Background: Exhaust noise is known to be a major pollutant in the environment and workplaces due to the development of industry and transportation. Exhaust noise can be reduced to normal levels by mufflers or silencers. A reactive muffler efficiently dampens noise at low frequencies by reflecting sound waves. Therefore, muffler design is of great importance in exhaust noise reduction. Transmission loss (TL) is an essential characteristic of mufflers, demonstrating their acoustical properties. Any acoustical appliance is selected based on its damping performance and reliability. Predicting TL through experimentation is different from theoretical calculations. Methods: In the present study, a double-expansion chamber muffler was designed as a reflective muffler on a laboratory scale by equations. Next, TL was evaluated by an impedance tube applying a 4-microphone technique to determine the acoustical performance of the designed muffler. Results: Findings revealed that the TL of the muffler at 312 Hz frequency obtained 27.5 dB agreement with the required TL of the muffler of 25 dB. In addition, the TL of the muffler against frequency attenuates noise in broadband frequencies. Conclusions: These results indicated that the built muffler provides desired TL for exhaust chambers. Therefore, equations can be used as a precise method for muffler design. Furthermore, multi-expansion chamber mufflers are useful for reducing noise at a wide range of frequencies.
Purpose Noise pollution is a common health hazard worldwide which is emitted along with chemical air pollutants, simultaneously from many sources. Some studies have been conducted to control these pollutants, simultaneously with promising results being achieved. Dielectric beads have been used in air pollution control technologies, successfully and probable effectiveness of them in noise reduction can be promising in dual use of them in the exhausts emitting noise and air pollution, simultaneously. Methods In order to investigate the effectiveness of dielectric beads in noise reduction, two types of them; namely glass and ceramic beads, were placed separately inside the connecting tube of a double-expansion chamber muffler. Then the transmission loss (TL) of muffler was examined using impedance tube. A factorial design was used to evaluate and optimize the effect of noise related parameters on TL of such a system. Results Results show that the presence of dielectric beads has significant effect on TL of muffler. The maximum TL was obtained as 74.76 dB for muffler with ceramic beads, under the optimal condition of 5250 Hz and 120 dB. Measurement of TL and sound absorption coefficient (SAC) of glass and ceramic beads showed that the noise reduction in muffler with ceramic and glass beads is probably due to SAC in ceramic beads and noise reflections in glass beads, respectively. Conclusion These results promise the dual use of dielectric beads in the exhausts emitting noise and air pollution simultaneously.
Sulfur dioxide, a noxious air pollutant, can cause health and environmental effects, and its emissions should be controlled. Nonthermal plasma is one of the most effective technologies in this area. This study evaluated the efficiency of a packed-bed plasma reactor (PBR) and in-plasma catalysis (IPC) in SO2 removal process which were finally optimized and modeled by the use of the central composite design (CCD) approach. In this study, SO2 was diluted in zero air, and the NiCeMgAl catalyst was selected as the catalyst part of the IPC. The effect of three main factors and their interaction were studied. ANOVA results revealed that the best models for SO2 removal efficiency and energy yielding were the reduced cubic models. According to the results, both PBR and IPC reactors were significantly energy efficient compared with the nonpacked plasma reactor and had high SO2 removal efficiency which was at least twice larger than that of the nonpacked one. Based on the results, the efficiency of IPC was better than in PBR, but its performance decreased over time. However, the PBR had relatively high SO2 removal efficiency and energy efficiency compared to the nonpacked reactor, and its performance remained constant over the studied time. In optimization, the maximum SO2 removal efficiency and energy efficiency were 80.69% and 1.04 gr/kWh, respectively (at 1250 ppm, 2.5 L/min, and 18 kV as the optimum condition) obtained by the IPC system which were 1.5 and 1.24 times greater than PBR, respectively. Finally, the model’s predictions showed good agreement with the experiments.
