of subsidised kerosene. The study also reveals that the below poverty line (BPL) population in these states has inflated at a rapid scale which could get affected with the new policy. Although kerosene, as a source of energy, is not green, it needs to be subsidised till there is a universal access to electricity.

Macroscopic spray characteristics of kerosene and diesel based on two different piezoelectric and solenoid injectors

In this study, the behaviours like injection momentum and spray characteristics for piezoelectric and solenoid injectors were compared. With piezoelectric injector, the macroscopic spray characteristics of kerosene and diesel were investigated. The characteristic like spray penetration, spray velocity, spray angle and air entrainment were used to understand the fuel spray behaviours. The result shows that the piezoelectric injector has the advantage of faster injection response and needle opening than the conventional solenoid injector, which will enable precise and rapid injection control and must be beneficial to air–fuel mixing before ignition in a real engine. Due to the lower value of viscosity in kerosene, the injection durations for kerosene are longer than diesel. Also longer injection intervals will be needed for kerosene to realize multiple injections. Kerosene has shorter spray penetration and lower spray velocity compared with diesel, while the spray angle of kerosene is larger than diesel. Entrained air mass is a typical trade-off result of comprehensive influence of spray penetration, spray angle and charge density. Kerosene sprays get more entrained air than diesel, which means the usage of kerosene has advantage in fuel–air mixing.

The Lighting Transition in Africa From Kerosene to LED and the Emerging Dry-Cell Battery Problem

Non-electrified people in Africa, still more than 500 million today, have been using kerosene and candles for their lighting purposes for decades. The lighting quality of these sources is low and in particular kerosene usage is associated with harmful soot emissions. Alleviating this grievance has always been a major goal of electrification programs. The present paper shows that in recent years a transition has taken place among the rural non-electrified population in Africa: without any external support from governmental or non-governmental organisations people have replaced kerosene lamps and candles through LED lamps, which are mostly powered by dry-cell batteries. LED lamps are available in rural shops virtually everywhere and provide brighter and cleaner lighting than traditional lamps. The downside of this massive increase of LED usage is a soaring consumption of dry-cell batteries. Because of the toxic content of many dry-cell batteries and since people dispose of discharged batteries inappropriately in latrines or the nature, harmful effects on the local environment are likely. We conclude by suggesting that rapid action is needed to put in place an effective waste management system.

Direct Current and Alternative Current Based Solar Micro-Grid in Rural Energy Infrastructure

In India kerosene uses as primary source of lighting- 43% of rural and 7.1% of urban households, even most populated African countries (Uganda, Ethiopia, and Kenya) more than 60% of the population relies on kerosene as the primary lighting fuel. Though they have access to grid electrification the unreliable supply leaves them in complete darkness and hence compelling them to think of alternatives. Poor electrification and unreliable supply lead to usage of kerosene based lighting devices such as kerosene lamps, which not only provides lowly quality illumination but also results in hazardous smoke. Off-grid electrification can provide an alternative solution for many low demand users at lower cost than grid extension and market growth of rural energy service. Costs of off-grid technologies have decreased significantly over the last few years hence making it affordable. Morden micro grid has come up with a way to make lighting system accessible to most of the rural households. Solar based renewable energy technologies extensively development in the last decade, the Solar photo voltaic cell converts light energy into direct current using the photovoltaic effect. Battery devices storing the extra power generated at day time and used during nights. Inverters and power Store Electronic Systems are used to convert direct current power generated by solar photo voltaic systems to alternative current, and utilization of direct current /alternative current in renewable energy power system at higher capital cost. But the internal rate of interest makes it superior to other system. This paper a latest researcher’s review of assessment of Direct current (DC) and Alternative current (AC) based Solar Micro-grid in rural community. The paper is therefore structured as follows: overview of micro-grid AC and DC system with case studies. Sensibility analysis in Compression with decentralized Diesel Genset (DG) based on Net present value (NPV) Internal rate of interest (IRR) for DG set 92% (not included as environmental economics), the IRR for solar micro-grids 50% and solar micro-grids with Government subsidy 80%. Opportunities and challenges involved in the implementation of solar mini grid in rural energy infrastructure.

