Possibility of using waste tire composites reinforced with rice straw as construction materials

Agricultural lignocellulosic fiber (rice straw)-waste tire particle composite boards were manufactured for use as insulation boards in construction, using the same method as that used in the wood-based panel industry. The manufacturing parameters were: a specific gravity of 0.8 and a rice straw content (10/90, 20/80 and 30/70 by wt.% of rice straw/waste tire particle). A commercial polyurethane adhesive for rubber was used as the composite binder. The water proof, water absorption and thickness swelling properties of the composite boards were better than those of wood particleboard. Furthermore, the flexibility and flexural properties of the composite boards were superior to those of other wood-based panel products. The composite boards also demonstrated good acoustical insulation, electrical insulation, anti-caustic and anti-rot properties. These boards can be used to prevent impact damage, are easily modifiable and are inexpensive. They are able to be used as a substitute for insulation boards and other flexural materials in construction.     

Rice straw-wood particle composite for sound absorbing wooden construction materials

In this study, rice straw-wood particle composite boards were manufactured as insulation boards using the method used in the wood-based panel industry. The raw material, rice straw, was chosen because of its availability. The manufacturing parameters were: a specific gravity of 0.4, 0.6, and 0.8, and a rice straw content (10/90, 20/80, and 30/70 weight of rice straw/wood particle) of 10, 20, and 30 wt.%. A commercial urea-formaldehyde adhesive was used as the composite binder, to achieve 140-290 psi of bending modulus of rupture (MOR) with 0.4 specific gravity, 700-900 psi of bending MOR with 0.6 specific gravity, and 1400-2900 psi of bending MOR with a 0.8 specific gravity. All of the composite boards were superior to insulation board in strength. Width and length of the rice straw particle did not affect the bending MOR. The composite boards made from a random cutting of rice straw and wood particles were the best and recommended for manufacturing processes. Sound absorption coefficients of the 0.4 and 0.6 specific gravity boards were higher than the other wood-based materials. The recommended properties of the rice straw-wood particle composite boards are described, to absorb noises, preserve the temperature of indoor living spaces, and to be able to partially or completely substitute for wood particleboard and insulation board in wooden constructions.     

Wood Composite as an Energy Efficient Building Material: Guided Sunlight Transmittance and Effective Thermal Insulation

Among many other requirements, energy efficient building materials require effective daylight harvesting and thermal insulation to reduce electricity usage and weatherization cost. The most commonly used daylight harvesting material, glass, has limited light management capability and poor thermal insulation. For the first time, transparent wood is introduced as a building material with the following advantages compared with glass: (1) high optical transparency over the visible wavelength range (>85%); (2) broadband optical haze (>95%), which can create a uniform and consistent daylight distribution over the day without glare effect; (3) unique light guiding effect with a large forward to back scattering ratio of 9 for a 0.5 cm thick transparent wood; (4) excellent thermal insulation with a thermal conductivity around 0.32 W m^?1 K^?1 along the wood growth direction and 0.15 W m^?1 K^?1 in the cross plane, much lower than that of glass (≈1 W m^?1 K^?1); (5) high impact energy absorption that eliminates the safety issues often presented by glass; and (6) simple, scalable fabrication with reliable performance. The demonstrated transparent wood composite exhibits great promise as a future building material, especially as a replacement of glass toward energy efficient building with sustainable materials.     

Mechanical and thermal properties of particle boards made from farm residues

Five farm residues were used for the manufacture of low-density particle boards in a hot platter press using urea formaldehyde as the binding material. Mechanical and thermal properties of the boards were evaluated. The maize-cob board was superior to other boards in mechanical and screw/nail holding strength, suggesting its use for interior applications, while paddy-straw board and coconut-pith board were found to be suitable for insulation purposes.     