Air pollution is a major health problem in developing countries and has adverse effects on human health and the environment. Non-thermal plasma is an effective air pollution treatment technology. In this research, the performance of a dielectric barrier discharge (DBD) plasma reactor packed with glass and ceramic pellets was evaluated in the removal of SO2 as a major air pollutant from air in ambient temperature. The response surface methodology was used to evaluate the effect of three key parameters (concentration of gas, gas flow rate, and voltage) as well as their simultaneous effects and interactions on the SO2 removal process. Reduced cubic models were derived to predict the SO2 removal efficiency (RE) and energy yield (EY). Analysis of variance results showed that the packed-bed reactors (PBRs) studied were more energy efficient and had a high SO2 RE which was at least four times more than that of the non-packed reactor. Moreover, the results showed that the performance of ceramic pellets was better than that of glass pellets in PBRs. This may be due to the porous surface of ceramic pellets which allows the formation of microdischarges in the fine cavities of a porous surface when placed in a plasma discharge zone. The maximum SO2 RE and EY were obtained at 94% and 0.81 g kWh−1, respectively under the optimal conditions of a concentration of gas of 750 ppm, a gas flow rate of 2 l min−1, and a voltage of 18 kV, which were achieved by the DBD plasma packed with ceramic pellets. Finally, the results of the model's predictions and the experiments showed good agreement.
Poor water quality and lack of access to improved sanitation continue to pose a significant threat to human health. The burden of disease analysis suggests that lack of access to safe water supply, sanitation and hygiene is the third most significant risk factor for poor health in developing countries with high mortality rates. Diarrhoea is the leading disease associated with unsafe water supply, sanitation and hygiene and is responsible for the deaths. The study observed that out of the 150 respondents, 37% are 31-40 years, followed by 20-30 years with 32%. 130 (86.7%) respondents have got married, and 61% of the respondents are female. 85% adopted the nuclear family system, and 50% of respondents are illiterates in the study areas. 85% of respondents are daily wage earners, 37%are earnings rupees between 2000-2500 per month. 27% of respondents are landless labours, and 37% of households possess below 2 acres of land. 40% of respondents suffer from health problems, and 44% consume rice as their staple food. 62% of respondents have debts, and 33% got from money lenders. 62% of respondents do not have toilet facilities and go open defecation. 92% of respondents stated that toilet makes dignity, saves time and energy, saves their children school days, makes adolescent girls privacy, save wage loss, and toilet makes quality life.
Background: Ending open defecation has been identified as a top priority for reducing global inequalities in water and sanitation (WASH). It is explicitly referenced in sustainable development goals (SDGs) target 6.2 and closely associated with more comprehensive efforts to end extreme poverty by 2030. Since 2000, the global rate of open defecation has decreased from 21% to 9% (0.7 percentage points per year). However, the 673 million people still practicing open defecation in 2017 were increasingly concentrated in a small number of countries, and these will need to be the primary focus of efforts to end open defecation by 2030. Objectives: To study the socio-economic background of Adivasis, to study the status of sanitation in rural areas, to examine whether economic conditions affect open defecation, to examine whether better sanitation facilities improve health conditions and to examine whether improved sanitation facilities impact the quality of life and thereby dignity of tribal women. Methods: Essentially it is an empirical study and a multi-stage random sample design was adopted. Data were collected from 120 sample households from two villages, i.e., Bandarigudem and Nadikudi of Khammam districts in Telangana State through a structured questionnaire. Statistical tools like frequency distribution, percentages, cross-tabulation with Chi-Square test, and a case study method were used. Results & Discussion: This paper found that 35% of Adivasis have health problems, and 73% said that they are getting treatment with RMP. 87% have toilet facility and more than 12% still defecate openly. 18.3% said that they faced different problems at open defecation, and 50% of women not using sanitary napkins. Nearly 90% of respondents wash their hands after toilets and coming from outside of the home. Ten per cent of respondents said that they do not have an awareness of sanitation. Therefore, the study confirmed that the sanitation facilities considerably made the women's dignity and quality of life better in the study area. Moreover, four case studies also focused on open defecation problems in the study area.
