Preparation of Lapsi (Choerospondias axillaries roxb.) pulp using IMF technology and study on storage stability

The work was carried out to study the storage stability and food safety aspects of lapsi (Choerospondias axillaries roxb.) pulp stock prepared using Intermediate Moisture Food Technology. Three recipes were designed with the TSS of 55, 60 and 65 oBx and the TSS/Acidity ratio of 20, 25 and 30 respectively so as to achieve the theoretical water activity level of 0.86 to 0.90. Further three treatments using no preservative, potassium sorbate (0.3%) as preservative and pasteurisation with hot filling were done to those recipes. All samples were found to be safe from the food poisoning organism Staphylococcus aureus. All preservative added and pasteurised samples as well as 65 oBx sample with no preservative were stable up to 5 months storage and no Mold growth were observed. Mold observed after 2 month in 55 oBx sample and after 69th day in 60 oBx sample with no preservative. Preservative added samples were faint in colour while pasteurised samples were dark due to browning reaction during heating. No preservative used sample was best in appearance. 65 oBx with no preservative sample was good design but protection from air to prevent browning and use of sorbate to further extend shelf life was found necessary

Computational estimation of soybean oil adulteration in Nepalese mustard seed oil based on fatty acid composition

The experiment was carried out for the computational estimation of soybean oil adulteration in the mustard seed oil using chemometric technique based on fatty acid composition. Principal component analysis and K-mean clustering of fatty acid composition data showed 4 major mustard/rapeseed clusters, two of high erucic and two of low erucic mustard type. Soybean and other possible adulterants made a distinct cluster from them. The methodology for estimation of soybean oil adulteration was developed based on weighted least square error principle using Microsoft Excel Solver program. This principle was successfully validated on the real soybean mustard oil blends. Moreover, the method was further evaluated on the 4000 training set and 3999 validation set simulated blends of mustard and soybean oil based on 212 fatty acid composition data. The blending was simulated with data from different literature from different part of the world along with data collected in our laboratory. The simulated blend consisted of random mixture of up to 16 samples. These are more extreme conditions than that can usually be expected in real scenario

Use of calcium carbide for artificial ripening of fruits : its application and hazards

A review of different articles related to artificial ripening was done. Focus was given on the hazards and applications of calcium carbide for artificial ripening, being a very common practice in Nepalese Market. Litterateurs showed many hazardous aspects of carbide use and also standard procedures of safety handling aspects. But being banned by regulation, due to its hazardous aspects and lack of proper handling methods among users, it was concluded that the use of calcium carbide is to be strictly monitored and controlled

Mustard and rapeseed oils: authenticity, seed roasting and oxidative stability

This PhD thesis contributes to a better understanding of the chemistry of mustard and rapeseed oils in the field of authenticity, formation of antioxidants during roasting and their effects on the oil oxidative stability. At first, a chemometric methodology based on Monte Carlo simulation was developed to evaluate the authenticity of mustard and rapeseed oils. In the second part, the isolation of a potent radical scavenger, canolol, from the roasted mustard seed oil was carried out and its identity was confirmed via spectrometric data (NMR, UV, MS) and chemical synthesis. Canolol was found to be formed during seed roasting by decarboxylation of sinapic acid. In the third part, the oxidative stability of roasted and unroasted mustard seed oils collected from the Nepalese market was evaluated. Furthermore, the effects of seed roasting on the oxidative stability of mustard and rapeseed oils was investigated. These studies showed that canolol could play an important role in the oxidative stability of roasted rapeseed oil; in contrast, it could only play a limited role in the much higher oxidative stability of roasted mustard seed oil. In fact, the oxidative stability of roasted mustard seed oil was mainly correlated with the phospholipid content and the Maillard type browning reaction products formed during roasting. At last, the Maillard type reactions involving phospholipids and their antioxidant potential were evaluated in a model system containing phosphatidylethanolamine and glucose. The reaction products not only increased the oil oxidative stability but also increased the stability of tocopherol and plastochromanol-8 during oil storage. The occurrence of such reactions in an apolar medium was demonstrated by identifying some of the reaction products by liquid chromatography-time of flight mass spectrometry (LC-TOF MS). Such antioxidants could find a wide application in different food products

Total polyphenols content and antioxidant activity of different tea commercially produced in Nepal

This study was conducted to assess and compare the total polyphenol content (TPC), antioxidant activity of different tea varieties commercially produced in Nepal. Nine different brands of tea samples, three from each CTC, orthodox and green tea were collected from different parts of Kathmandu valley. TPC was analyzed as per folin-ciocalteu method and antioxidant activity as per DPPH (2, 2-diphenyl-1-picrylhrdrazine) free radical scavenging capacity. The TPC was found to be 4.60, 8.79, 18.20mg of phenol equivalent (PE)/gm of sample in CTC, orthodox and green tea respectively. Green tea Emerald and green tea Kanchanjunga contained the highest level of polyphenol. Antioxidant activity (for 0.36 mg of tea sample) was found to be 25.04, 43.86, and 72.39% for CTC, orthodox and green tea respectively. Moreover, some commercial brands of green tea (Emerald and Kanchanjunga) showed the highest antioxidant activity. The TPC and antioxidant activity of different commercial brands of tea were found to be positively correlated (r=0.97)

