Analysis of Standards Establishment for the Testing of Electrical Appliances

As science and technology continue to develop,power equipment has become an indispensable part of industrial production and daily life.Whether it is the precise automation machinery utilized on production lines or the convenient electrical appliances found in households,their functionality relies heavily on electrical technology.Nonetheless,without stringent safety and performance assurances,these devices could potentially endanger lives and property.Thus,this paper explores the development strategy for establishing a standardized system within the electrical testing service industry,aiming to ensure safety and reliability.

Technologies for Asphalt Pavement Surface Testing in Road and Bridge Construction

Asphalt pavement is currently one of the main components in the construction of roads and bridges.However,from a practical point of view,various quality problems are prone to occur in the surface layer of asphalt pavement,which will lead to the poor overall quality of road and bridge projects.Therefore,it should be applied reasonably.Advanced testing technologies are used to test the mixture quality,compaction,segregation,thickness,and other aspects of the asphalt pavement surface layer,so as to improve the quality of the asphalt pavement surface layer,and then improve the overall quality of road and bridge construction.Therefore,this paper mainly analyzes the technologies for asphalt pavement surface layer testing in road and bridge engineering construction.

Problems of Rural Food Safety and Strategies of Constructing Supervision System

This paper expounds the practical necessity of constructing diversified rural food safety supervision system as follows: it is the necessary requirements of guaranteeing people's health and life safety; it is an important component of governmental function of social management and the logical extension of administrative responsibilities; it is the basis of maintaining order of rural society and constructing harmonious society. The main problems existing in the supervision of rural food safety are analyzed as follows: first, the legislative work of rural food safety lags behind to some extent; second, the supervision of governmental departments on rural food safety is insufficient; third, the industrial supervision mechanism of rural food security is not perfect; fourth, the role of rural social organizations in supervising food safety is limited; fifth, the farmers' awareness of food safety supervision is not strong. Based on these problems, the targeted strategies of constructing diversified rural food safety supervision system are put forward as follows: accelerate the legislation of rural food safety, and ensure that there are laws to go by; give play to the dominant role of government, and strengthen administrative supervision on rural food safety; perfect industrial convention of rural food safety, and improve industrial supervision mechanism; actively support the fostering of social organizations, and give play to the role of supervision of organizations; cultivate correct concept of rights and obligations of farmers, and form awareness of food safety supervision.

Safety Risks and Preventive Measures for Construction Supervision of Construction Projects

Based on the analysis of construction project safety risk and its preventive measures, it is first necessary to clarify the safety risks and existing problems of construction project supervision and to formulate effective construction procedures. It is necessary to check the production safety of the construction unit, strengthen the company's own safety production management, and reasonably control the risk to familiarize with the construction drawings, and make a special construction plan for the work of the bottom line. Finally, an elective solution is drawn to comprehensively expound the importance of construction project construction safety risk and its preventive measures.

Process Monitoring and Terminal Verification of Cable-Stayed Bridges with Corrugated Steel Webs under Contruction

In this paper,the construction process of a cable-stayed bridge with corrugated steel webs was monitored.Moreover,the end performance of the bridge was verified by load test.Owing to the consideration of the bridge structure safety,it is necessary to monitor the main girder deflection,stress,construction error and safety state during construction.Furthermore,to verify whether the bridge can meet the design requirements,the static and dynamic load tests are carried out after the completion of the bridge.The results of construction monitoring show that the stress state of the structure during construction is basically consistent with the theoretical calculation and design requirements,and both meet the design and specification requirements.The final measured stress state of the structure is within the allowable range of the cable-stayed bridge,and the stress state of the structure is normal and meets the specification requirements.The results of load tests show that the measured deflection values of the mid-span section of the main girder are less than the theoretical calculation values.The maximum deflection of the girder is−20.90 mm,which is less than−22.00 mm of the theoretical value,indicating that the girder has sufficient structural stiffness.The maximum impact coefficient under dynamic load test is 1.08,which is greater than 1.05 of theoretical value,indicating that the impact effect of heavy-duty truck on this type of bridge is larger.This study can provide important reference value for construction and maintenance of similar corrugated steel web cable-stayed bridges.

