Housing Materials Research Articles

Developing adjustable stiffness for smart material of magnetorheological elastomer to diminish vibration

Many vibration isolators, such as passive vehicle mounting devices, have an inflexible stiffness. This article presents the development of a smart material vibration isolator based on magnetorheological elastomer (MRE), which has adjustable stiffness to minimize unwanted vibrations. The objective of this research is to first create a design for the vibration isolator, and then simulate a magnetic circuit. The Finite Element Method Magnetics (FEMM) software was employed to simulate the effectiveness of the electromagnetic circuit in generating a magnetic field through the vibration isolator by employing MRE samples. Pure iron was chosen as the material for the housing of the vibration isolator test rig. To attain an optimal magnetic field, an inventive design of the magnetic circuit, including examination of the wire type, size, and coil turn number, along with the housing material of the test rig, was performed. The study analyzed the performance of the MRE vibration isolator concerning different current inputs in the coil. The results indicate that the stiffness value of the MRE-based isolator system can be more effectively modified by increasing the current inputs. Therefore, a larger current input leads to a greater change in stiffness.

The Reintroduction of Bobâlna Hill Into the Tourist Circuit

The reintroduction of Bobâlna Hill into the tourist circuit. Bobâlna Hill is the highest part of the Cluj and Dej Hills, an integrated part of the Someșan Plateau, with an altitude of 693 m. From a geomorphological point of view, it falls within the erosive-structural level formed on the horizon of the Dej tuff, of Lower Pannonian age. At the foot of the hill, a series of subsequent valleys developed, such as Olpret Valley to the north, northeast and east, Măr Valley and Lujerdiu Valley to the south, and Luna Valley to the west and southwest respectively. From a geological point of view, Bobâlna Hill is composed by the Dacitic tuff of Dej, interspersed with marls, clays, sandstones with coals and marly shales. Due to its altitude and the rocks it is made of, Bobâlna Hill determined the meaning of the evolution of the other natural components of the environment, flora, fauna, soils, as well as the hydrography. The development of human communities in the adjacent communes was deeply influenced by the presence of Bobâlna Hill. The hill is located about 30 km west of Dej City. Its area of polarization is more visible on the territories of Bobâlna, Aluniș, Cornești, Recea-Cristur and Panticeu communes. Bobâlna Hill has been the source of building materials for houses and other buildings for a long time. There are still buildings made of “Băbdiu stone” today. In addition to resistance over time, tuff has a beautiful appearance and was accessible to people. In June 1437, an army of peasants gathered on Bobâlna Hill, armed with pitchforks and scythes, ready to fight to regain their rights and freedom. The uprising in Bobâlna took place as a result of burdensome feudal obligations towards the state, the feudal lord and the Catholic church, but also because of numerous abuses. On June 8, 1937, the leaders of the villages in the Olpret area formed an initiative committee to build a monument in honour of the peasants who revolted in 1437, on Bobâlna Hill, at an altitude of 693 meters. The initiative was successful and a limestone monument was built, unveiled on December 21, 1957. Starting from 1968 and up to 1989, popular celebrations were organized, most of them just above, on the Bobâlna plateau. The heroes of the 1437 uprising were commemorated and it was an occasion of joy, reunion and party for the inhabitants of the area. Between the years 1989-1999, the celebrations stopped, but they were resumed in 1999, 2001 and 2002. The last celebration was in 2015, in the school yard in Bobâlna commune, but it had a smaller scale. In the years 2021 and 2022, the first two editions of the Revolution Race event took place, on Bobâlna Hill. Revolution Race is a sporting event that highlights nature, history and rural traditions. The “Înflorești” Sports Club Association participated to the organization of the two events in partnership with the Go4Fun Association and the administration of the municipalities of Bobâlna and Cornești. Over 300 runners from Romania and abroad participated in each edition. Starting from the advantages offered by the natural setting, the presence of Bobâlna Hill, and the significance of the historical event of 1437, Bobâlna municipality is currently designing a long-term development strategy based on ecological rural tourism. Keywords: Bobâlna Hill, Revolution Race, Bobâlna Monument

Housing conditions, cooking fuels, and health-related quality of life among rural middle-aged and elderly in northwest China: A ten-year balanced panel study

