Atambient Temperature Research Articles

Effect of retained austenite on the fatigue behavior of modified bainitic 100Cr6 steels considering local phase transformation

Since highly loaded components, such as roller bearings, tend to have relatively high lifetime scatter caused by microstructural defects, an increased defect tolerance of the material can improve the performance as well as the reliability of these highly stressed components. To increase the defect tolerance of the roller bearing steel 100Cr6, two different laboratory melts with either 1.5 wt.-% Al or 1.5 wt.-% Si in addition to the standard composition were developed. After an adapted heat treatment, both steels exhibited a bainitic microstructure with a relatively high content of retained austenite with more than 20 vol.-%. Considering the effects of the retained austenite, a defined mechanical stability is essential to avoid excessive deformation-induced transformation from the retained austenite into α′-martensite, which can lead to shape deviations in components. However, besides the increased deformability of the austenitic phase, local phase transformations in the vicinity of defects can increase the defect tolerance. The fatigue tests performed at ambient temperature (AT) and at T = 100 °C, show a higher fatigue strength of the Si-alloyed steel due to a refined microstructure and revealed for both steels a relatively high austenite stability, since no macroscopic phase transformation was observed. The high austenite stability can be explained by a relatively high carbon content of the austenitic phase. However, in contrast to the Al-alloyed steel, a decrease in the fatigue strength and in the defect tolerance due to the increased temperature were observed for the Si-alloyed steel, which indicates a more pronounced phase transformation at AT. The lower carbon content and the finer distribution of the retained austenite, when compared to the Al-alloyed steel, are supposed to be the reason. While a smaller carbon content decreases the phase stability, the refined austenite distribution results in a higher probability of retained austenite presence in the vicinity of a defect.

The impact ofurine storage methods onthe results ofquantitative bacterial culture indog and cat.

Quantitative bacterial culture (QBC) isthe gold standard for determining urinary tract infections. However, the majority ofurine samples were sent toalab for further bacterial culture. Therefore, the storage condition was vital tomaintain the quality and accuracy ofthe urine samples. The main objective ofour study was toexamine the urine QBC outcomes of(1) immediate culture, (2) culture after urine sample storage atambient temperature for 24 h, and (3) culture after urine sample storage at4°C for 24hours. There were 49 feline samples and 30 canine samples included inthis study. All QBC samples kept atambient temperature and refrigerator were consistent with immediate QBC incats. Eight positive results from immediate QBC were inaccordance with refrigerated results indogs. There were ten positive results inthe room-temperature sample with two false-positive results. Our study showed that storing conditions atroom temperature orrefrigeration for 24 h does not impact the results ofQBC incat urine samples. For dog samples, chilled samples have ahigher accuracy rate than room temperature samples, although the overall agreement was still satisfactory.

Effect of packaging materials and storage time on anthocyanins stability of red cabbage-roselle mixed drink

This study aimed to investigate the effect of different packaging materials on anthocyanins' stability of red cabbage-roselle mixed drink during 6-month storage. The mixed drink was pasteurised and hot-filled into three different packaging materials, i.e., transparent glass bottle, beverage metal can, and polypropylene (PP) bottle, then stored at ambient temperature (29±2°C). During storage, packaging materials and storage time significantly affect the anthocyanin content, colour density, and polymeric colour percentage of red cabbage-roselle mixed drink packed in a glass bottle, can, and PP bottle. Polymeric colour percentage and degradation index of red cabbage-roselle mixed drink were found to increase significantly during storage at the ambient temperature, whereas total anthocyanin content and colour density decreased significantly irrespective of packaging materials used. The correlation analysis reveals that total anthocyanin content has a significant positive correlation with colour density but negatively correlates with polymeric colour percentage and degradation index regardless of packaging materials used. The total anthocyanin content decreases significantly irrespective of the packaging materials used. The mixed drink in glass bottles significantly (p<0.05) has the highest retention of anthocyanins content, followed by mixed drinks stored in cans and PP bottles. Therefore, glass bottles should be chosen as the most suitable packaging material to store the mixed drink, followed by cans and PP bottles as glass bottles provide better stability of anthocyanins for a red cabbage-roselle mixed drink.