Adoption of solar home lighting systems in India: What might we learn from Karnataka?

Karnataka has been among the most successful markets for solar lighting systems (SLS) among Indian states. In order to understand the dynamics of systems adoption and operation, that have fostered market based adoption of solar lighting, we interviewed rural households from six districts that had purchased solar lighting systems using loans at market rates, the rural banks that provided loans and the solar firms that marketed the technology. We found that a large proportion of households in our sample were connected to the grid but chose to install solar lighting because they considered the power supply from the grid to be unreliable. Households in our sample reported savings on electricity costs and reduced kerosene usage for lighting. In addition to providing credit, banks also play a key role in ensuring good service and maintenance; the viability of the SLS market is thus critically dependent on the role that the banks play as intermediaries between consumers and solar firms in rural areas. Government programs should be carefully designed to match the incentives of firms, banks and consumers if the successes of the ‘Karnataka model’ are to be repeated and amplified.

Reverse Flotation in Muş-Elmakaya Lignite Beneficiation

The aim of this study was to investigate the possibility of cleaning Muş-Elmakaya lignite by the reverse flotation method. Experimental studies were conducted on Muş-Elmakaya lignite samples containing high ash and sulfur content. Preliminary flotation studies showed that gangue minerals were floated instead of the lignite sample in the flotation medium. For this purpose, the effects of some parameters that markedly influence the effectiveness of reverse flotation, such as grinding time, solid concentration, pH, collector type and amount, depressant amount, and frother amount on the reverse flotation, were investigated. Flotation results showed that while a clean coal assaying 29.04% ash with combustible yield of 78.14% could be obtained in the usage of Aero 3477 as the ionic collector, a clean coal assaying 27.40% ash with a higher combustible yield of 81.19% could be obtained in the usage of kerosene as the conventional collector.

Technical and economic studies on lighting systems: A case for LED lanterns and CFLs in rural Ghana

Abstract Studies have shown that 50.1% of Ghana’s 22,900,927 population use kerosene as fuel source for lighting. Statistics further established that 75.6% of Ghana’s rural population and 19.9% of the urban population use kerosene as fuel for lighting. This situation has brought about diverse problems of poor indoor air quality. For instance, a survey conducted among 113 non-electrified households in 16 rural communities, located in six regions in Ghana that use kerosene lanterns established that 69% of the households observed soot particulates in a household member’s nostril in the morning. In light of the known health effects of kerosene usage for lighting in poorly ventilated structures and the recent global increases in the prices of petroleum products, this study is designed to assess the suitability of solar-powered LED and CFL lighting systems as replacement for kerosene lanterns. The technical analysis was done by measuring the luminous flux of each lighting system on a flat surface measuring 1 m by 1.2 m using a portable lux meter. The economic analysis was based on a two-year simple payback period. Results from the study showed that the cost of illumination ranges from $0.061 per thousand lux-hours (klxh) for Goshen solar lantern to $0.261 per klxh for Gentlite solar lantern with kerosene lantern costing $0.227 per klxh. The analysis established that switching to the solar-LED and CFL systems (lanterns A, B and D) would have a payback time of less than two years when replacing the wick-type kerosene lantern with between $11.60 and $61.60 to save annually. When evaluated in terms of total cost of ownership (fixed and variable), the solar-powered LED and CFL systems emerged as the most cost-effective solution. Emissions analysis conducted revealed that the solar-powered systems save between 80.15 and 256.49 kg CO2/year. The annual CO2 emissions per kerosene lantern were estimated to be 60.99 kg. Therefore, the most significant deduction from the study is that the solar-powered LED and CFL lighting systems are a viable and cost effective off-grid lighting alternative for fuel-based lighting systems in rural Ghana.

