Modifikasi dan uji performansi mesin perontok lada dengan mekanisme perontok silinder berjaring

Pepper is one of Indonesia's leading agricultural products. However, post-harvest handling of pepper, such as the threshing process, is still done traditionally. Efforts to overcome these problems done by developing a mechanical threshing process, including by designing and construction a mesh thresher cylinder type of pepper threshing. Test results show, this pepper thresher has a weakness, namely low threshing efficiency so that it needs to developed. Based on these conditions, research is needed that aims to develop, modify and done performance tests on the pepper thresher. The modification was made by making the contact angle between the thresher cylinder and the threshing net is 60o and resulted length of the threshing contact field of about 5.23 cm. The independent variable was the thresher cylinder rotational speed varied into 540, 471, 451 and 352 rpm. The dependent variables were capacity, threshing efficiency and percentage pepper of damage. The results of the analysis showed that the rotational speed of the threshing mechanism had a very significant effect on the capacity, threshing efficiency and the percentage pepper of damage. Increasing the speed of the thresher cylinder can increase the capacity and percentage of damaged pepper, but reduce threshing efficiency. The threshing efficiency increase of the pepper thresher before and after modification was from 35.8% to 95.93% on the approaching treatment.

The Interferences of Indonesian Grammatical Aspects into English: An Evaluation on Preservice English Teachers’ EFL Learning

Decades-long researches in a language in contact field have proved that when a learner learns a new language, his/her knowledge regarding their first language might interfere with their learning. If it occurs, the learning process will be more challenging. The data in this research was collected by using document study technique on twenty-five research outlines written by preservice English teachers in order to investigate the potential of interferences of Indonesian subject – verb agreement pattern into English. To do so, a descriptive study was adopted. The data was analysed by incorporating error and contrastive analyses. The finding of this research confirmed that four types of subject – verb agreements pattern of English had been interfered by that of Indonesian. The grammatically incorrect sentences, which were caused by such interferences, occurred very individually. It means that the interference varies from one preservice English teacher to another.

Study on Logarithmic Crowning of Tapered Roller Profile Considering Angular Misalignment

The angular misalignment of the tapered roller contact pair aggravates the stress edge effect and the stress concentration effect at the contact field, which in turn would affect bearing capacity and fatigue life of the contact pair. In this paper, based on the angular misalignment, the geometric interference model of the tapered roller contact pair was established. And two types of logarithmic crowning models for the roller profile design were theoretically deduced, in which design redundancy was considered through the quadratic processing of the pre-pressure. Then, with the discrete convolution and fast Fourier transform (DC-FFT) method and the conjugate gradient method (CGM), contact characteristics of the tapered roller with these two logarithmic profiles were verified. The results show that two profiles can effectively prevent the stress edge/concentration effect, improve contact pressure distribution and stress field of the roller in misalignment state, and ensure that the contact condition in alignment state is not greatly affected. The logarithmic crowning scheme is also suitable for the profile design of heavy-duty tapered rollers and can provide a reference for the crowning of other finite-line contact pairs under angular misalignment.

Deep Learning Model Comparison for Vision-Based Classification of Full/Empty-Load Trucks in Earthmoving Operations

Earthmoving is an integral civil engineering operation of significance, and tracking its productivity requires the statistics of loads moved by dump trucks. Since current truck loads’ statistics methods are laborious, costly, and limited in application, this paper presents the framework of a novel, automated, non-contact field earthmoving quantity statistics (FEQS) for projects with large earthmoving demands that use uniform and uncovered trucks. The proposed FEQS framework utilizes field surveillance systems and adopts vision-based deep learning for full/empty-load truck classification as the core work. Since convolutional neural network (CNN) and its transfer learning (TL) forms are popular vision-based deep learning models and numerous in type, a comparison study is conducted to test the framework’s core work feasibility and evaluate the performance of different deep learning models in implementation. The comparison study involved 12 CNN or CNN-TL models in full/empty-load truck classification, and the results revealed that while several provided satisfactory performance, the VGG16-FineTune provided the optimal performance. This proved the core work feasibility of the proposed FEQS framework. Further discussion provides model choice suggestions that CNN-TL models are more feasible than CNN prototypes, and models that adopt different TL methods have advantages in either working accuracy or speed for different tasks.

Mobile Phone Fingerprinting: A Picture is Worth a Thousand Words

The United States Department of Homeland Security (DHS) relies on the use of biometrics as an important component of its mission to keep America safe. Risks are involved with the current systems that use contact fingerprint technology such as the transmission of pathogens by contacting the scanner. Touchless systems address this risk but also introduce new challenges. Sixty National Institute of Standards and Technology (NIST) employees participated in the study to determine the usability of three mobile phone devices as well as the image quality of the resulting fingerprint images. All participants had previous experience with capturing their prints using a contact device and as a result tried to touch the screen on the mobile phone to capture their fingerprints. All the participants had mobile phones and were aware of the phone’s features including a camera and capture process for the mobile phone devices involved using the phone’s camera to take a photo of fingerprints. We believe that participants did not equate the capture process to taking a photo of their fingers and were using an existing mental model for capturing their fingerprints and as a result they touched the phone’s glass screen. The devices provided little if any or often somewhat confusing instructions to assist the user and little if any feedback regarding the success of the capture. To study the image quality of the prints, we assisted the participants in collecting a set of prints using both the mobile phone devices and the contact field devices. We compared the image quality and the interoperability of the contactless captures with the legacy contact captures. Currently the image quality and interoperability is less than desirable.