ObjectiveTo investigate the impacts of improving housing conditions and transitioning to clean cooking fuels on health-related quality of life (HRQOL) among middle-aged and elderly populations in rural China. Methods: Using a 10-year longitudinal follow-up study, we examined changes in housing conditions, cooking fuel use, and HRQOL among 690 Chinese adults aged 45 above in rural areas. HRQOL was assessed using the European Quality of Life-5 Dimensions 3 Levels (EQ-5D-3L) questionnaire. Generalized estimating equations were utilized to analyze correlations between variables. Results: Using four-period balanced panel data of 10 years, there were significant differences in the self-reporting of mobility, self-care, usual activities, pain / discomfort and anxiety / depression in rural middle-aged and elderly people (p < 0.05). In terms of the EQ-5D index score and EQ-VAS score, showed a decreasing trend (p < 0.05). The housing area, housing material type, utilization of sanitary toilets, separation of housing and kitchen were separated and non-solid fuels used as cooking fuel were significantly associated with high HRQOL (p < 0.05). Conclusions: This study found that good housing conditions and the use of non-solid cooking fuel had positive effects on health-related quality of life of middle-aged and elderly people in rural areas of northwest China.

Extensive Experimental Thermal Runaway and Thermal Propagation Characterization of Large-Format Tabless Cylindrical Lithium-Ion Cells with Aluminum Housing and Laser Welded Endcaps

Large-format tabless cylindrical lithium-ion cells are expected to enhance performance and reduce cost of next generation vehicles. The influence of innovative new tab designs, increased dimensions and new housing materials are however still unexplored and must be revealed to unlock safe future battery systems. In this study, the thermal runaway and thermal propagation characteristics of sophisticated state-of-the-art large-format tabless cylindrical cells with aluminum housing and laser welded endcaps are extensively characterized. Multiple abuse test setups on cell and battery level are custom designed close to the true boundary conditions in real world applications. Results show cells with aluminum housing require careful choice of trigger methods as the low melting point and less mechanical strength compared to conventional nickel-plated steel housings introduce additional challenges. The tabless design was found to act as a strong mechanical connection that prevents shifting of the electrode assembly. Instead, axial ruptures of the jelly roll may occur. The leftover high density material conglomeration that is in tight contact with the inner housing wall transfers heat into the surroundings and is critical for thermal propagation safety. Strong interstitial potting compound with low thermal conductivity successfully prevented any major convective heat transfer into the neighboring cells by venting gas.

Dynamic Cost Consideration of Local Materials for Mass Housing Construction in Nigeria

There are lots of building materials that can be sourced locally for building construction purpose. Material is a major component of construction cost and a reduction in the cost of material can also result to reduction in overall construction cost. The cost of building materials poses a significant threat to both the construction industry and people aspiring to own houses. One major way to bring down the cost of materials for affordable housing is a shift toward the usage of local materials. This study therefore investigates the dynamic cost consideration of local materials for mass housing construction in Nigeria. The objectives are to ascertain the available local materials used in housing construction in Nigeria, the factors affecting the use of local building materials for housing construction in Nigeria, and examine the benefits of using local materials for housing construction in Nigeria. The study utilized a literature and field survey research design. The population of the study was the construction professionals that are involved in the usage of local materials. Purposive sampling technique was used to select a sample of 46 from the frame. Frequency and percentage were used to analyze the data. The study reveals 11 local materials in Nigeria but most of the materials are either “rarely used” or “seldom used” with the exception of just eight of them that are “often used”. The literature survey also reveals that earth or soil local materials are largely used for housing construction floor finishing. Durability and cost of production contribute most among 14 factors that contribute to the usage of local materials with 57% while air quality properties have least contribution. The result equally showed that provision of affordable housing and reduced construction cost stand top among the eight benefits of local materials highlighted in this study from 65% of the responses. The study recommends that government should formulate policy that should play down the agitations on the use of imported building materials by encouraging research in the production of local building materials. Producers of local materials should also take cognizance of the factors that contribute to the usage of local materials and ensure that they are incorporated in the materials to enhance their usage. The study will contribute significantly to the usage of local materials and improvement of their qualities. Keywords: Building Materials, Cost, Benefits, Housing Construction, Local Materials.

