Average Noise Research Articles

GPS displacement dataset for the study of elastic surface mass variations

Abstract. Quantification of uncertainty in surface mass change signals derived from Global Positioning System (GPS) measurements poses challenges, especially when dealing with large datasets with continental or global coverage. We present a new GPS station displacement dataset that reflects surface mass load signals and their uncertainties. We assess the structure and quantify the uncertainty of vertical land displacement derived from 3045 GPS stations distributed across the continental US. Monthly means of daily positions are available for 15 years. We list the required corrections to isolate surface mass signals in GPS estimates and screen the data using GRACE(-FO) as external validation. Evaluation of GPS time series is a critical step, which identifies (a) corrections that were missed, (b) sites that contain non-elastic signals (e.g., close to aquifers), and (c) sites affected by background modeling errors (e.g., errors in the glacial isostatic model). Finally, we quantify uncertainty of GPS vertical displacement estimates through stochastic modeling and quantification of spatially correlated errors. Our aim is to assign weights to GPS estimates of vertical displacements, which will be used in a joint solution with GRACE(-FO). We prescribe white, colored, and spatially correlated noise. To quantify spatially correlated noise, we build on the common mode imaging approach by adding a geophysical constraint (i.e., surface hydrology) to derive an error estimate for the surface mass signal. We study the uncertainty of the GPS displacement time series and find an average noise level between 2 and 3 mm when white noise, flicker noise, and the root mean square (rms) of residuals about a seasonality and trend fit are used to describe uncertainty. Prescribing random walk noise increases the error level such that half of the stations have noise > 4 mm, which is systematic with the noise level derived through modeling of spatially correlated noise. The new dataset is available at https://doi.org/10.5281/zenodo.8184285 (Peidou et al., 2023) and is suitable for use in a future joint solution with GRACE(-FO)-like observations.

Noise Control of Blunt Flat-Plate Using Slit and Dielectric Barrier Discharge Plasma

This paper investigates the combination of a slit at the blunt trailing edge of the flat plate and dielectric barrier discharge plasma to control the vortex shedding of the plate and its associated tonal noise. The noise and flow characteristics of the plate were measured using a far-field microphone array and the particle image velocimetry technique, respectively. The results show that the vortex shedding and the tonal noise can be significantly suppressed by the slit alone, with an average noise reduction of approximately 10 dB in the test Reynolds number. In addition, installing a plasma actuator inside the slit further suppresses the vortex shedding and reduces tonal noise. However, the additional control efficiency of the plasma decreases with increasing wind speeds, with a further 8 dB reduction at a wind speed of U∞=10 m/s (corresponding to an inducing blowing rate BR of 4.5%). However, only an additional 1.5 dB noise reduction is achieved at U∞=20 m/s (BR=2.25%). The particle image velocimetry snapshots were analyzed by proper orthogonal decomposition. The measurements clearly show the variation in vortex shedding at the trailing edge of the plate, revealing the underlying flow mechanisms that lead to the observed noise variations and frequency changes.

A high-performance conical-neck helmholtz resonator-based piezoelectric self-powered system for urban transportation

As urbanization accelerates, the issue of traffic noise escalates. Efficiently harnessing this prevalent acoustic energy and facilitating its collection and conversion has emerged as a notable challenge in contemporary research. This paper introduces a piezoelectric self-powered system anchored on a Conical-Neck Helmholtz Resonator-Based Piezoelectric Self-Powered System (CNHR-PSS) which places the piezoelectric device inside a Conical-Neck Helmholtz resonator. This system amalgamates acoustic energy harvesting, traffic noise abatement, and traffic condition discernment. It combines by two parts, including a Piezoelectric Self-Powered Node (PSN) and a machine learning algorithm. The PSN, employing the Conical Neck Helmholtz Resonator and piezoelectric module, seizes noise and transmutes it into electrical energy, showcasing robust scalability. Multiple PSNs coalesce to form a sound barrier for traffic noise mitigation. Concurrently, the voltage signals emanated by the PSN also encapsulate traffic status information. The algorithm extracts feature from the output signal and employs machine learning to decipher traffic conditions. Simulative and theoretical analyses affirm that the system can efficaciously harvest acoustic energy from urban traffic noise and attenuate noise, with a pinnacle output power of 0.52mW and an average noise reduction of 13.16 %. The recognition accuracy of traffic conditions via SVM attained 100 %. The investigative outcomes underscore the exemplary performance of this self-powered system, rendering it a viable solution for applications in traffic noise mitigation and intelligent transportation.

Assessment of noise complaints as an indicator of long-term effects of aircraft noise on communities surrounding aerodromes

Aircraft noise is considered by many as the most burdensome part of aircraft operations. Communities neighbouring airports often express concerns about the possible health effects of chronic exposure to noise. To quantify the long-term effects of environmental noise exposure, researchers often use the metric of annoyance. Annoyance is widely considered to be the most well-corroborated health effect of aircraft noise and a moderating factor for other suspected health effects. Annoyance can also be correlated to average cumulative noise levels, such that higher levels of chronic noise likely evoke higher levels of annoyance within the population. Annoyance data is typically collected using extensive surveys and/or interviews, which are costly and time-consuming. In the absence of annoyance data, complaints are often used as a proxy for annoyance. This research used complaint, noise and annoyance data to demonstrate that complaints do not equate to annoyance, nor do they correlate to cumulative noise metrics. Thus, while complaint data may prove useful in analyzing short-term response to operations, it should not be relied upon for the assessment of long-term impacts from aircraft noise exposure, nor should it be used to direct noise and annoyance mitigation initiatives.

Explainable machine learning models with privacy

AbstractThe importance of explainable machine learning models is increasing because users want to understand the reasons behind decisions in data-driven models. Interpretability and explainability emerge from this need to design comprehensible systems. This paper focuses on privacy-preserving explainable machine learning. We study two data masking techniques: maximum distance to average vector (MDAV) and additive noise. The former is for achieving k-anonymity, and the second uses Laplacian noise to avoid record leakage and provide a level of differential privacy. We are interested in the process of developing data-driven models that, at the same time, make explainable decisions and are privacy-preserving. That is, we want to avoid the decision-making process leading to disclosure. To that end, we propose building models from anonymized data. More particularly, data that are k-anonymous or that have been anonymized add an appropriate level of noise to satisfy some differential privacy requirements. In this paper, we study how explainability has been affected by these data protection procedures. We use TreeSHAP as our technique for explainability. The experiments show that we can keep up to a certain degree both accuracy and explainability. So, our results show that some trade-off between privacy and explainability is possible for data protection using k-anonymity and noise addition.

Noise and thermal performance of a sub-attofarad capacitance sensor for precision measurements, with applications in gravitational wave detectors.

We describe the design principles, fabrication, and characterization of a precision AC resonant capacitance bridge (RCB) sensor, based on a resonant differential planar printed circuit board transformer with a solid (ungapped) MnZn ferrite core, demonstrating a short-term sensitivity at 293K of 0.225 ± 0.005 aF/√Hz at around 120kHz resonance frequency and 1Hz Fourier measurement frequency. At 120K, the RCB short term noise sensitivity is 0.118 ± 0.005 aF/√Hz. We compare the ungapped configuration to five different RCBs: three with a core gap of 65 μm and two with a core gap of 130 μm. Their average room temperature short term noise sensitivities are 0.30 ± 0.01 and 0.45 ± 0.01 aF/√Hz, while the cryogenic operation of these transformers at 120K resulted in averaged sensitivities of 0.23 ± 0.01 and 0.36 ± 0.01 aF/√Hz, respectively. Multi-hour room temperature runs, with one core of each of the three gap types, proved the stability of their long-term sensitivities of 0.234 ± 0.005, 0.338 ± 0.009, and 0.435 ± 0.010 aF/√Hz for the ungapped (40-h duration) and the 65 and 130 μm (28-h duration) cores, respectively. At 0.1mHz, a critical frequency for space gravitational wave detectors, the respective sensitivities are 0.25 ± 0.02, 0.35 ± 0.02, and 0.53 ± 0.07 aF/√Hz. Measurements with the ungapped transformer configuration for temperatures from 325 to 349K further validate the dependence of the noise model on temperature and permeability. The performance of our RCB with an ungapped core matches the calculated performance value and shows an improvement in signal-to-noise ratio of two or more compared with capacitance bridges developed for similar applications. A further factor of about two noise reductions is achieved by cooling to 120K.

