Internal Door Research Articles

Indoor Exchange Rates and Penetration From Outdoors in an Instrumented Terraced House (Townhouse) Using Gas Tracers: Implications for Particles and Gases Indoors

Air exchange rate is a key determinant of indoor air quality which is highly variable within the rooms of a naturally ventilated terraced house (townhouse). Window opening can increase the air exchange rate, but internal door opening between rooms inside decreases the rate. Inert perfluorocarbon gas‐phase tracers demonstrated flow within the house, and the penetration of tracers released outside into the house showed a strong dependence on wind speed and wind direction. Between experiments, it was found that the tracer could be detected within certain parts of the house weeks after the initial release, with implications for pollutants and their impact on the indoor environment. A limited number of reactive tracer experiments suggested an upper limit for indoor [OH]~1 × 105 molecule cm-3 with up to 0.5 ppt of [NO3] estimated, leading to an estimated indoor lifetime for d5 isoprene of many hours. Ultrafine particulate matter generated in the kitchen travels throughout the house, and the persistence of elevated aerosol concentrations is seen even in well‐ventilated rooms, with implications for particle exposure in the evening and during the night.

Design and analysis of coir fibre reinforced polypropylene based internal car door panel

In today’s world demand for durability and recyclability are among the main factors considered while choosing a material for any products to be made. In the automobile sector apart from exterior parts of the vehicles, the interior parts should also be durable as it faces different types of loads in various situation. Internal door panel is considered as one of the most important interior part of the vehicle as it has to undergo different forces from the user side and also are meant to reduce the impact force on the passenger in an accident. Natural fiber reinforced polymer composites are considered to be very durable and are lighter than a lot of other materials present in the market. They have higher impact strength, higher tensile strength than a regular material. The Young’s modulus of coir fibers usually lies between 4 and 6 GPa. In this work coir fiber reinforced polypropylene was used as the material for the internal door panel. It has an elastic modulus of 1.9 GPa and has a tensile strength of 34 MPa. A FEA was done on the door panel to determine whether it is going to be a suitable replacement of the current material which is being used and if the maximum stress exceeds the ultimate tensile strength then whether the remaining stress will affect the human body in a fatal way or not. The deformation seen was around 1.036 mm with the maximum stress being 3.877 × 107 N/m2, which is an acceptable value for protecting the occupant. When a load of 100 N was put on the armrest it showed a maximum deformation of 1.213 × 104 N/m2 which is not more than the Young’s modulus meaning it can handle a load on the armrest when someone put their hand on it. The maximum deformation in the armrest was only 6.49 × 10−4 mm, showing it is suitable as a material for the internal car door panel.

Role of ventilation on the transmission of viruses in buildings, from a single zone to a multizone approach.

In a virus pandemic context, buildings ventilation has been recognized as a solution for preventing transmission of the virus in aerosolized form. The impact of the widespread recommendation of window opening and sealing door on ventilation circuits needs to be considered with a multizone approach. We modeled the airflow distribution in a building where people are isolating in a pandemic context, including one infected person. We analyzed the impact of opening the window and sealing the door in the quarantine room on exposures and probability of infection for occupants of the flat and of adjacent flats. In order to study the sensitivity of the results, we tested three ventilation systems: balanced, exhaust‐only, and humidity‐based demand‐controlled, and several window‐ and door‐opening strategies. When the door of the quarantine room is sealed, we observe that opening the window in the quarantine room always results in increased exposure and probability of infection for at least one other occupant, including in neighbors' apartments. When all internal doors are opened, we observe moderate impacts, with rather an increase of exposure of the occupants of the same apartments and of their probability of infection, and a decrease for the occupants located in other apartments. Based on the analysis on the airflows distribution in this case study, we conclude that sealing the internal door has more influence than opening the window of the quarantine room, whatever the ventilation system. We observe that this widespread recommendation to open the window of a quarantine room and to seal the door is based on the consideration of a single zone model. We illustrate the importance of moving from such a single zone approach to a multizone approach for quantifying ventilation and airing impacts in multizone buildings as residences in order to prevent epidemics of viruses such as SARS‐CoV‐2. It highlights the need of air leakage databases.