Gas chromatographic analytical method for the analysis of oxygenated polar fatty acids

A gas chromatographic method for analysis of oxygenated polar fatty acids (epoxy, hydroxy and oxo) is described. The challenge of polar fatty analysis in the past has been interferences due to co-elution of the various compounds present in the complex mixture. The method uses a three step SPE separation technique to fractionate the fatty acids so that each fraction is free of interfering compounds thus reducing co-elution. The epoxy and oxo fatty acids have been analysed in one portion. Due to the high polarity of the hydroxy fatty acids it is only possible to analyse them after silylation. The elution profile of the hydroxyl fatty acids can be simplified by hydrogenation which reduces the number of compounds allowing better chromatographic interpretation. The method has proven to be sensitive and exhibits low LODs which is promising towards more robust analytical methods. Application of the validated method on fresh oil samples has revealed that it is an effective tool to quantitatively screen polar fatty acids in trace amounts and can be very useful for exposure assessment studies

Textile-Reinforced Mortar (TRM) System as a Strengthening Technique on Reinforced Concrete Beams

There is considerable investment in construction industry in Qatar for civil infrastructures and taking into account the severe environmental conditions, they would entail for proper maintenance, repair and strengthening for safe, continuous, uninterrupted, and efficient functionality. Reinforced concrete (RC) structural members, which constitute majority of construction works in Qatar, can be easily deteriorated by the deleterious effect of seawater exposure in the form of humidity or direct splashing for sea-level and offshore structures. Such deterioration can also be due to the exposure to extreme high temperatures, severe humidity and high chloride. All such environmental effect can significantly reduce the life-span of RC structures by up to 10-15 years. The cost of rehabilitation and strengthening is usually estimated in millions of dollars. Traditional methods of strengthening corrosion-damaged structures involve the replacement of the corroded bars and the substitution of deteriorated concrete layers with new concrete. Our study proposes an “optimum strengthening technique” for RC structures to mitigate the prevailing conditions of Qatar. This relatively new technique utilizes “textile-reinforced mortar (TRM)” to strengthen concrete beams. TRM systems consist of one or more layers of textiles made of carbon, glass, or Polyparaphenylene benzobisoxazole (PBO) grids that are sandwiched between layers of associated cementitious mortars. The cement-based mortar used in TRM acts as a barrier against chloride ions penetration thus protecting the main reinforcing bars from corrosion attack. Textiles' lightweight, high tensile strength, corrosion resistance, and ease of application make the strengthening system appealing. The potential of TRM for the repair and strengthening of concrete structures is not just the result of its physio-mechanical performance but also the ease and simplicity of installation that does not require any sophisticated equipment or retraining of the construction work. In addition, the compatibility between the mortar used and the concrete substrate is inherited since both materials have the cement as a common “base”. TRM systems, with their innovative features, ensure the endurance of the rehabilitation process and consequently the sustainability of the strengthened structure. Recently in the last few years, several research works in the USA and Europe in the field of TRM strengthening technique have been reported for masonry and concrete structural members. Majority of these works is limited to single type of textile (either carbon, PBO or glass) and on limited types of reinforcement levels. The work presented here compares two different types of TRM systems in the same domain, performed on three different levels of reinforcement ratios representing flexural deficient, lightly reinforced and typical under-reinforced beams. Experimental works were done to state the efficiency and effectiveness of textile reinforced mortar (TRM) in increasing the ductility and the flexural capacity of reinforced concrete (RC) beams. The aim of the experimental work was to investigate the parameters that contribute to the increase in the load carrying capacity of beams strengthened with TRM system. Eighteen medium-scale rectangular RC beam specimens, 2500 mm long, 150 mm wide and 260 mm deep, were prepared at three different reinforcement ratios of “ “ρ” _“s” ^“1” “ = 0.5%;” o “ρ” _“s” ^“2” “ = 0.72%;” f: “ρ” _“s” ^“1” “ = 0.5%; “ “ρ” _“s” ^“2” “ = 0.72%; “ “ρ” _“s” ^“3” “ = 1.27%.” The strengthened beams utilized two TRM types namely carbon and Polyparaphenylene benzobisoxazole (PBO) TRM systems respectively. The RC beam specimens were tested in flexure under four point loading until failure with a clear span of 2.2 m. The strengthening technique was applied to the soffit of the beam (flat type) altering the number of layers of textile. Three beams (of three different reinforcement ratios) without TRM strengthening were used as control specimens. Nine beams were externally reinforced by one (“ρ” _“T-c” ^“1” “ = 0.014%”), two (“ρ” _“T-c” ^“2” “ = 0.028%”) and three (“ρ” _“T-c” ^“3” “ = 0.041%”) layers of carbon TRM system. Six beams were strengthened with one (“ρ” _“T-PBO” ^“1” “ = 0.009%”) and two (“ρ” _“T-PBO” ^“2” “ = 0.018%”) layers of PBO TRM system. From Based on the experimental observations, a reasonable gain in flexural strength and energy absorption was achieved for both the TRM systems. An increase of the initial stiffness was achieved for strengthened specimens; however, an apparent decrease in the overall ductility was observed with TRM strengthening. Results showed that the flexural capacity of strengthened beams increased to an average of 38% for carbon TRM system and an average of 26.7% for PBO TRM system over that of their control (un-strengthened) specimens. The highest increase in the load carrying capacity was 77.51% for a specimen having with the main reinforcement ratio of D12 (“ρ” _“s” ^“2” “ = 0.72%)” and was strengthened with carbon TRM system using three layers of carbon textile. Ductility index (ΔI) and energy absorption (Ψ) values were also calculated in order to know the behavior of ductility and flexural capacity in each of the beam specimen. The term ductility index (ΔI) is defined as the ratio between the deflection at the ultimate load and that at yield load, representing its ability to stretch/deform under sustained load before fracture. During experimentation, it was observed that the average values of ductility indices of using carbon as strengthening material were 1.1 × , 1.2 × and 0.5 × for “ρ” _“s” ^“1” “ = 0.5%,” “ρ” _“s” ^“2” “ = 0.72% and “ “ρ” _“s” ^“3” “ = 1.27%” beam specimens respectively to that of their control specimen. Similarly the average values of ductility indices of using PBO as strengthening material were 2.42 × , 0.75 × and 0.56 × for “ρ” _“s” ^“1” “ = 0.5%,” “ρ” _“s” ^“2” “ = 0.72% and “ “ρ” _“s” ^“3” “ = 1.27%” specimens respectively to that of the control specimen. Also the term energy absorption (Ψ) is defined as the area under the load- deflection curve up to the ultimate load, representing the amount of energy absorbed by the specimen before complete failure. The average values of energy absorption for using carbon as strengthening material were 1.8 × , 1.2 × and 1.6 × for “ρ” _“s” ^“1” “ = 0.5%,” “ρ” _“s” ^“2” “ = 0.72% and “ “ρ” _“s” ^“3” “ = 1.27%” beam specimens respectively to that of the control specimen. Similarly the average values of energy absorption for using PBO as strengthening material were 2.0 × , 1.0 × and 1.5 × for “ρ” _“s” ^“1” “ = 0.5%,” “ρ” _“s” ^“2” “ = 0.72% and” “ρ” _“s” ^“3” “ = 1.27%” specimens respectively to that of the control specimen. Therefore, both the adopted TRM systems performed exceptionally well within the scope of the work, with carbon TRM system showing a relatively higher increase in the capacity of strengthened specimens and PBO TRM systems exhibiting relatively more ductile failure with higher bond strength between the TRM surface and concrete substrate. Moreover, crack patterns for the strengthened beam showed effective distribution of cracks/damage over the length of beam as compared to severe and concentrated damage in the associated control un-strengthened beams. Further, during the experimentation, it was seen that the technique of applying the TRM system also considers the contractor's ease where the construction workers (although not very skilled) can easily implement the technique after being given simple demonstrations. The study puts forth proper procedures and standards to the construction industry on the rehabilitation and strengthening of the existing concrete structures using innovative TRM strengthening technique. Successful implementation of the project will result in “state-of-the-art recommendations for design and construction specifications”, which will place Qatar and research at Qatar University in a leadership position not only limited to the Gulf region. Furthermore, this can potentially act as an “important initiation for the development of new industrial opportunities” in the country.qscienc

