Setting Of Distance Research Articles

Solution of electromagnetic scattering field of adjacent transmission towers based on reciprocity theorem

Due to the large number of transmission towers being built, the dense distribution of transmission towers is inevitable in some areas. Densely distributed transmission towers will generate severe electromagnetic coupling, which will affect the setting of the passive interference protection distance between transmission towers and adjacent radio stations. Therefore, based on the traditional algorithm for solving the electromagnetic scattering field of a single electrically large target in wide area space, the electromagnetic coupling effect between multiple adjacent transmission towers within a range of 10 times the signal wavelength was considered. Based on the reciprocity relationship between the scattering electric field and the source and the introduced auxiliary field source as the intermediate variable, the electric field integral equation of the secondary scattering field generated by the electromagnetic coupling effect of adjacent transmission towers was derived, and the secondary scattering field is superimposed with the primary scattering field of the transmission generated by the electromagnetic wave excitation of the radio station, obtaining the electromagnetic scattering field at any point. In order to verify the accuracy of the algorithm proposed in this article, the scaled model experiments for the electromagnetic coupling effect between two transmission towers in an anechoic chamber were conducted. The average error of the algorithm proposed in this article is 6.73%, while the error of traditional algorithms is 20.18%. Compared with the traditional algorithm, the accuracy of the proposed algorithm is improved by 13.45%.

Is combined MPFL reconstruction and tubercule tibial osteotomy superior to isolated reconstruction? A systematic review and meta-analysis

PurposeThere is no consensus for management of patellar instability, even in the case of malalignment. The purpose of the review is to evaluate outcomes in the literature of MPFL reconstruction with and without tibial tubercle osteotomy. MethodsTwo databases PubMed and Scopus were searched for studies comparing MPFL reconstruction with and without concomitant tibial tuberosity osteotomy. PRISMA guidelines were followed. Data on functional outcomes via Kujala score, redislocation rates and return to sport rates were reported. Results9 studies included data from 806 knees: 463 submitted to isolated MPFL reconstruction, and 343 submitted to the combined surgery. Patients submitted to the combined procedure had all TT-TG values superior to 18, while the ones with isolated reconstruction had more heterogeneous values, varying between 13 and 20 mm. 77.78% of the studies reported on postoperative Kujala scores, with a mean value of 83.53 in patients who underwent MPFL reconstruction alone and 83.72 in those who underwent the combined procedure. The mean difference between the two groups was −0.83, with the improvement of the score statistically significant in 22.22% of the studies, regardless of the surgery. Concerning redislocation rate, odds ratio comparing both procedures was 0.84 (p = 0.67). ConclusionThe principal finding is that the MPFL reconstruction with or without TTO resulted in similar functional outcomes, assessed by the Kujala score, and low complications concerning recurrent patellar dislocation. More robust literature is needed in the setting of a high TT-TG distance. Level of evidenceIV.

Analysis of Optimal Buffer Distance for Linear Hazard Factors in Landslide Susceptibility Prediction

A linear hazard-causing factor is the environmental element of landslide susceptibility prediction, and the setting of buffer distance of a linear hazard-causing factor has an important influence on the accuracy of landslide susceptibility prediction based on machine learning algorithms. A geographic information system (GIS) has generally been accepted in the correlation analysis between linear hazard-causing factors and landslides; the most common are statistical models based on buffer zone analysis and superposition analysis for linear causative factor distances and landslide counts. However, there is a problem in the process of model building: the buffer distance that is used to build the statistical model and its statistical results can appropriately reflect the correlation between the linear disaster-causing factors and landslides. To solve this problem, a statistical model of landslide density and distance of linear disaster-causing factors under different single-loop buffer distances was established based on Pearson’s method with 12 environmental factors, such as elevation, topographic relief, and distance from the water system and road, in Ruijin City, Jiangxi Province to obtain the most relevant single-loop buffer distance linear disaster-causing factor combinations; random forest (RF) machine learning models were then used to predict landslide susceptibility. Finally, the Kappa coefficient and the distribution characteristics of the susceptibility index were used to investigate the modeling laws. The analysis results indicate that the prediction accuracy of the most correlated single-loop buffer distance combination reaches 96.65%, the error rate of non-landslide points is 4.2%, and the error of landslide points is 11.3%, which is higher than the same single-loop buffer distance combination, confirming the reasonableness of the method of using correlation to obtain the linear disaster-causing factor buffer distance.