Study on Mechanical Behavior of Coconut Fiber Composite as an Alternative Material for Mobile Phone Housing

Mobile phone is one of the most widely used electronic products. Housing is part of a very important component of mobile phone. Mobile phone housing refers to the outer housing of the device that encompasses its internal components. Mobile phone housing materials have been widely developed, such as polyester, polyurethane, carbon fiber, wood and leather. This paper proposes to conduct tensile tests and fabrication of mobile phone housing to determine the mechanical characteristics of coconut fiber composites as an alternative material for mobile phone product. Finite element simulation of drop test is then conducted to determine the impact robustness of a product. The investigation of tensile characteristics was carried out using variations in fiber direction. Vacuum assisted resin infusion is used as a method for manufacturing mobile phone housing product. Finite element simulation of mobile phone housing with various drop test positions was also conducted and the impact behaviour of coconut fiber composite housing materials was also obtained. It was shown that coconut fiber can be used as an alternative material for mobile phone housing. The design of the mobile phone housing also needs to be considered at the corner position of the housing because this is the location where the maximum impact stress occurs.

Lifestyle and home

Home is a special place where time flows in a very special way. At home, the walls help, and the past never dies. Home is my fortress and a place where I meet my loved ones. Home is both a protective cover facing the outside world and a reflection of the most personal, deep and secret recesses of the soul. In the section devoted to housing, we present the materials of two round tables held with young people in Novosibirsk and Irkutsk. How do representatives of the next generation imagine their home?They will tell us about it. The problem of co-housing was already solved a hundred years ago within the concept of Socialist City (and brought extremely controversial results), but today this theme is returning, while attracting the attention of architects and sociologists on a new digital design platform. Similarly, there is a renewed interest in traditional materials for residential housing, especially, wood. How to teach young architects of the “era of concrete, glass and metal” the skills of designing in wood? This section contains articles devoted to it.

Tendencies of Termites of the Genera Anacanthotermes Jacobson to Damage the Wooden Parts of Buildings

We have focused our research on determining whether the timbers used as a building material by the population today are resistant or nonresistant to termite damage. The main purpose of this was to learn which types of trees cannot be used as building materials for houses or other structures. In this, we used Salix, Populus, Aleagnus, Ulmus, Pinus, and Betula wood species. We carried out research both in the laboratory and in the field (termite nests and residential buildings). In this case, damage by termites of these pieces of wood placed around termite nests accounts for one year. Salix and Populus wood materials were 86.6±6/50.0±4 percent in laboratory conditions, 93.3±5/90±5 in home, and Pinus and Betula wood materials were 6.6±0.7/0 in laboratory conditions and 13, 3±2/3.3±0.8 percent in home were damage noted. The causes of serious damage to wooden materials by termites are mainly due to the increase of humidity and the growth of fungi. When fungal cultures were isolated from damaged wood and their morphological characteristics were studied, it was found that wood decay fungi belonging to the genera Alternaria and Cladosporium were present. When studying the content of substances difficult to decompose by enzymes and microorganisms in the wood materials, it was found lignin that 20.1±0.3% was present in Salix and 41.2±0.3% in Betula wood. It has been found that in areas with high humidity, wood materials are decomposed by fungi and other microorganisms and the microorganisms multiply faster, As a result, wood more damage by termites. Lignin and some of its compounds prevent the growth of microorganisms. Wood materials made from trees belonging to the genera Pinus and Betula are resistant to termite damage due to their high lignin content.

Real Time Assessment of Smart Concrete Inspection with Piezoelectric Sensors

Utilization of an Electromechanical impedance (EMI) technique with Piezoelectric (PZT) sensors has showed potential for Structural Health Monitoring (SHM). The changes in mechanical structure via flexural bending and cracking can be detected by monitoring the deviations in electrical impedance signals recorded with embedded PZT sensors. This paper has conducted a comprehensive study on the potential of an EMI technique with embedded PZT sensors with 3D Concrete Printing (3DCP) structures subjected to flexural bending test until plastic failure. The impact of different Piezoelectric housing methods and materials has been studied comprehensively through the monitoring of EMI signals. Experimental results indicate that material housing types and thickness affect the sensitivity of EMI readings but also performed as a reinforcement when a load is directly applied. The embedded PZT sensors with the EMI technique have shown strong potential to address the cost and lifecycle challenges posed by traditional construction methods as the insertion of PZT sensors seamlessly functions with 3DCP workflows. Further developmental work can be carried out to address the sensitivity of the sensor, performance as a reinforcement, and installation automation. The results proved that the coated sensors could detect fractures in 3DCP concrete with decreased sensitivity on thicker coating layers through the variance in materials and coating thickness in the paper.

