Use of the selective agar medium CREAD for monitoring the level of airborne spoilage moulds in cheese production

It was investigated if a selective medium for common cheese spoiling moulds (CREAD) could give more relevant information than a general mould medium in hygienic air-sampling in cheese factories. A total of 126 air-samples were taken in six Nordic cheese factories using the general mould medium DG18 and CREAD. The level and genera of air-borne mould was determined. Identification to species-level was performed for a selection of samples. In five cheese factories the mycobiota was dominated by Penicillium spp. and in one cheese factory by Cladosporium spp. The concentration of air-borne moulds varied between the cheese factories ranging from 1 to 270 cfu/m3 on DG18 with a median value of 17. The number of mould colonies was in general lower at CREAD. Identification indicated that CREAD supported growth of common spoilage moulds for cheese, such as Penicillium palitans and P. commune. The mycobiota on DG18 also consisted of moulds not commonly associated with spoilage of cheese, such as Cladosporium spp., P. brevicompactum and P. chrysogenum. Contamination of cheese with mould is periodically a problem in production of semi-hard cheese and the level of air-borne mould is therefore routinely monitored in cheese factories. A clear correlation between the total number of moulds in air and mould growth on products is not always found. The conclusion from the investigation is that it is recommended to use a selective medium for cheese spoilage moulds, such as CREAD in hygienic monitoring.     

Downward Flame Spread Rate Over PMMA Rods Under External Radiant Heating

Fire Technology - There are multiple situations in which fires may occur at environmental conditions that are different than standard atmospheric conditions. Changes in ambient pressure, oxygen...     

Background corrections for laser-induced-fluorescence measurements of nitric oxide in lean, high-pressure, premixed methane flames

An experimental technique is presented that both minimizes and accounts for the interference background when laser-induced-fluorescence (LIF) measurements are made of NO in lean, high-pressure, premixed, CH(4)/O(2)/N(2) flames. Measurement interferences such as fluorescence and Raman scattering from secondary species become increasingly important for high-pressure LIF studies. O(2) fluorescence interferences are particularly troublesome in lean premixed flames. An excitation-detection scheme that minimizes the effects of these interferences is identified. A procedure that corrects the resulting LIF signal so as to account for any remaining interference signal is then developed. This correction is found to vary from less than 10% of the overall NO signal at atmospheric pressure to over 40% of the overall signal at 14.6 atm for LIF measurements of NO in a series of worst-case flames (phi = 0.6, dilution ratio 2.2). The correction technique is further demonstrated to be portable over a useful range of flame conditions at each pressure.     

Three-dimensional modeling of removal torque and fracture progression around implants

In the present study, a model for simulations of removal torque experiments was developed using finite element method. The interfacial retention and fracturing of the surrounding material caused by the surface features during torque was analyzed. It was hypothesized that the progression of removal torque and the phases identified in the torque response plot represents sequential fractures at the interface. The 3-dimensional finite element model fairly accurately predicts the torque required to break the fixation of acid-etched implants, and also provides insight to how sequential fractures progress downwards along the implant side.     

Tuning the Electrolyte Solvation Structure to Suppress Cathode Dissolution,Water Reactivity,and Zn Dendrite Growth in Zinc-Ion Batteries

The cycle life of aqueous zinc-ion batteries (ZIBs) is limited by the notable challenges of cathode dissolution, water reactivity, and zinc dendrites. Here, it is demonstrated that by tuning the electrolyte solvation structure, the issues for both the electrodes and the electrolyte can be addressed simultaneously. Specifically, a fire-retardant triethyl phosphate (TEP) is demonstrated as a cosolvent with strong solvating ability in a nonaqueous/aqueous hybrid electrolyte. The TEP features a higher donor number (26 kcal mol⁻¹) than H₂O (18 kcal mol⁻¹), preferring to form a TEP occupied inner solvation sheath around Zn²⁺ and strong hydrogen bonding with H₂O. The TEP coordinated electrolyte structure can inhibit the reactivity of H₂O with V₂O₅ and leads to a robust polymeric-inorganic interphase (poly-ZnP₂O₆ and ZnF₂) on zinc anode effectively preventing the dendrite growth and parasitic water reaction. With such an optimized electrolyte, the Zn/Cu cells perform high average Coulombic efficiency of 99.5%, and the full cell with a low capacity ratio of Zn:V₂O₅ (2:1) and lean electrolyte (11.5 g Ah⁻¹) delivers a reversible capacity of 250 mAh g⁻¹ for over 1000 cycles at 5 A g⁻¹. This study highlights the promise of a successful electrolyte regulation strategy for the development of high-performance and practical ZIBs.     