Spatial Distribution and Accessibility Measurements for Elderly Day Care Centers in China’s Urban Built-up Area: The Case of Tianjin Nankai District

The elderly community day care model is an emergent solution to the aging problem influenced by the Eastern perspective of family in China. Due to the structural problem of spatial disorder in most of China’s urban built-up areas, the planning and construction of elderly day care centers (EDCCs) is facing great challenges. This study aims to comprehensively compare the spatial distribution and accessibility measurement methods for elderly residents and EDCCs in typical Chinese urban built-up areas based on the accessibility theory and spatial analysis methods from the community living circle perspective. The results show that different spatial distribution analysis methods have their own emphases and limitations, requiring comprehensive application in practice. The potential model method is most suitable for the accessibility measurement in this scenario. The threshold setting of service distance for the urban built-up areas public service facilities in the current Chinese standard needs to be further optimized. The existing EDCCs suffer from serious quantity deficiencies and misplaced supplies in the region. These findings can reveal the EDCCs distribution characteristics of typical Chinese urban built-up areas and provide new insights for urban planners and policy makers who are assessing the equity and efficiency of public service facilities.

Analysis of droplet characteristics and cooling lubrication effects in MQL milling of 316L stainless steel

The infiltration and cooling effect of lubricant droplets in the cutting zone largely depend on setting minimum quantity lubricant (MQL) system parameters appropriately. The study determines the optimal spray angle and spray distance relying on the geometric position relationship between the nozzle and the overall cutting zone. A numerical model that combines computational fluid dynamics (CFD) and discrete phase model (DPM) is presented to simulate droplet transport process for dynamic milling and one-tooth milling by flow field distribution and droplet characteristics. The influences of different spray distances and spray angles on the infiltration process and cutting tool temperature are analyzed. The experiments aimed at verifying the results of the analysis are conducted by measuring cutting force, cutting temperature, surface roughness, surface microtopography and tool wear. The result indicates that the spray distance has a significant impact on the jet divergence, and insufficient lubrication or excessive lubrication is effectively avoided with the optimal cutting distance. Spraying in the direction of cutting-out promotes the accessibility of the lubricant and greater concentration of droplets in the cutting zone, especially later in the cutting process, which results in increased infiltration, reduced friction, and improved heat dissipation. Moreover, experiments demonstate that the optimal state of jetting in the direction of cutting-out is 46 °C lower than that of dry cutting, the surface roughness is reduced by 19.8%, and the wear amount is reduced by roughly 34%. This study has a better understanding of the setting of spray distance and spray angle in MQL milling and the development of equipment, which provides theoretical guidance for the optimization of MQL system parameters in practical applications.

Investigation of SOD control on leather carbonization in diode laser cutting

ABSTRACT Laser beam machining has a significant advantage over hand cutting of leather in terms of output rate and efficiency. The pulsed mode diode laser was chosen for leather cutting in this investigation owing to its controlled optical power and less power consumption while the continuous mode lasers are uncontrollable. There is no technique available in the field of adaptive control approach for Stand-off Distance (SOD) in diode laser leather cutting application. Hence an attempt has been made to investigate the effectiveness of SOD on leather surface carbonization using power diode-based laser beam machining approach. Chrome tanned goat leather was taken as workpiece due to its widespread application in the manufacture of footwear, apparel, and wallets. An adaptive controller has been developed using ultrasonic sensor which sets the standoff distance accordingly from the workpiece surface to the laser diode, which reduces the overall time consumption for manual setting of standoff distance and enhances the machining process. This study reports the carbonization values during leather cutting under the adaptive control of standoff distance.

Discussion On The Optimization of Circumferential Distance Of The System Bolt In A Highway Tunnel

The setting of circumferential distance of system anchor rod in highway tunnel is related to the safety of tunnel structure, and also affects the project cost. The “code for design of highway tunnels” issued in 2018 also adjusted the circumferential spacing arrangement of the system bolts of the tunnel. Based on a highway tunnel project, the circumferential spacing of system bolts in deep buried section of grade V surrounding rock is adjusted from 0.8m to 1.2m, and the numerical simulation and comparative analysis before and after the optimization of bolt spacing are carried out. The field monitoring and measurement data show that the surrounding rock deformation after adjustment has little effect, and the cavern is stable as a whole, which can guide the optimization implementation of subsequent sections.