Contractor Perspective on Overcoming Cost Consideration as a Barrier to Using Sustainable Building Materials in Affordable Housing: A Systematic Review

The construction industry greatly contributes to environmental degradation, and sustainable building materials are becoming more important in minimizing this impact. However, the construction industry, especially affordable housing projects, confronts several obstacles that make it difficult to employ sustainable building materials widely. Many studies have investigated and advocated various barriers to using sustainable building materials within the construction industry. However, no attention has been paid to the cost consideration barrier for using sustainable building materials in Malaysia's affordable housing. In light of these challenges, This paper presents a systematic literature review that takes a broad approach, includes stringent inclusion and exclusion criteria, a thorough search strategy that includes a variety of databases and additional sources, a strict study selection procedure with multiple reviewers, quality assessment of included studies, and a narrative synthesis of findings focusing on several strategies for overcoming the cost consideration issues in using sustainable building materials in Malaysia's affordable housing from a contractor perspective. This study is important to improve affordable houses’ costs and ensure their residents’ comfort. By implying these strategies, Contractors may reduce costs and encourage sustainable construction materials in affordable housing projects.

Protracted displacement and housing systems in intermediary cities: the case of Syrians in Torbalı, Türkiye

This article investigates the dynamics of complex housing systems within the context of large-scale protracted displacement in Turkey/Türkiye. It presents new empirical findings from a qualitative study conducted in Torbalı, a rapidly growing intermediate city with a significant population of Syrian displaced people. Drawing on theoretical and conceptual insights from housing studies, urban studies and migration studies, the article assesses the ways in which displacement materialises in place through housing and contributes to city-making and urbanisation processes informally, incrementally, and in locally and historically contingent manners. We argue that the forms and dynamics of emerging housing exhibit both continuity but most markedly significant disjuncture from past housing trajectories in Torbalı. This challenges the implicit assumption of legal uniformity of self-builders common in incremental housing debates and suggests that the notion of incremental housing has limited relevance in contexts of protracted urban displacement. Furthermore, findings underline the significance of legal dimensions in energising housing informalities; in grading socio-legal statuses of resident populations; in bounding displaced people’s mobilities; in demarcating labour flows; in moulding rental markets; and in directing the flows of housing materials. These in turn shape current and future urban built environments and mould the ways in which the urbanisation of refuge manifests.

Large-Scale Self-Assembly of anisotropic graphene oxide films via blade Coating: Sustainable design and Stimuli-Responsive performance for biomimicry

Sustainable structural design, utilizing material to imitate natural biological systems, presents both promise and challenges. By avoiding interfacial problems encountered in composite counterparts, such designs offer self-adaptive materials for smart housing and green architecture, etc. In this study, we demonstrate the feasibility of large-scale self-assembly of graphene oxide (GO) flakes into anisotropic films through a simple blade coating technique. Through the application of blade coating to a highly concentrated nematic GO suspension, we successfully fabricate GO films with morphological gradient and patterning. Additionally, we propose a statistical analysis method utilizing scanning electron microscopy (SEM) images for the characterization of materials with macroscopic surface morphology. Furthermore, we explore the application of these GO films as low-dimensional soft actuators, revealing their outstanding stimuli-responsive performance and self-adaptation to environment. Such robust and flexible films can be used as integral building elements in the bioinspired design of sustainable smart housing facilitating remote robotization and sensing capabilities.

Environmental evaluation of family house materials impacts on climate change, land and water use, acidification and ecotoxicity

The construction industry plays a significant role in contributing to various environmental impacts, including climate change, acidification, and ecotoxicity, among others. This research paper presents a scientific analysis focused on the environmental evaluation of a masonry residential house by life cycle assessment (LCA) methodology. Specifically, it investigates the environmental impacts associated with the production phase of materials using the SimaPro software, which employs the Ecoinvent database. The ReCiPe method is utilized to calculate the comprehensive environmental impacts, with particular emphasis on climate change, terrestrial acidification, ecotoxicity, land use, and water use. To accurately determine the environmental impacts of the house materials, an allocation approach is employed, taking into account the function and location of the materials within individual structures. The calculated share of climate change per house materials amounted to 21.59 kg CO2 eq/m2/year, while the share on water scarcity was estimated at 15.87 m3/m2/year. The research findings reveal that vertical structures exhibit the highest environmental impacts across all impact categories, while horizontal structures demonstrate comparatively lower values.

