Acoustical and Thermal Characterization of Insulating Materials Made from Wool and Sugarcane Bagasse

Utilizing agricultural waste and natural fibers minimizes environmental impact and can improve the acoustic and thermal conditions of buildings. Natural fibers can be an alternative to non-biodegradable synthetic sound-absorbing materials. This study aimed to investigate the acoustic and thermal properties of insulating materials made from wool and sugarcane bagasse. Thermal conductivity, thermal resistance, acoustic and moisture absorption, and fire properties of five insulating materials made from sheep wool, goat fiber, camel wool as well as pith and fiber bundles of sugarcane bagasse were determined. The measurement of the sound absorption coefficient was performed in an impedance tube. The thermal resistance and thermal conductivity coefficient were measured according to the ASTM D5334–08 Standard. The findings show that camel wool has the highest sound-absorbing performance, thermal insulation, and fire-resistant properties. The lowest value of the noise reduction coefficient (NRC) was 0.52 for goat fiber, and the highest was 0.74 for camel wool. The maximum sound absorption coefficient of camel wool was 0.95 at a frequency above 1000 Hz. Thermal conductivity varies between 0.038–0.046W/(M.K). Hence, all materials tested can be considered thermally insulating. The results showed insulating materials made from wool, especially camel wool, had better performance than fiber and pith of sugarcane bagasse

Evaluation of the adsorption capacity of nano-graphene and nano-graphene oxide for xylene removal from air and their comparison with the standard adsorbent of activated carbon to introduce the optimized one

Introduction: Volatile organic compounds from industrial activities are one of the most important pollutants released into the air and have adverse effects on human and environment. Therefore, they should be removed before releasing into atmosphere. The aim of the study was to evaluate xylene removal from air by nano-grapheme and nano-graphene oxide in comparison with activated carbon adsorbent. Material and Method:  After preparing adsorbents of activated carbon, nano-graphene, and nano-graphene oxide, experiments adsorption capacity in static mode (Batch) were carried out in a glass vial. Some variables including contact time, the amount of adsorbent, the concentration of xylene, and the temperature were studied. Langmuir absorption isotherms were used in order to study the adsorption capacity of xylene on adsorbents. Moreover, sample analysis was done by gas chromatography with Flame Ionization Detector (GC-FID). Results: The adsorption capacities of activated carbon, nano-graphene oxide and nano-graphene for removal of xylene were obtained 349.8, 14.5, and 490 mg/g, respectively. The results of Scanning Electron Microscope (SEM) for nano-graphene and nano-graphene oxide showed particle size of less than 100 nm. While, the results of Transmission Electron Microscope (TEM) showed particle size of 45nm for nano-graphene and 65 nm for nano-graphene oxide. Also, X-Ray Diffraction (XRD) showed cube structure of nano-adsorbents. Conclusion: In constant humidity, increase in exposure time and temperature caused an increase in the adsorption capacity. The results revealed greater adsorption capacity of xylene removal for nano-graphene compared to the activated carbon, and nano-graphene oxide

Study of Biomechanical Risk Factors for Musculoskeletal Disorders in the Bakery Business Based on ART and OCRA Index

Background:Bakery workers, Beacause of their nature, are at risk of musculoskeletal disorders caused by ergonomic factors. The purpose of this study was to evaluate the biomechanical risk factors for musculoskeletal disorders in bakery workers. Methods: In the current study, all tasks of sangak, taftoon, and lavash bakery in Gonabad were selected based on the census method. Next, Hierarchical Task Analysis (HTA) method was used for task analysis, and the job was degraded to tasks, actions, and movements. For the following step, the ART and OCRA method was implemented to identify common risk factors in repetitive tasks that can contribute to developing musculoskeletal disorders of upper limbs. Analysis of the results in this study was performed using SPSS 17. Results: According to the results study, the ART and OCRA index score for shater and chonegir tasks for all three kinds of bakeries is at high risk (red zone). In ART index score of arm movements, repetition, force, head/neck posture, and back posture for shater and choonegir task in lavash and taftoon bakery and shater task in sangak bakery is in its maximum levels. This reflects the level of red risk and indicates that in these tasks, fast arm movements, repetition, force, head/neck posture, and back posture are recognized as major occupational risk factors in these tasks. Conclusion: The results showed that the risk of musculoskeletal disorders owing to repetitive tasks is relatively high in the bakery and ergonomic interventions are required to redesign the job. This study shows the use of the ART method as a practical, applicable, easy, and convenient method for evaluation and ergonomics interventions in repetitive work tasks