Vibration Analysis of Composite Internal Door Panel of a Car

Abstract: The main objective behind this paper is to develop a suitable model of internal door panel for cars, to conduct a static structural analysis of internal door panel by finite element method and to compare the performance of glass fiber material with previously recommended materials of internal door panel. This paper deals with the mechanical behavior and vibration analysis of glass fiber-based polymer composite beam structures. Glass fiber has been widely used for many applications due to its high strength, flexibility, stiffness and resistance to chemical this extended work the inactive basic Limited Component Investigation of inside entryway board of a vehicle by considering glass fiber composite materials was conducted. The entryway board of the vehicle was utilized to create the geometric show of the inward entryway board by CATIA V5 R20 modeling program. This 3-D geometric demonstration was imported to utilize ANSYS Workbench 19.0. Model analysis of the internal door panel has been done using ANSYS software.

Improvement of fire door design using experimental and numerical modelling investigations

PurposeFire door should withstand a high temperature without deforming. In the current paper, the challenges of improving the behaviour of the conventional fire door were described using various internal stiffeners in pair swinging-type fire door.Design/methodology/approachThe temperature distribution on the outside door surface was measured with distributed eight thermocouples. Subsequently the internal side was cooled with pressurized water hose jet stream of 4 bar. The transient simulation for the thermal and structure analysis was conducted using finite element modelling (FEM) with ANSYS 19. The selected cross sections during numerical simulation were double S, double C and hat omega stiffeners applied to 2.2 m and 3 m door length.FindingsDuring the FEM analysis, the maximum deformations were 7.2028, 5.4299, 5.023 cm for double S, double C and hat omega stiffeners for 2.2 m door length and 6.57, 4.26, 2.1094 cm for double S, double C and hat omega stiffeners for 3 m door length. Finally, hat omega gives more than three times reduction in the deformation of door compared to double S stiffeners which provided a reference data to the manufacturers.Research limitations/implicationsThe research limitation included the limited number of fire door tests due to the high cost of single test, and the research implication was to achieve an optimal study in fire door design.Practical implicationsAchieving the optimum design for the internal door stiffeners where the hat omega stiffener gives minimum door deformation compared to the other stiffeners was considered the practical implication. The work included two experimental fire door tests according to the standard fire test (ANSI/UL 10C – Positive Pressure of Fire Tests of Door Assemblies) for a door of 2.2 m length with double S stiffeners and a door of 3 m length with hat omega stiffeners, which achieved minimum deformation.Originality/valueThe behavior and mechanical response of door leaf were improved through using internal hat omega stiffeners under fire testing. This study was achieved using FEM in ANSYS 19 for six cases of different lengths and stiffeners for fire doors. The simulation model showed a very close agreement with the experimental results with an error of 0.651% for double S and 1.888% for hat omega.

Production and characterization of bamboo and sisal fiber reinforced hybrid composite for interior automotive body application

Composite materials have high strength to weight ratio with low density and high stiffness to weight, high strength ratios, and high fatigue strength to weight ratio compared to traditional engineering materials making them find wide applications in structural constructions. When the lightweight composite materials which are made of lightweight natural fibres are used in automotive application, the fuel economy of the vehicle improves reducing the related harmful emissions. The aim of this research is to develop and characterize the performance of sisal and bamboo reinforced polyester hybrid composite (BSFRHC) with different fibre orientation of sisal and unidirectional (UD) bamboo fibre. Next, BSFRHC was fabricated with 20% total fibre volume fraction. Of this total fibre volume, the composite is fabricated in 3:1 bamboo to sisal fibre ratio using hand lay-up technique. Then tensile, compressive, impact and flexural tests were carried out. In general, it is concluded that as varying fiber orientation, the tensile strength varies. The higher tensile strength is observed with 0° fibre orientation of bamboo/sisal fiber reinforced hybrid composite. From compressive strength of the hybrid composite reinforced with bamboo/sisal fibre, it is observed that the 0°-fibre orientation composite is exhibiting higher compressive strength than 90° fibre orientation composite and bidirectional (0°/90°) fibre orientation composite. Unidirectional 90° fibre orientation was found to have a higher tensile and flexural strength whereas unidirectional 90° and bidirectional (0°/90°) fibre orientation nearly have the same value of tensile strength, whereas bidirectional (0°/90°) was found to be having higher flexural strength than unidirectional 90° fibre orientation. Impact analysis of vehicle internal door panel made of BSFRHC was done using ANSYS Software. Furthermore, it is found that the bamboo and sisal fibre reinforced hybrid composite in unidirectional 0° has the potential to be used for automotive interior part application.