Guideline of Test Suite Construction for GUI Software Centered on Grey-Box Approach

In this paper, the test suite construction for GUI (Graphical User Interface) software may be executed centered on grey-box approach with the prior test design of window access controls for unit testing, including front-end method of white box and follow-up black box method for integration testing. Moreover, two key opinions are proposed for the test suite construction for GUI software, the first one is that the “Triple-step method” should be used for unit testing with the prior disposing of data boundary value testing of input controls, and another one is that the “Grey-box approach” should be applied in integration testing for GUI software with necessary testing preparation in the precondition. At the same time, the testing of baseline version and the incremental testing should be considered for the test case construction to coordinate with the whole evolution of software product today. Additionally, all our opinion and thought are verified and tested with a typical case of GUI software—PQMS (Product Quality Monitoring Software/System), and results indicate that these methods and specific disposing are practical and effective.

Laminated Solid Timber Slab with Transverse Prestressing Using the Strategy of Interleaved Vertical Displacement of Lamellae

This article presents a study on the structural behavior of transversely prestressed laminated timber slabs,focusing on an innovative approach:vertically misaligned lamellae.This misalignment,achieved by sliding vertically the wooden lamellae rather than aligning them,enhances the slab’s cross-section moment of inertia,thereby improving load-bearing capacity and stiffness.Testing involved two groups of structural size specimens:one with vertically aligned lamellae(control group)and the other with misaligned lamellae(study group).Results showed the study group exhibited 42%superior stiffness and 10%less load capacity compared to the control.Failures typically occurred individually in the lamellae,particularly in those with defects or lower modulus of elasticity,concentrated in the middle third of the slabs’free span where tensile stresses peak.Despite a higher number of failed lamellae,the study group demonstrated promising performance.Analysis of prestressing bar indicated no damage at all in the thread,suggesting potential for reducing bar diameter.These findings offer crucial insights into applying these slabs in timber construction as well as to any kind of construction.

Views on Differential Management in Safety Supervision of Construction Engineering

Given the advances in science and technology,rapid development of socialist market economy and continuous advance of urbanization,it is necessary to enlarge the scale of engineering construction.As the form of engineering structure becomes more complex,large-scale and high-level projects with deep foundation have appeared in engineering construction.For construction engineering,one of its technologies includes solving the difficulties in construction.It is required to deal with the safety risk of construction in time to guarantee safety construction,timely solve the management difficulties and contradictory problems of the project and ensure both the safety of engineering construction and the rationalization of the institution setting of the safety supervision on the project.

FIDIC new conditions of contract and their applying prospects for the construction industry in China

In this paper, the author gives a brief introduction to the evolution of FIDIC conditions of contract, particularly the background of the 1999 new editions. A detailed discussion is made of the applying prospects referring to the new editions of FIDIC Conditions of Contract in China in 6 aspects: revisions of the existing model contract forms; finding solutions to the payment delay problem; advocating the Design/Build and EPC turnkey project delivery system; clarifying the roles of supervising engineers and opening up the new regions of their work. This paper also prepares a short form model contract for small projects in China, improving the settlement of construction disputes.

Geotechnical,Mineralogical and Chemical Characterization of the Missole II Clayey Materials of Douala Sub-Basin(Cameroon)for Construction Materials

Geotechnical tests conducted on clayey materials of Missole II, Douala sub-basin of Cameroon showed that these materials present: fines particles (55 to 78 wt.%), sand (22 to 44 wt.%), and plasticity index of 13.8 to 21.6%. The X-ray diffraction (XRD) and the chemical analysis revealed a kaolinite amount of 46 to 56 wt.%, 19 to 27 wt.% of illite, 12 to 19 wt.% of quartz, 3 to 5 wt.% of goethite, 2 to 5 wt.% of hematite, 1.5 to 5 wt.% of anatase, 2 to 3 wt.% of feldspar-K with 52.87 to 63.11 wt.% of SiO2, 18.08 to 24.31 wt.% of Al2O3, 3.28 to 11.45 wt.% of Fe2O3 and a small content of bases (<2 wt.%). The results of geotechnical tests combined to those of the XRD and the chemical analysis showed that the Missole II clayey materials are suitable for the manufacture of bricks, tiles and sandstones.

