scholarly journals Zinc Removal from ZnO Industrial Wastewater by Hydroxide Precipitation and Coagulation Methods: The Role of pH and Coagulant Dose

2020 ◽  
Vol 11 (2) ◽  
pp. 35-42
Author(s):  
Ratnawati Ratnawati
Keyword(s):  
Reaction Time ◽  
Industrial Wastewater ◽  
Waste Treatment ◽  
Liquid Waste ◽  
Reaction Times ◽  
Quality Standards ◽  
Government Regulations ◽  
Zinc Removal ◽  
Zn Concentration

Liquid waste from the ZnO industry must be treated to meet the quality standards of wastewater into water bodies, according to the Minister of Environment Regulations No.5, 2014. It still contains 79 mg/L of Zn metal, cloudy with turbidity above 500 NTU, and COD value around 222 mg/L. This study aims to determine the effect of pH on reducing Zn metal and the coagulant dose to minimize turbidity and COD in liquid waste produced by the ZnO factory in Depok, West Java. The waste treatment has been carried out by adding alkaline to neutralize the acid conditions in the equalization basin. However, the results have not met the requirements. It is necessary to vary the pH (8.5; 9.0; 9.5; 10.0 and 10.5) to precipitate of Zn optimally, modify the dose of coagulants (50; 100 and 150 mg/L) and reaction times (10; 15 and 20 minutes) to reduce its turbidity and COD concentration. The best results were obtained at a pH of 9.5 with a coagulant dose of 50 mg/L and a reaction time of 10 minutes. This condition can reduce Zn concentration (79 to 3.71 mg/L), turbidity (557 to 1.42 NTU), COD (222 to 68 mg/L) with a removal efficiency of 95.3%; 99.7%; and 69.4% respectively. These values have met the standard requirements according to government regulations.

Effects of Uncertainties of Time and Occurrence on Reaction Time of Mentally Handicapped Students

1981 ◽  
Vol 53 (2) ◽  
pp. 355-360 ◽  
Author(s):  
Paul R. Surburg
Keyword(s):  
Reaction Time ◽  
Reaction Times ◽  
Reaction Time Task ◽  
Mentally Handicapped ◽  
Treatment Groups ◽  
Time Task

The purpose of this study was to determine the effects of uncertainties of time and occurrence on reaction time of mildly handicapped students. 33 students were randomly assigned to the following treatment groups: no catch-trials, 10% catch-trials, and 20% catch-trials. Randomly varied foreperiods of 1.5, 3.0, and 4.5 sec. were used in a reaction time task. The role of catch-trials varied over four days of testing. Reaction times following 3.0- and 4.5-sec. were significantly faster than measurements following a 1.5-sec. foreperiod.

scholarly journals Learning to search. The importance of eye movements in the decrease of response times during a visual choice reaction time task

2016 ◽  
Vol 9 (5) ◽  
Author(s):  
Aleksandra Kroll ◽  
Monika Mak ◽  
Jerzy Samochowiec
Keyword(s):  
Eye Movements ◽  
Reaction Time ◽  
Choice Reaction Time ◽  
Visual Target ◽  
Response Times ◽  
Reaction Times ◽  
Reaction Time Task ◽  
Visual Tasks ◽  
Target Searching

Reaction times are often used as an indicator of the efficiency of the processes in thecentral nervous system. While extensive research has been conducted on the possibleresponse time correlates, the role of eye movements in visual tasks is yet unclear. Here wereport data to support the role of eye movements during visual choice reaction time training.Participant performance, reaction times, and total session duration improved. Eyemovementsshowed expected changes in saccade amplitude and resulted in improvementin visual target searching.

scholarly journals Symbolic distance: Unfamiliar versus familiar space

Psihologija ◽  
2007 ◽  
Vol 40 (1) ◽  
pp. 93-110 ◽  
Author(s):  
Radmila Stojanovic ◽  
Suncica Zdravkovic
Keyword(s):  
Reaction Time ◽  
Linear Relation ◽  
Mental Representations ◽  
Reaction Times ◽  
Distance Effect ◽  
Professional Orientation ◽  
Symbolic Distance Effect ◽  
Symbolic Distance ◽  
Male Subjects