Assessing the risk of COVID-19 from multiple pathways of exposure to SARS-CoV-2: Modeling in health-care settings and effectiveness of nonpharmaceutical interventions

We assessed the risk of COVID-19 infection in a healthcare worker (HCW) from multiple pathways of exposure to SARS-CoV-2 in a health-care setting of short distance of 0.6 m between the HCW and a patient while caring, and evaluated the effectiveness of a face mask and a face shield using a model that combined previous infection-risk models. The multiple pathways of exposure included hand contact via contaminated surfaces and an HCW’s fingers with droplets, droplet spray, and inhalation of inspirable and respirable particles. We assumed a scenario of medium contact time (MCT) and long contact time (LCT) over 1 day of care by an HCW. SARS-CoV-2 in the particles emitted by coughing, breathing, and vocalization (only in the LCT scenario) by the patient were considered. The contribution of the risk of infection of an HCW by SARS-CoV-2 from each pathway to the sum of the risks from all pathways depended on virus concentration in the saliva of the patient. At a virus concentration in the saliva of 101–105 PFU mL−1 concentration in the MCT scenario and 101–104 PFU mL−1 concentration in the LCT scenario, droplet spraying was the major pathway (60%–86%) of infection, followed by hand contact via contaminated surfaces (9%–32%). At a high virus concentration in the saliva (106–108 PFU mL−1 in the MCT scenario and 105–108 PFU mL−1 in the LCT scenario), hand contact via contaminated surfaces was the main contributor (41%–83%) to infection. The contribution of inhalation of inspirable particles was 4%–10% in all assumed cases. The contribution of inhalation of respirable particles increased as the virus concentration in the saliva increased, and reached 5%–27% at the high saliva concentration (107 and 108 PFU mL−1) in the assumed scenarios using higher dose–response function parameter (0.246) and comparable to other pathways, although these were worst and rare cases. Regarding the effectiveness of nonpharmaceutical interventions, the relative risk (RR) of an overall risk for an HCW with an intervention vs. an HCW without intervention was 0.36–0.37, 0.02–0.03, and <4.0 × 10−4 for a face mask, a face shield, and a face mask plus shield, respectively, in the likely median virus concentration in the saliva (102–104 PFU mL−1), suggesting that personal protective equipment decreased the infection risk by 63%–>99.9%. In addition, the RR for a face mask worn by the patient, and a face mask worn by the patient plus increase of air change rate from 2 h−1 to 6 h−1 was <1.0 × 10−4 and <5.0 × 10−5, respectively in the same virus concentration in the saliva. Therefore, by modeling multiple pathways of exposure, the contribution of the infection risk from each pathway and the effectiveness of nonpharmaceutical interventions for COVID-19 were indicated quantitatively, and the importance of the use of a face mask and shield was confirmed.

Study on safe distance between human body and wireless charging system of electric vehicles with different power and frequencies

In this paper, a wireless charging system and a human body model with various operating frequencies and output power are constructed to study the safe distance between the human body and the charging system when the electric vehicle is wirelessly charging. The models are simulated for electromagnetic fields and electromagnetic thermal effects. This paper mainly focuses on the induced electric field intensity of the human body and main organs during the static charging of electric vehicles under different operating conditions in a wireless charging system. The results are compared with the standards established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) to derive the minimum safe distance for electric vehicles charged wirelessly. The results show that when the system works at a frequency of 85 kHz with output power of 3.7 kW, 7.7 kW, 22 kW, 33 kW, 66 kW, and 150 kW, the minimum safe distance between the human body and the system is 0.5 m, 0.6 m, 0.7 m, 1.0 m, 1.2 m, and 1.7 m; when the system works at an output power of 66 kW with frequency of 85 kHz, 300 kHz, 500 kHz, and 700 kHz, the corresponding minimum safe distance is 1.2 m,0.9 m, 0.8 m, and 0.6 m. Moreover, the induced electric field intensity distribution of human organs at different power is also calculated, and the results show that the induced electric field intensity of the liver and kidney is higher than that of other organs. When the human body is at the minimum safe distance, the temperature changes caused by the electromagnetic heating effect of various organs are within the normal adjustment range of the human body, indicating the rationality of the minimum safe distance when the electric vehicle wireless charging system works under parameters of this paper. It provides a theoretical basis for the setting of the safe distance of the electric vehicle wireless charging system.

The Modeling and Simulation Research on High-Voltage Transmission Line Distance Protection Devices

Transmission line protection is a very important part of the power system. In order to effectively study the distance protection of high-voltage transmission lines, this paper introduces the setting and operation of distance protection., build the mode with Simulink tool box in the software of Matlab, and simulate the mode by S functions. The simulation results illustrate the Matlab software can effectively reflect the behavior of the distance protection when there are some faults in the simulated transmission line, which proves a simple and effective method to research the relay protection in the power system.