Thermo-mechanical behavior of CLT beam-to-girder assemblies connected with T-shaped dowelled connections before, during and after fire exposure

Purpose3-ply cross-laminated timber (CLT) is used to investigate the thermo-mechanical performance of intermediate-size assemblies comprised of T-shaped welded slotted-in steel doweled connections and CLT beams at ambient temperature (AT), after and during non-standard fire exposure.Design/methodology/approachThe first set of experiments was performed as a benchmark to find the load-carrying capacity of the assembly and investigate the failure modes at AT. The post-fire performance (PFP) test was performed to investigate the residual strength of the assembly after 30-min exposure to a non-standard fire. The fire-performance (FP) test was conducted to investigate the thermo-mechanical behavior of the loaded assembly during non-standard fire exposure. In this case, the assembly was loaded to 67% of AT load-carrying capacity and partially exposed to a non-standard fire for 75 min.FindingsEmbedment failure and plastic deformation of the dowels in the beam were the dominant failure modes at AT. The load-carrying capacity of the assembly was reduced to 45% of the ambient capacity after 30 min of fire exposure. Plastic bending of the dowels was the principal failure mode, with row shear in the mid-layer of the CLT beam and tear-out failure of the header sides also observed. During the FP test, ductile embedment failure of the timber in contact with the dowels was the major failure mode at elevated temperature.Originality/valueThis paper presents for the first time the thermo-mechanical performance of CLT beam-to-girder connections at three different thermal conditions. For this purpose, the outside layers of the CLT beams were aligned horizontally.Highlights Load-carrying capacity and failure modes of CLT beam-to-girder assembly with T-shaped steel doweled connections at ambient temperature presented.Residual strength and failure modes of the assembly after 30-min partially exposure to the non-standard fire provided throughout the post-fire performance test.Fire resistance of the assembly partially exposed to the non-standard fire highlighted.

Thermomechanical behavior of Glulam-beam connected to CLT-wall assemblies with steel doweled connections before, during and after fire

PurposeThermomechanical behavior of intermediate-size beam-to-wall assemblies including Glulam-beams connected to cross-laminated timber (CLT) walls with T-shape steel doweled connections was investigated at ambient temperature (AT) and after and during non-standard fire exposure.Design/methodology/approachThree AT tests were conducted to evaluate the load-carrying capacity and failure modes of the assembly at room temperature. Two post-fire performance (PFP) tests were performed to study the impact of 30-min (PFP30) and 60-min (PFP60) partial exposure to a non-standard fire on the residual strength of the assemblies. The assemblies were exposed to fire in a custom-designed frame, then cooled and loaded to failure. A fire performance (FP) test was conducted to study the fire resistance (FR) during non-standard fire exposure by simultaneously applying fire and a mechanical load equal to 65% of the AT load carrying capacity.FindingsAt AT, embedment failure of the dowels followed by splitting failure at the Glulam-beam and tensile failure of the epoxy between the layers of CLT-walls were the dominant failure modes. In both PFP tests, the plastic bending of the dowels was the only observed failure mode. The residual strength of the assembly was reduced 14% after 30 min and 37% after 60 min of fire exposure. During the FP test, embedment failure of timber in contact with the dowels was the only major failure mode, with the maximum rate of displacement at 51 min into the fire exposure.Originality/valueThis is the first time that the thermomechanical performance of such an assembly with a full-contact connection is presented.

Composition and mixing state of Arctic aerosol and cloud residual particles from long-term single-particle observations at Zeppelin Observatory, Svalbard

Abstract. The Arctic region is sensitive to climate change and is warming faster than the global average. Aerosol particles change cloud properties by acting as cloud condensation nuclei and ice-nucleating particles, thus influencing the Arctic climate system. Therefore, understanding the aerosol particle properties in the Arctic is needed to interpret and simulate their influences on climate. In this study, we collected ambient aerosol particles using whole-air and PM10 inlets and residual particles of cloud droplets and ice crystals from Arctic low-level clouds (typically, all-liquid or mixed-phase clouds) using a counterflow virtual impactor inlet at the Zeppelin Observatory near Ny-Ålesund, Svalbard, within a time frame of 4 years. We measured the composition and mixing state of individual fine-mode particles in 239 samples using transmission electron microscopy. On the basis of their composition, the aerosol and cloud residual particles were classified as mineral dust, sea salt, K-bearing, sulfate, and carbonaceous particles. The number fraction of aerosol particles showed seasonal changes, with sulfate dominating in summer and sea salt increasing in winter. There was no measurable difference in the fractions between ambient aerosol and cloud residual particles collected at ambient temperatures above 0 ∘C. On the other hand, cloud residual samples collected at ambient temperatures below 0 ∘C had several times more sea salt and mineral dust particles and fewer sulfates than ambient aerosol samples, suggesting that sea spray and mineral dust particles may influence the formation of cloud particles in Arctic mixed-phase clouds. We also found that 43 % of mineral dust particles from cloud residual samples were mixed with sea salt, whereas only 18 % of mineral dust particles in ambient aerosol samples were mixed with sea salt. This study highlights the variety in aerosol compositions and mixing states that influence or are influenced by aerosol–cloud interactions in Arctic low-level clouds.