Feasibility of sliding base isolation for rubble stone masonry buildings in the Himalayan Mountain range

This paper studied the feasibility of a sliding base isolation layer to be used in rubble stone masonry buildings in rural areas in the Himalayan Mountain range to provide robust protection to important building like schools against strong earthquakes. In this paper, we carried out on-site investigations, quasi-static tests, and shaking table tests focusing on constructability as well as isolation performance. From the results of the feasibility study, the combination of styrofoam, concrete slab, and grease was found to be the most feasible to be used as the upper element, the lower element, and the lubricant, respectively, in the sliding isolation layer. The key features of the present sliding base isolation layer are: 1) the use of the materials that exist in rural mountain areas or those that can be easily transported from the neighboring towns and cities and 2) ease of construction and minimal change from the current construction practice. From the shaking table tests, we identified the conditions, e.g., grease amount, grease type, normal stress at the interface, and roughness of concrete slab surface, to achieve dynamic friction coefficients ranging from 0.08 to 0.16, suitable for sliding base isolation

高性能材料を用いた歴史的組積造構造物の耐震補強技術の開発

京都大学0048新制・課程博士博士(工学)甲第16390号工博第3471号新制||工||1525(附属図書館)29021京都大学大学院工学研究科建築学専攻(主査)教授 上谷 宏二, 教授 田中 仁史, 教授 西山 峰広学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDFA