Improvement of natural fiber's properties and evaluation of its applicability as eco-friendly materials in noise pollution control.

Purpose: The use of green and eco-natural fibers due to availability, biodegradability, reasonable cost, and non-toxic effects are known as potential acoustic materials in research. Nevertheless, in this area, the use of chemical treatment in natural fibers as an effective strategy to improve the overall properties and acoustic performance is faced with limitations. So that the current paper aims to investigate the effect of alkali treatment on the mechanical and acoustical properties of jute fibers and evaluation of its applicability in noise pollution control. Methods: To determine the effect of alkali treatment on the sound absorption behavior of jute fibers, a sufficient amount of both types of fibers (raw and treated) were used to the fabrication of acoustic samples with thicknesses of 30, 40 and 50 mm at a density of 200 kg/m3. The acoustic evaluation was measured by the Impedance tube system according to transfer function method using by the standard ISO 10534-2. The morphological and tensile properties of fibers were evaluated by the Scanning Electron Microscopy (SEM) and tensile test (ASTM C1557-14 standard). Moreover, Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD) were used to study and compare the chemical properties of raw and treated fibers. Results: The result showed that the mean tensile strength and crystallinity index (CI) of treated fibers comparing with raw fibers increased by 61.66% and 3.26% respectively. The use of Alkali treatment helped to improve sound absorption performance of jute fibers with different thicknesses. Furthermore, noise reduction rate (NRC) in treated acoustic samples compared to untreated with a thickness of 50 mm increased from 0.66 to 0.69. Conclusion: Finally, the alkali treatment has enhanced the properties of jute fibers and confirmed the applicability of these fibers in acoustic absorption. Supplementary Information: The online version contains supplementary material available at 10.1007/s40201-022-00799-x.

Influence of Fe3O4 and Carbon Black on the Enhanced Electromagnetic Interference (EMI) Shielding Effectiveness in the Epoxy Resin Matrix.

The present study aims to investigate the shielding properties of the electromagnetic interference of polymer nanocomposites with different weight percentages of magnetite nanoparticles and cost-effective carbon black nanoparticle (CBN) on different thicknesses. X-ray diffraction test, Raman spectroscopy, the scanning electron microscopy, and the transmission electron microscope analysis were used for investigating the crystallographic structure, morphology and microstructure of the material. The nanocomposites were successfully prepared using a simple mixing and casting. Their shielding efficiency was measured by a vector network analyzer (VNA) in the frequency range of 8.2 ~ 12.4 GHz. The maximum total shielding efficiency was 36.6 dB at 8.2 GHz for a weight percentage of 15% Fe3O4 composite and 50% CBN (0.7 mm thickness). The results showed that with an increase of nanocomposite thickness, there is a shift of absorption shielding efficiency peak toward a higher frequency. In addition, nanocomposites had the greatest shielding effectiveness in the low-frequency range. It was found that the proper combination of electrical and magnetic losses causes excellent wave absorption. These findings indicated that epoxy resin with a combination of optimal weight percentage of magnetite and carbon black nanoparticle can be used as a suitable shielding in low thickness.

Predicting and classifying hearing loss in sailors working on speed vessels using neural networks: a field study.

BACKGROUND:  Noise-induced hearing loss (NIHL) is one of the main risk factors affecting people's health and wellbeing in the workplace. Analysing NIHL and consequently controlling the causing factors can significantly affect the improvement of working environments. Methods: One hundred and twelve male sailors participated in this study. They were classified into three groups depending on occupational noise exposure: (A) none, i.e., sound pressure level (SPL) lower than 70dBA, (B) exposed to SPL in the range of 70-85dBA, and (C) exposed to SPL exceeding 80dBA. In a first phase, hearing loss shaping risk factors were identified and analysed, including hearing loss in different frequencies, age, work experience, sound pressure level (SPL), marital status, and systolic and diastolic blood pressure. Then, neural networks were trained to predict the hearing loss changes of personnel and used to determine the weight of hearing loss factors. Finally, the accuracy of predicting models was calculated relying on Bayesian statistics. Results and conclusion: In the present study using neural networks, five models were developed. Their accuracy ranged from 92% to 100%. The frequencies of 4000Hz and 2000Hz showed the strongest association with the hearing loss of the sailors. Also, including systolic and diastolic blood pressure did not have any impact on predicted hearing loss, indicating that SPL was poorly correlated with extra-auditory effects.