Quality of paper boards from arecanut leaf sheath

A study was carried on utilizing arecanut leaf sheath for making paper boards. Paper boards were made with various combinations of arecanut leaf sheath with waste paper, 1:1, 1:2, 1:3, 3:1, 2:1, control (100% areca leaf sheath) and the qualities of these paper boards were tested as per the Bureau of Indian Standards (IS: 1060 (part-I)-1966). The paper boards made with more arecanut sheath materials had more resistance to water absorption. The addition of paper increased the substance weight of the paper boards. The 2:1 and 3:1 combinations of arecanut leaf sheath and waste paper had best tear strength, tensile strength, bursting strength and water resistance with minimum substance weight.     

Thermal resistance units

A proposal is made for standardization of the constant of proportionality used to derive thermal resistances in units of seconds per metre. The choice of a standard value equal to the volumetric specific heat of air at STP would reduce ambiguity in current publications and offer a rational conversion for the clo unit of insulation, as 1 clo = 200 sm^?1 (2 s cm^?1), which gives an alternative easily visualised reference for clothing insulation.     

Transfer of Campylobacter jejuni from raw to cooked chicken via wood and plastic cutting boards

Aims: We quantified Campylobacter jejuni transferred from naturally contaminated raw chicken fillets and skins to similar cooked chicken parts via standard rubberwood (RW) and polyethylene cutting boards (PE). Methods and Results: RW and PE cutting boards (2·5 × 2·5 cm²) were constructed. RW surfaces were smooth and even, whereas PE was uneven. Scoring with scalpel blades produced crevices on RW and flaked patches on the PE boards. Raw chicken breast fillets or skin pieces (10 g) naturally contaminated with Camp. jejuni were used to contaminate the cutting boards (6·25 cm²). These were then briefly covered with pieces of cooked chicken. Campylobacter jejuni on raw chicken, the boards, and cooked chicken pieces were counted using a combined most‐probable‐number (MPN)‐PCR method. The type of cutting board (RW, PE; unscored and scored) and temperature of cooked chicken fillets and skins were examined. Unscored PE and RW boards were not significantly different in regards to the mean transfer of Camp. jejuni from raw samples to the boards. The mean transfer of Camp. jejuni from scored RW was significantly higher than from scored PE. When the chicken fillets were held at room temperature, the mean transfer of Camp. jejuni from scored RW and PE was found to be 44·9 and 40·3%, respectively. Conclusions: RW and PE cutting boards are potential vehicles for Camp. jejuni to contaminate cooked chicken. Although cooked chicken maintained at high temperatures reduced cross‐contamination via contaminated boards, a risk was still present. Significance and Impact of the Study: Contamination of cooked chicken by Camp. jejuni from raw chicken via a cutting board is influenced by features of the board (material, changes caused by scoring) and chicken (types of chicken parts and temperature of the cooked chicken).     

Fungal colonization of synthetic substrates for use in space craft

Summary Materials being used or considered for use in space flight were examined for their susceptibility to fungal colonization. The materials included soft goods (clothing) and insulation and fabrication products such as Velcro^® attachments and elastic cord binders. Materials were exposed for at least 28 days in a highhumidity chamber colonized with over 50 species of fungi, including those species recommended for determining recalcitrance of materials to fungal biodegradation. At least nine of 25 products demonstrated extensive microscopic colonization by fungi, mostly byAcremonium obclavatum. Challenge procedures that rely on observations with the unaided eye, or 40×magnification of growth by a restricted number of fungal species with a cellulosic substrate as a positive control, are insufficient for determining the resistance of synthetic substrates to fungal colonization.     

