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The purpose of the present study is to make known the impact caused by the new tax regime for micro-enterprises and to describe the advantages or disadvantages generated by this tax collection instrument, used as a means to reduce the levels of informality and to promote tax culture. The methodology used was descriptive, the type of research was theoretical - documentary bibliographic and qualitative approach, which analyzed primary sources such as websites, theses, magazine portals, portals of governmental sites, news portals, books, in addition to the critical analysis of the authors on the main case of the company DISPROALCEX S.A. The main result shows that the new tax regime for micro-enterprises is a tax collection instrument used as a means to reduce the levels of informality and promote the tax culture. A. The main result shows that the income tax payable under the general regime was USD 6,274.84, while the income tax payable under the microenterprise regime was USD 15,922.18, showing a significant increase of USD 9,647.34, since the costs and expenses for the period 2020 could not be deducted. The reforms established by the Internal Revenue Service condition the productive process in some micro-enterprises in the sector, reducing their economic and financial liquidity.

I-joists manufactured using wood composites are intended for dry service condition. Situations arise where I-joists are exposed to excessive weather conditions. This exposure to moisture can degrade structural properties of I-joists. In a follow-up to a previous published study (King et al 2014) looking at the short-term exposure to moisture (138 d), this study extends the exposure days further to 1351 d (approx. 3.5 yr) to gain an insight into property changes and fine-tune the degradation model presented by King et al (2014). Long-term exterior exposure was associated with continued declines in maximum load and deflection at maximum load, but the rate of property loss decreased as the exposure period was extended. Bending failure modes shifted back from web buckling to shear type failures at the web-web and web-flange joints.

Switching temperature (Tsw) is a key parameter governing the service condition of shape memory polymers (SMPs). However, tuning Tsw of SMPs often requires sophisticated synthesis or intricate proce...

Pan-girder (PG) bridges became popular in Texas, USA, in the 1950s and 1960s as a viable alternative for short-span bridges due to their speed of construction, low-labour requirements and cost–effectiveness. However, these bridges were designed for lighter live loads than the current AASHTO HL-93 loading, resulting in gradual decline in their usage. Existing PG bridges may have various structural and non-structural deteriorations because they are nearing or have crossed their service lives. In this study, the existing condition of four selected PG bridges in the Dallas–Fort Worth metroplex were visually inspected to assess their current condition. The bridges exhibited significant concrete spalling, cracking and crushing, resulting in exposed and corroded steel rebars. The newest bridge, built in 1992, experienced less severe damage than the other three bridges built in 1955–1971. The bridges’ safety could be compromised due to deteriorations and lighter design live loads. Therefore, the following recommendations were made: (a) glue a polyvinyl chloride pipe on the form-lowering holes extending beyond the concrete surface of the arch to minimise water infiltration and related damage; (b) conduct load testing and ratings to verify the structural safety and load-carrying capacity of the deteriorated bridges; and (c) retrofit to upgrade the existing bridge condition and safety and mitigate against further damage.

UK railway drainage systems are facing increasing challenges due to poor completeness of the asset inventory, long asset life cycles, more intense use of the UK railway system, and a changing climate. It is therefore important for drainage managers to acquire a better understanding of the current and future condition of the drainage assets for which they are responsible. This study presents a Markov model for simulating the potential future service condition of various classes of UK railway drainage assets based on observed historical changes in asset condition. Linear regression analysis was performed on distinct asset groups and the influence of the characteristics of asset construction material, size, shape, and location on the rate of the degradation process was quantified. These results were incorporated with the continuous time Markov chain model to improve the accuracy of the degradation rate prediction for several drainage asset classes. The model is illustrated on a case study of the Network Rail drainage assets showing the minimum number of samples required to make a reliable estimation of the service condition degradation process.