800 MPa Class HSLA Steel Block Part Fabricated by WAAM for Building Applications: Tensile Properties at Ambient and Elevated (600°C) Temperature

An 800 MPa class high strength low-alloy (HSLA) steel block part was deposited on substrate with similar composition by gas metal arc welding (GMAW)-based wire arc additive manufacturing (WAAM). The base plate could be removed after deposition or retained as part of the additive manufacturing (AM) part, forming the hybrid additive manufacturing (HAM) part. Tensile tests of the AM part and the HAM part were performed at ambient temperature (AT) and elevated temperature (ET, 600°C held for 4 h) for potential applications in high-rise buildings. Microstructure observations and low temperature impact tests were also conducted. Results show that microstructure of the deposit mainly consists of lower bainite and granular bainite. AT yield strength (YS) of the deposit along the deposition, transverse, and vertical directions is ∼770 MPa. ET YS of the deposit along the lateral and building directions could reach 373 MPa, 48.4% of the AT YS. Fracture elongation along all directions could exceed 18.0% for both AT and ET. Low temperature (−50°C) impact absorbed energy of the deposit could exceed 84 J along all directions. Mechanical properties of the HAM part are similar or superior to those of the AM part along the vertical direction, except the AT fracture elongation, which is one-fifth lower. Good strength-ductility-toughness balance of the made part verified the feasibility of using WAAM to manufacture 800 MPa HSLA steel block parts that have potential applications in high-rise buildings, especially considering ET YS of the part might be improved by alloying redesign to meet the performance requirements of building steel.

Thermo-mechanical behavior of Glulam beam-to-girder assemblies with steel doweled connections before, during and after fire

PurposeThe purpose of this paper is to investigate the thermo-mechanical behavior of intermediate-size glued-laminated beam-to-girder assemblies connected with T-shaped slotted-in steel doweled connections at ambient temperature (AT), after and during non-standard fire exposure.Design/methodology/approachAT tests were performed using a universal testing machine (UTM) to evaluate the load-carrying capacity and failure modes of the assembly at room temperature. Post-fire-performance (PFP) tests were conducted to study the impact of 30-min and 60-min partial exposure to a non-standard fire on the residual strength of the assemblies. The assemblies were subject to fire in a custom-designed frame, then cooled and loaded to failure in the UTM. A fire-performance test was conducted to investigate the fire-resistance during non-standard fire exposure by simultaneously applying fire and mechanical load with the custom frame.FindingsAt AT, embedment failure of the dowels followed by brittle splitting failure were found to be the dominant failure modes in the beams. In the PFP tests, embedment failure and plastic bending of the dowels were the only observed failure modes. The residual strength of the assembly was reduced by 23.7% after 30-min and 47.8% after 60-min of fire exposure. Ductile embedment failure of the timber in contact with the dowels was the only failure mode observed during the fire-performance test, with the maximum rate of displacement at 57 min into the fire.Originality/valueData are presented for full-contact (no gap) connections in Glulam assemblies. PFP results are first to be published.