Molecular simulation for the effect of electric fields on the yield behaviour and cracking process of insulation paper

In operation, the insulation paper used for transformers is subject to electric stress. This paper may deteriorate as a result of the accumulation of mechanical stress and the polarisation of the electric field. The effect of electric fields on insulation paper is typically investigated through macroscopic tests; thus, the microscopic mechanism must be explored further. In this study, single- and multi-chain cellulose models were constructed to simulate the yield behaviour of cellulose under a strong electric field (10¹⁰ V m^? 1) through molecular dynamics. The cracking process of insulation paper was also examined according to density functional theory. Results indicated that both single- and multi-chain celluloses yield under a strong electric field. This yield behaviour is consistent with that of the electric field, and it eventually breaks the cellulose chains. The energy gap between the lowest unoccupied and the highest occupied molecular orbitals suggested that cellulose molecules may encounter insulation breakdown at an electric field strength of 10⁵ V m^? 1. Furthermore, the initial fracture in the molecular chain of cellulose was observed under the weakest glycosidic bond.     

北京市主要建筑保温材料生命周期与环境经济效益评价

在低碳、绿色、环保、生态成为当代城市文明的主题下,建筑保温材料作为建筑节能最主要的解决途径之一备受关注,以北京市75%节能6层模拟住宅为例,利用DeST-h软件计算得出其墙体传热系数K值为0.40 W m-2K-1,节约电量42.31 kW h-1m-2,通过计算可节约标煤17.09 kg/m2,减少CO2排放量42.19 kg/m2,减少SO2排放量1.27 kg/m2,减少NOx排放量0.635 kg/m2,减少煤粉尘排放量11.5 kg/m2,减少煤烟尘排放5.75 kg/m2,环境效益36.66元/m2。并利用生命周期原理进行简化计算出4种常见保温材料岩棉、XPS、EPS和聚氨酯的50a建筑寿命周期中的总能耗分别为6.55×106、6.63×106、6.58×106、6.77×106kJ/m2,其中不同阶段能耗所占的比例从大到小依次为运行能耗生产能耗运输能耗。保温材料资金回收年限、环境效益回收年限和能耗回收年限的大小顺序:聚氨酯XPS≈EPS岩棉,三者顺序基本一致。并对建筑外墙保温材料科学评价与发展趋势进行探讨。     

Efficacy of electrolysed oxidizing water in inactivating Vibrio parahaemolyticus on kitchen cutting boards and food contact surfaces

AIM: To determine the efficacy of electrolysed oxidizing (EO) water in inactivating Vibrio parahaemolyticus on kitchen cutting boards and food contact surfaces. METHODS AND RESULTS: Cutting boards (bamboo, wood and plastic) and food contact surfaces (stainless steel and glazed ceramic tile) were inoculated with V. parahaemolyticus. Viable cells of V. parahaemolyticus were detected on all cutting boards and food contact surfaces after 10 and 30 min, respectively, at room temperatures. Soaking inoculated food contact surfaces and cutting boards in distilled water for 1 and 3 min, respectively, resulted in various reductions of V. parahaemolyticus, but failed to remove the organism completely from surfaces. However, the treatment of EO water [pH 2.7, chlorine 40 ppm, oxidation-reduction potential 1151 mV] for 30, 45, and 60 s, completely inactivated V. parahaemolyticus on stainless steel, ceramic tile, and plastic cutting boards, respectively. CONCLUSIONS: EO water could be used as a disinfecting agent for inactivating V. parahaemolyticus on plastic and wood cutting boards and food contact surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: Rinsing the food contact surfaces with EO water or soaking cutting boards in EO water for up to 5 min could be a simple strategy to reduce cross-contamination of V. parahaemolyticus during food preparation.     

Fungal growth on different insulation materials exposed to different moisture regimes

Commercially available paper, flax, glass wool and rock wool insulation materials were tested for sensitivity to moisture and the ability of fungi to grow on them under different moisture regimes. Three levels of moisture were used, ambient, simulated rain and water holding capacity. After wetting, the materials were inoculated with a mixture of fungi and incubated at 26°C in boxes with high moisture levels for 4 weeks. The greatest degree of fungal growth was observed on paper and flax insulation materials initially conditioned to ambient moisture levels. Paper and flax insulation were strongly affected by moisture, with all treatments showing losses in dry mass of approx. 20%, except for paper subjected to simulated rain treatment in which the loss was 39%. Glass and rock wools were not sensitive to moisture and were resistant to fungal degradation, showing only traces of fungal growth and minimal loss in dry mass over 4 weeks.     