Effect of the level of manual performance disability caused by exposure to vibration among sailors working on sailing speed vessels.

BACKGROUND: hand-arm vibration is one of the typical annoying physical factors. Hand-arm vibration syndrome (HAVS) is a disorder caused by vibrating working tools which vibrate hands beyond the threshold. Long-term HAVS may result in damage to blood vessels, chronic numbness in the fingers, bone injury, and muscular weakness. People are exposed to high-rate noise vibration in a variety of situations, including vessel employment and operating in tiny boats. Moreover, the extant study was conducted to examine manual function disability levels caused by Sailing Speed Vessels (SSV) vibration. METHODS: The extant study was quasi-experimental research in which, 52 male sailors in SSVs were chosen as the experimental group, and 27 office personnel were selected as the control group. The demographic factors questionnaire, DASH questionnaire, grip and pinch strength tests, the neurosensory exam, and the skill-dexterity test were all employed in this study. SPSS23 software was used to analyze the data. RESULTS: The findings suggested that the experimental group experienced greater vibration disorder symptoms than the control group. Because the experimental group had a higher score, the individuals experienced poorer circumstances in terms of arm, shoulder, and hand impairment as compared to the control group. The mean grip strength of hands and fingers in two hands of the experimental group was lower than the control group (P < 0.05). There was a statistically significant relationship among grip strengths of both experimental and control groups (P < 0.05). There was a reduction in skill and dexterity of both dominant and non-dominant hands of members in the experimental group. According to the statistical tests, there was no significant association between dominant (P = 0.001) skills and non-dominant (P = 0.010) hands in experimental and control groups. There was not also any significant relationship between skill and dexterity of both hands (P = 0.001) and the dominant hand tweezer test (P = 0.001) in two experimental and control groups. There was a statistically significant association between experimental and control groups in terms of assembly skill and dexterity (P = 0.482). CONCLUSION: Individuals who are at risk of vibration experience less physical and sensory function. DASH score, grip strength, skill, and dexterity could predict the reduction in physical function disability.

Development of modified rapid entire body assessment (MOREBA) method for predicting the risk of musculoskeletal disorders in the workplaces.

BACKGROUND: Rapid Entire Body Assessment (REBA) technique is one of the tools developed for predicting the risk of musculoskeletal disorders based on the effective risk factors. This method has several limitations. The present study was aimed to develop the Modified Rapid Entire Body Assessment (MOREBA) method to more accurately predict the risk of musculoskeletal disorders. MATERIALS: This cross-sectional study was performed on 300 male workers of a steel factory with a variety of job tasks in Iran. Then, the information related to the various physical risk factors was extracted through observation of their duties and conversation with them. Also, the subjects were asked to complete the Persian version of Cornell musculoskeletal discomfort questionnaires (CMDQ). Then, a theoretical model was drawn in AMOS software. Computed coefficients were used to develop the MOREBA equation. In the end, the final scores were categorized by ROC curves, and the validation of the novel method was investigated using linear regression analysis. RESULTS: The parameters evaluated in the MOREBA method included contact stress, rapid and sudden movement, throwing motion, hand-arm vibration, whole-body vibration, temperature, and work-rest cycle in addition to the parameters of the REBA method, including awkward posture, coupling, force, load, static activity, and repetitive activity. The results showed that the strain produced by the physical risk factors with the total effect coefficient of 0.783 could significantly affect the musculoskeletal symptoms. The computed coefficients of the risk factors were applied to develop a novel index. The final score of the MOREBA method was categorized into four levels by optimal cut-off points of 12.37, 16.51, and 24.35. Based on the results, the MOREBA and REBA methods could justify 67 and 55% of the variations of musculoskeletal symptoms, respectively. CONCLUSIONS: The results revealed that modifications conducted in the REBA method were effective, and the MOREBA method can provide a more accurate prediction of the risk of musculoskeletal disorders.

Risk assessment of fire, explosion and release of toxic gas of Siri-Assalouyeh sour gas pipeline using fuzzy analytical hierarchy process.

