Mold Problems Research Articles

The use of cold plasma technology in solving the mold problem in Kashar cheese.

In this study, the possibilities of using cold plasma technology in solving the mold problem, which is one of the most important problems in Kashar cheese, were investigated. For this purpose Kashar cheeses were exposed to cold plasma with different gas compositions. As a result of the study 3-4 log reduction was achieved for both Aspergillus flavus and Penicillium crysogenum. The pH and aw values of samples were decreased with cold plasma application. The b* values of samples increased while L* and a* values decreased. When all the results obtained are considered as a whole, it can be said that cold plasma technology improves the physicochemical properties of Kashar cheese and provides significant decrease in mold count of the product.

The Hollow Die Design of Suspension Protective Type

Because semi-hollow aluminum profiles are quite common in practice and have a large market demand, these profiles are characterized by a long cantilever, large tongue ratio, high complexity of mold design, and mold problems that have been bothering enterprises. These profiles are characterized by the long cantilever, large tongue ratio, high complexity of mold design, and mold problems that always have troubled enterprises. In order to solve this kind of mold strength problem, the engineering and technical personnel at home and abroad have carried out extensive research and have also obtained some successful experience. For example, mature die structures include split extrusion die and inlaid extrusion die, but these structures have certain applicable objects and conditions in practical application and have certain limitations in structure. Therefore, it is necessary to propose new and effective high-strength dies. A new type of die was present. The new die structure was named covering and protection die. With a actual product, the determination of structure parameters that it included the arrangement of portholes and the structure design of the chamber and the selection of bearings were introduced in detail. The features of the new structure were simple and easy to be processed. The practice shows that the new die can extended the life, increase of efficiency and reduce cost. The high precision dimensions and good surface quality were obtained. The new die is worth promoting. The purpose is to provide reliable data and reference for further research and development of the structure of semi hollow aluminum profiles.

Performance of a CO2-based demand controlled dual core energy recovery ventilation system for northern housing experiencing varying occupancy

Indoor air quality and health are major areas of concern in northern and remote communities where homes experience varying occupancy, often overcrowding and are influenced by ventilation. Heat/energy recovery ventilators installed in the north are selected to provide required minimum ventilation rate set by ventilation standards (ASHRAE 62.2, etc.). Northern overcrowded homes become under-ventilated, leading to deteriorated IAQ, mold and health-related problems. This paper present results from a side-by-side testing of a CO2-based demand-controlled ERV versus a constant air flows ERV, using twin houses with simulated occupancies. The control strategy was based on the difference in CO2-concentration between exhaust/return air from the house and outdoor air. The implemented strategy based on a CO2 sensor network connected with an ERV continuously exhausting stale air from kitchen and bathrooms was simple and efficient in adjusting ventilation rate based on occupancy rate. The CO2-based demand-controlled ERV provided a much better control of indoor CO2 concentrations in the main floor and master bedroom, and with lower CO2 concentrations in bedrooms during night time, compared to the reference house with concentrations exceeding 2000 ppm. However, the CO2-based demand-controlled ERV had higher power consumption than conventional ERV with constant air flows.

The effect of various boron compounds on the antimicrobial activity of hardened mortars

• Six different boron compounds (5% by mass to cement) were used to prepare cement mortars. • Dicalcium hexaborate pentahydrate (COL) and borax pentahydrate (BPH) were compatible with cement mortars. • COL and BPH addition decreased the flexural and compressive strength values within acceptable limits. • COL and BPH addition inhibited C. albicans and A. niger growth by at least 99%. This study has examined the effect of boron compounds on the mechanical and antimicrobial properties of hardened mortars. The antimicrobial activity of six different boron minerals and compounds was tested against six microorganisms, including Gram-positive and Gram-negative bacteria, yeast, and fungus. Cement mortars containing 5% (w/w) boron mineral addition by weight of cement were exposed to flexural and compression tests on the 7th, 28th and 90th days. At the end of the 90th day, the hardened mortar specimen prepared with 5% dicalcium hexaborate pentahydrate (COL) or 5% borax pentahydrate (BPH) decreased the compressive strength 7.41 % and 31.5 %, and flexural strength 13.5 % and 32 %, respectively. Although, there are decrements in both compressive and flexural strength, values remain within the acceptable limits specified in the material code. The antimicrobial activity of these specimens was evaluated with surface antimicrobial activity tests. The hardened mortar specimen containing boron compounds showed antimicrobial activity against C. albica ns and A. niger . It can be concluded that from these results, using 5 % COL and 5 % BPH as an additive or replacement to the mortar, is an alternative way to create antimicrobial surfaces within environments that have complained of mold problems and biodegradation, such as in reinforced concrete structures or in conventional buildings that need to be free of pathogenic microorganisms.