Commercial Yellow Sticky Strips more attractive than yellow boards to western cherry fruit fly (Dipt., Tephritidae)

Bright yellow sticky rectangles made of paper boards were previously identified as the most effective traps for capturing western cherry fruit fly, Rhagoletis indifferens Curran (Dipt., Tephritidae). However, no data on the effectiveness of commercial sticky yellow plastic traps against R. indifferens have been reported. In tests conducted in sweet cherry trees [Prunus avium (L.) L.] in Washington state (USA) using ammonium carbonate as the chemical lure, commercial plastic ‘Yellow Sticky Strips’ made of translucent high‐impact polystyrene captured ~two or three times more flies than commercial sticky yellow‐folded Pherocon^® AM and Alpha Scents boards. Yellow Sticky Strips also minimized captures of non‐target flies and bees per surface area compared with Pherocon^®AM and/or Alpha Scents boards. Trap size and adhesive type were not factors for greater catches of R. indifferens. However, more flies were caught on the shade‐facing side of Yellow Sticky Strips, which was brightly illuminated, than on the shade‐facing side of boards, which was darker, suggesting differential light passage was a factor. The Yellow Sticky Strips could be very useful for monitoring R. indifferens in detection programmes and based on the results of this study can replace yellow boards. They are also useful because they are relatively unattractive to non‐target insects.     

Supercritical CO2 Foaming of Thermoplastic Materials Derived from Maize: Proof-of-Concept Use in Mammalian Cell Culture Applications

Background

Foams are high porosity and low density materials. In nature, they are a common architecture. Some of their relevant technological applications include heat and sound insulation, lightweight materials, and tissue engineering scaffolds. Foams derived from natural polymers are particularly attractive for tissue culture due to their biodegradability and bio-compatibility. Here, the foaming potential of an extensive list of materials was assayed, including slabs elaborated from whole flour, the starch component only, or the protein fraction only of maize seeds.

Methodology/Principal Findings

We used supercritical CO₂ to produce foams from thermoplasticized maize derived materials. Polyethylene-glycol, sorbitol/glycerol, or urea/formamide were used as plasticizers. We report expansion ratios, porosities, average pore sizes, pore morphologies, and pore size distributions for these materials. High porosity foams were obtained from zein thermoplasticized with polyethylene glycol, and from starch thermoplasticized with urea/formamide. Zein foams had a higher porosity than starch foams (88% and 85%, respectively) and a narrower and more evenly distributed pore size. Starch foams exhibited a wider span of pore sizes and a larger average pore size than zein (208.84 vs. 55.43 μm², respectively). Proof-of-concept cell culture experiments confirmed that mouse fibroblasts (NIH 3T3) and two different prostate cancer cell lines (22RV1, DU145) attached to and proliferated on zein foams.

Conclusions/Significance

We conducted screening and proof-of-concept experiments on the fabrication of foams from cereal-based bioplastics. We propose that a key indicator of foamability is the strain at break of the materials to be foamed (as calculated from stress vs. strain rate curves). Zein foams exhibit attractive properties (average pore size, pore size distribution, and porosity) for cell culture applications; we were able to establish and sustain mammalian cell cultures on zein foams for extended time periods.     

Under-Representation of Women on Dental Journal Editorial Boards

Introduction

Each journal’s editorial and advisory board plays a critical role in resolving gender bias in the peer-review and publication process. Thus, this study aimed to quantify women’s participation in editorial and advisory boards of major dental journals. Gender data on editorial and advisory boards were extracted from major dental journals, which were then categorized by journal specialty focus. The gender of the editor-in-chief and associate editor-in-chief was noted to assess the effect of journal leadership on women’s participation in journal boards. For comparison purposes, data were also obtained regarding the percentage of women faculty for each dental specialty.