Electrical Discharge Machining (EDM): Practices in Malaysian Industries and Possible Change towards Green Manufacturing

Electrical discharge machining (EDM) is material removal process by a series of rapid recurring electrical discharges between the cutting tool (electrode) and the work piece in the presence of dielectric fluid. The process benefits Malaysian mould and die industries especially in making electrical, automotive and household products. Visits were conducted to a few EDM industries in Klang Valley in identifying the industrial practices. Hydrocarbon based dielectric usually kerosene is widely used by the Malaysian industries. The paper highlights on findings obtained from industrial interviews: machine used and products made, types of electrode materials, machining technique, usage of dielectric and measuring quality of machined products. Calculation on the usage of kerosene and related cost at a company is presented. Estimation of kerosene as waste is provided. Suggestions on alternative machining method such as machining with distilled water or dry EDM are given.

Impacts of solar home systems on social development in rural Bangladesh

This study was carried out to find the impacts of solar home systems (SHSs) application at selected villages in Gazipur district, Bangladesh. A questionnaire-based survey method was used to collect primary data from the period of October 2004 to January 2005. The research reveals that solar electrification provided direct and indirect benefits to the users of the system, with many implications of a permanent nature. Reduction of kerosene usage was the main impact of SHSs. It resulted in less pollution, higher quality light and more hours of light in the evening, as well as less work for cleaning kerosene lamps. Very few income generation activities were created after acquiring SHSs in the studied villages. But the people who were engaged with business using traditional fuel, switched to solar light that added a little bit more income due to extended working hours in the evening. Women and children were found to benefit from the quality of light for household work and studying in the evening. Users became accustomed to the better quality of light and could not perceive returning back to kerosene lamps. Solar electrification also added to the overall comfort and satisfaction of the consumers.

NOX AND VOC MEASUREMENTS AND HEALTH RISK ASSESSMENT IN AN INFORMAL SETTLEMENT IN DURBAN

A previous study by Muller et al. (2003) investigated NOx, benzene, toluene, ethylbenzene and xylene levels in households in the densely settled informal settlement of Cato Crest located within the Durban Metropolitan area. AHealth Risk Assessment based on the United States EPA approach showed that the residents of Cato Crest experienced significant health risks as a result of exposure to these pollutants largely as a result of kerosene usage in their homes. Specifically, the study which was conducted in September 2000 in 14 households, showed that exposure to NOx over a 24-hour period indicated a potential health risk in all the households, that benzene poses a health risk in 50% of the households, whereas there is no health risk associated with exposure to toluene. A follow-up study was conducted in July 2006 targeting similar households and pollutants to investigate whether comparable results were found in a typical winter period, when air quality is generally expected to deteriorate.

Health risk assessment of kerosene usage in an informal settlement in Durban, South Africa

In Durban, South Africa studies have shown that more than seven out of ten households in low-income metropolitan areas rely on kerosene for domestic purposes, leading to widespread problems of poor indoor air quality. In light of the known health effects of kerosene usage, this study aimed to quantify the health risk for people living in a densely populated informal settlement known as Cato Crest within the Durban metropolitan area. The pollutants investigated included nitrogen dioxide, benzene and toluene. Nitrogen dioxide is known to affect both respiratory and immune systems, benzene is carcinogenic while toluene has a neurological health end point. All three pollutants are harmful when inhaled. The United States Environmental Protection Agency (US EPA) health risk assessment (HRA) framework was applied. Information on the exposure patterns of residents in Cato Crest were acquired through questionnaires in which data on fuel use, building structure, cooking habits and time-activity patterns were collected. Air quality monitoring of nitrogen dioxide and volatile organic compounds was also conducted in the households. The time-activity pattern survey revealed that the exposure periods of individuals in Cato Crest were far greater than the default exposure periods used by the US EPA. The results of the HRA showed that the residents of Cato Crest may experience significant health risks as a result of kerosene usage in their homes. Exposure to 1-h nitrogen dioxide concentration is not likely to produce adverse health effects, whereas exposure over a 24-h period indicates a potential health risk to sensitive individuals in two of the households when US EPA exposure values are used and in all of the households when locally derived exposure values are used. Benzene poses a health risk to sensitive individuals in 50% of the households when local exposure parameters are used, whereas there is no health risk associated with exposure to toluene.