The symbolic distance effect was investigated using both realistic distances and distances represented on the map. The influence of professional orientation and sex on mental visualization was measured. The results showed that an increase of distance leads to an increase in reaction time. The slope for realistic distances was steeper. Male subjects always had longer reaction times, although the effect differs for the two types of distances. Professional orientation did not play a role. The obtained relation between reaction time and distance is a confirmation of theories proposing that mental representations encompass structure and metric characteristics. The confirmed role of the effect of symbolic distance additionally supports Kosslyn?s theory: there is a linear relation between the time and distance.

scholarly journals To Google or Not: Differences on How Online Searches Predict Names and Faces

Mathematics ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1964
Author(s):  
Carmen Moret-Tatay ◽  
Abigail G. Wester ◽  
Daniel Gamermann
Keyword(s):  
Reaction Time ◽  
Bayes Factor ◽  
Reaction Times ◽  
Online News ◽  
Additional Test ◽  
Contextual Diversity ◽  
Computer Calculations ◽  
Online Searches ◽  
The Stability

Word and face recognition are processes of interest for a large number of fields, including both clinical psychology and computer calculations. The research examined here aims to evaluate the role of an online frequency’s ability to predict both face and word recognition by examining the stability of these processes in a given amount of time. The study will further examine the differences between traditional theories and current contextual frequency approaches. Reaction times were recorded through both a logarithmic transformation and through a Bayesian approach. The Bayes factor notation was employed as an additional test to support the evidence provided by the data. Although differences between face and name recognition were found, the results suggest that latencies for both face and name recognition are stable for a period of six months and online news frequencies better predict reaction time for both classical frequentist analyses. These findings support the use of the contextual diversity approach.

Evaluation of the Influence of Illiteracy on Neuropsychological Performances by Elderly Persons

1993 ◽  
Vol 77 (3) ◽  
pp. 859-866 ◽  
Author(s):  
D. Grossi ◽  
G. Correra ◽  
C. Cause ◽  
M. A. Ruscitto ◽  
V. Vecchione ◽  
...  
Keyword(s):  
Reaction Time ◽  
Reaction Times ◽  
General Strategy ◽  
Elderly Persons ◽  
Formal Schooling ◽  
Rural Village ◽  
Early School ◽  
Constructional Apraxia ◽  
Better Than

The aim of the present study was to verify the role of the primary notions acquired in early school in the formation of a general strategy in elaboration of information. For this purpose we selected a tiny rural village in southern Italy which comprises a substantial number of elderly persons having very little formal schooling. These subjects were screened using a test battery composed of classic neuropsychological tests and reaction-time tests. In the subjects studied we observed a significant correlation between the amount of education and the neuropsychological performances, although no such correlation existed for reaction times. Subjects having little schooling (up to 3 years) performed better than the illiterate persons on the Constructional Apraxia test and on the Raven Matrices. However, the reaction times were similar in these groups. On this basis we claim that reaction-time tests might form a basic tool in evaluating cognitive performances of persons with very little schooling. Further, the primary notions learned during the first few years of schooling induce an improvement in mental strategies that is well-preserved in the normal aging process.

Role of peroxidase and chitosan in removing chlorophenols from aqueous solution

1996 ◽  
Vol 34 (10) ◽  
pp. 151-159 ◽  
Author(s):  
Hossein Ganjidoust ◽  
Kenji Tatsumi ◽  
Shinji Wada ◽  
Mitsuo Kawase
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Horseradish Peroxidase ◽  
Industrial Wastewater ◽  
Aluminum Sulfate ◽  
Enzymatic Reaction ◽  
Hexamethylene Diamine ◽  
Natural Coagulant

