Unsealed Condition Research Articles

Yogurt drink spoilage profiles: Characterization of physico-chemical properties and coliform potability analysis

This study aims to determine the yogurt drink spoilage profiles and its physico-chemical properties correlation as to investigate the coliform potability level upon exposure to an open air (unsealed condition). The commercially available three induced contamination of fruit (berry) flavoured yogurt drinks (labelled as A0 (original-flavoured Farm Fresh™), A1 (Farm Fresh™), A2 (Marigold™) and A3 (Nestle®)) were created to pre-run a spoilage indicator model system with regards to the colony formation unit (cfu) and its physico-chemical properties. Physio-chemical analysis (e.g., Brix, pH, colour and contact angle) and microbiological analysis were performed at 30 min intermittently for up to 4.5 h as soon as the food sample was unsealed (room environment condition: 27 ± 2 °C; relative humidity (RH): 73 ± 1%). The results showed the presence of yeast and fungus in yogurt drinks after all samples were opened and exposed to the environment. The total formation of yeast colonies and fungi of all three-yogurt berry drink brands on DRBC agar were inevitably high during the treatment (p < 0.05). The amount of cfu/ml of yeast and fungus was higher than the total coliform colony (Escherichia coli) formed throughout the sampling period. The pH analysis showed a significant decrease throughout the treatment due to the accumulation of lactic acid which resulted in high acidity (p < 0.05). The colour profiles of A1 brand showed a significant improvement as compared to A2 brand due to the increasing redundancy degree (p < 0.05). However, the A3 brand has a significant low reduction value, which is the degree of yellowness due to the microorganism’s contamination. Finally, the contact angle analysis at 0:00–3:00 h, the range of contact angle of A1 (exclusively selected due to highly pathogenic spoilage) was 45.34–42.80° while at 3:30–4:30 h was 58.66–61.12° with diameter 0.9 and 0.7 cm respectively. In conclusion, the presence of yeast and mould was first detected in the samples as early as 0:30 h (1.4 × 104 cfu/ml) and become unsatisfactory after being exposed to environment for 4 h and 30 min. The contact angle spoilage indicator exceeds from 45.34° (control) to 58.66° as to tangibly indicate the unsatisfactory values in terms of microbiological quality and potentially harmful to the consumers.

Evaluation of a Filtering Facepiece Respirator and a Pleated Particulate Respirator in Filtering Ultrafine Particles and Submicron Particles in Welding and Asphalt Plant Work Environments.

Manufacturing sites, such as welding, casting, and asphalt production (fumes), generate vast numbers of ultrafine particles of <0.1 µm in size and submicron particles close to the ultrafine range (0.1–0.5 µm). Although cumulative masses of these particles are negligible in comparison to the larger particles, the health effects are more severe due to the higher penetration in the human lower respiratory tract, other body parts crossing the respiratory epithelial layers, and the larger surface area. This research investigates the effectiveness of two common commercially available N95 filtering facepieces and N95 pleated particulate respirator models against ultrafine and submicron particles. Two specific types of respirators, the N95 filtering facepiece and the N95 pleated particulate models, in both sealed and unsealed conditions to the manikin face, were tested at various commercial and academic manufacturing sites, a welding and foundry site, and an asphalt production plant. Two TSI Nanoscan SMPS nanoparticle counters were used simultaneously to collect data for particles of 10–420 nm in size from inside and outside of the respirators. While one of them represented the workplace exposure levels, the other one accounted for the exposure upon filtration through the respiratory surfaces. The results showed the particles generated by these manufacturing operations were mostly within the range of from 40 to 200 nm. Results also indicated that while the percentage of filtration levels varied based on the particle size, it remained mostly within the desired protection level of 95% for both of the N95 respirator models in sealed conditions and even for the N95 pleated particulate model in the unsealed condition. However, in the case of the N95 filtering facepiece model, unsealed respirators showed that the percentage of penetration was very high, decreasing the protection levels to 60% in some cases. Although the number of workplace airborne particle levels varied considerably, the filtration percentages were relatively consistent.