Analysis of the internal door technological process

Abstract Designing and proper implementation of effective processes and providing the customer with high quality products undoubtedly determines the stable position on the market. The aim of the study was to analyse the cost and value of the technological process of doors in the context of creating added value and to identify unnecessary processes (not creating added value) in relation to which appropriate corrective actions could contribute to their elimination. Thanks to the application of remedial measures, consistent with the lean manufacturing concept, the study eliminated, among other things, operations related to unnecessary transport and storage of products, which resulted in both the reduction of time and costs of process implementation.

Parametric Energy Simulations of a Nordic Detached House Heated by a Wood Stove

Wood stoves are widely used in Nordic countries. They offer a good opportunity to use biomass for space-heating and to reduce the peak power of all-electric buildings. However, wood stoves are highly concentrated heat sources with limited control compared to other typical heat emission systems, which makes the assessment of their impact challenging. This study introduces a simulation-based parametric study of a detached house equipped with a wood stove located in Oslo, Norway. The respective impact of different building parameters and stove nominal powers on the building performance is illustrated. The analysis shows that the annual total space-heating needs (i.e. the sum of the base load, modelled as ideal heaters representing the electrical radiators, the stove and the heating of the ventilation supply air) increased significantly due to the higher average indoor temperature. The resulting heat emission efficiency of the stove ranged between 66% and 90%. However, the stoves covered between 28% and 62% of the total space-heating needs. When using the stove, the maximum hourly-averaged power for the electrical radiators decreased between 5 W/m2 and 31 W/m2 during the peak hours of the electricity grid. The building thermal mass, insulation level, as well as the combination of internal door position with the bedroom temperature setpoint, had a significant impact on the calculated values. Finally, the study revealed that the occupant behaviour modelling should be improved to better capture the wood stove impact on the energy performance using building simulations.

Roles of the reference service life (RSL) of buildings and the RSL of building components in the environmental impacts of buildings

The Life Cycle Assessment of a building is a complex analysis that also involves the use of the predicted Reference Service Life (RSL) of the building components and materials, as well as the predicted RSL of the whole building. The RSL values of individual materials and building components can be obtained from different sources and are not exactly comparable. In the present study, the influence of selected RLS values on an LCA assessment was evaluated. Three different RSL databases were used as the sources of the data to estimate the environmental impacts of selected building components (internal wooden door and external finishing coat). Two scenarios were presented. In the first scenario a building component can be reused in another building, while in the second scenario the reuse of the building component is not possible. The study showed that dependent on the selected RSL database, the results can differ by up to a factor of five. Therefore, it is very important to describe clearly the maintenance scenarios for a building in order to have a reliable comparison of the results of LCA assessments.

Internal door closing habits in domestic premises: Results of a survey and the potential implications on fire safety

It is generally accepted that keeping doors closed provides a means of protection by limiting smoke and fire spread. In the design of domestic buildings, it is therefore often assumed that occupants maintain a habit of keeping internal doors closed. The paper presents the results of an online survey to determine respondents’ internal door closing habits for their domestic premises. This attracted 304 responses (250 of which were from the UK) and was then followed by a more detailed survey, attracting 26 replies, to elaborate on respondents’ rationale behind their habits. The findings indicate that the overall probability that a kitchen, living room and bedroom door are closed while occupants are sleeping is 46%, 45% and 60%, respectively. It was found that the type of property, and whether respondents have children or pets, all have an influence on door closing habits. Respondents who lived in apartments were found to be up to 27% less likely to close kitchen or living room doors but more likely to close bedroom doors before going to sleep (+19%). In all instances, respondents with pets were typically more likely to keep doors open (ranging from 0% difference to +16%). However, when considering door closing behaviours for pet owners independent of the property type, it was found there was no statistically significant difference for bedroom door closing habits when sleeping. The analyses in this paper ultimately point towards the potential for daily household activities to take priority over the safety benefits which internal doors can provide.

Predictions of summertime overheating: Comparison of dynamic thermal models and measurements in synthetically occupied test houses

Summertime overheating in UK dwellings is seen as a risk to occupants' health and well-being. Dynamic thermal simulation programs are widely used to assess the overheating risk in new homes, but how accurate are the predictions? Results from two different dynamic thermal simulation programs used by four different experienced modellers are compared with measurements from a pair of traditional, semi-detached test houses. The synthetic occupancy in the test houses replicated curtain operation and the CIBSE TM59 internal heat gain profiles and internal door opening profiles. In one house, the windows were always closed and in the other they operated following the TM59 protocol. Sensors monitored the internal temperatures in five rooms and the local weather during a 21-day period in the summer of 2017. Model evaluation took place in two phases: blind and open. In the blind phase, modellers received information about the houses, the occupancy profiles and the weather conditions. In the open phase, modellers received the test house temperature measurements and, with the other modellers, adjusted their models to try and improve predictions. The data provided to modellers is openly available as supplementary information to this paper. In both phases, during warm weather, the models consistently predicted higher peak temperatures and larger diurnal swings than were measured. The models' predicted hours of overheating were compared with the measured hours using the CIBSE static threshold of 26℃ for bedrooms and the BSEN15251 Category II threshold for living rooms. The models developed in each phase were also used to predict the annual hours of overheating using the CIBSE TM59 procedure. The inter-model variation was quantified as the Simulation Resolution. For these houses, the blind phase models produced Simulation Resolution values of approximately 3% ± 3 percentage points for TM59 Criterion A and 1% ± 1 percentage point for TM59 Criterion B. The Simulation Resolution concept offers a valuable aid to modellers when assessing the compliance of dwellings with the TM59 overheating criteria. Further work to produce Simulation Resolution values for different dwelling archetypes and weather conditions is recommended. Practical application: Overheating in UK homes is a serious and growing risk to health and well-being. Dynamic thermal models are used to predict overheating risk in existing and proposed dwellings. Comparisons between predicted temperatures and temperatures measured in two test houses shed light on the accuracy of predictions for existing homes. CIBSE Technical Memorandum TM59 provides a strategy for predicting overheating risk in proposed dwellings. There are, however, differences between models' predictions. The concept of Simulation Resolution is introduced to quantify this inter-model variability. It provides modellers with a firm basis on which to determine whether TM59 overheating predictions are robust.

Development and Characterization of Sisal Fiber Reinforced Polypropylene Composite Materials

In most of the developing countries, plastic polypropylene is not fully recycled and converted in-to use after it is once used. Sisal fiber is also widely available in different developing countries like Ethiopia. Adding this two materials and developing automotive interior part was taken as a primary motive for it reduces cost and is environmentally friendly. Thus, the main purpose of this research is to develop composite material from natural fibre (sisal fiber) reinforced with recycled plastic waste (polypropylene) for interior automobile accessories specifically for internal door trim panel application. This research examines effect of fiber length, fiber loading and chemical treatment of fiber on the physical and chemical properties of the sisal fiber reinforced polypropylene (SFRPP) composite material. The waste polypropylene and the treated and untreated sisal fiber with variable length and weight ratio (fiber/matrix ratio) were mixed. Flammability of sisal fiber reinforced Polypropylene (SFRPP) composites material was examined by a horizontal burning test according to ASTM D635 and chemical resistance of the sisal fibre reinforced PP composites was studied using ASTM D543 testing method. The result on the flammability test shows that treated fiber has lower burning rate than untreated fiber and decreases with increase in fiber length and fiber loading. The resistance of the composites to water has increased as the fiber length increases and decreased as the fiber loading increase. Generally, SFRPP composite is found to have better resistance to water than NaOH and H2SO4 and treating the fiber has brought considerable improvement on chemical resistance of the composite. Fiber loading and fiber length has positive and negative effect on the flammability of the SFRPP composite respectively.

Frequent Door Openings During Cardiac Surgery Are Associated With Increased Risk for Surgical Site Infection: A Prospective Observational Study

Preliminary studies that analyzed surrogate markers have suggested that operating room (OR) door openings may be a risk factor for surgical site infection (SSI). We therefore aimed to estimate the effect of OR door openings on SSI risk in patients undergoing cardiac surgery. This prospective, observational study involved consecutive patients undergoing cardiac surgery in 2 prespecified ORs equipped with automatic door-counting devices from June 2016 to October 2017. Occurrence of an SSI within 30 days after cardiac surgery was our primary outcome measure. Respective outcome data were obtained from a national SSI surveillance cohort. We analyzed the relationship between mean OR door opening frequencies and SSI risk by use of uni- and multivariable Cox regression models. A total of 301 594 OR door openings were recorded during the study period, with 87 676 eligible door openings being logged between incision and skin closure. There were 688 patients included in the study, of whom 24 (3.5%) developed an SSI within 30 days after surgery. In uni- and multivariable analysis, an increased mean door opening frequency during cardiac surgery was associated with higher risk for consecutive SSI (adjusted hazard ratio per 5-unit increment, 1.49; 95% confidence interval, 1.11-2.00; P = .008). The observed effect was driven by internal OR door openings toward the clean instrument preparation room. Frequent door openings during cardiac surgery were independently associated with an increased risk for SSI. This finding warrants further study to establish a potentially causal relationship between OR door openings and the occurrence of SSI.

Finite Element Analysis of Internal Door Panel of a Car by Cons idering Bamboo Fiber Reinforced Epoxy Composite

In this paper work the dynamic structural Finite Element Analysis of internal door panel of a vehicle by considering bamboo fiber reinforced epoxy composite (BFREC) materials was conducted. The objective of the paper is to develop a suitable model of internal door panel for Toyota DX car, to conduct a transient dynamic structural analysis (stress and displacement analysis) of internal door panel by finite element method, to compare the performance of BFREC material with previously recommended materials of internal door panel. The door panel of Toyota Corolla DX model vehicle was used to develop the geometric model of the internal door panel by CATIA V5 R20 modeling software. This 3-D geometric model was imported to using ANSYS Workbench 15.0. The transient dynamic structural FEA was done after assigning loading and boundary conditions. The applied load considered for this analysis is the self-inertial weight of the panel due to the acceleration field produced while the door is closing. The equivalent stress and the displacement are noted and investigated to compare with the literatures revised. The result shows that, bamboo fiber reinforced epoxy composite panel has the smallest mass and equivalent stress values, as compared with the lignocellulosic composite and polypropylene one. Based on these realities, it is recommended that bamboo fiber reinforced with epoxy composite materials are suitable for internal structural automotive panel applications.

Algade 9 i Aalborg – Husenes udvikling fra vikingetid til nutid

Algade 9 i Aalborg – Husenes udvikling fra vikingetid til nutid

Investigation of PCM as retrofitting option to enhance occupant thermal comfort in a modern residential building

This study investigated the feasibility of PCM as a retrofitting option to reduce the zone air temperature and improve occupant thermal comfort under free running condition in an existing house in Melbourne, Australia. Both the experimental and numerical approach were applied in this study. In the experimental study, PCM was installed in the ceiling of one of the rooms and indoor air temperatures of two rooms (one with PCM and the other without PCM) were recorded. A simulation model was developed using building simulation software EnergyPlus and validated using the recorded experimental temperature data. The results showed up to 1.1°C reduction in BED 2 indoor air temperature during daytime and 34% reduction in thermal discomfort hours through the passive installation of PCM on the ceilings. Several simulations including different user behaviour scenario (windows and internal door operations) were carried out to identify the influence of user behaviour on the effectiveness of PCM. It was observed that integration of PCM is more effective in reducing thermal discomfort hours if windows are kept open at night for night purging and the internal doors are remained closed at all time to prohibit any mixing with surrounding zones without PCM. Further improvement in PCM effectiveness was observed when similar amount of PCM was spread in the ceiling and walls.

Simplified Space-heating Distribution Using Radiators in Super-insulated Apartment Buildings

The necessity to drastically reduce the space-heating (SH) needs of residential buildings in Europe has prompted the emergence of building concepts based on a super-insulated building envelope, such as the passive house (PH) standard. In these envelopes, the SH distribution system can be simplified because it is theoretically not necessary anymore to place a heat emitter in each room, or in front of each window. There is lack of fundamental knowledge to support this simplification of the SH distribution system. The present contribution especially focuses on apartment buildings heated using a reduced number of radiators. It aims at comparing the balance between energy efficiency, thermal comfort and user satisfaction using simplified SH distribution. For this purpose, two flats built according to the Norwegian PH standard have been investigated using building simulations (using IDA-ICE), field measurements and occupant interviews. With a simplified distribution, one may suspect that occupants experience the thermal environment of rooms without heat emitter as too cold, typically bedrooms. On the contrary, the super-insulation and the high-efficiency heat recovery prevent significant temperature zoning to takes place between rooms. Even though the SH distribution is simplified, occupants rather complain about the bedroom temperature which is too warm if they do not open windows. Unfortunately, this way to control indoor temperature has a strong adverse influence on the space-heating needs, which is here investigated for different control strategies. Another limitation is the time needed to heat a bedroom only using internal door opening. It takes several hours to adjust to a higher set-point temperature; an aspect that can be critical if the bedroom temperature should be changed between daytime and nighttime.

A simulation study of the changes in PM2.5 concentrations due to interzonal airflow variations caused by internal door opening patterns

Short-term variations in interzonal airflows can cause significant fluctuations in gaseous or particulate matter concentrations in indoor environments and therefore, interzonal airflow variations need careful consideration when modelling indoor pollutant concentrations. This study investigates the potential accuracy of modelling interzonal airflow variations and assesses the effect of interzonal airflow variations on indoor pollutant concentrations. A variable interzonal airflow is compared with a time-weighted average interzonal airflow, and the differences in the resulting estimates of indoor pollutant concentrations are analysed. Interzonal airflow variations were simulated by the opening/closing of internal doors for periods of 1, 2, 5, 10, 15 and 30 min. Based on experimental comparison, it can be concluded that the modelling approach used, accurately predicts PM2.5 concentrations for interzonal airflow variations for durations of 10 min or greater, with increasing accuracy for longer durations. The simulations demonstrate that both the time of occurrence and duration of the interzonal airflow variations are critical in determining indoor concentrations, and indicating that a time-weighted average interzonal airflow is not a suitable substitute for modelling interzonal airflow variations, as it under-predicts mean PM2.5 concentrations by up to 28%.

OVOS DE Enterobius vermicularis EM SALAS DE ESPERA E BANHEIROS DE UNIDADES BÁSICAS DE SAÚDE (UBS) DO MUNICÍPIO DE NOVA SERRANA-MG: CONTRIBUIÇÕES PARA O CONTROLE

In this study, the presence of intestinal helminth eggs was evaluated in samples collected from five Basic Health Units (BHU) using the Graham’s technique (1941), in the city of Nova Serrana (MG). In the total of 8 collections, 40 chair seats and 40 attendance tables were sampled in the reception and, on the toilet doors, 64 internal door handles and 64 external door handles. All the slides were analyzed by light optic microscopy with 10X and 40X magnifications in the Microscopy Laboratory FUNEDI / UEMG and re-examined in the Medical Malacology and Helminthology Laboratoryof the Research Center René Rachou (FIOCRUZ-Minas). The results indicated the presence of Enterobius vermicularis eggs, mostly viable, with infection rates calculated by simple proportion. In the reception the contamination percentage was 25.0% on attendance tables and 17.9% on chair seats; in the toilets, 35.7% of internal door handles and 21.4% of external door handles presented eggs. There were no eggs and larvae of other helminths, only pollen grains, vegetable fibers and fungal spores. Lectures were held with employees of BHU to present the results and discuss measures that can be taken to prevent contamination of people who attend and work at these sites. The data showed that the BHU toilets and waiting rooms can be important vehicles of dispersal and contamination with enteroparasites. Health education measures are important and must be undertaken among the health center users and employees as they lead people to understand the problem, change their habits and discuss solutions to prevent and control this and other diseases.

Análise do valor na conformação de tailored-blanks

Uma forma encontrada na indústria automobilística de reduzir os consumos associados à fabricação é a utilização de chapas de diferentes espessuras soldadas a laser. Essas chapas são comercialmente denominadas de tailored blanks, onde os principais objetivos são as reduções do peso e do custo final do produto. As abordagens da análise do valor em tailored blanks se tornam cada vez mais adequada visto esta ser uma tecnologia cada vez mais usada na produção de veículos. A peça em estudo foi o reforço interno da porta dianteira de um veículo quatro portas nacional. O objetivo deste trabalho foi à utilização da metodologia da Análise do Valor, na obtenção de resultados financeiros que possam tornar o produto mais competitivo, segundo a análise das funções do produto. Como resultado destaca-se que o custo no Brasil da utilização de tailored blanks, para a peça de tamanho médio que foi estudada em 2004, mostrou-se financeiramente inviável. O custo de manufatura por estampagem é muito superior à economia gerada pela redução de consumo da matéria-prima.