Effective communication between patients and doctors is fundamental to high-quality healthcare, patient safety, and overall satisfaction. However, the onset of COVID-19 has prompted significant shifts in communication from in-room and face-to-face interactions to virtual consults. The impact of this pandemic related change on patient-doctor communication goals, processes, attributes, and environment remains unclear. We undertook a scoping review involving the systematic search of seven academic databases for relevant articles published up to and including June 2021. In total, 47 articles were identified that met the inclusion criteria. We applied the patient-doctor communication framework to guide our deductive thematic analysis of articles included, sorting results from reported studies and position papers into themes and sub-themes. The theme of communication goals highlighted sub-themes related to patient safety, convenience, affordability, and satisfaction; preparation included sub-themes on technology interventions, workforce training, and digital literacy; participant attributes included compassion for doctors and rebuilding trust among patients; and communication process included issues related to telemedicine or video conferencing, challenges with diminished patient privacy, and distractions in the patient's home setting. Finally, the environment theme included insights into doctors' workload, isolation, and anxiety and how changes requiring increases in virtual consults iteratively altered confidence in care provision and communication with patients. Results of the scoping review provide important insights for strengthening virtual patient-doctor interactions, including target areas for training and professional development during and beyond the current pandemic.
The anti-emetic activity of the leaves methanolic extracts of Cassia angustifolia Vahl., Cassia holosericea Fresen., Cassia italica Miller. Lam. ex F.W. Ander and Cassia purpurea Roxb., was evaluated in young chicks. Emesis was induced by copper sulfate (50 mg/kg), and the extracts were tested orally at a dose of 150 mg/kg. All the extracts significantly decreased the number of retching (p < 0.05 and p < 0.01) compared with standard chlorpromazine.
The current study was designed to explore the analgesic effects of methanol extracts from the leaves of Samanea saman Merr. and Prosopis cineraria Druce., using tail immersion test. Thermal stimuli produced painful reactions in mice by dipping the tail tips of the mice into hot water. Methanol extracts of the leaves of Samanea saman Merr. and Prosopis cineraria Druce. were administered intraperitoneally at the dose of 100mg /kg body weight. Pethidine 50mg/Kg intraperitoneally was used as a standard analgesic drug. The tail-flick latency delay was measured at 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 hours after the intraperitoneal administration. Both extracts produce analgesic effects when compared with pethidine.
Metabolic dysfunction-associated fatty liver disease (MAFLD) and type 2 diabetes (T2D) are interconnected metabolic disorders with significant health implications. However, a comprehensive understanding of the extent of their co-occurrence in Africa is lacking. The aim of this review was to determine the prevalence of MAFLD and its association with glycemic control (HbA1c) in persons with T2D in Africa. A systematic search was conducted on PubMed, Medline, Embase, Scopus, Global Health, and Web of Science from their inception to December 6, 2023. Data on MAFLD prevalence and correlation coefficients regarding its association with glycemic control were pooled through random effect meta-analyses. Potential sources of heterogeneity were investigated using subgroup analysis and meta-regression. A total of 10 studies were included in the meta-analysis of MAFLD prevalence, while 2 were incorporated in the analysis of the association between MAFLD and glycemic control. The pooled prevalence of MAFLD in persons with T2D was 48.1% (95% CI: 36.1–60.3). The subgroup analysis revealed regional variations in MAFLD prevalence, with rates of 44.7% (95% CI: 28.7–62.0) in sub-Saharan Africa and 55.3% (95% CI: 36.2–73.0) in Northern Africa. Additionally, we observed an increasing trend in MAFLD prevalence, recording 55.1% (95% CI: 43.6–66.1) in the recent five years. There was a weak positive correlation between MAFLD and HbA1c (r = 0.33, 95% CI: 0.18–0.47). The findings of this study highlight a high prevalence of MAFLD in persons with T2D in Africa, with a suggested link between MAFLD and suboptimal glycemic control. Therefore, healthcare providers should prioritize the screening and management of MAFLD in individuals with T2D to enhance their metabolic health.