Strength degradation of glass epoxy composites under hygrothermal environment

The composite structures are being used in marine applications like boat hulls, propeller blades etc. Apart from these, the composites are used as structural materials exposed to different kinds of degrading environment like temperature and relative humidity. When a fiber-reinforced composite structure is exposed to a hygrothermal environment and mechanical loads, changes in material properties are related to irreversible material strength degradation. The present study deals with the mechanical strength degradation of glass fiber reinforced polymer matrix composites when subjected to hygrothermal environment. The composite cross ply laminates were manufactured by using compression molding process with two types of curing processes cold press and hot press with a bi-directional E-Glass WR 360 as reinforcement, LY556 as resin and HY951 as hardener. The mechanical properties such as Tensile, ILSS, moisture absorption was investigated with different temperatures like 32 °C, 50 °C and 85 °C with time holding of 30 min, 60 min and 90 min in 5% of brine solution. The same mechanical properties are compared with specimens under sealed condition with unsealed condition.

Metakaolin-based geopolymer coatings on metals by airbrush spray deposition

Metakaolin-based geopolymer coatings with a thickness of about 60 μm were prepared on 2024 Al alloy and low carbon steel substrates by airbrush spray deposition. Curing in a sealed condition led to a limited geopolymerization reaction and corrosion of the uncoated surface in the metal substrates. Fourier-transform infrared spectroscopy and X-ray diffraction measurements of the coatings cured in an unsealed condition at 40–150°C confirmed the formation of the geopolymer network. Coatings cured at 80°C possessed a favorable microstructure, while some microcracks were present in the coatings after curing at 150°C due to shrinkage and residual stresses. The adhesion strength, measured by scratch tests, showed high values of critical load for samples cured at 80°C. For samples cured at 150°C, the coating was completely removed upon loading when the geopolymer was deposited on Al but not when on mild steel. Immersion tests demonstrated that the stability of the coatings in distilled water increased with increasing curing temperature.

A new shock-wave test apparatus for liquid CO2 blasting and measurement analysis

Liquid CO2 blasting of coal or rock body technology is widely used for improving permeability, pressure relief, cutting proof, and roadway development. Due to the lack of proper apparatus for blasting measurement, the determination of blasting parameters is often not under scientific basis. A newly designed experimental apparatus is developed to monitor shock-wave pressure of liquid CO2 blasting. The apparatus mainly consists of testing tube and base bracket. The testing tube is fixed on the base bracket by fixed ring. The base bracket is fixed to the ground by expansion bolts to ensure the stability of the apparatus and personnel safety during blasting. Three testing tubes with inner diameter of 48, 68, and 82 mm are designed and manufactured to simulate different sizes of boreholes. Monitoring holes are drilled on the testing tube to monitor blasting shock-wave pressure in real time. The maximum pressure of the shock-wave and its acting duration can be obtained. Experimental results also revealed that the normal direction of the gas outlet is the effective shock-wave acting area where the maximum pressure reaches more than 160 MPa. The shock-wave pressure is in non-linear relationship with the distance from gas outlet. By comparison of the blasting tube sealed to unsealed condition, it is found that sealing can be effected by increment in shock-wave pressure of about 43.3%. The research results provide a basis and reference work for determination and optimization of liquid CO2 blasting parameters.

Fabrication of Plate-Like Sr&lt;sub&gt;3&lt;/sub&gt;Ti&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;7&lt;/sub&gt; Particles Using Molten Salt Synthesis

Plate-like Sr3Ti2O7powders with anisotropy were prepared by KCl molten salt synthesis (MSS) method, the effect of different SrCO3/TiO2ratio and calcination condition on the phase transition, particle size and morphology of powders were investigated. The results show that SrTiO3phase coexist with Sr3Ti2O7phase and SrTiO3is the main phase as the SrCO3/TiO2ratio is 1.15~1.25:1. Pure Sr3Ti2O7phase can be obtained as the SrCO3/TiO2ratio is 1.55~1.65:1. The aspect ratio of plate-like particles increases firstly and then decreases as the SrCO3/TiO2ratio increases. The sealed and unsealed condition has no influence on the phase structure of the powders. But the aspect ratio of unsealed particles is smaller than that of sealed particle. Finally, the formation mechanism for Sr3Ti2O7particles was discussed.

Effects and mechanisms of surface treatment of hardened cement-based materials with colloidal nanoSiO2 and its precursor

A dense surface structure of cement-based material is important for its resistance to the impacts of environment. Effectiveness and mechanisms of colloidal nanoSiO2 (CNS) and its precursor, tetraethoxysilane (TEOS), on surface-treatment of the one-month-old cement mortar by brushing technique were studied in this work. It revealed that CNS decreases the water absorption ratio of mortar when cured at 50°C and/or in sealed condition, but its effect is negligible when samples are cured at 20°C. A greater reduction of water absorption ratio is found in TEOS-treated mortar at 20°C or 50°C and under sealed or unsealed condition. Pozzolanic reaction between CNS/TEOS and Ca(OH)2 was observed by XRD, IR and EDS techniques. In addition, filler effects as revealed by SEM/EDS techniques were ascribed to for the densification of the exposed hardened mortar. Pore size distribution analysis conducted on mercury intrusion porosimeter showed that TEOS is more effective than CNS in filling pores finer than 50nm, while CNS is found effective in filling capillary pores coarser than 50nm.