BACKGROUND: Risk assessment of gas pipelines is very important because of various hazards and economic losses. Using fuzzy logic increases the reliability and accuracy of the results. The purpose of this study is to evaluate the fuzzy risk of fire, explosion and release of toxic gas in the pipeline using fuzzy analytical hierarchy process. METHODOLOGY: Extraction of all hazards from HAZOP and HAZID was carried out. Fuzzy risk assessment was performed using MATLAB software. Using fuzzy hierarchy process analysis, the weight of each basic risk item (BRI) was summed up in a framework, and the fuzzy risk level was determined with a five-state criterion including highly desirable, favorable, moderate, undesirable and highly undesirable. RESULTS: The final risk score was equal to 0.1492, which according to the five-state criterion the risk level is in the favorable area. The highest risk score was related to hot work with open flame item with a risk score of 0.2485. CONCLUSIONS: The final risk score of fire, explosion and release of toxic gas in Siri-Assaluyeh gas pipeline is in the optimal area. Fuzzy risk assessment, compare to conventional risk matrices, provides more data to safety managers about the hazards and their rankings. Accordingly, the results are expected to be applicable to the safety managers while making decisions related to the risk management of gas pipelines.

Comprehensive analysis and investigation of accident/occupational disease responsibility rates: A case study for accidental CO poisoning.

One of the major problems of courts and insurance companies is the lack of a proper technique to determine the rate of responsibility of the parties involved in the accident. The aim of this study was to determine the Accident/Occupational Diseases Responsibility Rates (AOD RR) for complex events. Accordingly, a case study of a complex accident of carbon monoxide (CO) poisoning was selected and Occupational Accident Tree Analysis (OATA) and Occupational Accident Component Analysis (OACA) techniques, which were solely used to investigate occupational accidents, were used with the new names Accident/Occupational Disease Tree Analysis (AOD TA) and Accident/Occupational Disease Component Analysis (AOD CA) to evaluate their applicability to investigate non-occupational accidents and occupational diseases. For this purpose, causes of CO penetration to victims' room was assessed using gas tracking methods. Finally, Fuzzy Accident/Occupational Disease Tree/Component Analysis (FAOD TA and FAOD CA) techniques were developed and used for determining AOD RR in fuzzy environment. The results showed that the AOD RR obtained by AOD TA and AOD CA based on the average of experts' personal opinions and consensus between experts, and AOD TA and AOD CA in a fuzzy environment were close to each other, with the power terminal and the power cable crossing route being the main routes of transmission and penetration of CO to the victims' room. Also, the owner, contractor, tenant, and serviceman were responsible for the CO poisoning of victims. It can be concluded that any hole, crack, or fission in the building can result in CO penetration to the individuals' living rooms, and gas tracking in early winter, especially in older buildings, plays a very significant role in preventing residents' poisoning. Further, due to the uncertainty of AOD TA and AOD CA techniques, it is recommended to use FAOD TA and FAOD CA techniques for increasing the accuracy of the results. This will enhance the court and insurance companies' trust in the opinions of accident investigation experts, decrease delays in the proceedings, and prevent any violation of the individual rights.

Epidemiology and risk factors of needlestick injuries among healthcare workers in Iran: a systematic reviews and meta-analysis.

BACKGROUND: Occupational contact with blood and body fluids poses a significant risk to healthcare workers. The aim of this systematic review is to investigate the epidemiology and risk factors affecting needlestick injuries (NSI) in healthcare personnel in Iran. METHODS: In March 2020, researchers studied six international databases such as Medline/PubMed, ProQuest, ISI/WOS, Scopus, Embase, and Google Scholar for English papers and two Iranian databases (MagIran and SID) for Persian papers. Joanna Briggs Institute (JBI) Critical Appraisal Checklist was used to assess quality of studies. The method of reporting was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. RESULTS: A total of 43 articles were included in the analysis. Results showed that females (OR = 1.30, 95 % CI 1.06-1.58, P value = 0.009), younger age (OR = 2.75, 95 % CI 2.27-3.33, P value < 0.001, rotated shift workers (OR = 2.16, 95 % CI 1.47-3.15, P value < 0.001), not attending training courses (OR = 1.30, 95 % CI 1.07-1.56, P value = 0.006), working in the surgery ward (OR = 1.83, 95 % CI 1.33-2.50, P value < 0.001), less work experience (OR = 1.43, 95 % CI 1.04-1.95, P value = 0.025) apposed a greater risk factors for NSI among healthcare workers. CONCLUSION: Based on the results of this review, factors such as young age, less work experience, work shift, and female gender are considered as strong risk factors for NSI injury in Iran. Preventive measures including education programs can reduce the burden of NSI among healthcare personnel.

Presentation of a model-based data mining to predict lung cancer.

BACKGROUND: The data related to patients often have very useful information that can help us to resolve a lot of problems and difficulties in different areas. This study was performed to present a model-based data mining to predict lung cancer in 2014. METHODS: In this exploratory and modeling study, information was collected by two methods library and field methods. All gathered variables were in the format of form of data transferring from those affected by pulmonary problems (303 records) as well as 26 fields including clinical and environmental variables. The validity of form of data transferring was obtained via consensus and meeting group method using purposive sampling through several meetings among members of research group and lung group. The methodology used was based on classification and prediction method of data mining as well as the method of supervision with algorithms of classification and regression tree using Clementine 12 software. RESULTS: For clinical variables, model's precision was high in three parts of training, test and validation. For environmental variables, maximum precision of model in training part relevant to C&R algorithm was equal to 76%, in test part relevant to Neural Net algorithm was equal to 61%, and in validation part relevant to Neural Net algorithm was equal to 57%. CONCLUSION: In clinical variables, C5.0, CHAID, C & R models were stable and suitable for detection of lung cancer. In addition, in environmental variables, C & R model was stable and suitable for detection of lung cancer. Variables such as pulmonary nodules, effusion of plural fluid, diameter of pulmonary nodules, and place of pulmonary nodules are very important variables that have the greatest impact on detection of lung cancer.

Ambient x-ray pollution assessment at inspection gates of airports- a case study of Mehrabad and Imam Khomeini Airports in Iran.

BACKGROUND: As a well-known, physical carcinogen, ambient X-ray pollution assessment would be of great importance in today's modern world. Accordingly, the present study was done to measure the exposure level of ambient X-ray at inspection gates of two airports in Iran. According to which, the X-ray was measured at different points of the inspection gates including closed and opened Curtain, as well as seating place of operators beside the X-ray inspection systems. The recorded data were then analyzed by "sign" and t-tests. RESULTS: The total average exposure level of the measured x-ray was 2.68 ± 0.73 µsv.h(-1). The measured x-ray exposure level was 2.07 ± 0.61 (µsv.h(-1)) released from RAPISCAN X-ray inspection system and 3.3 ± 1.34 (µsv.h(-1)) emitted from HEIMANN X-ray inspection system. Comparison of average x-ray doses of the systems in both airports showed that the minimum and maximum exposure levels were recorded at 1(m) far from the devices and at the entrance of the devices, respectively. CONCLUSIONS: The exposure levels at all measurement points were lower than the occupational exposure limit. This reveals the fact that the exposed operators are not probably at risk of adverse health effects.

Outpatient and inpatient services satisfaction in Iranian military hospitals.

BACKGROUND: Many diagnostic and treatment procedures are done in hospitals and clinics. Offering services in these areas have a prominent role in promoting patients' satisfaction levels and their prospective about health services. OBJECTIVES: This study is going to assess the satisfaction levels of patients referring to the six military hospital clinics in Iran. MATERIALS AND METHODS: In this cross-sectional study, 330 outpatients and 696 inpatients admitted to the six military hospital clinics in Iran were randomly questionnaires from June to August 2008. Basic socio-demographic data along with a clinic satisfaction level assessment questionnaire were filled for outpatients. A hospital satisfaction level assessment questionnaire also was applied to record inpatients' data. All collected data were recorded and then analyzed tests X2 and ANOVAs was used and with significantly lower levels of 5% (P < 0.005). RESULTS: We found that 96% of the study population was satisfied with clinic services and more than 98% of the respondents were satisfied with inpatient ward services. In clinic services, the satisfaction level in numbering and waiting time, access to the clinic, physical environment, welfare and helping facilities, and personnel and physicians' behavior were 78.2%, 80.6%, 89.1%, 91.2% and 93.6% respectively (P < 0.001). With regard to inpatient services, the satisfaction level of patients with physician services, nursing routine services, behavior of nurses, nutritional condition, welfare facilities, reception unit services, discharge unit services and accounting unit services were 94.7%, 91.9%, 91.9%, 91.5%, 91.5%, 91.2%, 90.8% and 88.2%, respectively (P = 0.013). CONCLUSIONS: On the basis of the findings, most respondents reported having a favorable satisfaction with clinic and hospital health services. However, planning to reduce patient's waiting time in clinics and training physicians to offer more instructions to the patients seems necessary. Since discharge and accounting unit services had the lowest satisfaction levels of inpatients services, responsible managers must have special attention to these official processes.