KMUTT Research and Development Journal

Green Consumption Behaviors of Students : Confirmatory Factor Analysis

Paitoon Pimdee

The present work investigated the concept of green consumption, which is a form of sustainable consumer behavior that entails selective purchasing and use of environmentally friendly and sustainable products such as renewable energy and organic products. Focus was given to the development of measures to evaluate green consumption along with the investigation of factors related to green consumption behavior and the relationships between the factors. The population of the study consisted of 1,200 undergraduate
university students enrolled within Thailand’s Office of Higher Education Commission (OEHC) system in 2014, which were selected by using multistage random sampling. The research instrument was a green consumption behavior questionnaire with the index of discrimination ranging between 0.31-0.68 and having a reliability of 0.88. A second-order Confirmatory Factor Analysis using LISREL 9.10 was undertaken on four factors indicating green consumption behavior including discriminate purchasing, selective usage, waste reduction as well as dissemination and participation. The developed model fitted with the empirical data with non-significant χ2, p=0.081, RMSEA=0.044, GIF=0.968, AGFI=0.912, ECVI < ECVI for Saturated Model, Model ACI < Saturated ACI, NFI=0.990, FI=0.997, RMR=0.011 and SRMR=0.031.

Efficiency Comparison of Conventional Estimators and Modified Searls Estimators

Wichayaporn Singnual, Jirawan Jitthavech

The objective of this research was to compare the mean square errors (MSEs) of the means estimated from simple random sampling by seven estimators: ratio estimator, two linear regression estimators based on the modified Searls estimators as well as conventional estimators proposed by Searls, Sisodia and Dwivedi, Koyuncu and Kadilar and Shabbir and Gupta. The study utilized real-life data on the number of teachers per school of 1,009 schools in Bangkok and its surrounding provinces. It was found
that two linear regression estimators based on the modified Searls estimators outperformed the rest. This observation is in agreement with that of the theoretical study in the past.

Development of Business Model Using Lean Startup Methodology

Natanai Trinestsampan, Suthas Ratanakuakangwan

This paper reports the study and application of the lean startup methodology, which is used by the startups in the IT industry for launching their new products into the market, to develop a new business model for commercializing an innovation to the public through a case study of the innovative leg prostheses. This new business model development is based on the value proposition and capture approach that is difficult to imitate. It starts with the processes of searching for the problems and the real value through the principal activity of the iterative build-measure-learn cycle with the principal participation of the customers to the creation and validation of the prototype and its value as required by the customers to obtain the minimum viable product (MVP). In this study, the model is simply and systematically described by nine indicating elements and their integration, the so-called business model canvas. For the case study, a business model was developed and was validated by innovative leg prostheses developers and business entrepreneurs; the results showed that results obtained by the proposed model and those by the experts agreed. Thus, the
proposed methodology can be applied to develop a new business model for any other innovative tangible products as well.

Effects of Solvent Type and Concentration of Citric Acid on the Extraction of Antioxidants from Hom Nin Rice

Anek Halee, Boonyakrit Rattanapun

This research aimed to study the use of different solvents for the extraction of antioxidants from Hom nin rice. The solvents used were water, methanol and ethanol in combination with citric acid at concentrations of 0, 0.05 and 0.1mol/dm3. The effectiveness of the antioxidants was measured by the ABTS DPPH and FRAP assays. The contents of phenolic compounds and anthocyanins were also determined. The results showed that the extracts obtained using water with 0.1 mol/dm3 of citric acid exhibited the highest anthocyanin content (23.01 μg/ml). Water was noted to have similar extraction efficiency to methanol. However, using water as an extraction solvent led to the extract with higher anthocyanin content and antioxidant activity (via both the ABTS and FRAP assays) than by using methanol.

Packing Effect of a Crystalline Material with Different Particle Sizes on Heat Evolution of Pastes

Punnaman Norrarat, Weerachart Tangchirapat, Chai Jaturapitakkul

This paper investigated the heat evolution of pastes due to packing effect of a crystalline material with different particle sizes. Ground river sand was used as a crystalline material and was ground to have two different particle sizes and were used separately as a replacement of Portland cement type I at rates of 0, 50, 60, and 70% by weight of binder. Heat evolution of paste containing ground river sand was measured using an isothermal conduction calorimeter up to 72 h. In addition, the compressive strengths of mortars at the age of 24 and 74 h were investigated. The results showed that ground river sand with different particle sizes had a slight effect on the heat evolution of paste. For pastes with the same replacement rate, the heat evolution of pastes were slightly increased with the decreased of the particle size of the ground river sand. Pastes containing ground river sand with d50 of 4.8 μm and d50 of 32.2 μm at 12 and 72 h had the heat evolution due to packing effect ranging from 4.0 to 22.7 J/g. The heat evolution due to packing effect was low during the first 12 h and increased with age and was constant at the age of 24 to 72 h. The compressive
strength of mortar containing ground river sand at 50-70% developed continuously at the ages of 24 to 72 h while the cumulative of heat evolution of paste containing ground river sand tended to be constant.

Effect of Palm Oil Fuel Ash on Alkali-Silica Reaction of Mortar

Suwat Ramjan, Weerachart Tangchirapat, Chai Jaturapitakkul

This research aimed to study the effect of palm oil fuel ash (POFA) on the alkali-silica reaction of mortar. POFA was ground until the particles were retained on a sieve No. 325 by 33±1 and 5±1% by weight. Ground POFA was then used to replace Portland cement type I at 10, 20, 30 or 40% by weight of binder to investigate the alkali-silica reaction of mortar. The ratio by weight between binder to fine aggregate of 1 to 2.25 was used; a highly reactive aggregate was also used to cast a mortar. A constant water to binder (w/b) ratio of 0.47 was used for all mortar mixtures. After casting for 24 h, mortar bars were cured in water at 80°C for a period of 24 h. The bars were then immersed in 1 N of sodium hydroxide (NaOH) solution at 80°C for a period of 28 days. The results showed that POFA of both high and low finenesses, which were used to replace Portland cement, could reduce the alkali-silica reaction in mortars. Moreover, using a higher amount of POFA, either with high and low finenesses, could reduce more expansion of mortars due to the alkali-silica reaction.