Early-age autogenous and drying shrinkage behavior of cellulose fiber-reinforced cementitious materials

The objective of this study was to determine how the early-age shrinkage behavior of cementitious materials is affected by the addition of saturated cellulose fibers under sealed and unsealed conditions. The sealed condition simulates autogenous shrinkage exclusively while the unsealed condition introduces drying shrinkage, as well. Although the primary focus was to determine whether saturated cellulose fibers are suitable to mitigate autogenous shrinkage as an internal curing agent, evaluating their effect under drying conditions provided further insight into the overall shrinkage behavior of the composite material. At additions of 1% by mass of cement, the cellulose fibers were found to show significant drying shrinkage cracking control while providing some internal curing. In addition, early-age shrinkage test results were supplemented with a quantitative measure of fiber dispersion based on comparing theoretical and experimental values of the fiber volume fraction in hardened cementitious samples. Results indicated that improved dispersion leads to improved properties.

Increasing Our Understanding of Reactivity to Pedometers in Adults

To investigate the presence of reactivity, if any, to wearing sealed and unsealed pedometers, with and without step count recording. On the first visit to the laboratory, 63 participants (41 females and 22 males; age = 23.6 +/- 9.6 yr, body mass index = 22.7 +/- 3.0 kg x m(-2)), blinded to the study aim, were provided with a sealed pedometer (New Lifestyles NL-1000) and informed that it was a "body posture monitor" (covert monitoring). Participants wore the pedometer throughout waking hours for 1 wk. On return to the laboratory, stored step counts were downloaded, and participants were informed that the device was a pedometer. Participants wore the pedometer under three more conditions-sealed, unsealed, and unsealed plus logging daily steps in an activity diary-each having a duration of 1 wk. The order of participation in each condition (sealed/unsealed/diary) was balanced across participants. Mean daily step counts recorded during the four conditions were compared using a repeated-measures ANOVA. There was a significant overall effect of condition (P < 0.001; covert monitoring = 8362 +/- 2600 steps per day; sealed condition = 8832 +/- 2845 steps per day; unsealed condition = 9176 +/- 3299 steps per day; diary condition = 9635 +/- 2709 steps per day), with post hoc analyses revealing that mean step counts were significantly higher in the diary condition than those reported during both the covert and sealed conditions (both P < 0.003). No significant gender effects were observed (P = 0.33). The greatest increase in step counts occurred in the diary condition, suggesting that reactivity to pedometers is greatest when participants are requested to wear an unsealed pedometer and record their step counts. This has validity implications for short-term pedometer studies investigating habitual free-living activity that require participants to provide a daily log of their step counts.

Reactivity: an issue for short-term pedometer studies?

Objectives:To investigate the influence of wearing a pedometer and recording daily step counts on ambulatory activity.Methods:During the first visit to the laboratory, 50 healthy volunteers, blinded to the study aim,...

Asset Management Strategy for Unsealed Low-Volume Roads in New Zealand

The majority of rural local roads in New Zealand are unsealed low-volume roads that require regular grading, and a contractor has developed an asset management strategy for unsealed roads. Key facets of this strategy included establishment of a companywide asset management team responsible for implementing the strategy, creation of a new senior management position dedicated to delivering this strategy, and integration of asset management principles and processes into normal business. This unsealed roads maintenance strategy identified the need for a low-cost, effective tool for roughness monitoring that quantitatively reflects the unsealed network condition and is not based on subjective perception, which is the current situation. After a review of all existing roughness measurement systems from around the world, the Opti-Grade system from Canada was acquired and is being used on unsealed road networks throughout New Zealand. An example of the benefits of outsourcing road maintenance to private contractors is the fact that it was the contractor that identified the need for a low-cost roughness measurement tool to provide an objective operational performance indicator for rural local roads, initiated the development described in this paper, and implemented its use. This paper explains the processes involved in developing and implementing this strategy and the benefits to both the road authority and the company.