Analisis Keterkaitan Antara Aktivitas Kendaraan Bermotor dengan Tingkat Kebisingan: Studi Kasus di Jalan Gatot Subroto, Kota Palu

The elevation of mobility in Palu has evolved into a new noise issue. Noise from motorized vehicles has quite an impact on the tranquility of areas that directly intersect with the highway. Gatot Subroto Axis Road is an instance of a congested road as public facilities such as educational institutions take the crowd of the area. The study aims to analyze the relationship of vehicle activities toward noise level at Gatot Subroto. The research method uses field measurement by a sound level meter (SLM), tripod, and counter. Noise sampling standards refer to SNI 8427:2017 regarding measuring environmental noise levels. Data was collected for one day on weekdays and weekends with three take times at three sampling points. Noise level analysis is carried out using frequency distribution. The next data analysis is to look for the equivalent noise level or LAeq. The noise level points varied between 71,6 dBA-84,02 dBA. The traffic volume reached a peak at 853. The p-value was 0,72 which was above 0,05. The regression test was Y=0,0048x+72,904, and R2 showed 0,15 points, which means that 15% of the noise level was affected by traffic volume. In conclusion, the average noise level at Gatot Subroto Axis Road exceeded the quality standards set according to the Decree of the Minister of State for the Environment No. 48 of 1996, which is 55 dB(A). Despite no significant difference in noise levels on weekdays and weekends based on the t-test, the noise level is affected by traffic volume. Noise from motorized vehicles has quite a big impact on the tranquility of areas that directly intersect with the highway. he limitation of this research is the limited amount of data due to the small number of research points and the insufficient number of days, so further research is needed.

Assessing the importance of landscape, anthropogenic and spatial factors in predicting urban nesting sites: the Columbidae of the city of Rabat (Morocco) as a case study

Abstract To adequately control the urban bird populations, the determinants of nest habitat selection must be identified and its processes well understood. In this study, we investigated this issue with regard to Columba palumbus (WP) and Streptopelia decaocto (CD) in the city of Rabat, Morocco. We used data from landscape composition, anthropogenic presence, and spatial structure, to identify the best predictors that cause variation in the CD (84 nests) and WP (141) nest occurrence using generalized linear mixed models and variation partitioning analyses (VP). Our results show that WP nest occurrence was positively associated with urban park cover and long distances to agricultural areas and negatively with short distances to roads. Significant interactions between the average noise intensity and the number of passers-by/5 min and between maximum NDVI and density of roads also explain WP nest occurrence. In CD, the nest occurrence was positively associated with covers of built-up areas and parks, the density of roads, and average noise intensity, and negatively with short distances to roads and the number of passers-by/5 min. The VP revealed that the joint effect of landscape composition and space was the most robust in explaining the WP nests occurrence, whereas the pure fraction of space and the joint effect of human presence and space were the most robust in CD. As CD and WP nest in several Mediterranean cities, it would be worthwhile to test the generality of our results using the same analytical approach in other urban areas.

Low-noise co-arm differential sensor for an optical frequency comb sampling an E-field test system.

Optical frequency comb (OFC) technology can realize the rapid measurement of electric fields (E-fields) with large bandwidth. However, this technology suffers from the problem of high intensity noise, resulting in low sensitivity and a blind frequency region. In order to solve the above problems, a dual-path optical E-field sensor with a common reference arm based on a lithium niobate optical waveguide is proposed. The introduction of the reference arm improves the balance of optical paths and the degree of integration. A segmented electrode is also designed to ensure the generation of reverse electrical signals on two Mach-Zehnder interferometers (MZIs). After exiting from the differential photodetector (PD), the intensity noise can be removed, and the sensitivity of the sensor can be improved. After testing, the maximum intensity noise reduction is about 37 dB, the average noise reduction is about 22.3 dB, and the blind frequency region can be eliminated with the co-arm differential optical E-field (CDOE) sensor in the process of measuring the signal. This sensor can be used in the 1 MHz-12 GHz bandwidth with a sensitivity better than 10 mV/m·√Hz.