Cyclic deformation behavior of metastable austenitic stainless steel AISI 347 in the VHCF regime at ambient temperature and 300 °C

Very high cycle fatigue (VHCF) tests on metastable austenitic stainless steels using an ultrasonic fatigue testing (USFT) system are challenging due to the transient material behavior and associated pronounced self-heating effects. Because the conventional measurement of stress-strain hysteresis is not possible in USFT, the cyclic deformation behavior can’t be described in a conventional manner. Hence, an energy-based approach is proposed for the characterization of cyclic deformation behavior of austenitic stainless steels in the VHCF regime at ambient temperature (AT) and elevated temperature. Therefore, in-situ dissipated energy and temperature measurements were performed. At AT both values underwent a change during cyclic loading, while at 300 °C only the dissipated energy changed. The investigated metastable austenitic stainless steel AISI 347 (X6CrNiNb1810, 1.4550) showed cyclic softening in the high cycle fatigue (HCF) regime (Nf < 107) at both testing temperatures, which led to specimen failure. In the VHCF regime, cyclic hardening was observed, which resulted in reaching the limiting number of load cycles Nl = 2 × 109 without specimen failure. This change in the cyclic deformation behavior by a small reduction of the stress amplitude led to a horizontal course of the Woehler curve in the VHCF regime and resulted in the true endurance limit for the investigated material. At AT, ferromagnetic α′-martensite was detected in all fatigued specimens using magnetic measurements. At 300 °C only specimens which reached the limiting number of cycles without failure exhibited a small amount of α′-martensite.

Effect of post-additive manufacturing surface modification temperature on the tribological and tribocorrosion properties of Co-Cr-Mo alloy for biomedical applications

In this paper, the effect of post-additive manufacturing (AM) surface modification temperature on the tribological and tribocorrosion properties of Co-Cr-Mo alloy was investigated. A Co-Cr-Mo alloy, which is mainly used as a bearing surface for manufacturing a femoral head in MOM (metal-on-metal) bearings, was treated by ultrasonic nanocrystal surface modification (UNSM) at ambient temperature (AT) and high temperature (HT). This study aimed at reducing the coefficient of friction (COF), specific wear rate (SWR) and also at enhancing the tribocorrosion resistance (TCR) of AM-based Co-Cr-Mo alloy by the application of UNSM. UNSM at HT sample demonstrated better tribological and tribocorrosion properties than the UNSM at AT and the as-printed Co-Cr-Mo alloy samples. COF and SRW reduction and TCR enhancement mechanisms were comprehensively discussed based on the changes in surface morphology, microstructure and mechanical properties after UNSM at AT and HT. Several biomedical applications that are being used a cast/wrought Co-Cr-Mo alloy may be benefited from the reduction in COF and SRW, and enhancement in TCR of Co-Cr-Mo alloy manufactured by AM and a replacement of cast/wrought with AM-based one can be considered.

Generation of UCiPSC-derived neurospheres for cell therapy and its application

BackgroundNeural stem cell (NSC) therapy remains one of the most potential approaches for the treatment of neurological disorders. The discovery of human induced pluripotent stem cells (hiPSCs) and the establishment of hiPSC-derived human neural stem cells (hiNSCs) have revolutionized the technique of cell therapy. Meanwhile, it is often required that NSCs are stored and transported to a long distance for research or treatment purposes. Although high survival rates could be maintained, conventional methods for cell transportation (dry ice or liquid nitrogen) are inconvenient and expensive. Therefore, the establishment of a safe, affordable, and low-cost strategy to store and transport easily accessible hiPSCs and hiNSCs, with characteristics that match fetal hNSCs, is incredibly urgent.MethodsWe reprogrammed human urinary cells to iPSCs using a non-integrating, virus-free technique and differentiated the iPSCs toward iNSCs/neurospheres and neurons, under Good Manufacturing Practice (GMP)-compatible conditions. The pluripotency of iPSCs and iNSCs was characterized by a series of classical methods (surface markers, karyotype analysis, and in vitro as well as in vivo differentiation capabilities, etc.).ResultsHere, our results showed that we successfully generated hiNSCs/neurospheres from more available, non-invasive, and more acceptable urinary cells by a virus-free technique. Next, we demonstrated that the iNSCs differentiated into mature cerebral cortical neurons and neural networks. Interestingly, hiNSCs survived longer as neurospheres at ambient temperature (AT) than those cultured in a monolayer. Within 7 days approximately, the neural viability remained at > 80%, while hiNSCs cultured in a monolayer died almost immediately. Neurospheres exposed to AT that were placed under standard culture conditions (37 °C, 5% CO2) recovered their typical morphology, and retained their proliferation and differentiation abilities.ConclusionsIn this study, we provided a simple method for the storage of NSCs as neurospheres at AT as an alternative method to more costly and inconvenient traditional methods of cryopreservation. This will enable hiNSCs to be transported over long distances at AT and facilitate the therapeutic application of NSCs as neurospheres without any further treatment.