Determination of construction art and parameters for passenger dedicated line grouting test within karst area

There are many karst areas within Wuhan-Guangzhou route. Karst grouting is one of the main construction procedures of the sub-grade construction. Through construction art tests,construction principles,water and cementation ratio,grouting construction key points and quality check requirements were determined. Grouting quantity and pressure can be determined according to different geology conditions. Recommendations for quality problems such as bad practicability of grouting,unexpected dissipation of slurry,slurry belching,and overfeeding of slurry going to non-grouting area were proposed.

Characterization of Mechanical Properties of Waste Slurry Modified by Recycled Sand and Cement

In order to study the modification effect of recycled sand on cement reinforced waste slurry(CWS),triaxial test,scanning electron microscope test and X-ray diffraction test were carried out.The mechanical test of recycled sand and cement reinforced waste slurry(RCWS)shows that the deviatoric stress–strain curve of RCWS samples changes from hardening type to softening type with the increase of recycled sand content;the peak stress increases with the increase of recycled sand content;recycled sand can enhance the shear strength of CWS by increasing both cohesion and internal friction angle.The microscopic test shows that recycled sand can improve the structural compactness by cementing with hydrated calcium silicate and can reduce the void ratio and orientation index of RCWS samples.Finally,the mathematical model between shear strength parameters and void ratio is established.The research shows that adding an appropriate amount of recycled sand and cement has a good modification effect on waste slurry.This is an effective method to treat two kinds of construction wastes:construction waste slurry and waste concrete.

Mechanical Properties of a Eucalyptus-Based Oriented Oblique Strand Lumber for Structural Applications

Wood and wood-based composite materials have gained increasing attention in the sustainable building industry because of their renewability and environmental friendliness.Oriented oblique strand lumber(Eucalyptus Strand Wood,ESWood),which is manufactured from fast-growing small diameter eucalyptus wood(Eucalyptus urophylla×E.grandis),is introduced in this paper.Small clear specimen tests were conducted to determine the mechanical properties of ESWood material while full-scale component tests were performed to observe the structural performance of ESWood beams.A comparison of mechanical properties of ESWood with other wood/bamboo-based materials is then reported.From the results presented herein,it appears that the strength and stiffness properties of ESWood are affected by grain directionality and glued layers.However,it still has preferable mechanical properties as a building material,which is comparable or superior to those of other engineered wood/bamboo-based products(e.g.,Sitka spruce,LVL,OSL,Glulam,and Glubam).Furthermore,results from full-scale component tests show the stable mechanical performance of beams made by ESWood.This study makes a significant contribution to a potential utilization of fast-growing eucalyptus for general use in construction,and the presented mechanical tests results can serve as a fundamental data for more applications of ESWood in practical engineering.

Cyclic Shear Tests on Key Connection Joints of Modularized Constructions

Modularized construction is a new type of prefabricated building system with green environmental protection and excellent performance. There are few studies on the seismic performance of its key connection joint. This paper presents a new type of assembled connection joint for the high-rise modularized construction. Cyclic shear tests of full-scale joints were carried out, and the key indexes of their seismic performances including the hysteretic performance, ductility, and energy dissipation capacity were analyzed and obtained. The results show that the hysteresis loops of longitudinal and lateral cyclic shear tests were both plump in shapes. The ductility coefficients were 4.54 and 4.98, and the energy dissipation coefficients were 1.83 and 1.43, respectively. The test joint had good ductility and energy dissipation capacity. The positions of yield failure of specimens were mainly concentrated in the connection areas between the column and short beam or end-plate. The research can provide the technical reference for the seismic design and engineering application of related modularized constructions.