A unified stability theory for classical and monotone Markov chains

AbstractIn this paper we integrate two strands of the literature on stability of general state Markov chains: conventional, total-variation-based results and more recent order-theoretic results. First we introduce a complete metric over Borel probability measures based on ‘partial’ stochastic dominance. We then show that many conventional results framed in the setting of total variation distance have natural generalizations to the partially ordered setting when this metric is adopted.

KOMBINASI PENAMBAHAN SHIELDING TIMBAL MESIN FLUOROSCOPY BAGASI DAN PENGATURAN JARAK PEKERJA TERHADAP SUMBER RADIASI MENURUNKAN PAPARAN RADIASI SINAR X DAN KELELAHAN MATA PADA PEKERJA SCREENING DI BANDARA INTERNASIONAL X

Screening is ordinary process airport passanger was machine baggage. X-ray radiation gives impact to eye because eye sensitive of radiation. Many kinds of eye strain symptom got by screening worker such eye poignant. It is neressary to give intervention to decrease the radiation exposure and eye strain for worker by increasing lead shielding on the fluoroscopy machine baggage and setting of worker distance toward the source of radiation.&#x0D; Experimental research with pre-post test control group design. A sampel of 30 people were taken with a simple randomized method which was subdivided into group 1 as a control group without the additional treatment of lead shielding and working distance regulation of the radiation source, group 2 with the addition of a shielding and setting distance as far as 2 m. the study was conducted in August 2017. The variables evaluated were exposure to the received radiation of workes and the strain of the workers eyes.&#x0D; The result of the research is a combination of lead shielding on machine baggage fluoroscopy and setting of working distance to X ray source at X International Ariport significantly (p&lt;0,05) in decreasing radiation exposure received by worker equal to 74,59% and worker eye strain 68,85% for a distance of 1,5 m and decreased radiation exposure to the workers as much as 93, 69% and the eye strain on the worker 89,79% at a distance of 2 m from the radiation source.&#x0D; Concluded that the combination of increasing lead shielding and the setting of worker distance toward the source of radiation decrease thr radiation exposure and eye strain on the screening worker at X International airport.

Enhanced real time coordination of distance and user defined over current relays

Faults on the transmission lines are primarily cleared by pilot wire differential protection as well as from zone-1 and zone-2 of distance relays, depending upon their location on the lines. If the main distance relays fails to operate, then standard time inverse directional over current (DOCR) relays are set as backup protection in coordination with main distance relays. The desired coordination time margins between main distance relays and backup standard time inverse over current relays should be maintained at start of zone-1 and zone-2 of distance relays. Coordination of fixed zone-2 setting of distance relays with standard time inverse relays results in poor tripping time of backup DOCR.In this research article, zone -2 setting of distance relays are made adaptive, so that minimum coordination time margin is maintained for complete reach of distance relays. User defined time inverse over current relays are proposed in conjugation with flexible feature of zone-2 setting of distance for improving the operating time of backup DOCRs. The performance of the proposed algorithm is validated in real time simulation with hardware in loop testing of numerical distance and user defined DOCR. From hardware in loop simulation results, it is observed that the performance of the proposed combined distance &DOCR coordination algorithm is in close concurrence with simulated results. The sensitivity of proposed algorithm is checked for different phase as well as ground faults with different fault resistance and it is also observed that the proposed algorithm is highly robust for different fault conditions.

The contribution of the tibial tubercle to patellar instability: analysis of tibial tubercle-trochlear groove (TT-TG) and tibial tubercle-posterior cruciate ligament (TT-PCL) distances.

The purpose of this study is to assess the reliability of measuring the tibial tubercle to posterior cruciate (TT-PCL) distance compared to the tibial tubercle to trochlear groove (TT-TG) distance on magnetic resonance imaging (MRI), establish baseline TT-PCL values in patellar instability patients, and determine the predictive value of an excessive TT-PCL distance (≥24mm) for recurrent patellar instability compared to a TT-TG distance ≥20mm. TT-TG and TT-PCL distances were calculated on MRI in a randomized and blinded fashion by two reviewers on 54 patients (59 knees) with patellar instability. Interobserver reliability was assessed using interclass correlation coefficients (ICC). TT-PCL distances were also assessed to establish mean values in patellar instability patients. The ability of excessive TT-PCL and TT-TG distances to predict recurrent instability was assessed by comparing odds ratios, sensitivities, and specificities. Interobserver reliability was excellent for both TT-TG (ICC=0.978) and TT-PCL (ICC=0.932). The mean TT-PCL in these 59 knees was 21.7mm (standard deviation 4.1mm). Twelve (20%) of 59 knees had a single dislocation, and 47 (80%) exhibited 2 or more dislocations. The odds ratios, sensitivities, and specificities of a TT-TG distance ≥20mm for identifying patients with recurrent dislocation were 5.38, 0.213, and 1.0, respectively, while those of a TT-PCL distance ≥24mm were 1.46, 0.298, and 0.583, respectively. Of the 10 knees with a TT-TG distance ≥20mm, all 10 (100%) had recurrent instability, while 14 (73.7%) of the 19 knees with a TT-PCL ≥24mm experienced multiple dislocations (n.s.). Both TT-PCL and TT-TG can be measured on MRI with excellent interobserver reliability. In this series, the mean TT-PCL value in patients with patellar instability was 21.8mm, but the range was broad. A TT-PCL distance ≥24mm was found to be less predictive of recurrent instability in this series. For patients experiencing multiple episodes of patellar instability in the setting of a normal TT-TG distance, obtaining the TT-PCL measurement may provide a more focused assessment of the tibial contribution to tubercle lateralization. III.