Context: Menstruation is one of the most basic characteristic features of girls and inadequate knowledge of adolescent girls about menstruation can result in faulty menstrual hygiene management (MHM) and inappropriate dietary management both of these can causes diseases which is a major threat for adolescent health in developing countries like Bangladesh. Aim: To identify current knowledge, attitudes, and practices related to menstruation and menstrual hygiene management (MHM) among adolescent girls. Settings and Design: It is a descriptive cross-sectional study conducted in Jashore, Bangladesh. Methods and Materials: A pre-formed, pre-tested questionnaire was used. The questionnaire-based survey was conducted among randomly selected 250 adolescent girls between 10 and 19 years. Statistical analysis used: Data were analyzed statistically by Microsoft office excels and SPSS windows version 16 software programs. Results: Among 250 adolescent girls majority had their menarche between 12 and 15 years of age, 70% of adolescent girls of this study belonged to lower class families. This study revealed that 85% of the respondents had regular menstruation whereas 15% had irregular menstruations also. Most of them faced different types of Premenstrual syndrome including 76% from headache, 80% from lower abdominal pain, and 62.5% from fatigue and weakness. Only 56% had previous knowledge about puberty before attaining menarche. There was a statistically significant correlation between the mother’s education and the knowledge of participants about menstruation at puberty. All the participants used to bath and wash hand after changing pads whereas 80.8% used to avoid all types of exercises. Almost 94% of respondents used to dispose of their napkins properly. The micro-nutrient deficiency was also common; especially 49.2% were suffering from Iron deficiency and 69.6% from folic acids deficiency. Conclusion: Awareness programs regarding both menstrual hygiene and dietary management can aid to alleviate some complications during puberty and ensure better health for adolescent girls.
Background: Irritable bowel syndrome (IBS) is a very common gastrointestinal dis-order worldwide, but research regarding this disease is rare in Bangladesh. This studyaimed to assess the prevalence of IBS and its associated risk factors among universitystudents in Bangladesh.Methods: This is a cross-sectional study. A total of 300 randomly selected partici-pants were included in this study. By using a structured questionnaire and anthropo-metric methods, we collected all the required data for our study. The diagnosis of IBSwas based on Rome III criteria.Results: The overall prevalence of IBS was 39.3%, but the majority (77.3%) had nobasic awareness of IBS. In our study, anxiety and depression (χ2 = 6.817; odds ratio[OR] = 1.910; 95% confidence interval [CI] = 1.172, 3.113; P = 0.011) had a signif-icant relationship with IBS and IBS had a significant (P < 0.001) relationship withfood intolerance (χ2 = 8.737; OR = 2.130; 95% CI = 1.284, 3.531), chest pain(χ2 = 7.482; OR = 2.035; 95% CI = 1.218, 3.401), and insomnia (χ2 = 19.320;OR = 2.907; 95% CI = 1.794, 4.709). In our dietary data, the intake patterns of vege-tables (P = 0.000), fast food (P = 0.000), and tea–coffee (P = 0.003) showed astrong significant association with IBS. On the other hand, monthly household income(P = 0.154) and body mass index (BMI) (P = 0.138) showed no significant associa-tion with IBS. Among our study subjects, IBS-constipation (54.2%) was more com-mon than IBS-diarrhea (27.1%) and IBS-mixed (18.6%). Moreover, among the 118IBS respondents, 67.8% had a headache with increased flatulence (95.8%) as the mostcommon IBS-related complication.Conclusion: IBS is common in university students of Bangladesh and is associatedwith anxiety, depression, and particular dietary patterns.
Department Of Mathematics, National University Of Skills (nus), Tehran, Iran.
Police Academy, Egypt