Additive manufacturing is extending its influence on various modern industries, including automobile, aerospace, aviation, and maritime. This is specifically true for selective laser melting since it is capable of manufacturing dense parts from metal and alloy powders. Thus, the performance of materials processed by selective laser melting has become the focus of many studies recently. However, their fatigue endurance is yet to be understood comprehensively, and few studies have been carried out on this topic thus far. The lack of understanding is often attributed to the considerable number of manufacturing parameters, which also hinders employing selective laser melting for typical industrial applications. Among the various materials processed by selective laser melting, steel is one of the most attractive ones to manufacturers due to its broad range of properties and applications. This paper aims to describe the studies carried out on the fatigue properties of diverse types of steel manufactured by selective laser melting. It also reviews the parameters which are recognized to be effective on the fatigue behaviour of these steels. These parameters include building orientation, heat treatment, surface quality, energy density, and service condition of the final product. Recent studies on selective laser melting along with the variety of its influential parameters on the fatigue strength highlight a knowledge gap towards reaching a comprehensive understanding of the fatigue behaviour of steels manufactured by this process. Based on this fact, some of these gaps are discussed as the potential topics for the future studies in the field of additive manufacturing at the end of this review.

The mechanical strength of Ni-based single-crystal superalloys under service condition is related to the thermo-mechanical properties of the disordered γ matrix. Here we use density functional theo ...

For some applications of implantable polymeric devices, material degradation and disappearance with time is necessary. In such a case, control in the polymer applications can be achieved through understanding the process of degradation. Heat effect on physical changes of polymeric materials under service condition should also not be overlooked. Poly octanediol citrate/Nano silica composite was developed and tested for glass transition (Tg) and physical degradation within the environmental factors that impact the use of the Poly octanediol citrate/Nano silica composite for medical application. Degradation correlated well with the nano silica content while the indicated low Tg value confirmed the amorphousness of the Poly octanediol citrate/Nano silica composite at 37°C.

The performance data are presented for the highly-efcient container glass-melting furnaces. The service condition are defned for the melting tank's lining given that the pull rate being 2,5‒3,0 tons/m2per day and the specifc glass working being 7000‒8000 tons/m2per furnace campaign. The recommendations are given on the fusion-cast baddeleyite-corundum and vibro-cast sintered chromealumina-zirconium refractories using in the melting tank's structural units.Ill. 2. Ref. 18. Tab. 1.

An evaluation method of the technical condition of vehicle is put forward. Through the calculation and analysis of the big data recorded in the history of automobile maintenance and repair, the fuzzy analytic hierarchy process is used to establish the evaluation index system of the technical condition of the vehicle, so as to comprehensively evaluate the service condition of the vehicle, the performance of the vehicle, and the vehicle system It is helpful to evaluate the technical status of vehicles and promote the upgrading and improvement of equipment technology.

The limit state criteria for a mining shovel mechanical equipment that contains the faults of a rotor imbalance-type are studied in the article. On the bases of a statistical analysis of mining shovel failures, it is demonstrated that rotor imbalance is a prevailing reason for their accident-caused failures. On the bases of three-year monitoring of supporting elements vibrating activity the vibratory norms for electrical mining shovel rotors that take into account their service condition are substantiated.

Controlling the maintenance OPEX is one of the major challenges that any utility faces. The challenges lie in how to optimize the three main factors: risk, performance, and cost. Besides, no utility can depend on a unique type of maintenance, there is always a combination of a different kind of maintenance such as breakdown, preventive, risk-based, conditionbased,..etc. So, what is the answer to this question: what type of maintenance needs to be followed to keep the transformer in service in with high performance? There is no specific answer to this question. Each type of maintenance can be applied based on the transformer`s operating environment. However, most of the utilities apply preventive and condition-based maintenance. To justify this answer, some data need to be analyzed to assess the maintenance performance and recommend what are enhancement need to be added. One of these approaches is to apply in service condition-based assessment to study the health of the assets based on the current maintenance practice. Furthermore, study both historical maintenance recordsand failure rates will help to understand the relationship between the effectiveness of maintenance and service efficiency.This relation can come in two shapes. One is to do the right things by developing a set of maintenance activities that need to be performed during the maintenance to ensure its effectiveness. Second, is to do things right by enhancing the maintenance crew capabilities and competencies to ensure high efficiency. After analyzing all these factors mentioned above, It has been noticed that in-service condition-based assessment of the transformer is a powerful tool that can be used to enhance and build an effective strategy. It will not only involve a set of activities during the maintenance, but it also covers the whole life cycle of the transformer. Besides, it highlights the gaps in the maintenance process and procedures, and provide indications where enhancement need to be applied based on international practice. These changes were observed on the cost and performance in the benchmarking study that was done through International Transmission Operation and Maintenance Study (ITOMS) which was a good indication of the effectiveness of strategy used for transformers. However, as part of the asset management approach, continuous improvement will continue to reach the vision that has been set in the maintenance optimization and to prepare for the future significant increase in transformer aging.

Built with compressed straw as structural or non-structural walls, the straw bale building can date back to the twentieth century in Nebraska. Besides its great thermal and acoustic insulation, buildings with straw can also lead to low impact on environment and health. It was introduced into Northeast China in 1999 by Adventist Development Relief Agency (ADRA). In order to investigate straw bale buildings’ service condition in Northeast China, a survey on 25 straw bale buildings of four villages and in Tangyuan County was conducted and a straw bale house was selected to test its interior air temperature and wall surface temperature compared to a similar clay brick house. Based on an inspection of existing buildings, serious issues relating to thermal bridge and wall cracks seized our concentration. Large areas of cracks appeared on exterior plaster, and obvious dewing on interior surface of thermal bridge could be observed, seriously influencing inhabitant environment. On the basis of in-depth analysis on these serious problems, in order to accommodate the environmental conditions in Northeast China, revisions on wall construction and exterior plaster details were put forward, making recommendations for future straw bale construction design to promote references for further generalization in China.

The degradation of buildings needs to be investigated more and more, mainly due to the increasing demands of performance and service life specified for the facades. Otherwise, the definitions of rehabilitation and pathology are increasingly associated with the evolution of performance over time. Measuring the degradation allows to evaluate the service condition of the component, identifying whether it has already reached or exceeded the specified service life. The aim of this chapter is to describe the Degradation Measurement Method developed to quantify the degradation in facades. Guidelines for anomaly inspection, mapping and quantification operations are presented, as well as for calculating the FGD indicator. An application is made with the purpose of exemplification in two degraded samples, as well as the application to identify the service life value for several samples is also presented. The daily use of this methodology has allowed constant improvements and also the development of more accurate models to quantify the degradation.

The driving comfort, which is mainly determined by the pavement evenness, is one of the most important indexes for evaluating the pavement service condition. Current evaluation indexes for the pavement evenness, such as the international roughness index (IRI), are mainly determined by the vibration acceleration method. However, the driver is at the core in the human-vehicle–road-environment system. Few studies have focused on the physiological state as a response to accelerations induced by pavement unevenness and evaluate the driving comfort on this basis. In this study, the Root Mean Square of the Successive Differences (RMSSD) derived from the driver's heart rate variability (HRV) in the time domain and was selected as an index value for the driver's physiological state. Using an advanced indoor testing platform, the RMSSD values of five drivers were recorded by a KF2 electrocardiogram tester. The relationship between the RMSSD, the driving speed and the IRI underwent detailed analyses. The results of the tests show that the vertical vibration is identical when the drivers are driving on the simulated pavement with the same IRI value; however, the RMSSD values of different drivers were different, i.e., the perception of the same pavement evenness is subjective. Therefore, when evaluating the driving comfort based on the pavement evenness, it is necessary to consider the physiological index. The results obtained in this study have proven the feasibility of measurement of RMSSD value to evaluate the pavement evenness and driving comfort. They are therefore a powerful augmentation of existing evaluation methods and also provide a new reference for further optimization of the pavement surface performance.