Enhancing Soft Tissue Differentiation with Different Dual-Energy CT Systems: A Phantom Study

To quantitatively evaluate the possible advantages of quantifying and differentiating various soft tissues using virtual monochromatic images (VMI) derived from different dual-energy computed tomography (DECT) technologies. This study involved four DECT scanners with different technologies. CIRS phantom images were acquired in single-energy (SECT) and DECT modes with each scanner. The analysis focused on five equivalent soft-tissue inserts: adipose, breast, liver, muscle, and bone (200 mg). The signal-to-noise ratio (SNR) was calculated for each equivalent soft-tissue insert. Finally, the contrasts of tissue pairs between DECT and SECT images were compared using Wilcoxon signed-rank tests adjusted for multiple comparisons. Average CT numbers and noise showed a significant difference pattern between DECT with respect to SECT for each CT scanner. Generally, energy levels of 70 keV or higher led to improved SNR in VMI for most of the equivalent soft-tissue inserts. However, energy levels of 40–50 keV showed significantly higher contrasts in most of the equivalent soft-tissue insert pairs. DECT images at low energies, especially at 40–50 keV, outperform SECT images in discriminating soft tissues across all four DECT technologies. The combined use of DECT images reconstructed at different energy levels provides a more comprehensive set of information for diagnostic and/or radiotherapy evaluation compared to SECT. Some differences between scanners are evident, depending on the DECT acquisition technique and reconstruction method.

POTENTIAL HAZARDS AND RISK FACTORS OF THE WORK ENVIRONMENT IN THE FOUNDRY INDUSTRY X

Background: Workers have a risk of work accidents and Occupational Diseases (PAK) caused by the work process, behavior at work, and the work environment. Identification of potential hazards and risk assessment is the first step to find hazards in the workplace and then carry out control measures to create a safe and healthy workplace.
 Objective: Knowing potential hazards, environmental risk values, and physical working conditions in the Metal Casting Industry of X.
 Method: The method used in this study is a descriptive survey. The number of samples in this study were 36 workers. Data collection techniques are carried out through observation activities using sheetsJob Safety Analysis (JSA) and risk assessment sheets, interviews using interview guides, and measurements of physical working conditions usingenvironment meter. The data analysis carried out is descriptive analysis which provides an overview of potential hazards and environmental risk values.
 Results: Overall there are 54 potential hazards in the production process at CV Dwi Jaya Logam which consist of a wet mold making process, there are 12 potential hazards, dry mold making CO method2 there are 10 potential hazards, metal smelting has 20 potential hazards, pouring molten metal into the mold has 6 potential hazards, and disassembling the mold has 6 potential hazards. There are 28 potential hazards in the production process at CV Mulya Jaya consisting of grinding there are 6 potential hazards, cutting iron using a saw machine there are 2 potential hazards, drilling there are 6 potential hazards, turning there are 4 potential hazards, making holes using machinesscrap there are 3 potential hazards, the formation of workpieces using machinesmilling there are 2 potential hazards, welding has 3 potential hazards, and product painting has 2 potential hazards. Overall, the physical working environment conditions in the form of temperature and lighting at CV Dwi Jaya Logam and CV Mulya Jaya did not meet the requirements, while the results of noise measurements at the two locations met the requirements.
 Conclusion: Potential hazards found in the metal casting industry CV Dwi Jaya Logam, namely 54 potential hazards which are divided into 2 levels of risklow, 10 levels of riskmoderate, 30 levels of risk high, and 12 levels of riskextreme. CV Mulya Jaya Metal casting industry identified 28 potential hazards divided into 4 risk levelslow, 4 levels of riskmoderate, 12 levels of risk high, and 8 levels of riskextreme. These potential hazards come from the physical work environment (temperature, lighting, and noise) and the production process at each work step. The results of measurements of the physical working environment in the form of temperature do not meet the requirements according to the Regulation of the Minister of Manpower of the Republic of Indonesia No. 5 of 2018, the average lighting measurement results are also . do not meet the requirements according to Regulation of the Minister of Health No. 70 of 2016, and the average noise measurement results meet the requirements according to the Indonesian Minister of Manpower Regulation No. 5 of 2018.

M-type refractive index profile erbium-doped fiber for high-efficiency multicore EDFA.

Cladding-pumped multicore erbium-doped fiber is an important element for future spatial division multiplexing (SDM) amplification. We propose an M-type erbium-doped multicore fiber to achieve high-efficiency SDM amplification. The performance of cladding-pumped erbium-doped fiber with a central refractive index depression has been investigated, and the M-type fiber has better amplification performance than conventional fibers by reducing the signal mode overlap with the doped region. The experiment results show that the M-type 4-core erbium-doped fiber has a gain improvement of 2.8 dB compared with conventional 4-core fiber. The pump conversion efficiency (PCE) has been enhanced from 4.47% to 8.01%. For a 7.0 W pump power at 976 nm, the M-type fiber exhibits an average gain of 20.0 dB and an average noise fiber of 6.8 dB at the L-band. The core-to-core gain variation is less than 1.6 dB.

Water-vapor absorption database using dual comb spectroscopy from 300 to 1300 K part I: Pure H2O, 6600 to 7650 cm-1

We present broadband dual frequency comb laser measurements of pure H2O absorption (natural isotopic abundance of 99.7 % H216O) from 6600 to 7650 cm−1 (1307–1515 nm) with a spectral point spacing of 0.0068 cm−1. Twenty-nine absorption spectra were collected at temperatures between 300 and 1300 K (±0.81 % average uncertainty) and pressures ranging from 0.5 to 16 Torr (±0.27 %) with an average residual absorbance noise of 7.4E-4 across the spectrum for all measurements. We fit measurements using a quadratic speed-dependent Voigt profile to determine 17,030 absorption parameters for 5986 transitions found in HITRAN2020. The measured parameters include line strength, line center, self-broadening, and self-shift, along with their power-law temperature-dependence exponents, and speed-dependent self-width parameters. A second version of the retrieved parameters with fits that do not include speed-dependence is also presented. We explore various trends to enable parameter extrapolation for weak transitions that were not covered in this work. We measured line parameters for an additional 614 features not presently catalogued in the HITRAN2020 database. In aggregate, these updates improved RMS absorbance error by a factor of 2.6 on average, and the remaining residual is predominantly spectral noise. This updated database improves high-temperature spectroscopic knowledge across the 6600–7650 cm−1 region of H2O absorption. An accompanying paper (Part II) describes similar measurements and a new database for air-broadened H2O absorption.

Structural, acoustical, and thermal evaluation of an experimental house built with reinforced/hollow interlocking compressed stabilized earth brick-masonry

With the increasing demand on affordable construction that addresses the global challenges of the modern world, earthen construction is being reintroduced and investigated as a potential sustainable and affordable building method. Compressed stabilized earth blocks (CSEBs) are a common form of enhanced earthen building materials. Previous studies focused on the structural performance of CSEB walls and prisms consisting of one type of bricks with the same mixture, analyzed their thermal and acoustic properties as units only, or evaluated the thermal performance of solid unreinforced CSEB masonry.The present research is the first complete structural, acoustical, and thermal investigation of an experimental house built with a novel reinforced/hollow interlocking compressed stabilized earth brick-masonry (ICSEB) using varying stabilizer contents, compliant with the Egyptian code for building with stabilized soil—Part One: Building with compressed stabilized soil units (EG-SE2016). Methods depend on experimental testing, codified theoretical calculations, finite element analysis, and live measurements. According to the structural experimental testing program, reinforcement was found to triple the load bearing capacity of ICSEB columns and, although minimal rebars were used in the ICSEB walls, it has improved their load bearing capacity by 23% for single walls (125 mm) and 58% for double walls (250 mm). In addition, doubling the thickness of the unreinforced ICSEB walls increased the load bearing capability by 164%, while raising the thickness of the reinforced wall from 125 mm to 250 mm increased the load bearing capacity by more than threefold (3.38). Based on the codified theoretical calculations and findings of the finite element analysis, it is safe to recommend reinforced double ICSEB walls as a reliable construction for a two-story residential building. Acoustically, double ICSEB walls attained the noise reduction index value of 40 dB, which is required by the Egyptian code for acoustic insulation and noise control in residential buildings, to protect against the average outdoor noise levels of 65–70dBA. Thermally, reinforced double ICSEB walls kept the indoor air temperature and relative humidity values within the thermal comfort zone, 23.9–25.7 °C and 28–36%, respectively, despite the fluctuating outdoor temperatures and relative humidities (16–37 °C and 7–88%, respectively). Indoor air temperatures were 1.5–2 °C lower than those of concrete masonry walls. Additional research is required to evaluate resistance to environmental aspects, such as exposure to water, wind, and corrosion, and to further investigate their thermal and acoustical properties.

Optimized design of small sized low noise magnetic shielding cylinder

Magnetic shielded cylinder (MSC) is crucial in various applications, especially in the realm of medical weak magnetic signal measurement. However, designing a small volume, low noise MSC is a multi-objective optimization problem, with the objectives conflict with each other. To address the complexity arising from numerous variables in the optimal design of MSC with a small volume and low-noise, this paper proposes an optimal design method based on non-dominated sorting genetic algorithm II (NSGA-II) to realize the optimal design of MSC with a high shielding factor, small volume and low-noise. Firstly, an analytical model for the shielding factor of the MSC is established, and a multi-objective optimization model is given. Then, the NSGA-II algorithm is employed to obtain a series of Pareto frontier optimal solutions. Finally, the efficacy of this method is evaluated through simulation and experimentation. The results reveal that the radial and axial shielding factors of the optimized MSC achieve maximum values of 8.6 × 107 and 9.5 × 106 respectively. Meanwhile, the average axial noise and radial noise of the MSC between 1 and 100 Hz are 22 fT/Hz1/2 and 20 fT/Hz1/2 respectively. Practice has proven that this method can be used to optimize the design of small-volume, low-noise magnetic shields to improve the performance of magnetic shields.

Efficient shallow learning mechanism as an alternative to deep learning

Deep learning architectures comprising tens or even hundreds of convolutional and fully-connected hidden layers differ greatly from the shallow architecture of the brain. Here, we demonstrate that by increasing the relative number of filters per layer of a generalized shallow architecture, the error rates decay as a power law to zero. Additionally, a quantitative method to measure the performance of a single filter, shows that each filter identifies small clusters of possible output labels, with additional noise selected as labels outside the clusters. This average noise per filter also decays for a given generalized architecture as a power law with an increasing number of filters per layer, forming the underlying mechanism of efficient shallow learning. The results are supported by the training of the generalized LeNet-3, VGG-5, and VGG-16 on CIFAR-100 and suggest an increase in the noise power law exponent for deeper architectures. The presented underlying shallow learning mechanism calls for its further quantitative examination using various databases and shallow architectures.

Operating Room Noise Environment and Behavior in Children Undergoing General Anesthesia: A Randomized Controlled Trial.

Excessive operating room noise impairs communication, distracts from monitoring equipment, and may increase patient and provider stress. This study investigates the effects of reduced noise on perioperative behavior in children undergoing general anesthesia and on anesthesia provider response time. Healthy children (the American Society of Anesthesiologists class I-II), 2-8 years of age, and their anesthesia providers were randomized into a control or treatment group exposed to reduced stimulation during induction and emergence. Primary outcomes were patient behavior and provider response time. Secondary outcomes were postoperative pain scores, provider responses exceeding 30 seconds, and median and maximum noise exposure. 64 children (27 females and 37 males) were randomized into a control or treatment group, of whom 32 (50%) underwent tonsillectomy/adenoidectomy and 32 (50%) underwent dental procedures. The average age was 4.6 (SD 1.43) years. Children exposed to reduced noise were less likely to be "fussy about eating" (p=0.042), more "interested in what goes on around them" (p=0.008), and had fewer temper tantrums (p=0.004) on postoperative day one or two and on postoperative day five, six, or seven. No other differences were found between groups in behavioral assessment scores or provider response times. Our study is the first to show that a low-stimulus environment improves postdischarge behavior. Provider response time was unaffected by reduced noise, and the average and peak noise exposure levels did not exceed national safety guidelines. This trial is registered with NCT03507855 and NCT03504553.

Evaluation of flow, supply, and demand for noise reduction in urban area, Hamadan in Iran.