Application of Laser Welding in Electric Vehicle Battery Manufacturing: A Review

Electric vehicle battery systems are made up of a variety of different materials, each battery system contains hundreds of batteries. There are many parts that need to be connected in the battery system, and welding is often the most effective and reliable connection method. Laser welding has the advantages of non-contact, high energy density, accurate heat input control, and easy automation, which is considered to be the ideal choice for electric vehicle battery manufacturing. However, the metal materials used for the electrodes of the battery and the connectors used to connect the battery are not the same, so the different materials need to be welded together effectively. Welding different materials together is associated with various difficulties and challenges, as more intermetallic compounds are formed, some of which can affect the microstructure, electrical and thermal properties of the joint. Because the common material of the battery housing is steel and aluminum and other refractory metals, it will also face various problems. In this paper reviews, the challenges and the latest progress of laser welding between different materials of battery busbar and battery pole and between the same materials of battery housing are reviewed. The microstructure, metallographic defects and mechanical properties of the joint are discussed.

Demographic predictors of disaster preparedness behaviour: Sylhet and Sunamganj, Bangladesh

ABSTRACT Bangladesh is a country prone to natural disasters, and disaster preparedness behavior (DPB) is an important factor in reducing the damage caused by these disasters. However, DPB has been neglected at the national level. This study aimed to investigate disaster preparedness behavior (DPB) among households in two districts in Bangladesh, Sylhet and Sunamganj. The researchers collected data through face-to-face interviews with 536 households and used the Public Readiness Index to measure DPB scores. The study found a surprisingly low level of preparedness among households, with an average DPB score of 2.42 out of 8. Individual and household characteristics, including sex, marital status, income level, previous disaster experiences, losing someone due to disaster, having a differently-abled member, house ownership, and house material, were identified as the prime predictors of DPB scores. However, these factors only explained 25.1% of the variance, suggesting that other predictors may also exist. The study recommends that policymakers prioritise the most disaster-vulnerable groups and develop policies that support these households and their members. This could include education and awareness campaigns, material support to households, and community-based approaches to disaster preparedness. However, the study has some limitations, including its limited generalizability and reliance on self-reported data. Further research is needed to identify other associated factors, such as disaster risk, intensity, vulnerability, and awareness, to gain a better understanding of DPB in Bangladesh.

Research on the Application of Industrial Robot Surface Grinding and Polishing Technology in Lithium Battery Cooling Shell

In modern intelligent manufacturing, when using industrial robots to complete precision machining of lithium battery heat dissipation housing materials such as assembly, grinding, polishing, and deburring, it is not only necessary to track the position of the robot’s end effector, but also to consider the contact force generated when the actuator contacts the working environment. This project takes the research on position and force control in robot automatic polishing process as the starting point. Due to the uncertainty and high degree of nonlinearity in the control process, machine vision is introduced into the process of robotic precision machining systems, combining visual inspection systems and feedback control systems to achieve grinding trajectory planning, verify the feasibility of the control scheme, and develop a robotic lithium battery housing material processing experimental platform to meet the requirements for precision machining of the free surface of the lithium battery heat dissipation workpiece, The surface roughness parameters of the lithium battery heat dissipation workpiece after precision machining by the robot should meet the requirements of the arithmetic mean deviation of the contour.

The association of sociodemographic, nutrition, and sanitation on stunting in children under five in rural area of West Java Province in Indonesia.