Chlorophenols removal from industrial wastewater by horseradish peroxidase and coagulant was investigated. It was found that an enzymatic reaction time of less than one hour was enough for the reaction to reach 95% completion. Chitosan, which is a natural coagulant, was an effective coagulant as compared to mineral coagulants such as aluminum sulfate (ALUM), hexamethylene diamine epichlorohydrin polycondensate (HX), polyacrylamide (PAM), and polyethyleneimine (PEI). A combination of 0.4 U/mL peroxidase to 2 ppm chitosan along with 0.8 mM of hydrogen peroxide resulted in over 95% chlorophenol removal from aqueous solution.

scholarly journals The scalar property during isochronous tapping is disrupted by a D2-like agonist in the nonhuman primate

2019 ◽  
Vol 121 (3) ◽  
pp. 940-949 ◽  
Author(s):  
Karyna Yc ◽  
Luis Prado ◽  
Hugo Merchant
Keyword(s):  
Reaction Time ◽  
Rhesus Monkeys ◽  
Reaction Times ◽  
Reaction Time Task ◽  
Property A ◽  
Scalar Property ◽  
Temporal Precision ◽  
Musical Cognition ◽  
Dose Dependent

Dopamine, and specifically the D2 system, has been implicated in timing tasks where the absolute duration of individual time intervals is encoded discretely, yet the role of D2 during beat perception and entrainment remains largely unknown. In this type of timing, a beat is perceived as the pulse that marks equally spaced points in time and, once extracted, produces the tendency in humans to entrain or synchronize their movements to it. Hence, beat-based timing is crucial for musical execution. In this study we investigated the effects of systemic injections of quinpirole (0.005–0.05 mg/kg), a D2-like agonist, on the isochronous rhythmic tapping of rhesus monkeys, a classical task for the study of beat entrainment. We compared the rhythmic timing accuracy, precision, and the asynchronies of the monkeys with or without the effects of quinpirole, as well as their reaction times in a control serial reaction time task (SRTT). The results showed a dose-dependent disruption in the scalar property of rhythmic timing due to quinpirole administration. Specifically, we found similar temporal variabilities as a function of the metronome tempo at the largest dose, instead of the increase in variability across durations that is characteristic of the timing Weber law. Notably, these effects were not due to alterations in the basic sensorimotor mechanism for tapping to a sequence of flashing stimuli, because quinpirole did not change the reaction time of the monkeys during SRTT. These findings support the notion of a key role of the D2 system in the rhythmic timing mechanism, especially in the control of temporal precision. NEW & NOTEWORTHY Perceiving and moving to the beat of music is a fundamental trait of musical cognition. We measured the effect of quinpirole, a D2-like agonist, on the precision and accuracy of rhythmic tapping to a metronome in two rhesus monkeys. Quinpirole produced a flattening of the temporal variability as a function of tempo duration, instead of the increase in variability across durations that is characteristic of the scalar property, a hallmark property of timing.

scholarly journals Bioremediation of Tofu Industrial Wastewater Using Anaerobic-Aerobic Solution of EM4

2020 ◽  
Vol 17 (3) ◽  
pp. 233-241
Author(s):  
Trisca Deffy ◽  
Widya Nilandita ◽  
Ida Munfarida
Keyword(s):  
Removal Efficiency ◽  
Industrial Wastewater ◽  
Treatment Process ◽  
Liquid Waste ◽  
Quality Standards ◽  
Detention Time ◽  
Aerobic System

This research using a bioremediation treatment process with anaerobic-aerobic system by mixing tofu liquid waste and EM4 solution into the reactor. The variation of EM4 solution that will be used in this research is 1/20 of concentration with 1/10 of concentration and detention time. This research was conducted for 8 days. The result showed that EM4 solution was able to reduce BOD, COD, and TSS by usinng variations in concentration and detention time. The most significant decrease in BOD, COD, adn TSS levels occured on the 8 day. BOD levels for the first reactor at a concentration of 1/10 with a removal efficiency of 48,98% and a second reactor with  removal efficiency of 48,98%. For the 1/20 concentration the removal efficiency was 37,33% and in second reactor the removal efficiency was 37,34%. COD levels for the first reactor at a concentration of 1/10 with a removal efficiency of 61,82% and a second reacotor with removal efficiency of 62,10%. For the 1/20 concentration the removal efficiency was 30,39% an in second reactor the removal efficiency was 34,98%. TSS levels for the first reactor at a concentration 1/20 with removal efficiency of 41,17% and in the second reactor the removal efficiency of 43,59%. At 1/20 concentration the removal efficiency of TSS levels was 1,02% in the first reactor and in the second reactor the removal efficiancy was 5,10%. Bioremediation using EM4 solution can be used to reduce levels of BOD, COD, and TSS of tofu liquid waste according to the applicable quality standards