Biogenic Amines and Bacterial Communities of Adjuevan, a Traditional Fermented Fish Used as a Condiment in Côte D’Ivoire

Adjuevan is an Ivorian traditional and popular fermented fish used as a condiment. However, fermentation process and storage conditions may lead to the production of biogenic amines (BA) which an excessive consumption can induce severe human toxicological effects. Therefore, samples of adjuevan produced from the fish species Chloroscombrus chysurus, Galeoides decadactylus and Thunnus thynnus were collected from local producers, stored both at ambient temperature (28-30°C) and in a refrigerator (4°C) over a period of eight weeks. At two-week intervals, BA were determined by HPLC and the bacterial communities analysed using high-throughput sequencing (NGS) of the 16S rRNA gene. Results showed that histamine, cadaverine, putrescine and tyramine were the major compounds. In adjuevan from T. thynnus , the level of histamine (the most toxic BA) decreased from 654.91 mg/kg to 287.90 mg/kg at ambient temperature (AT), while it decreased first and then increased to 612.99 mg/kg in a refrigerator. In total, 21 bacterial genera with relative abundance superior to 1% and belonging to 14 families and 5 phyla were detected. Bacillaceae family was the most represented in the different samples all the storage time, particularly at ambient temperature. For the storage in a refrigerator, Staphylococcaceae and Enterococcaceae were the most abundant. The analysis of correlation showed that the increase of Lentibacillus leads to a decrease of the major BA at ambient temperature. On the contrary, the increase of Staphylococcus, Lactobacillus, Psychrobacter, Peptostreptococcus and Fusobacterium leads to an increase of these biogenic compounds. They could be therefore BA producers in adjuevan.

Short-term effects of increased CO2, nitrate and temperature on photosynthetic activity in Ulva rigida (Chlorophyta) estimated by different pulse amplitude modulated fluorometers and oxygen evolution.

Short-term effects of pCO2 (700-380 ppm; High carbon (HC) and Low carbon (LC), respectively) and nitrate content (50-5 µM; High nitrogen (HN) and Low nitrogen (LN), respectively on photosynthesis were investigated in Ulva rigida (Chlorophyta) under solar radiation (in-situ) and in the laboratory under artificial light (ex-situ). After six days of incubation at ambient temperature (AT), algae were subjected to a 4 °C temperature increase (AT+4 °C) for 3 d. Both in-situ and ex-situ maximal electron transport rate (ETRmax) and in situ gross photosynthesis (GP), measured by O2 evolution, presented highest values under HCHN, and lowest under HCLN, across all measuring systems. Maximal quantum yield (Fv/Fm), and ETRmax of photosystem (PS) II [ETR(II)max] and PSI [ETR(I)max], decreased under HCLN at AT+4 °C. Ex situ ETR was higher than in situ ETR. At noon, Fv/Fm decreased (indicating photoinhibition), whereas ETR(II)max and maximal non-photochemical quenching (NPQmax) increased. ETR(II)max decreased under AT+ 4 °C in contrast to Fv/Fm, photosynthetic efficiency (α ETR) and saturated irradiance (EK). Thus, U. rigida exhibited a decrease in photosynthesis under acidification, changing LN, and AT+4 °C. These results emphasize the importance of studying the interaction between environmental parameters using in-situ versus ex-situ conditions, when aiming to evaluate the impact of global change on marine macroalgae.

