Abstract

This study was conducted to determine the effect of changing operational parameters to the energy consumption of a refrigerator. The parameters considered were room temperature, food loading at the freezer and food compartment, relative humidity and the thermostat settings. Result shows that energy consumption would increase as one of the parameters increases. An increase of 1 kilogram of load in food compartment or in a freezer compartment resulted to an increase of energy consumption by 2546 joules. It was observed that energy consumption increased exponentially as the thermostat setting increased from minimum to maximum. Increasing the ambient temperature resulted to an increase of energy consumption by 156.14 joules. The results of this study were considered important in the proper handling of refrigerators for energy saving.

Index Terms

Energy consumption, food loading, thermostat, ambient temperature

Abstract

This paper exposes the choice-based conjoint analysis using the study on boarding house profile preferences. The analysis provides a utility value that can determine the type of boarding house preferred by the respondents. The entire process of analysis, from the making of the questionnaire to the estimation of utilities and simulation of market shares, was run through XLSTAT software. The multinomial logit estimation was used to calculate the utility values. The results showed that the respondents are more likely to live in a boarding house with the following characteristics: a monthly payment of 800 php, accepts only 2 boarders per room, exclusive for male (or female), has a curfew time and has a security guard.

Index Terms

Conjoint Analysis; Choice-based conjoint analysis; XLSTAT – Conjoint; utilities

Abstract

This study was focused on creating an interior floor slab system that can be prefabricated in modular form out of ferrocement technology. The design of the system was outlined using the of mechanics of materials and the modified theory of plates in meeting the requirements of the local building and National Structural (NSCP) Codes including the American Concrete Institute (ACI) guide for ferrocement design. All constituent materials were tested to conform to the ACI and applicable American Society for Testing Materials (ASTM) standards. The water-cement ratio was 1: 0.485 and, cement-sand ratio of 1:2.75 was applied. The wire mesh reinforcement use galvanized square welded mesh with ¾” x ¾” opening and 0.95mm thickness which was economical. The results from the said tests were used in the design that was modeled to meet the geometric and, serviceability in terms of deflection limits obtained from the theory of plates and the local codes, and strength based on flexural capacity requirements. A 600mm x 600mm with a computed thickness of 40mm was the final design output, with 8mm skeletal steels that serves as connection studs to joist. Two layers of 0.95mm square welded wire mesh was the result of the calculation using the basic occupancy rating for residential loads. The slab modules were subjected to a central load using a universal testing machine (UTM) to test the actual capacity. Based on the results, the behavior of the ferrocement modules conforms to the theoretical formulations and the computed flooring system loads. The carrying capacity of the slabs was observed to have doubled than what was expected. All the requirements for serviceability and flexural strength were substantially attained. Actual application was also engaged to determine material usage and productivity rates including direct cost comparison with the conventional ordinary reinforced concrete slab with an area of 2.52m x 2.95m resulting from about 7.47% cost savings in material, labor and, equipment costs. The cost savings were further supplemented by additional cost savings because of the reduction of the dead weight of the slab system of about 38.71% of the weight of the conventional system. The reduction in dead weight reduces the requirement for the sizes of beams, columns and, footing which consequently reduce the stresses transferred to the supporting soil strata. Results of the study have shown that ferrocement is an excellent and safe technology for an interior prefabricated modular slab design for economic reasons. However, it was important to strictly follow the methods outlined in the construction guide to achieve the required results.

Index Terms

Ferrocement, prefabrication, slab, modular

Abstract

The increasing concern over the level of environmental and human health problems caused by synthetic pesticides has encouraged researchers to look for alternative and safer organic pesticides. In this study, the decoction and crude ethanol extracts of Zingiber officinale, Tinospora rumphii Boerl and Gliricidia sepium were used to determine its insecticidal activity against maize weevils (Sitophilus zeamais M.), red flour beetles (Tribolium castaneum) and mosquito larvae (Aedes aegypti). Contact and larvicidal bioassay methods were employed to determine the mortality rate of the plant extracts against the test samples at various concentrations and exposure time. The results revealed that the crude ethanol extracts were more efficient to be considered as an organic insecticide or larvicide as compared to its decoction counterparts. Generally, the decoction and crude ethanol extracts of the stem-bark of Tinospora rumphii were considered as a potent pesticide against maize weevils, red flour beetles and mosquito larvae. In addition, the red flour beetle has the highest mortality rate among the test organisms tested at various concentrations of all plant extracts. Concentration-dependent toxicity relationship was also observed in the larvicidal bioassay of all plant extracts used. The variability of the factors involved in each assay were statistically analyzed and proved to be significant with each other using one-way analysis of variance and univariate analysis (p<0.01).

Index Terms

Pesticidal, Zingiber, decoction, bioassay

Abstract

This study was done to evaluate the viability of using ferrocement technology as cast for concrete beams and columns. The evaluation followed four phases: preliminary, design, construction and application phases. A modified reinforcement design of beam and column was processed in the preliminary phase. In the design stage, parameters were set, the possible loads determined and materials tested. A 0.485 water-cement and 1:2.75 cement sand ratios were used for the mortar mix and a ½” x ½” gauge 23 galvanized win materials compared to conventional formwork welded wire mesh for reinforcement. Construction phase includes the load testing of the fabricated 200mm x 300mm x 200mm beam samples using Reaction Frame Test (RFT). Ferrocement form prototype has a nominal capacity of 0.015kN-m for a deflection of 0.02mm deformation while achieved during the actual test which has an impressive capacity of 0.267kN-m for a deflection of 0.02mm, thus makes the design form applicable. A modified beam with 4.1’ x 1” x1/8” angle bars and a capacity of 14.32kN-m and is comparable to a conventional beam with 4-12mmØ deformed rebars that has a capacity of 14.32kN-m. An application phase is the construction of a new proposed system to actual and compared this to the conventional system. The comparative analysis shows a 31% cheaper cost compared to conventional formwork without reusing materials and 9% cheaper cost when materials are used twice. The labor needed for the new system almost equaled to that estimated for conventional system when materials are used twice with only 4 to 5% savings. The new system is time efficient with 11 to 17% savings in number of days as compared to using conventional framework systems. Results showed that ferrocement as formwork is viable and has achieved the necessary requirements of a good formwork this study must have. Furthermore, economic efficiency goes beyond what is expected, granted that the new system is done in considering the project in its entirety and that procedures and manual according to this study are properly followed.

Index Terms

formwork, beams, columns, ferrocement

Abstract

The purpose of this study is to expose the Cox regression modeling. Cox proportional hazards regression builds a predictive model for time-to-event data. It will yield an equation for the hazard or the probability of the occurrence of event as a function of several explanatory variables. The data used is actual marriage data. The method used for parameter estimation is based on proportional hazards assumption and the diagnostic checking is based on residuals. The statistical software used is R, and the methods of the analysis in R, are presented in this paper. Finally, the model that best fits to the data includes an interaction term which verifies all the diagnostic checking.

Index Terms

Cox proportional hazards model; hazard function; Schoenfeld and Martingale residuals; survival analysis; survival function