Temperature versus Relative Humidity: Which Is More Important for Indoor Mold Prevention?

Temperature is known as one of the abiotic factors that can affect mold growth. Many mold growth prediction models consider temperature as one of the parameters that can significantly impact mold growth indoors, and hence temperature has been targeted by different indoor mold prevention strategies on different premises. For example, European guidelines for libraries suggest a temperature of 19 °C to preserve books. However, running low temperature air-conditioning (AC) costs substantially more energy, and thus a higher temperature (e.g., 25.5 °C) has been regularly proposed as the recommended indoor temperature for general indoor environments in Hong Kong. It is, therefore, needed to understand whether or not the reduction of indoor temperature would lead to better effectiveness of mold prevention. Using Cladosporium cladosporioides (C. cladosporioides) as the model, its germinating spores were challenged in C. cladosporioides to wet-dry cycles with different combinations of relative humidity (RH, 40%, 60% and 80%) and temperature (19 °C and 28 °C) levels. The survival, lipid peroxidation and catalase (CAT) activity of the treated spores were monitored and compared. C. cladosporioides spores showed similar levels of viability, lipid peroxidation and CAT activity when they were exposed to 19 °C and 28 °C at the same RH, but substantially lower survival and higher oxidative stress were observed under the wet-dry cycles with 40% RH dry periods compared with 60% and 80% RH at both temperatures, suggesting that indoor temperature does not tend to affect the resistance of C. cladosporioides to wet-dry cycles as significantly as the RH level of the dry period. Collectively, this study suggests a more important role for moisture over temperature in indoor mold prevention. The outcome of this study may facilitate the sustainable management of indoor mold problems in buildings.

Pervasive fungicide resistance in Botrytis from strawberry in Norway: Identification of the grey mould pathogen and mutations

AbstractControl of grey mould, caused by Botrytis spp., is a major challenge in open field strawberry production. Botrytis was isolated from plant parts collected from 19 perennial strawberry fields with suspected fungicide resistance in the Agder region of Norway in 2016. Resistance to boscalid, pyraclostrobin and fenhexamid was high and found in 89.1%, 86.0% and 65.4% of conidia samples, respectively. Multiple fungicide resistance was common; 69.6% of conidia samples exhibited resistance to three or more fungicides. Botrytis group S and B. cinerea sensu stricto isolates were obtained from 19 and 16 fields, respectively. The sdhB, cytb, erg27 and mrr1 genes of a selection of isolates were examined for the presence of mutations known to confer fungicide resistance to boscalid, pyraclostrobin, fenhexamid and pyrimethanil plus fludioxonil, respectively. Allele‐specific PCR assays were developed for efficient detection of resistance‐conferring mutations in cytb. Among B. cinerea isolates, 84.7%, 86.3% and 61.3% had resistance‐conferring mutations in sdhB, cytb and erg27, respectively. A triplet deletion in mrr1, resulting in ΔL497, commonly associated with the multidrug resistance phenotype MDR1h, was detected in 29.2% of Botrytis group S isolates. High frequencies of resistance to several fungicides were also detected in Botrytis from both imported and domestically produced strawberry transplants. Fungicide resistance frequencies were not different among fields grouped by level of grey mould problem assessed by growers, indicating factors other than fungicide resistance contributed to control failure, a fact that has important implications for future management of grey mould.