自動錠剤包装機適応のタブレットケースの改良と錠・カプセル剤の品質管理

The automatic dispensing system which is connected between the prescription ordering system and automatic tablet counting and packing system (ATC) machine has been developed in recent years. The quality control of tablets and capsules (unsealed) in ATC and the stability of these drugs after ATC package must be considered for packing these drugs in a one dose-package by automatic dispensing system. Therefore, we selected 190 drugs (tablets and capsules) from the drugs adopted in our hospital and stored in a light-resistant or moistureproof place as mentioned in package inserts, and investigated the stability of these tablets and capsules (unsealed condition) with time when they were stored in the ATC tablet cases provided in our dispensary and under the conditions of constant temperature and humidity (in a dark place, at 20°C and 52%RH). In our study, we used a new tablet case devised for improving the light-resistant and maintained appropriate conditions of temperature and humidity in the dispensary by using an air conditioning system continuously. As a result, the quality control of these drugs stored in ATC was greatly improved. The appearance of ASPARA K®, DEPAKENE ®and AUGMENTIN ® were changed markedly under the sealed condition in ATC by temperature and humidity. We judged from our findings that the application of these three drugs to the automatic dispensing system is by far difficult since there are still problems to be solved for the quality control of these drugs.

内圧を受ける岩盤空洞建設のための岩石力学的調査について

In an abandoned coal mine, a test tunnel has been newly driven in the massive sandy-shale rock mass from the main roadway located at a depth of 365m from the surface, and several in-situ measurements and laboratory tests have been conducted. The Barton's Q-value to classify the rock mass was evaluated to be 11.1, which means there will be little problems accompanying the excavation and maintenance of the cavern. It should be noticed, however that the physical properties of the rock are sensitive to the water content due to some clay minerals contained in it. Therefore, sufficient countermeasures should be taken into account when designing the cavern.Three types of test using boreholes were conducted to know the resistability for pressure and the stiffness of the rock mass. It was confirmed that the pressurized hole, when its surface is sealed, behaves elastically for the pressure up to 16 MPa and has a fatigue limit of more than 4.6 MPa. However, for unsealed condition, small value of 8 MPa was recorded as the breakdown pressure when the pressurized area was intersected by the fractures.

The acoustic reflex in children without an hermetic seal.

In clinical practice with children, the hermetic seal is either often not obtainable or is lost before acoustic reflex measures are obtained. In a recent study, Surr and Schuchman (Archives of Otolaryngology 102, 160--161, 1976.) found that in the majority of cases reflex thresholds could be measured in adults with normal middle ears in the absence of an hermetic seal. This study was designed to find out whether the conclusions of Surr and Schuchman could be extended to children. Sealed and unsealed reflexes were compared in 30 children, ages 3 to 7, with normal middle ears. Results indicated that: (1) approximately two-thirds of the children demonstrated reflexes in the unsealed condition; (2) differences between sealed and unsealed reflex thresholds were not clinically significant; (3) in most cases, unsealed reflexes were measurable at all frequencies or at none; (4) neither size of ear canal volume nor amplitude of the sealed reflex at 10 dB SL seemed to be related to the presence or absence of the unsealed reflex. It was concluded that reflex thresholds obtained in the absence of an hermetic seal may be considered valid but the absence of an unsealed reflex should not be considered diagnostically significant.

Effect of Sealing Variables on the Degree‐of‐Seal

At least three separate effects occur during sealing (a) gross water adsorption by the bulk and surface of the porous layer, probably also accompanied by anion loss (as in the case of ‐anodized films), (b) an oxide transition near the barrier‐porous layer interface, which results in a net decrease in the amount of barrier layer and a net increase in the amount of porous layer cross‐linking, and (c) a seemingly thin‐layer effect that takes place with aging and may be localized in the pore base region of the porous layer. A two‐ step current density program was used to prepare 7.4–7.6 µm (0.3 mil) anodic films on alloy 1100, using a 1.7M electrolyte at 25°C. These coatings were then sealed for from 10 to 65 min, at temperatures from 65° to 95°C, in weakly buffered sealing baths whose pH was adjusted within the region of 5.0 to 6.5. Corresponding films were also left in the unsealed condition. Data for these films were obtained using 1 kHz impedance measurement of coating permeability, effluent gas detection (EGD technique) of partial water contents, and infrared determinations of coating structures. For these 7.4–7.6 µm (0.3 mil) coatings, the greatest benefit was derived with the following sealing conditions: sealing pH range, 6.15 ± 0.15; seal time, 30 min, but not more than 40; sealing temperature, 95°C‐to‐boiling, or higher, as might be achieved by pressurized steam sealing.