Comparative Study of Quality Aspects and Shelf Life of Salted and Unsalted Smoked Products From Spotted Snakehead (Channa Punctatus) at Various Storage Conditions

This study was conducted to prepare and evaluate the quality and shelf life ofsmoked spotted snakehead, taki (Channapunctatus) stored at ambient temperature(30-35ºC) and refrigeration temperature (4ºC) after treating with no salt (T1) and 20%salt (T2). Sensory assessment, initial and final proximate analysis, TVB-N value andmicrobial analysis (SPC) were carried out for the smoked products stored for differentstorage periods. According to sensory assessment, smoked taki remained inacceptable condition for 4 and 6 days in T1 and T2, respectively while stored atambient temperature. However, at refrigeration temperature, smoked taki remained inacceptable condition for 59 and 74 days in T1 and T2, respectively. Biochemicalassessment of smoked product showed that protein, lipid and ash content increaseddue to significant loss of moisture during smoking of fish. No appreciable changes inproximate composition were observed for any of the two storage conditions. Valuesof TVB-N content of T1 showed rapid increase in comparison to T2 during storage.Microbial load (SPC) of smoked fish decreased due to the smoking processcompared to the initial microbial load of fresh fishes but increased with the increaseof storage period. Considering all the quality parameters it was found that smokedfish in treatment T2 maintained its excellent quality and longer shelf-life in bothstorage conditions than treatment T1.&#x0D; Res. Agric., Livest. Fish.7(2): 303-310, August 2020

A dendrite-suppressed flexible polymer-in-ceramic electrolyte membrane for advanced lithium batteries

Lithium-ion batteries (LIBs) using solid-state electrolytes (SSEs) can improve safety and energy density comparable with the liquid electrolytes (LE)-based counterparts. Especially, employing garnet-type SSEs to prepare solid-state LIBs are promising to achieve high-energy cells. However, the unbending and brittle issues of the inorganic SSE films are not suitable to fabricate flexible and stretchable energy storage devices. Here, We find that introducing specific polymer (30 wt%) into Li6.75La3Zr1.75Ta0.25O12 (LLZTO) can strongly increase the strength of the composite polymer-in-inorganic electrolyte (CIE) film. Both in-situ and ex-situ characterizations demonstrate that CIE delivers an excellent ability to suppress the growth of Li dendrites due to the close packing of LLZTO and effective filled grain boundaries and voids inside the CIE film by the polymer. The CIE inherits impressive electrochemical performance from LLZTO. As a result, the assembled LiFePO4 (LFP)/CIE/Li cell delivers better cell performance than LFP/LE-separator/Li cell at ambient temperature (AT). The assembled high-voltage cathode (Li1.2Mn0.6Ni0.2O2, 4.8 V)/CIE/Li cell also displays an excellent cell performance at AT. The present study offers new insights into exploring of flexible polymer-in-ceramic electrolytes for high-voltage LIBs with improved safety and energy density.

Yield and NPK Uptake of Rice as Influenced by Si Fertilization under Ambient and Elevated Temperature

Application of silicon (Si) influences the stress resistance, and thereby could boost up the growth and yield of rice. An experiment was conducted to investigate the effect of Si fertilization on rice cv. Binadhan-8 at ambient and elevated temperature during Boro season of Bangladesh. Significant differences were observed in the studied parameters: plant height, SPAD reading, yield and concentration of NPK in grain and straw of rice. At ambient temperature (AMT) condition, plant height, SPAD reading, grain and straw yield were also the highest in case of 10 g pot-1 Si application. Moreover, the highest NPK contents in grain and straw were observed in the application of Si @ 10 g pot-1, whereas the lowest NPK contents were mostly recorded in control (0 g Si pot-1). The increased rate of Si contributed to the NPK absorption in grain, yield attributes and yield of rice up to 10g pot-1 Si application. On the other hand, yield contributing characters, grain yield and NPK uptake were showed a similar response to Si application at elevated temperature (ELT). But, the yield contributing characters as well as grain yield at ELT showed less performance in comparison to AMT. Therefore, the application of Si could be recommended to optimize the yield attributes, yield and NPK uptake of rice.

Characterizing the effect of packaging material and storage temperature on the flavor profiles and quality of soy sauce

The effect of packaging material and storage temperature on two types of soy sauce was investigated. Ethanol content decreased significantly in all tested samples after storage (P < 0.05). While the changes of physicochemical properties and CIELAB color space indexes varied with soy sauce types, packaging materials and storage temperatures. The changes of volatile profiles after storage indicated that storage temperature was a key factor resulting in flavor scalping. It also suggested that there was no significant difference of flavor compounds sorption between glass bottle and polyethylene terephthalate bottle. The abundances of acids and alcohols increased after stored at ambient temperature (AT) and low temperature (LT) for 90days, but phenols decreased. The effect of the packaging material, raw soy sauce type and storage temperature resulted in changing the intensities of fruity, caramel-like, mushroom-like note as well as smoky note. For the inoculated soy sauces, 1-octen-3-ol, ethyl hexanoate and ethyl octanoate in the samples were dominant in samples stored at AT, while the samples stored at LT were characterized by multiple components according to the results of principal components analysis. These results were benefit for understanding the main factors affecting the flavor profiles and quality of soy sauce during storage, as well as optimizing the storage condition.