Noise pollution is one of the consequences of urbanization that can cause environmental disturbances in urban areas. Urban ecosystems provide noise reduction services through Urban Green infrastructures (UGIs). Many studies have been conducted to evaluate and model traffic noise, but none have addressed the flow, supply, and demand of noise reduction ecosystem services. The main purpose of this paper is to present a new methodology for estimating flow, supply, and demand for noise reduction in Hamadan city that has not been mentioned in any paper so far. UGIs were classified into six main categories: agricultural lands, gardens, parks, abandoned lands, single trees, and street trees. A total of 57 sampling stations for sound measurement were made in August 2018. The current map of noise pollution (flow) was created using the Kriging method. The amount of supply was measured up to a distance of 50 meters from the main roads based on two approaches (the distance effect and the sound barrier effect). To quantify the demand, the current sound intensity level in the noise-sensitive land uses was compared with standards. Zonal statistics was used for spatial analysis of supply-demand in the urban neighborhood as a working unit. Results showed that at distances of 5m, 10m, 15m, and 20m, the average noise reduction was found to be 1.61, 2.83, 3.92, and 5.33 dB, respectively. Sound barriers at distances of 5m and 10m resulted in an average sound reduction of 1.61 and 2.83 dB, respectively. Individual trees, strip trees, abandoned lands, parks, and gardens led to a decrease in traffic noise by 0.3, 1, 0.1, 3.5, and 4.5 dB, respectively. The clustering analysis revealed a significant spatial clustering of noise pollution in Hamedan. The results and new methodology of this research can be used in similar areas to estimate the supply and demand of noise reduction and also for decision-makers to take management actions to increase supply and meet the demand for noise reduction service.

Шумовое загрязнение территории многоэтажных жилых застроек города Ставрополя

The article provides measurement results and an assessment of the noise load on the territory of the «Perspektivny» and «Rossiysky» residential complexes in Stavropol. Noise measurements were carried out in the spring-summer and autumn-winter periods of 2022–2023. The measurement results are presented as average noise exposure levels. Based on the data obtained, a mathematical model of the propagation of noise from traffic flow during the deciduous and leafless period was built. To conduct a study and assess the noise load in a multistorey building on the territory of the South-Western district of Stavropol. The measurement of the noise load was carried out in accordance with GOST 23337-2014 “Noise. Methods for measuring noise in residential areas and in residential and public buildings”. To analyze and compare the data obtained with the maximum permissible value, SanPiN 1.2.3685-21 “Hygienic standards and requirements for ensuring the safety and (or) harmlessness of environmental factors for humans” was used. The measurement results revealed excess of maximum permissible noise level on the territory of the residential complex «Perspektivny» and «Rossiysky», and the houses within the residential complex «Perspektivny» suffer most from the proximity of the roadway and the absence or partial landscaping. Noise values were recorded near residential buildings in the range of 70 dBA. On the territory of the residential complex “Rossiysky”, high indicators are found on the sidewalk near the South-Western bypass. No excess of maximum permissible noise load level was noticed directly at the houses. The resulting mathematical model reflects the dependence of the noise level on the presence and absence of foliage and the density of traffic flow. Based on the data obtained, we can conclude that the residential complexes «Perspektivny» and «Rossiysky» are subject to significant noise pollution. This can be attributed to shortcomings in the planning of territory development and the increase in the number of vehicles.

Investigation of the effect of camshaft profiles designed with the circular arc curve method for a common rail dual fuel engine on mechanical vibration and noise emissions

In this study, the design and manufacturing of cam profiles with different valve lifts were carried out using the geometric spring curve method for a single-cylinder, four-stroke common rail diesel engine. Subsequently, the impact of the designed cam profiles on vibration and noise emissions in conventional diesel combustion was examined. The effects of the cam profiles obtained using the circular spring curve method and fitted with Fourier series on the tappet's speed, acceleration, and leap were examined, and then the cam profiles to be manufactured were determined. Experimental tests were conducted on vibration and noise emissions using the manufactured cam profiles with pure diesel fuel at five different engine loads and a constant engine speed. When the results are examined, increasing the valve lift amount compared to the original cam resulted in an approximate 24% increase in vibration level, while decreasing the valve lift amount reduced the vibration level by approximately 20%. the effect of cam profile modification on average noise emissions was quite evident.