Are Energy-Vulnerable Households More Prone to Informative, Market, and Behavioral Biases?

The present paper focuses primarily on investigating whether energy-vulnerable households are more prone to informative, market, and behavioral biases. In this direction, a stated preference approach was used to elicit information about human behavior and cognitive barriers in the context of energy poverty based on both subjective and objective indicators. For the purposes of the survey, a questionnaire was developed that included around 40 questions about housing conditions and information, market, and behavioral barriers related to energy efficiency, energy vulnerability, etc., and specific survey hypotheses were tested employing non-parametric tests. The survey was carried out between November 2020 and January 2021 involving residents of Metsovo, a mountain settlement in Greece. In total, 303 participants took place in the survey through personal interviews, which were conducted remotely due to the COVID-19 pandemic-related distancing measures, using a video platform. The analysis shows that households that face thermal discomfort or are in arrears on energy bills seem to be more prone to certain behavioral and other biases. This conclusion is not confirmed for households that face condensation, mold and damp problems or are classified as energy-poor under the “ten percent rule”. The main conclusion drawn is that the income status of the household plays a greater role compared to its classification as energy vulnerable. Nevertheless, the findings of the study need to be confirmed by future research, because the research specifically on how energy poverty affects people’s decision making is extremely limited. In any case, the results are worrisome and illustrate the need for more effective energy poverty policies that will take into account the effects of scarcity on household decision making.

Evaluation of a Fenton reaction–based fungicide for disinfection of moldy houses in the evacuation zone of the Great East Japan Earthquake: Lab and field tests

Houses damaged by the Great East Japan Earthquake that have severe mold problems should be disinfected before or immediately after residents are allowed to return permanently. In this study, the efficacy of a fungicide based on the Fenton reaction was evaluated in lab and field tests. Use of Fenton’s reagent successfully disinfected aqueous solutions containing five species of fungi (Aspergillus niger, Aspergillus penicillioides, Aspergillus restrictus, Cladosporium sphaerospermum, and Wallemia sebi). Spraying Fenton’s reagent solutions (ferrous ions [pH = 3] and hydrogen peroxide [pH = 3]) onto the surface of wood samples inoculated with C. sphaerospermum significantly suppressed fungal growth (mold cover = 12–27%) compared with spraying distilled water (82–97%) or a hydrogen peroxide solution (73–80%). Field tests were performed in two houses in the evacuation area in Fukushima, Japan to evaluate fungicidal activity in a home environment. The airborne fungal counts of C. sphaerospermum, Penicillium, Aspergillus westerdijkiae, Alternaria, Fusarium, Aspergillus versicolor, and Eurotium were strongly decreased by spraying the Fenton’s reagent solutions (except for C. sphaerospermum in House B) (median disinfection rate = 99%). Fungi growing on floor and sink surfaces were inactivated by spraying with Fenton’s reagent solutions (except for Cladosporium spp. in House A and Aspergillus restrictus in House B) (median disinfection rate = 50–98%). Thus, Fenton reaction–based fungicides may be effective for remediation of mold problems in houses.

Framing the context of energy poverty in Croatia: A case-study from Zagreb

Like many other European countries, Croatia is also missing a systematic and adequate policy framework to tackle the problem of energy poverty. Currently, there is no distinction between energy and general poverty in Croatian legislation, and direct payments of utility bills are the only measure of help to (energy) poor households. Local and national authorities are lacking validated facts to make informed investments that would make a long-term impact on lowering energy demand, but also improving living conditions and quality of life of energy poor. To collect relevant data, 102 energy poor households in the City of Zagreb were visited and surveyed. Data analysis revealed a significant share of citizens living in low energy-efficient dwellings reducing heating during winter and with draught and mould problems. Wall retrofitting investment was investigated more closely by calculating a simple payback period and proving to be a cost-effective measure with many positive direct and indirect implications. The higher share of rented apartments in the group of the most energy-intensive dwellings presents a potential obstacle in conducting energy-efficiency measures and should anticipate the adoption of stricter renting regulations.

Building moisture diagnosis: Processing, assessing and representation of environmental data for root cause analysis of mould growth

The occurrence of surface condensation and mould can lead to concerns of poor indoor air quality and adverse health implications of occupants. Remedial actions require identification of the root causes, but this can be challenging even for experts. The focus of the research is the development of a diagnostic tool that helps to streamline root cause analysis. The diagnostic method comprises a protocol with guidelines for installation of sensors, easy data collection, and a set of calculations to process environmental information. Environmental parameters collected and calculated from an environmental monitoring exercise of dwellings with and without mould, include physical properties associated with the indoor surface of external walls and surrounding air conditions. The methodology relies on linking specific surface and air environmental parameters together with critical thresholds proposed for the control and avoidance of surface condensation and mould growth in dwellings. These parameters were assessed and used to determine the likely causal factors of a moisture imbalanced environment leading to surface condensation and mould growth; poor thermal building envelope performance, an imbalanced heat-moisture regime, and/or insufficient ventilation. Examples from different scenarios are presented to show the process towards environmental data collection, post-processing to compute and assess pertinent parameters, and the display of environmental conditions in a clear and easy-to-interpret manner. The novel developed system is a time-saving method for processing and represents environmental data. It provides a straightforward building moisture index (BMI) and a systematic diagnostic procedure for environmental assessment and possible causes of mould growth. This helps to support neutral decision making, to identify rectification strategies and direct to more cost-efficient solutions to existing damp and mould problems in buildings.

Exposure to indoor air contaminants in school buildings with and without reported indoor air quality problems

Reported indoor air quality (IAQ) complaints are common even in relatively new or renovated school buildings in Finland. However, detecting the causes for complaints with commonly used indoor air measurements is difficult. This study presents data on perceived and measured IAQ in six comprehensive school buildings in Finland. The aim of this study was to discover the possible differences of perceived and measured IAQ between schools with reported IAQ complaints and schools without reported IAQ complaints. The initial categorisation of schools with (‘problematic schools’) and without (‘comparison schools’) complaints was ensured via a validated indoor climate survey and a recently developed online questionnaire, which were completed by 186 teachers and 1268 students from the six schools. IAQ measurements of physical parameters, gaseous pollutants, particulate matter and bioaerosols were conducted in four problematic school buildings (26 classrooms) and two comparison school buildings (12 classrooms). Using air sampling as well as exhaust air filters and classroom settled dust to detect the presence of elevated concentrations of airborne cultivable microbes and pathogenic, toxigenic and mycoparasitic Trichoderma strains were the most indicative methods in distinguishing problematic schools from comparison schools. Other IAQ-related measurements did not detect clear differences between problematic and comparison schools, as the concentration levels were very low. The results indicate that the complaints reported by occupants could have been related to excess moisture or mould problems that had not been found or repaired. Ventilation pressure condition investigations and simultaneous exhaust and supply air filter dust culture should be addressed precisely in future studies.

Identifying and evaluating school environmental health indicators.

Children's health, attendance, and academic performance may be affected by school environmental hazards. While prior studies evaluated home environment and health, few have evaluated indicators of school in-/outdoor environment and health. This study addresses this knowledge gap by systematically reviewing and evaluating outdoor and indoor indicators of school environment and student's health and performance in New York State (NYS). We also evaluate statistical methodologies to address highly correlated indicators and integrate multiple exposures. Multiple school environmental indicators were identified from various existing NYS datasets. We summarized data sources, completeness, geographic and temporal coverage, and data quality for each indicator. Each indicator was evaluated by scientific basis/relevance, analytic soundness/feasibility, and interpretation/utility, and validated using objective NYS data. Finally, advanced variable selection methods were described and discussed. We have identified and evaluated multiple school environmental health indicators. It was found that mold and moisture problems, ventilation problems, ambient ozone, and PM2.5 levels are among the top priorities of school environmental issues/indicators in NYS, which were also consistent while using NYS data. Choice of best variable selection method should be made based on the research questions and data characteristics. The school environmental health indicators identified, and variable selection methods evaluated, in this study could be used by other researchers to help school officials and policy makers initiate prevention programs.