The prevalence of stunting in Indonesia has decreased gradually. The strategy to reduce stunting is currently prioritized on improving socio-economic levels, fulfilling food intake, and sanitation conditions. This study aims to analyze the association between sociodemographics, nutrition, and sanitation on stunting in rural West Java Province in Indonesia. A cross-sectional study was conducted in May-August 2022 among 247 mother-children pairs, selected by systematic random sampling from a rural area of West Java Province in Indonesia. The sociodemographic characteristics were measured using a structured questionnaire. The nutritional status of the children under five was assessed by length/height-for-age (HAZ), and was calculated using WHO Anthro software. Sanitation is assessed using observation and interviews with a structured questionnaire. The prevalence of stunting in children under five was 20.7% (5.3% severely stunted and 15.4% stunted). Binary logistic regression analysis using SPSS version 22.0 show that mother's height as the dominant factor associated with stunting in children under five (AOR = 3.45, 95% CI: 1.12-4.67, p = 0.008). In addition, children's age (AOR = 0.250, 95% CI: 0.104-0.598, p = 0.002); balanced diet practices (AOR = 1.57, 95% CI: 0.965-2.56, p = 0.069), and building materials (AOR = 1.869, 95% CI: 0.87-4.00, p = 0.108 are also related to stunting in children under five. Efforts to improve maternal nutrition need to be carried out from the period before pregnancy to the first 1000 days of life. Education on healthy home indicators, especially the use of this type of building materials for houses, needs to be done to improve sanitation as an effort to prevent stunting in children under five.

Evaluation of the thermal performance of EPS core panels: A multicriteria approach

To enhance the energy efficiency, it is crucial to develop construction systems that can effectively adapt to the diverse climates found in Brazil, particularly for application in social housing projects. This study aims to analyze the thermal viability of EPS core panels in Brazilian bioclimatic zones, which have been gaining prominence in the national market. For this, simulations were conducted using the EnergyPlus software to compare the performance of this material with that of masonry with ceramic blocks. The AHP-Gaussian method was employed to assist the decision-making process regarding the most viable system. The results indicated that EPS core panels with low solar absorptance in hot zones presented a 39.95% higher thermal load than masonry. On the other hand, in cold regions, EPS core panels were among the best solutions, reducing the thermal load by 50.39% in Curitiba when combined with high solar absorptance and shading of the openings. Consequently, through the multicriteria decision-making method, it was concluded that the use of EPS core panels in areas with high thermal amplitude offers advantages, while it should be avoided in hot regions. Thus, this study identified the technical feasibility of EPS core panels and masonry with ceramic blocks in Brazilian bioclimatic zones. It also offers guidance to professionals and public agents in the construction sector, helping them choose suitable materials for social housing. Additionally, this study presented innovation by demonstrating the benefits of employing multicriteria decision-making methods, expanding the possibilities for analyzing and selecting more energy-efficient construction systems.

Production and an advanced model for electrical conductivity of silicone rubber/carbon nanotube nanocomposites as outdoor insulator housing material

Considerable cause of the condensation mechanism of moisture and fog on the contaminated high-voltage insulator surface is the temperature difference between the insulator surface and the dew point which eventuate owing to the mechanism of radiative cooling. Condensation of moisture leads to creating a conducting path on the insulator surface and make the insulator to be a conductor and results in the electrical transmission line failure. In order to cover the above-mentioned temperature difference, carbon nanotubes (CNTs) are being applied to the silicone rubber which is the insulator housing material. This study is based on joule heating generation which decrease the electrical resistance of the high-voltage insulator surface. An advanced mathematical model which is based on Pukanszky formulation for estimation of composite tensile strength was presented for the effectual electrical conduction of silicone rubber - carbon nanotube nanocomposite (SCNT). SCNT samples were produced by the addition of dissimilar CNT concentrations to a high temperature vulcanizing (HTV) silicone rubber by solution-blending method. Comparison between experimental results and theoretical forecasts showed an excellent agreement. The obtained model disclosed that the lower ranks of tunneling resistivity and distance, the higher magnitudes of tunneling diameter, the higher concentration of longer and thinner CNTs, lower CNT curliness, higher fraction of networked CNTs, and deeper interphase can produce the maximum level of SCNT conductivity.

Thermal compensation design of achromatic andapochromatic optical systems using a 3D glass chart.

It is important to determine the ideal combination of housing materials, groups of refractive materials, and their optical powers for athermalizing achromatic and apochromatic optical systems. This study proposes a combined design approach that utilizes three or more glass types to resolve thermal aberrations and defocus achromatic and apochromatic optical systems. It selects a suitable glass type using a 3D glass chart and calculates the optical power analytically. Furthermore, a temperature-insensitive optical system with a 450-750nm band based on refractive materials (CDGM Glass Co., Ltd.) is designed, with the modular transfer function value of the center field of view decreasing by less than 0.024 in the temperature range of -40∘ C to +80∘ C and the secondary spectrum aberration decreasing by over three times and being maintained within 0.08mm.