Effects of Milk and Inulin on Physicochemical Properties of Rice Pudding Supplemented with Probiotic Cultures

Nutthaya Srisuvor

The objective of this research was to study the effect of milk and inulin addition on selected physicochemical properties of rice pudding supplemented with probiotic cultures. Four formula of rice pudding (with milk, water, with and without inulin) were investigated, either with or without the addition of Lactobacillus rhamnosus TISTR 047, L. rhamnosus TISTR 108 or L. plantarum TISTR 951. The physicochemical properties of probiotic rice pudding, i.e., total soluble solids, total solids, pH, total acidity, moisture content, apparent viscosity and consistency were analyzed. The results showed that the rice pudding with added milk had higher total soluble solids than that with added water. The samples with TISTR 108 and TISTR 951 strains in milk exhibited higher total acidity than those added with water. Addition of inulin into rice pudding with milk did not change the moisture content (p > 0.05) but the addition of inulin into the sample with water resulted in the samples with TISTR 108 and TISTR 951 having higher moisture content. Furthermore, the samples added with milk and without inulin and supplemented with TISTR 951 strains had the highest apparent viscosity. Milk and inulin did not change the consistency of the pudding with TISTR 047 and TISTR 108. However, milk and inulin promoted the survival of 3 species of probiotics in rice pudding, with the total probiotic content higher than > 8.82 log CFU g-1 during 21-day storage.

Mechanical Properties, Microstructure and Thermal Conductivity of Concrete Block Containing Fly Ash

Wunchock Kroehong, Sopon Sangpaen, Prapit Sitkanarak, Jerasak Wilairat

This paper presents the results on the mechanical properties, microstructure and thermal conductivity of concrete block containing fly ash at a ratio of binder : sand : stone dust of 1:2:8 by weight. Portland cement type I was replaced by fly ash at 10%, 20% and 30% by weight of binder, while the water-to-binder ratios of 0.70, 0.80, and 0.90 were used. Measurement of unit weight, water absorption, porosity, compressive strength, thermal conductivity and scanning electron microscopy were conducted. The results showed that the compressive strength of air-cured concrete block containing 30% fly ash was lower than that of a control concrete block. Nevertheless, when air cured for 7 days, the compressive strength was noted to be higher than that specified by the Thai Industrial Standard 58-1990, which is no less
than 2.5 MPa at 28 days. The unit weight of concrete block containing fly ash decreased with a decrease in the fly ash content, whereas its porosity and water absorption increased with the increased fly ash content. Concrete block with partial replacement of cement by fly ash exhibited lower thermal conductivity than the control concrete block. In addition, the thermal conductivity decreased with the increased water-tobinder ratio.

A Study of Features, Functions and Factors Affecting the Selection of Warehouse Management System Software

Pongchai Athikomrattanakul Athikomrattanakul, Pornpimon Tosem Tosem

This study aimed to investigate the features and functions of a warehouse management system software (WMS software), which is necessary in managing warehousing activities, and to investigate the factors that influence the selection of WMS software by collecting data from 100 medium and large manufacturing companies in Bangkok, which have different WMS software use histories. The study was conducted by exploring the features, main functions, and extra functions of the software. Factors to consider when purchasing software products and factors to consider when choosing software vendors were tested by 2-way ANOVA; ANOVA was used to determine whether the size of the industry and use history are important on the tested factors. From the survey results, the 4 groups of respondents perceived WMS
software features as important to most important. Functions of WMS software are vital at the medium to highest level. Extra functions are important components at the medium to high level. The respondents perceived the factors to consider when buying a WMS software product and to choose the suppliers as important to most important. The large industry groups and the group already possessing WMS software gave a higher score than the medium industry without WMS software in almost all issues. The investigation showed that the majority of the factors had no significantly different impact on the survey results, except for the picking system recommendation and put away system recommendation. Software can be used with every activity in a warehouse and can work with existing software/hardware as well as any ERP and structure or size of the software vendor.

Application of Simulated Annealing Algorithm for Finding Optimal Shape and Optimal Span-to-Depth Ratio for Steel Roof Trusses Design by using SSTAAD Program

Pongnathee Maneekul

This paper presents an application of SSTAAD program by using a proposed simulated annealing algorithm for finding optimal truss shape and optimal span-to-depth ratio of roof steel trusses. The objective function was the lowest weight per unit length of roof steel trusses. The structure items taken into account were grouped as: i) upper and lower chords, ii) diagonal web, iii) vertical web, and iv) support web, and nine design variables were formulated. The finite element method was employed to calculate nodal displacement and internal force of all the structure members. The numerical algorithm then searched for optimal design parameters with thirteen non-linear design constraints based on the Allowable Stress Design (ASD) method, following the American Institute of Steel Construction (AISC) standard. One hundred
and ninety roof truss samples were tested with the span-to-depth ratios ranged from 10 to 40, span space ranged from 10 to 40 metres, and roof slopes ranged from 5 to 40 degrees. The results showed that the top three best roof truss shapes were scissor, girder, and trapezoid shape, with the sample percentage of 67.9, 13.2 and 11.6, respectively. The best diagonal type was pratt, followed with warren and howe, with the sample percentage of 74.2, 24.2, and 1.6, respectively. The optimal span-to-depth ratios returning lightest roof structures ranged from 17 to 25.