An integrated control on thermal and noise environment of tropical building material

The environmental problems of thermal and noise environment are recently considered the most important contributors to the tropical building in an urban area. The porous tropical materials provide both a solution for cooling and airborne noise problem from the source to receiver when the wind is in the same direction. This research optimizes the integrated control of thermal and noise environment which are directed into building material evaluation. Surabaya is selected as representative of the hotter area of the lowland while Malang is determined as the colder urban area of the highland. An eco-tropical lightweight material, wood, is examined as a case study. The field measurement for surface material temperature and its transmission loss were conducted in order to give information on thermal and acoustical properties of the material. The optimization is conducted by comparing Sound Reduction Index and by Conduction Heat Flow. The results highlighted that for the same material, the thickness that effect on its mass is important for both thermal and noise control. The higher the thickness is, the higher the Sound Reduction Index and the lower the conduction heat flow are. Modifying material by adding the thickness of wood results that by material mass minimum 36.5 kg/m2, the critical lowland building meets the standard of World Health Organization noise limits and has lower heat gain.

Download Full-text

IMPLEMENTATION OF LABORATORY MEASUREMENT OF AIRBORNE SOUND INSULATION BASED ON ISO AND ASTM STANDARDS IN NATIONAL STANDARDIZATION AGENCY OF INDONESIA (BSN)

Jurnal Standardisasi ◽

10.31153/js.v23i1.861 ◽

2021 ◽

Vol 23 (1) ◽

pp. 77

Author(s):

Bondan Dwisetyo ◽

Maharani Ratna Palupi ◽

Fajar Budi Utomo ◽

Chery Chaen Putri ◽

Dodi Rusjadi ◽

...

Keyword(s):

Transmission Loss ◽

Laboratory Measurement ◽

Sound Insulation ◽

Reference Curve ◽

Airborne Sound ◽

Significant Difference ◽

Single Number ◽

Sound Reduction ◽

Reduction Index

<p>The implementation of laboratory measurement of airborne sound insulation based on ISO and ASTM standards was carried out at SNSU BSN. The aim of this work to realize the measurement of airborne sound insulation for several sample tests, where the procedure of the test is performed according to the updated standard ISO 10140 and ASTM E90. Besides, the single number rating also is determined based on ISO 717-1 and ASTM E413. This measurement has been conducted in the two reverberation rooms using pressure method consist of measuring the sound pressure level, measuring the reverberation time, obtaining the sound reduction index (R) or sound transmission loss (STL), and determination of a single-number ratings of the samples test. From the results, some parameter requirements such as the frequency range and the rounding procedure of R or STL influence the measurement result slightly. Subsequently, the significant difference is obtained for the determination of single number rating in the shifting procedure of the reference curve.</p>

Download Full-text

A Comparative Study of Sound Transmission Loss Provided by Glass, Acrylic and Polycarbonate

Jurnal Teknologi ◽

10.11113/jt.v60.1432 ◽

2013 ◽

Vol 60 (1) ◽

Author(s):

Elwaleed Awad Khidir ◽

Zambri Harun ◽

Mohd Jailani Mohd Nor ◽

Muhamad Razi

Keyword(s):

Transmission Loss ◽

Sound Transmission ◽

Sound Insulation ◽

Sound Transmission Loss ◽

Material Density ◽

Airborne Sound ◽

Single Number ◽

Reverberation Chambers ◽

Sound Reduction ◽

Reduction Index

This article presents an assessment for the airborne sound insulation provided by single glazed panels. The glazed panels were glass, acrylic and polycarbonate with a thickness of 4 mm. The experiments were conducted in a transmission loss facility consisting of semi anechoic and reverberation chambers. The panels were subjected to airborne sound and the data collected. Glass, acrylic and polycarbonate panel absorb noise most effectively above 500 Hz with the absorption peaks at 1000 Hz. The single number sound reduction index (RW) for glass, polycarbonate and acrylic were 41 dB, 38 dB and 37 dB, respectively. This could be attributed mainly to the material density which is higher for the glass. Keywords: Sound transmission loss; glazing; insulation; weighted index

Download Full-text

Sound Reduction of Ventilation Ducts through Walls: Experimental Results and Updated Models

Acoustics ◽

10.3390/acoustics3040044 ◽

2021 ◽

Vol 3 (4) ◽

pp. 695-717

Author(s):

Erik Nilsson ◽

Nikolaos-Georgios Vardaxis ◽

Sylvain Ménard ◽

Delphine Bard Hagberg

Keyword(s):

Transmission Loss ◽

Measurement Data ◽

Combined System ◽

Ventilation Ducts ◽

Negative Effect ◽

The Difference ◽

Pass Through ◽

Sound Reduction ◽

Ventilation Duct ◽

Reduction Index

Ventilation ducts can have a negative effect on the sound reduction index between two rooms if they pass through the dividing structure without treatments. The overall sound reduction of a ventilation duct is dependent on several factors including the transmission loss when sound is breaking in and out from the duct. This study aims to model the sound reduction of a combined system with a separating wall and a ventilation duct through it. Three walls, characterized according to ISO 717-1, are combined with three different ventilation ducts, two circular and one rectangular with different dimensions. Laboratory measurement data are used to determine the sound reduction of the different configurations and the type of treatments needed for each configuration. A proposed model with existing theory for describing sound transmission losses of circular and rectangular ventilation ducts predicts the shape of the measurement data for many frequency bands. A new theory part is developed through an iterative process for circular ducts, which is based on measurements with previous methods and studies as a guide because the existing prediction scheme is somewhat perplexing. For rectangular ducts, the existing theory has been updated to better match measurement data. The application of the proposed theory and model in this article shows similar results when compared to measurements. The difference in weighted sound reduction index between developed theories and measurement data is 0–1 dB for every configuration.

Download Full-text

Prediction of sound reduction index of plenum window by the surface impedance approach

Applied Acoustics ◽

10.1016/j.apacoust.2020.107851 ◽

2021 ◽

Vol 175 ◽

pp. 107851

Author(s):

Liangfen Du ◽

Siu-Kit Lau ◽

Siew Eang Lee

Keyword(s):

Surface Impedance ◽

Sound Reduction ◽

Reduction Index

Download Full-text

Assessment of heavy metals contamination and associated risks in shallow groundwater sources from three different residential areas within Ibadan metropolis, southwest Nigeria

Applied Water Science ◽

10.1007/s13201-021-01414-4 ◽

2021 ◽

Vol 11 (5) ◽

Author(s):

Saheed Adekunle Ganiyu ◽

Abimbola Temitope Oyadeyi ◽

Azeem Adedeji Adeyemi

Keyword(s):

Heavy Metals ◽

Cancer Risk ◽

Urban Area ◽

Ecological Risk ◽

Water Samples ◽

Risk Index ◽

Shallow Groundwater ◽

World Health ◽

Southwest Nigeria ◽

The Mean

AbstractThis study has been conducted to appraise the concentrations of selected heavy metals and total dissolved solids (TDSs) in the drinking water from shallow wells in parts of Ibadan metropolis, southwest Nigeria. Fifteen (15) water samples were collected from three representative residential locations [traditional core area (TCA), peri-urban area (PUA), and urban area (UA)] for geochemical analysis. Heavy metals and TDS were analyzed with the aid of atomic absorption spectrophotometer and calibrated meter, respectively. The mean concentration (mg/L) of Zn, Pb Mn, Fe, and Cd has been 3.930, 0.658, 0.0304, 1.698, and 0.501, respectively, and as a consequence, the order of abundance of studied metals was Zn > Fe > Pb > Cd > Mn. Concentrations of Zn, Fe, Pb, and Cd were higher than recommended standards in 60%, 86.7%, 100%, and 100% of groundwater samples, respectively. However, at all points tested, the mean concentrations of Mn and TDS in water samples lie within the safe limits set by World Health Organization. The evaluation of geoaccumulation index (Igeo), enrichment factor (EF), and contamination factor suggests that representative water samples were low-to-moderate contamination. The potential ecological risk index advocates low-to-moderate ecological risk in TCA and PUA, while it demonstrated exclusive “moderate” risk in UA. Further, the range of pollution load index (PLI) (0.55–1.32) in both TCA and PUA shows nil-to-moderate pollution status, while PLI values > 1 in UA indicate moderate contaminated state. The degree of contamination in groundwater showed the following trends: UA > TCA > PUA in the study area. Moreover, the results of EF and quantification of contamination of analyzed metals in water samples indicate geogenic and anthropogenic inputs. The contribution of studied metals to the incidence of non-cancer risk via oral intake within the residential sites follows the order: cadmium > lead > zinc > iron > manganese. The hazard index as a result of ingested heavy metals for the three population classes surpasses the acceptable range in the order of infant < child < adult. Cadmium and lead made considerable impact to the estimation of cancer risk in the study area for the three human population categories. Factor analysis extracted only one component that explained 94.64% of the entire variance, while cluster analysis identified three distinct groups based on similar water quality characteristics. Based on the findings of the study, awareness programs toward protecting the shallow groundwater sources should be launched, encouraged, and sustained. Moreover, the study suggests better hygienic practices and pre-treatment of contaminated water before consumption.

Download Full-text

Prevalence of Underweight, Overweight and Obesity in School-Aged Children in the Urban Area of the Northwestern Part of Romania

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18105176 ◽

2021 ◽

Vol 18 (10) ◽

pp. 5176

Author(s):

Tudor Lucian Pop ◽

Dana Maniu ◽

Daniela Rajka ◽

Cecilia Lazea ◽

Gabriel Cismaru ◽

...

Keyword(s):

Urban Area ◽

Urban Areas ◽

Severe Obesity ◽

Task Force ◽

National Level ◽

Overweight And Obesity ◽

Excess Weight ◽

World Health ◽

Northwestern Part ◽

Obesity In Children

Introduction: During the last three decades, there has been an excess weight epidemic due to changes in nutrition and lifestyle. Few data on the prevalence of overweight and obesity in children in Romania were published, without a single study representative at the national level. There are reports on the higher level of overweight and obesity in urban areas compared to rural ones. This study aimed to estimate the prevalence of underweight, overweight, obesity and severe obesity in children enrolled in schools from the urban area. Material and methods: For this cross-sectional study, children from 177 schools from the urban area of five counties from the northwestern part of Romania were included after the parents signed written informed consent. Anthropometric data were recorded (weight, height) based on World Health Organization (WHO) recommendations and Body-Mass-Index (BMI), and the z-score for BMI were calculated. The nutritional status was estimated using three reference criteria: WHO, International Obesity Task Force (IOTC) and the Center for Disease Control and Prevention (CDC). Results: We analyzed data of 21,650 children (48.19% boys) age between 7 and 18 years. The prevalence of overweight was 13.8%, 16.2% and 20.3%, of obesity was 10.7%, 10.0% and 5.7% and of severe obesity was 5.1%, 1.2% and 1.6% (using WHO, CDC and IOTF cut-offs). Underweight was present in 5.2% (WHO), 6% (CDC) and 2.6% (IOTF). The highest prevalence of overweight (including obesity) was found in children aged 10 years, and the lowest in adolescents at 18 years. Boys have a higher prevalence of excess weight than girls. Using IOTF cut-offs, the prevalence of obesity and severe obesity was lower than using WHO criteria. Conclusions: The prevalence of overweight (including obesity) in children from the urban area of Western Romania was recorded at alarming levels, higher in boys and at the pre-puberty ages. There are significant differences based on the reference system used. It is important to correctly choose the reference for the definition of overweight and obesity to have the correct estimation of the target for public health measures.

Download Full-text

Knowledge of HIV and benefits of male medical circumcision amongst clients in an urban area

African Journal of Primary Health Care & Family Medicine ◽

10.4102/phcfm.v6i1.722 ◽

2014 ◽

Vol 6 (1) ◽

Author(s):

Abidemi Faleye

Keyword(s):

Urban Area ◽

Hiv Transmission ◽

World Health ◽

Routine Practice ◽

Cross Sectional ◽

Innovative Methods ◽

Validated Questionnaire ◽

Preventative Strategy ◽

Set Up ◽

Health Organization

Background: Male medical circumcision (MMC) has been shown to reduce the risk of HIV transmission in circumcised men by up to 60%. Following recommendations from the World Health Organization, South Africa adopted MMC as a preventative strategy against HIV in 2010 and set up circumcision camps across the country. Concerns have been raised about condom avoidance following MMC because of a mistaken belief about the benefits of MMC.Aim and setting: The aim of this study was to describe the profile and knowledge about HIV and circumcision amongst men presenting for MMC in an urban area in KwaZulu-Natal.Methods: This was a cross-sectional descriptive study of 394 clients over the age of 18 years who presented to two MMC sites in Durban between November 2012 and March 2013. A validated questionnaire was used to collect data.Results: The mean age of clients presenting for MMC was 28 years. Most clients were black, single, unemployed and sexually active. The majority presented for MMC because they believed that MMC would reduce their risk of acquiring HIV infection. Knowledge about HIV transmission was very good and 86.3% of clients were aware that risky sexual behaviour suchas condom avoidance could reverse the benefits of MMC.Conclusion: The knowledge of HIV and benefits of MMC was very good amongst those presenting for MMC. However as MMC is primarily a preventative strategy, innovative methods to promote MMC prior to first sexual encounter need to be explored. Further research is needed to determine whether the benefits of MMC on the reduction of HIV transmission aresustained in routine practice. [Full text article to follow]

Download Full-text

Survey of hearing disorders in an urban population in Rondonia, Northern Brazil

Revista de Saúde Pública ◽

10.1590/s0034-8910.2013047004059 ◽

2013 ◽

Vol 47 (2) ◽

pp. 309-315 ◽

Cited By ~ 4

Author(s):

Maria Cecilia Bevilacqua ◽

Marcos Roberto Banhara ◽

Ariadnes Nobrega de Oliveira ◽

Adriane Lima Mortari Moret ◽

Katia de Freitas Alvarenga ◽

...

Keyword(s):

Hearing Loss ◽

Hearing Impairment ◽

Urban Area ◽

Pure Tone Audiometry ◽

Household Survey ◽

World Health ◽

Hearing Disorders ◽

Cross Sectional ◽

Northern Brazil ◽

Health Organization

OBJECTIVE: To identify the prevalence of hearing loss for the population in the urban area. METHODS: A cross-sectional household survey based on the World Health Organization Ear and Hearing Disorders Survey Protocol was conducted in 298 households in the urban area of Monte Negro, Rondonia, Northern Brazil, from 2005 to 2007. Ear examinations, behavioral audiometry and pure tone audiometry were conducted on 577 individuals. RESULTS: The results showed that 3.8% (95%CI 2.17;5.45) of population were classified in the disabling hearing impairment category. The prevalence of moderate hearing impairment was 3.4%; severe impairment was 0.4%; and profound hearing impairment was not found. CONCLUSIONS: The impairing hearing loss prevalence found in this study is within of the international prevalence for this level of hearing loss and smaller than observed in a previous study in the South region of Brazil.

Download Full-text