Benefits of Investigating the Thermal Component for Moisture Safety in Ventilated Attics

Cold ventilated attics often have mould problems in Sweden. This is valid both for old and sometimes newly built attics. Increased insulation on the attic floor is assumed to increase the problem. To investigate this, numerical 1D models like WUFI or WUFI+ are typically used. These models give results but the physical processes are not so transparent for the user due to the complex numerical techniques involved and takes a long time to simulate. The problem is mainly related to the temperature in the attic, the ventilation rate and possible of leaks from the living space. All exposed surfaces in the attic will buffer moisture variations. But if this buffering is neglected and the leakage is treated as a constant the moisture content in the attic is only dependent on the ventilation with outside air and the assumed leakage. This would make a pure thermal investigation meaningful. An analytical model for the thermal problem was developed that took into account radiation between the interior surfaces and the different boundary conditions at the outside and inside surfaces. Using this model a parameter study of exterior roofing insulation was done using a moisture transport model that only took into account convection exchange. The results were compared with WUFI Pro and WUFI+ simulations which included the moisture exchange between air and internal surfaces. The comparison showed that the pure thermal model gave, as expected, larger variations in relative humidity, but that the results were qualitatively very similar. This indicates that analytical solutions of thermal problems can be used as a base in qualitative investigations of certain combined heat and moisture problems.

Injection Mold Analysis Based on Moldex3D Car dashboard back cover Casting System

This paper is the injection mold design of the car dashboard back cover casting system. Two different types of gating systems for cold and hot are analysed and processed for mold structure design and problems that may arise during the production process of plastic parts. Moldex3D mold flow analysis software was used for simulation, and two different types of gating systems were analysed and compared. It is found that the advantages and disadvantages of different casting systems exist and the optimal design scheme is selected to improve the mold structure design and improve the production qualification rate of plastic parts.

Experimental Evaluation of the Ability of an Auxiliary Heating Device to Reduce the Condensation Risk around Built-in Wardrobes of Apartment Buildings in Winter

Recently, there has been an increase in the condensation and mould problems of apartment buildings in Korea owing to the high insulation and high air-tightness performance of buildings, which increase energy savings. Condensation is generally found in winter on furniture back panels and adjacent surfaces of the wall, floor, and ceiling. These problems are related to the weather conditions and indoor room conditions in winter. To solve these problems, an auxiliary heating device that can be installed was developed. The purpose of this study was to evaluate condensation risk in the condensation vulnerable areas around built-in furniture of apartment buildings by installing an auxiliary heating device. The experimental results reveal that condensation risk can be reduced by comparing the thermal environment around the built-in furniture with and without installation of an auxiliary heating device in winter. Furthermore, they reveal that it is possible to increase the surface temperature of vulnerable areas around built-in wardrobe by applying an auxiliary heating device to minimize condensation problems by using a minimum device.

Can Increased Endotoxin Levels in House Dust be used as an Indicator of a Mould Problem?

Endotoxins are common indoor biocontaminants. Our purpose was to investigate the association of endotoxin content with mould problems in house dust in buildings, to determine whether endotoxins can be used as an indicator of the presence of moulds in buildings. The participants were selected from the Clinic for Indoor Air Health Problems on the basis of symptoms attributed to indoor air problems. We examined their health status. House dust was collected in new vacuum cleaner bags from surfaces in the rooms of their homes or workplaces. We measured the endotoxin concentrations in the house dust of 13 homes and 9 workplaces of the 19 participants, using a quantitative limulus test. The median endotoxin concentrations in the house dust of their homes was 9.9, and the range was 1.9–103 EU/mg; and in the house dust of workplaces it was 4.5, and the range 0.5–81 EU/mg. We found higher house dust endotoxin concentrations in rooms in which moisture problems had been identified or in dwellings in which pets were kept. Our pilot study suggests that endotoxins may be a useful additional tool for estimating possible mould contamination at homes or workplaces.