Production of biogas from cattle waste at low temperature

Production of Bio gas from cattle waste and other biomass is now considered as one of the majorroutes to obtain gaseous fuel for sustainable development. In tropical countries like Indiathousands of rural families in villages are using 3 to 5 M3 biogas plants to suffice their dailycooking fuel need. All these plants are run on cattle waste. Since these plants are operated atambient temperatures, effect of temperature variation affects daily gas yield. The effect becomesvery prominent during winter season. In general about 50-60% reduction in daily biogas yield isobserved when ambient temperature is around l 5°C as compared to that produced at around 30-350C. A low cost and simple to operate technique to enhance biogas yield from the biogas plantduring winter season shall help to get optimum biogas yield from these plants during the winterseason. We thought of a simple technique of filtering the digested effluent slurry of biogas plantthrough a triple layer muslin cloth to obtain a filtrate, hence-forth called as clarified digestedslurry (CDS), rich in cell mass and then adding it back to the biogas plant along with the influentslurry. Experiments were carried out on 25 L capacity cattle dung biogas plant operated at 15°Cto see effect of recirculation of CDS. Addition of 25 and 40% v/v CDS in daily influent resultedin 15% and 37% increase in daily biogas yield. Recirculation of 40% v/v CDS supplementedwith Diammonium phosphate(DAP) increased the biogas yield by 75% v/v. In anotherexperiment use of clarified rumen fluid (CRF) to prepare influent slurry and added exclusivelyfor one day enhanced the daily biogas yield by 70% v/v for a period of two months. Popular dailywears in India called cotton dhoti or cotton sari can be used for the filtration of the slurry.

Storage Stability of Fish Waste Peptone at Ambient Temperature

Peptones from fish waste has been widely studied, however information about its shelf life is stilllimited. This study aims to test the storability of dried peptone from tuna and shrimp waste produced through hydrolysis using alcalase enzyme. Peptone powders were packed in HDPE plastic bottles and plastic coated aluminum foil, stored at room temperature, and periodically observed in quality (moisture content, aw, color and appearance). A test was also performed on their ability to support the growth of Staphylococcus aureusbacteria; all were compared to commercial peptone (Difco). Shrimp waste peptone had the highest moisture, ash calcium contents, while tuna peptone has the highest fat content. During five month storage at ambient temperature, all peptones experienced a slight decrease in quality. Aluminum foil performed better than HDPE bottles as a packaging material for peptones, i.e., able to maintain the moisture content, water activity, and appearance. Although the ability to support bacterial growth after five months of storage was slightly affected, the tested peptones were still able to beused as bacterial growing media. It can be concluded that fish waste peptones had comparable quality and shelf-life atambient temperature to commercial peptone.

Electrical and morphological study of thermally evaporated (Sb2S3)1-xSnx thin films

(Sb2S3)1-xSnx thin films with different concentrations (0, 0.05 and0.15) and thicknesses (300,500 and 700nm) have been deposited bysingle source vacuum thermal evaporation onto glass substrates atambient temperature to study the effect of tin content, thickness andon its structural morphology, and electrical properties. AFM studyrevealed that microstructure parameters such as crystallite size, androughness found to depend upon deposition conditions. The DCconductivity of the vacuum evaporated (Sb2S3)1-x Snx thin films wasmeasured in the temperature range (293-473)K and was found toincrease on order of magnitude with increase of thickness, and tincontent. The plot of conductivity with reciprocal temperaturesuggests, there are three activation energies Ea1, Ea2 and Ea3 for(Sb2S3)1-x Snx for all x content values and thicknesses whichdecreases with increasing tin content and thickness. Hall effectmeasurement showed that low thickness (Sb2S3)1-x Snx film exhibitn-type conductance whereas the film exhibit p-type towards thehigher thickness. The electric carrier concentration and mobilityshow opposite dependence upon tin content and thickness.