Kinematically Redundant Octahedral Motion Platform for Virtual Reality Simulations

We propose a novel design of a parallel manipulator of Stewart Gough type for virtual reality application of single individuals; i.e. an omni-directional treadmill is mounted on the motion platform in order to improve VR immersion by giving feedback to the human body. For this purpose we modify the well-known octahedral manipulator in a way that it has one degree of kinematical redundancy; namely an equiform reconfigurability of the base. The instantaneous kinematics and singularities of this mechanism are studied, where especially "unavoidable singularities" are characterized. These are poses of the motion platform, which can only be realized by singular configurations of the mechanism despite its kinematic redundancy.Comment: 13 pages, 6 figure

Korelasi Sifat Fisik Dan Kimia Tanah Dengan Intensitas Penyakit Busuk Pangkal Batang Tanaman Lada / Correlation of Physical and Chemical Soil Characteristics with Intensity of Foot Rot Disease of Black Pepper

Foot rot disease of black pepper caused by Phytophthora capsici is the most destructive disease in Southeast Sulawesi. The disease intensity is 61.2%. This disease is difficult to control because the pathogen is soil borne and influenced by various complex environmental conditions. The study aimed to determine the correlation of physical and chemical soil characteristics with disease intensity of foot rot of black pepper. Disease intensity was assessed from the subplots of black pepper plantation of 15x15 m2 consisting of 36-40 plants. Soil samples were randomly taken from the rhizosphere of the plants in each sub plot, mixed and taken as a composite. The physical and chemical analyses were conducted in the laboratory of Physics and Chemistry of the Faculty of Agriculture, Gajah Mada University. Disease intensity and soil characteristics were analyzed its correlation using a path analysis. The results showed that soil fertility in the study area was low. The path analyses indicated that physical and chemical properties that correlated with low disease intensity were high cation exchange capacity (CEC), base saturation (BS), potassium and phosphor available as well as moisture at field capacity, whereas those induced disease development were high content of clay fraction, sand fraction, porosity, total N, C-organic and salinity. The control strategy for foot rot disease in Southeast Sulawesi was possibly by increasing CEC, BS, potassium and phosphor available, as well as by improvement of soil texture that can lower high fraction of clay, sand and soil porosit

Deteksi Dan Penghitungan Kerapatan Inokulum Phytophthora Capsici Dalam Tanah Dengan Menggunakan Umpan Daun Lada

Phytophthora capsiciis a causal agent for footrot disease in pepper and classified as a soil-borne pathogen. The inoculums of P. capsici in the soilis difficultto detect. The dynamics of P. capsici population in the soil is frequently and rapidly fluctuates and hard to detect, causing the pathogen to produce disease rapidly. The aimsof this research were todetect the pathogen P.capsici using black pepper leaf baiting and to quantify the inoculum of the pathogen P.capsici in the soil belonging to several disease intensities of the black pepper foot rot in the field. The first experiment: detecting the pathogen P. capsici using black pepper leaf baiting in the soil artificially infested using several sporangia, anda second experiment: quantification of propagul of the P.capsici in various categories of intensity on the black pepper foot rot disease in the field. The research results showed that the black pepper leaf baiting could be used to detect the existence of the propagul of P.capsiciin the soil artificially infested in various densities of sporangia. The increase in disease intensity occurred in parallel with the greater density of P. capsici inocula in soil. The density of P. capsici inocula in the soil tended to decline when the disease intensity reached the highest level

Productividad de la rotación anual raigrás- maíz en galicia: evaluación durante cinco años en regadío y secano y bajo dos sistemas de siembra

Es un estudio sobre la productividad de la rotación anual raigrás- maíz en galicia: evaluación durante cinco años en regadío y secano y bajo dos sistemas de siembr

Epidemi Penyakit Busuk Pangkal Batang Lada Pada Kondisi Lingkungan Yang Bervariasi

Foot rot disease epidemic on black pepper in variety of environmental conditions. The foot rot disease on black pepper caused by Phytophthora capsici Leonian, is often destructive to farmers of black pepper. This research aims to study the infection rate and the pattern of development of the black pepper foot rot disease in various condition of the environment. The research was conducted in the areas of black pepper cultivation in the Ultisol and Entisol soils. In each location plots were set with few (75%) weeds. Variable observed was disease incidence. The data were used to analyze model of development of the black pepper foot rot disease and infection rate. Results of the research showed that the model of development of the black pepper foot rot disease was not affected by soil type, but the type of soil affected the infection rate. At the pepper plantation with abundance of weeds, the disease development followes Gompertz model. At the plantation with few weeds, however the disease developed in a logistic model. The rate of disease infection on the black pepper plant with abundant weeds lower compared with those with few weeds

A comparative study on the effectiveness of bupivacaine and ropivacaine for supraclavicular block

Background: Bupivacaine and Ropivacaine have been extensively studied &their properties with respect to onset, duration and quality of block. This study aims to detect whether addition of clonidine to both of them changes their properties. This study also aims to use lower than usual dosages for both the local anesthetics to prevent adverse effects of local anesthetics.Methods: After obtaining ethical approval, the study was carried out on patients undergoing elective upper limb surgeries. They were randomly divided into two Groups: Group B and Group R. The onset and duration of sensory and motor blockade and other parameters were assessed.Results: The onset of blockade, both sensory & motor was earlier in Ropivacaine as compared to Bupivacaine group. Mean duration of blockade, both sensory & motor, was more in the Bupivacaine group.  Conclusions: Addition of Clonidine enabled the use of low concentrations (0.25%) of both the anesthetics. Also, Ropivacaine (0.25%) has faster onset of sensory and motor blockade, shorter duration of action and less motor blockade compared to Bupivacaine

An instance of abnormally ripe ovaries in the Indian Mackerel, Rastrelliger kanagurta (Cuvier)

A case of abnormally ripe ovaries, the first of its kind, is reported wherein an additional lobe in stage VI was found along with the normal pair of ovaries in stage IV. The estimated number of ripe and maturing ova in this abnormal sac was 18,600 each

Machine Learning Frontier Orbital Energies of Nanodiamonds

Nanodiamonds have a wide range of applications including catalysis, sensing, tribology, and biomedicine. To leverage nanodiamond design via machine learning, we introduce the new data set ND5k, consisting of 5089 diamondoid and nanodiamond structures and their frontier orbital energies. ND5k structures are optimized via tight binding density functional theory DFTB and their frontier orbital energies are computed using density functional theory DFT with the PBE0 hybrid functional. From this data set we derive a qualitative design suggestion for nanodiamonds in photocatalysis. We also compare recent machine learning models for predicting frontier orbital energies for similar structures as they have been trained on interpolation on ND5k , and we test their abilities to extrapolate predictions to larger structures. For both the interpolation and extrapolation task, we find the best performance using the equivariant message passing neural network PaiNN. The second best results are achieved with a message passing neural network using a tailored set of atomic descriptors proposed her