Helical compression spring plays a vital role in vehicle application as it improves ride index, sustains the vehicle against extreme degrees of vibration and stress induced on the suspension system as a result of uneven road. Depending on the extent of load acting on the suspension system, material selection, design considerations and manufacturing processes, longevity and performance of the spring may be sustained, otherwise the spring may fail prematurely under severe loading condition. In this study, compression spring was designed using high carbon steel, stainless steel and chrome vanadium steel and the designed spring models were simulated for maximum Von-mises stress, maximum resultant displacement and resultant strain. Curb weight of the vehicle was considered in the analysis which involves the weight of the car with all fluids and components but without the driver, passengers, and cargo. At the end of the simulation, the three materials remained within the limit of their elasticity without any significant sign of failure under the applied load of 3888N. However, the difference between Von-mises stress obtained for Chrome vanadium and its yield strength was the highest (653MPa) followed by stainless steel (235MPa) before high carbon steel (109MPa). This implies that at increasing loading conditions, high carbon steel will be the first material to fail during operation, whereas, stainless steel and chrome vanadium may exhibit sustained level of longevity before failure as a result of the high chromium content and other alloying elements that gives them a better quality but at relatively high cost compared to high carbon steel which can satisfactorily undergo its service condition at relatively low cost.

The life enhancement program of an aero gas turbine combustor liner has been taken up through thermal barrier coating. Yttria-stabilized zirconia with a composition of Zr2O2 + 8 wt.% Y2O3 has been applied by atmospheric plasma spray on newly manufactured liner. A remarkable improvement in liner life has been observed under severe service condition. However, peel off of coating is noticed on the serviced components which are premature withdrawn for any other reasons. Reason for peel off has been studied metallurgically in detail. Coated samples were subjected to cross-sectional microanalysis. Based on the microanalysis suitable repair procedures are being adopted for serviced components. The process found very effective for a better life.

FTIR method is a common term used to monitor the lubricant oil service condition. The E2412-04 standard approved by ASTM presents a method for calculating oil condition monitoring parameters using FTIR spectroscopy. In this work, the values of ASTM parameters for 35 diesel engine oil samples were obtained to analyze the relationship between the ASTM parameters, such as the oxidation value, water content and other parameters, and the mileage of the vehicle. The driving environment of vehicle is demonstrated to be influential to lubricant oil oxidation using the ratio of oxidation rate in plateau area and in high temperature region. It is proposed that oxidation and nitration values are suitable for oil degradation analysis and oil replacement interval prediction. Further, considering the mileage, load ratio, temperature, air pressure and interference factors, the neural network of oil oxidation is constructed, and the method of oil replacement interval prediction is proposed.

The article presents a method for ranking various catchment areas of an urban area according to their current service condition of the walk environment and their improvement needs. The stud...

The quality of cable insulation in high voltage systems is of important concern. The cable insulation degradation is influenced by service condition and environmental impacts. This paper contributes to the knowledge on the influence of temperature on tan-delta of XLPE cable through an experimental investigation. The laboratory test experiment was conducted on cable samples of 10 meters each with terminations and without terminations at temperature ranges of 200 – 700C to evaluate the influence of temperature and terminations on tan-delta. The results show that tan-delta values of XLPE cables are influenced by insulation temperature.

Cu/Al compound materials, named as copper-clad aluminum bus bars, are widely used in heat dissipation of modern engineering. The thermal cycle tests were conducted at 200, 250 and 300 °C for different cycle times, respectively. Effects of thermal cycle temperatures and thermal cycle times on microstructures and mechanical properties of the interface were studied. The results show that the width of bonding layer and bond strength are significantly affected by thermal cycle temperatures and times. Nonetheless, the variety or the quantity of intermediate compounds is scarcely influenced. Al2Cu, Cu9Al4 and CuAl were identified on the interface. With the increase in cycle times, grains of the material grew up. However, grains of the interface grew up more apparently than those of Cu and Al. The knowledge may be applied in the establishment of service condition and quality evaluation of material.