Analyzing Response Time Distributions

2011 ◽  
Vol 219 (2) ◽  
pp. 117-124 ◽  
Author(s):  
Gene A. Brewer
Keyword(s):  
Reaction Time ◽  
Prospective Memory ◽  
Response Times ◽  
Memory Task ◽  
Reaction Times ◽  
Reaction Time Data ◽  
Fundamental Relation ◽  
Time Data ◽  
Experimental Conditions

The analysis of response times from prospective memory experiments has resulted in multiple theoretical propositions about the role of attention in prospective memory. Extant theories of prospective memory are in good agreement that attention is necessary for detecting intention-related cues. However, these theories were primarily formulated to describe differences in mean reaction times across experimental conditions. While this approach has been fruitful for establishing a fundamental relation between attention and prospective memory, reaction time modeling techniques can be applied to prospective memory data to better constrain theorizing. In the current work, the ex-Gaussian distribution is fit to data from a prospective memory task. The results from this analysis suggest that modeling reaction time data has the potential for clarifying our understanding of the role of attention in prospective memory.

scholarly journals The role of concern about falling on stepping performance during complex activities

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Shaira Viaje ◽  
Geert Crombez ◽  
Stephen R. Lord ◽  
Jacqueline C. T. Close ◽  
Perminder Sachdev ◽  
...  
Keyword(s):  
Reaction Time ◽  
Older People ◽  
Dual Task ◽  
Reaction Times ◽  
Cognitive Resources ◽  
Task Condition ◽  
Dual Task Condition ◽  
Visuospatial Task ◽  
General Concern

Abstract Background There is limited understanding of the underlying mechanisms explaining the role of concern about falling on fall risk in older people. Anxiety is known to interact with cognitive resources and, as people get older, they require more cognitive resources to maintain balance. This might affect an individual’s ability to perform cognitive-motor tasks concurrently. The aim of this study was to investigate the effect of a visuospatial dual-task on stepping performance in older people with and without concern about falling and the impact of repeating this task in those with high concern about falling. Methods Three-hundred-eight community-dwelling older people, aged 70 to 90 years old, participated in the study. Participants were asked to perform a Choice Stepping Reaction Time (CSRT) task in two conditions; once without any other tasks (single task condition), and once while simultaneously performing a visuospatial task (dual-task condition). Participants were asked to rate their levels of concern and confidence specifically related to each of the 25 stepping trials (before/after). We also measured general concern about falling, affect, and sensorimotor and cognitive functioning. Results Total stepping reaction times increased when participants also performed the visuospatial task. The relation between general concern about falling and stepping reaction time, was affected by sensorimotor and executive functioning. Generalised linear mixed models showed that the group with moderate to high levels of general concern about falling had slower total stepping reaction times than those with lower levels of concern about falling, especially during the dual-task condition. Individuals with greater general concern about falling showed reduced confidence levels about whether they could do the stepping tasks under both conditions. Repeatedly performing the stepping task reduced the immediate task-specific concern about falling levels and increased confidence in all participants. Conclusions These findings reveal that people with higher general concern about falling experienced more difficulties during a dual-task condition than people with lower levels of concern. Of further interest, better sensorimotor and cognitive functioning reduced this effect. Graded exposure has potential to reduce concern about falling during fear-evoking activities, especially in conjunction with therapies that improve balance, mood and cognitive function.

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