Passive Cooling Using Phase Change Material and Insulation for High-rise Office Building in Tropical Climate

Buildings consumed 40% of the world’s primary energy consumption. In hot climate countries, more than 50% of building’s energy was spent on the cooling system. Aimed to reduce building’s cooling load in a tropical country, this study compares building’s construction configuration for two types of air-conditioned rooms in a high-rise office building. The two types of air-conditioned rooms are: (a) air conditioned rooms operating during office hours and (b) IT rooms and data centre with 24hours cooling. Six scenarios were compared using four building’s configurations (baseline, adding insulation, adding phase change material (PCM), and adding both insulation and phase change material) to evaluate the most efficient construction and cooling settings for both room types. It was found that for air conditioned rooms operating during office hours, adding PCM with melting point 29°C and force night time ventilation is the most effective in reducing cooling load. Meanwhile, for a room with 24hours cooling load, adding insulation material is the most efficient. PCM was only fully effective when night time ventilation was introduced which allows the PCM to discharge. High thermal conductivity walls have the potential to create a mould problem in the building (due to differences in moisture pressure at night time between the internal and external of the building) which can be eradicated by using night time ventilation or adding insulation to the wall. PCM installation reduced the sensible cooling load but not the latent cooling load. Hence, mechanical cooling or dehumidifier is still required.

Moisture damage with magnesium oxide boards in Danish facade structures

Magnesium oxide boards have been widely used on facades in Denmark during 2010-2015. However, the magnesium salts absorb humidity from the ambient, and they begin to leak salty water, which is highly corrosive, and leads to moisture and mould problems in wooden members of the structures. MgO-boards were not tested for their hygrothermal function before being used on exterior wall structures, which has had detrimental consequences, such as an expected cost of repair of around 2 billion DKK. Properties for moisture transport and retention properties have been determined and will be shown together with some examples of damaged structures.

Effects of minor household interventions to block draughts on social housing temperatures: a before and after study

ABSTRACTHalf of New Zealand’s renters report damp or mould problems with their homes, which can have negative health implications. Tenants in a newly upgraded social housing complex complained of being cold. Sealing strips around doors and baffles in rangehoods were installed. This exploratory study’s objectives were to determine: (1) whether the interventions influenced indoor temperature, (2) the extent to which indoor temperature changed and (3) benefits to the tenants. The before-and-after rapid response study was conducted in five social housing units. Indoor temperature was subjectively and objectively measured. Using multivariate normal linear regression, units were found to be on average 1.36°C warmer post-intervention after adjusting for outdoor temperature. Tenants’ daily diary entries also claimed units were warmer post-intervention. Simple minor interventions to block draughts made a relatively big difference to indoor temperature and comfort of those living there. Such interventions are worthwhile, especially when housing is tenanted by vulnerable populations.

Environmental Moisture, Molds, and Asthma—Emerging Fungal Risks in the Context of Climate Change

ABSTRACTThe trend toward increasing frequency and intensity of storms has exacerbated mold and other moisture-related health problems, and can be extrapolated to the future. Mold growth therefore exhibits increasing significance in the context of changing climate. The decades-old hypothesis of mold causation and/or exacerbation of asthma previously has been deemed unproven, though not rejected. The present investigation assesses the status of this hypothesis within the industrial, regulatory, scientific, medical, and legal communities. To assure accuracy, statements from these communities are quoted. Recent high-level reviews, such as by the National Academy of Sciences Institute of Medicine and the United Nations World Health Organization, have failed to consider literature that was available, and studies postdating NAS IOM and UN WHO reviews have confirmed and augmented available literature. As a result, all nine of the Hill criteria of causation in epidemiology now are satisfied. I conclude that, with exposure of sufficient intensity and duration, some molds can cause asthma and/or exacerbate preexisting asthma, and that the hypothesis indeed has been accorded broad acceptance in the communities considered.