Results

Overall, in the major 69 dental journals, 14.8% of editorial board members were women. An one-way ANOVA analysis revealed statistically significant gender differences between journal specialty categories (p = 0.003) with some dental specialties’ journals demonstrating a relatively high participation of women as editorial board members. There was a significant positive correlation for various dental specialties between women’s representation in editorial and advisory boards and women in similar dental academic specialties (p = 0.02, r² = 0.55). Furthermore, there was a positive correlation between the presence of women in journal editorial leadership and the percentage of women serving as advisory board members (p = 0.03). Our results confirmed that the under-representation of women on dental journal editorial boards was significantly different between dental science specialties. When there were more women in journal editorial leadership positions, there was a higher participation of women as editorial and advisory board members. Journals should increase the numbers of women on editorial boards in order to secure diversity, improve publication quality and recognize women’s contribution to dental science.     

Killing of Campylobacter on contaminated plastic and wooden cutting boards by glycerol monocaprate (monocaprin)

Aims: Contamination in the kitchen with foodborne bacteria is a risk factor in human exposure to these pathogens, an important route being transfer of bacteria from contaminated cutting boards and other surfaces to humans. The aim of this study was to test microbicidal emulsions of glycerol monocaprate (monocaprin) against Campylobacter on contaminated cutting boards. Methods and Results: Plastic and wooden cutting boards, soiled with meat juice heavily contaminated with Campylobacter, were treated for 2 min with emulsions of monocaprin (MC) made in water or in buffer at low pH. Viable Campylobacter counts were reduced below the detectable level on plastic board surfaces after treatment with MC emulsions with or without 1·25% washing‐up liquids (WUL). The counts were also greatly reduced on wooden boards (P < 0·05). Conclusions: Monocaprin emulsions and mixtures of MC emulsions and WUL may be useful as sanitizers/disinfectants in kitchens and in other food preparing and processing facilities. Significance and Impact of the Study: Cleaning with MC emulsions with or without WUL may reduce the risk of human exposure to Campylobacter.     

Electrophysiological correlates of rapid escape reflexes in intact earthworms,Eisenia foetida. I. Functional development of giant nerve fibers during embryonic and postembryonic periods

Grids of recording electrodes etched onto printed circuit boards were used for noninvasive recording of medial (MGF) and lateral (LGF) giant nerve fiber spikes in developing earthworms, Eisenia foetida. Stereotyped patterns of throughconducted giant fiber spikes, evoked by light tactile stimulation, were first detectable in the normal crawling embryonic stage and continuned to be detectable throughout postembryonic development. Giant fiber spiking activity in normal crawling embryos was accompanied by stereotyped muscle activity and rapid escape withdrawal, suggesting that giant fiber reflex pathways are functionally intact before the worm hatches. For both the MGF and LFG, several age-de-pendent changes were noted, including the following: increases in spike conduction velocity, increases in giant fiber diameter, and decreases in spike duration. The MGF conduction velocity in normal crawling embryos was 1.1–1.6 m s^?1 (6–7 μm diameter) and increased to 7.0–8.5 m s^?1 (20–25 μm diameter) by 60 days after hatching. The LGF conduction velocity in normal crawling embryos was 0.7–1.1 m s^?1 (2.5–4.0 μm diameter) and increased to 4.0–5.5 m s^?1 (8–14 μm diameter) by 60 days after hatching. During postembryonic development MGF and LGF conduction velocities were linearly related to fiber diameter.     