Geotechnical and Geochemical Assessment of Natural Sands in Ahanta West Area, Southwestern Ghana

Geotechnical and geochemical assessment of natural sands being used as fine aggregates for construction purposes in Ahanta West and its Environs was carried out, as well as addressing the environmental problems associated with the exploitation of these sand through the sand winning activities. The results from geotechnical and geochemical tests were bench marked with British, American and Ottawa Standards for testing materials. Representative samples were taken from five different sand winning sites namely, Pompuni, Agona Banso, Fretsi, Tumentu stream and Fretsi river. The geotechnical tests carried out were specific gravity, grain size analysis, moisture content, silt content, permeability test using the constant head permeameter method. The photometer (Hydro Test HT 1000) was used to determine silica, sulphate and chloride concentrations in the sand samples. The oxides for the geochemical analysis were determined using the X-ray fluorescence (XRF) method. The results from the study areas showed that except for Fretsi, the specific gravity, grain size analysis, moisture content, silt content and permeability tests were within the acceptable range for natural sands. Sand samples from Pumponi and Agona Banso had the required Cu and Cc values of being well graded. Sulphate and chloride concentrations were within standards for all the samples;however, silica was low for all the samples. Fe2O3, Al2O3, MnO and Na2O did not meet the Ottawa sand standard. Natural sand is not recommended to be used for construction purposes however, these sands may be treated or blended if it is to be used for construction purposes. There are serious environmental implications for the sand-winning activities in the study areas such as stripped overburden, creation of pits and ponds, increased total suspended solids in surface waters, and destruction of aquatic habitats which needs to be addressed.

Measures to strengthen engineering quality supervision in construction management

With the continuous advancement of China's urbanization process,the demand for construction projects is increasing,which is both an opportunity and a challenge for construction companies.If the enterprises themselves can grasp the background and policy conditions to maintain a high level of construction engineering,then its enterprise benefits and future development prospects will be excellent.However,there are also many companies whose own reputation and actual benefits have been affected for poor engineering quality caused by poor construction management.This is exactly what we must pay attention to.This article will analyse and explore the relevant work to improve the engineering quality of different phases of engineering construction and to guide the management of the construction unit in the future from the perspective of the construction unit to strengthen the project quality supervision.

Defects in Concrete Elements: A Study of Residential Buildings of 30 Years and above in Onitsha Metropolis, Anambra State, Nigeria

Building defect is an issue in existing buildings that needs urgent tackling to prevent further problems. This study assessed the defects in concrete elements in residential buildings of 30 years and above in the Onitsha metropolis of Anambra State, Nigeria. Data collection instruments in the study include structured questionnaire, interviews, visual inspection/observations, archival records, recordings, photographs;and non-destructive testing of the concrete elements in an existing building in the study area. The population of this study constituted of the construction registered professionals and the existing buildings in study area. The sample for the study was based on the calculated sample size using Taro Yamani Formula. A total of 158 registered professionals were sampled from the population of 260. The questionnaires were purposively distributed to the registered professionals up to the required sample sizes of 158 and 129 questionnaires were properly filled and returned. The study used the SPSS and Microsoft Excel to analyze the data. The results were analyzed in percentages and figures using descriptive statistics and presented in the form of pie charts and tables. The finding of the study revealed that the causes and effects of structural defects on the concrete elements in existing buildings in the study area according to the rating are;exposed/corrosion of the embedded metals, faulty workmanship, overload and impacts, chemical attack, freeze-thaw deterioration, fire/heat, restraint to volume change. The visual observation revealed that the structural elements are characterized by heavy defects such as deep vertical, horizontal and diagonal cracks, exposed/ corrosion of the embedded metals, spalling of the concrete slabs. The existence of defects in the concrete members led to the low compressive strength of the concrete elements and the structural instability of the existing buildings as revealed by the non-destructive test. The non-destructive test result revealed that most of the tested concrete elements have low compressive strength value and such were remarked poor as they did not satisfy the assumed value. Essentially, the study concluded by recommending that regular monitoring, inspections and non-destructive testing of concrete elements should be conducted on existing aged and defected buildings to detect the structural stability of the buildings;and it is imperative to evacuate occupants from heavy structurally deteriorated and defected buildings since most of them have lost their residual design life span and ability to sustain imposed loads.

Construction of UHVAC Test Base

The construction of the UHVAC test base of SGCC is an important component of the pilot project on UHVAC power transmission and transformation in China. This paper introduces the layout, technical requirements and main test functions of the UHVAC test base as well as difficulties during construction. It lays stress on the characterization of a 1 000-kV single-circuit test line, a 1 000-kV one-tower double-circuit test line, a full voltage test site for UHV equipment, a climate laboratory, a corona cage and a long-wave-front impulse voltage generator.