A composite beam theory is developed to study the pretensioned concrete structures. This theoretical development defines the longitudinal interaction that occurs between the prestressing tendon and concrete under normal service condition. The transfer length and prestress loss due to slip, elastic shortening as well as the prestress gain due to external loads are solved with closed form solutions. Validation is provided and comparisons are made between the present and conventional approaches. It is found that there is excellent agreement between the predicted and tested concrete strain. The transfer length results calculated by design provisions are close to the predicted upper bound but test results can be anywhere between the predicted lower and upper bounds. Current immediate prestress losses formulas may result in overestimation and the degree of overestimation is dependent on prestressing tendon eccentricity. Overall, it is demonstrated that the approach presented in this study improves the accuracy and facilitates a better understanding of prestressed concrete mechanics while maintaining concise closed form solutions.

By means of creep properties measurement, microstructure observation and lattice parameters measurement, the microstructure evolution and creep behaviors of a directionally solidified nickel-based alloy under long-life service condition are investigated. The results show that the creep life of the alloy at 980 °C/90 MPa is measured to be 9714 h. During creep, the various morphologies of γ′ and γ phases display in the different regions of sample. Wherein, the γ′ phase in the region near fracture is firstly transformed into the rafted structure, while the γ′ phase in the stress-free region exhibits the bunch-like structure. The size of the rafted γ′ phase in thickness increases from 0.4 µm to 1.8 µm as the time of creep prolongs to 9714 h, the coarsening regularity of the rafted γ′ phase in thickness obeys the parabolic law. Moreover, the parameters and misfits of γ′/γ phases in the alloy increase with the creep time. When the creeping time is less than 3000 h, the deformation mechanisms of alloy are dislocations slipping in the matrix channels and climbing over the rafted γ′ phase. In the later stage of creep, the deformation mechanisms of alloy are dislocations slipping in the matrix channels and shearing into the rafted γ′ phase, the alternate activation of the main/secondary slipping dislocations promotes the coarsening and twisting of the rafted γ′/γ′ phases. Wherein, the coarsening of the rafted γ′ phase is thought to be a main reason of the alloy having a better creep resistance and longer life.

Automobile industries focus for the components alternative to conventional materials with composites. There is high demand for enhanced performance and light weight. The emphasis is given for composite mono leaf spring as potential item as it is made up of glass fibre reinforced plastics despite they are sensitive to damages such as crack, delamination, de-bonding etc., occurred during either manufacturing or in service condition. These damages grow in progression and results in catastrophic failure. This work aims to deal with structural health monitoring to study and analyse the damage levels in composite mono leaf spring such as detection, location and quantification of damage. An experimental investigation has been carried out to evaluate presence and severity of damage by vibration parameters and validated with simulation.

Buried culverts are important components of highway infrastructure. Most large culverts are built decades ago from corrugated metal or reinforced concrete materials and now have reached their design life. A variety of renewal techniques can be utilized to enhance load carrying capacity of the existing deteriorated culverts and extend their design life. Spray applied pipe lining (SAPL) is a trenchless renewal methodology that applies layers of liner on the interior surface of the deteriorated host culvert. The SAPL’s substances generally fall into two categories: cementitious and polymeric materials. Currently, there is no standard method available for structural design of SAPLs that resulting in various methods being applied by SAPL vendors. To provide the essentials for development of a design methodology for SAPLs, the objective of this paper is to examine the structural performance of full scale soil box testing of 60 in. (1.5 m) diameter circular invert deteriorated (invert-cut) corrugated metal pipes (CMPs) renewed with three different thicknesses of polymeric SAPL. The inverts of the CMPs were cut to simulate an invert deteriorated culvert in service condition and maximize the applied static load on the SAPL. The pipe samples were backfilled with loose SP soil and buried under two feet (0.6 m) of soil cover. The performances of SAPL renewed CMPs were compared with a same size invert-cut bare CMP under the same testing configuration. The results indicated that depending on thickness of the polymeric SAPL, application of this method could improve the structural capacity of a fully deteriorated invert CMP culverts up to 80%.