Tuning the Molecular Weight of the Electron Accepting Polymer in All‐Polymer Solar Cells: Impact on Morphology and Charge Generation

Molecular weight is an important factor determining the morphology and performance of all‐polymer solar cells. Through the application of direct arylation polycondention, a series of batches of a fluorinated naphthalene diimide‐based acceptor polymer are prepared with molecular weight varying from M_n = 20 to 167 kDa. Used in conjunction with a common low bandgap donor polymer, the effect of acceptor molecular weight on solar cell performance, morphology, charge generation, and transport is explored. Increasing the molecular weight of the acceptor from M_n = 20 to 87 kDa is found to increase cell efficiency from 2.3% to 5.4% due to improved charge separation and transport. Further increasing the molecular weight to M_n = 167 kDa however is found to produce a drop in performance to 3% due to liquid–liquid phase separation which produces coarse domains, poor charge generation, and collection. In addition to device studies, a systematic investigation of the microstructure and photophysics of this system is presented using a combination of transmission electron microscopy, grazing‐incidence wide‐angle X‐ray scattering, near‐edge X‐ray absorption fine‐structure spectroscopy, photoluminescence quenching, and transient absorption spectroscopy to provide a comprehensive understanding of the interplay between morphology, photophysics, and photovoltaic performance.     

Investigation of Lipid Oxidation in High- and Low-Lipid-Containing Topical Skin Formulations

Lipid oxidation can impact the odour of skin care products during storage. A study was conducted to identify and monitor representative markers for lipid oxidation in skin care products over time. Four lip care formulations and three skin care formulations with different lipid contents were stored at various cosmetic industry‐relevant conditions for 84 days. The skin care products were analysed for lipid hydroperoxides and secondary volatile oxidation products. A trained sensory panel performed an odour difference (triangle) test and odour‐profiled the products to detect and describe odour changes during storage. Several potential markers for lipid oxidation were identified. In skin care formulations, peroxide value (PV) analysis was a useful marker for lipid oxidation if the product was exposed to light during storage, but no clear changes were observed for PV in samples stored under other conditions. Furthermore, concentrations of several secondary volatile oxidation products increased during storage, and the highest increase was observed for products exposed to light. Pentanal and heptanal were found to be reliable markers for secondary volatile oxidation products in the skin care formulations (especially during exposure to light), whereas in the lip care formulations the best candidates were pentanal (especially during exposure to light and iron), 2‐methyl furan and 3‐methyl‐3‐buten‐2‐one (especially during exposure to light, iron and high temperatures).     

Evolution of the nanomorphology of photovoltaic polyfluorene blends: sub-100 nm resolution with x-ray spectromicroscopy

We investigate the influence of annealing on the morphology of intimately mixed blends of the conjugated polymers poly(9,9'-dioctylfluorene-co-bis-N,N'-(4-butylphenyl)-bis-N,N'-phenyl-1,4-phenylene-diamine) (PFB) and poly(9,9'-dioctylfluorene-co-benzothiadiazole) (F8BT) with scanning transmission x-ray microscopy (STXM). Through the use of a zone plate with theoretical Rayleigh resolution of 30?nm, we are able to resolve sub-100?nm bulk structure in these films. Surprisingly, for unannealed films spin-coated from chloroform we observe features with an average diameter of 85?nm. The high degree of photoluminescence quenching in these as-spun films (>95%) implies that there is significant intermixing within the 85?nm structures, indicating that a hierarchy of phase separation exists even on the length scale of less than 100?nm. With annealing up to 160?°C, close to the T(g) of the components, there is little change in the feature sizes observed by STXM, although an increase in variation of the composition is observed. With annealing above 160?°C the imaged features begin to evolve in size, increasing to 225?nm in extent, alongside large changes in composition with annealing to 200?°C. Comparing the evolution of morphology imaged by STXM with the change in photoluminescence quenching with annealing, we propose that phase separation first evolves via the evolution of relatively pure phases on the length scale of a few to tens of nanometres within the larger 85?nm structures. Once the length scale of compositional fluctuations exceeds 85?nm (for anneal temperatures above 160?°C) the hierarchy of phase separation is lost and the subsequent morphological evolution is readily imaged by STXM. Applying the results of an exciton diffusion and quenching model, we find good agreement between the size of the domains measured by STXM (above 180?°C) and the results of the model for an exciton diffusion length of 15?nm. The growth in domain size and towards purer structures has also been observed with resonant soft x-ray scattering.     

Associations between somatic cell counts at calving or prior to drying-off and clinical mastitis in the remaining or subsequent lactation

Data from 350 herds enrolled in the Norwegian Dairy Herd Recording System (NDHRS) were used to investigate the associations between the first two cow-milk somatic cell counts (SCC) test-days' results after calving or the three last SCC test-days prior to drying off in the first lactation and the hazard ratio (HR) of clinical mastitis (CM) during the remaining first or the subsequent second lactation respectively. Altogether, 9519 first lactations and 6046 second lactations were included. Cox regression analyses adjusted for herd frailty effect were used. In the first lactation, SCC>40000 cells/ml on the first or second test-day was significantly associated with an increased risk of a CM event in the remaining first lactation. HR, compared with 10000 cells/ml, increased from 1.6 (1.4) for SCC of 40000-60000 cells/ml to 6.9 (4.2) for SCC >800000 cells/ml, when using the first (second) SCC test-day in the first lactation. Cows with a geometric mean of the three last SCC test-days between 50000 and 100000 cells/ml and between 401000 and 800000 cells/ml in the first lactation had HR of CM during the second lactation of 1.3 and 2.8 respectively compared with a reference group of 10000-20000 cells/ml. If a CM episode in the first lactation occurred, the HR for having a CM event during the second lactation was 1.5. There was a significant frailty effect which disappeared if the incidence rate of CM at herd level was included in the model.