Disinfection of Bacillus subtilis spore-contaminated surface materials with a sodium hypochlorite and a hydrogen peroxide-based sanitizer

Aims: To evaluate a sodium hypochlorite and hydrogen peroxide solution (Ox‐B7) as a potential decontaminant of Bacillus subtilis spore‐contaminated surface materials (porous and nonporous). Methods and Results: Test materials were contaminated with B. subtilis spores to a final concentration in the range of 5·7–6·6 log CFU cm^?2. Ox‐B7 reduced spore counts by 99·999% (5 log) for both porous and nonporous surfaces within a 5‐min contact. Treatment with equivalent concentrations of only sodium hypochlorite reduced spore counts by 99% (2 log) on porous materials and by 99·99% (4 log) on nonporous materials. Hydrogen peroxide treatments reduced spores by less than 90% (<1 log) on both porous and nonporous materials when compared with untreated samples. Conclusions: A combination of sodium hypochlorite and hydrogen peroxide (Ox‐B7) effectively killed B. subtilis spores on both porous and nonporous surface materials. Significance and Impact of the Study: The combination of sodium hypochlorite and hydrogen peroxide can be used as an alternative disinfectant of spore‐contaminated surface materials, as it is more effective than when hydrogen peroxide or sodium hypochlorite are used separately.     

Thermal status of wet-suited divers using closed circuit O2 apparatus in sea water of 17–18.5°C

A wet suit may not provide adequate thermal protection when diving in moderately cold water (17–18°C), and any resultant mild hypothermia may impair performance during prolonged diving. We studied heat exchange during a dive to a depth of 5 m in sea water (17–18.5°C) in divers wearing a full wet suit and using closed-circuit oxygen breathing apparatus. Eight fin swimmers dived for 3.1 h and six underwater scooter (UWS) divers propelled themselves through the water for 3.7 h. The measurements taken throughout the dive were the oxygen pressure in the cylinder and skin and rectal temperatures (T _re). Each subject also completed a cold score questionnaire. The T _re decreased continuously in all subjects. Oxygen consumption in the fin divers (1.40 l · min⁻¹) was higher than that of the UWS divers (1.05 l · min⁻¹). The mean total insulation was 0.087°C · m² · W⁻¹ in both groups. Mean body insulation was 37% of the total insulation (suit insulation was 63%). The reduction in T _re over the 1st hour was related to subcutaneous fat thickness. There was a correlation between cold score and T _re at the end of 1 h, but not after that. A full wet suit does not appear to provide adequate thermal protection when diving in moderately cold water. Accepted: 21 January 1997     

Evaluation of waste chicken feathers as peptone source for bacterial growth

Aims: Peptones are one of the most expensive constituents of microbial media. This study was undertaken to prepare the peptone from waste chicken feathers through a new process. Methods and Results: The chemical analysis of chicken feather peptone (CFP) was performed. The ability of CFP to support the growth of the three test bacteria in liquid and agar media was comparable to those of three commercial peptones [tryptone peptone (TP), fish peptone and protease peptone (PP)]. Conclusions: CFP was found to be rich in ash (42·1 g 100 g^?1), protein (55·8 g 100 g^?1) and mineral contents. The maximum biomass yield (3·13 g l^?1) and colony number (83 × 10⁸ CFU ml^?1) for bacterium Bacillus subtilis were attained with CFP. The maximum biomass yields and colony numbers for Lactobacillus delbrueckii ssp. bulgaricus and Escherichia coli were reached in TP medium. Second high biomass yield (2·64 g l^?1) and colony number (75 × 10⁸ CFU ml^?1) for E. coli were achieved using CFP. Third high biomass yield (1·29 g l^?1) and colony number (90 × 10⁷ CFU ml^?1) for Lact. delbrueckii ssp. bulgaricus were obtained in CFP medium. Significance and Impact of the Study: Usability of waste chicken feathers as substrate for bacteria was investigated for the first time in the present study. The peptone may be used in industrial fermentations for production of antibiotics, organic acids, enzymes and biopolymer. It may be also used in clinical microbiology. A new chemical process was developed for peptone preparation. This process may be also employed for peptone preparation from other organic materials, especially fibrose protein‐containing materials.