Optimal setting of distance relays quadrilateral characteristic considering the uncertain effective parameters

Abstract In this paper a new method is presented for setting the quadrilateral characteristic of distance relay, considering sensitivity and selectivity criteria for protection zones. The main protection scheme used for transmission lines is distance protection. Due to the uncertainty of the effective parameters on relay’s estimated impedance the issue of optimal setting of the relay arises. In the proposed method of the paper, in addition to the variations of fault resistance, pre-fault load flow and measurement errors, the probabilistic changes of system topology and their corresponding effects are also considered. Optimal characteristic search is applied using Genetic Algorithm (GA). The obtained results for new method demonstrates a noticeable increase in the accuracy of this scheme compared to the conventional ones.

Modeling of Heat Transfer in Pipeline Steel Joint Performed by Submerged Double-Arc Welding Procedure

Submerged arc welding is the most applicable and productive procedure when thick sections have to be welded. Nevertheless, the manufacturers of pressure vessels, pipelines, ships and offshore structures keep on looking for new and modern design solutions of equipments and technologies which should lead to increase of welding process productivity. For instance, the longitudinal welds of pipelines are, mostly, performed by submerged arc welding procedure with multiple arcs and/or multi-wires, such as twin, tandem or twin-tandem, in order to increase the process productivity. However, achievement of optimal mechanical properties of the welded joint should remain the most important quality criteria. It is well known that dependence of the mechanical and metallurgical changes on heat transfer plays a major role in obtaining of safe welded structures and preserving of their structural integrity. That is why the investigation of heat transfer induced by the welding process is required. Furthermore, setting of distance between thermal sources and its influence on the overlapping phenomenon of temperature fields should be explored when submerged double-arc welding procedure is applied. Three dimensional finite element model of butt welded joint - used for simulation of heat transfer in pipeline steel joint performed by submerged double-arc welding process - is developed and described in this paper. Numerical results and a comparative analysis related to the temperature distribution, thermal history, and temperature variation in cross section of the welded joint at different time steps are discussed. Finally, important conclusions regarding the influence of distance between thermal sources on thermal effects and temperature fields overlapping are drawn.

Low-temperature evaporative glass scoring using a single-mode ytterbium fiber laser

Glass cutting is increasingly important in industry to cut glass into various sizes for high definition televisions, cell phones, laptops, and tablet computers. A conventional mechanical cutter is usually used to score the glass before a bending force is applied to separate the glass along the scoring mark. This paper presents a laser glass scoring technique aimed at replacing the mechanical cutter to reduce cracks. This scoring technique, denoted as the Low-temperature Evaporative Glass Scoring process (LEGS), is different because laser energy is not directly absorbed by the glass. To achieve the proposed laser scoring, a laser beam is focused through the glass onto a metal substrate. The metal substrate absorbs the laser energy to generate a metal vapor to etch the glass, forming a scoring mark. The feasibility of this glass scoring technique is demonstrated using a continuous-wave fiber laser, at a low power of 60W, and a 7075-T6 Aluminum alloy plate as the metal substrate. When the laser beam scans across the substrate, the laser energy creates a quasi-static aluminum molten pool, covered by an aluminum vapor at a temperature about 3000K. At an optimal setting of 51μm gap distance, 60W laser power, and 6mm/s scoring speed, a uniform scoring mark of 37μm width and 120μm depth was successfully generated on a piece of soda-lime glass without visible micro-cracks. The paper also discussed the uncertainties and their remedies involved in the LEGS process. To facilitate the process design, a model for predicting the aluminum vapor temperature was developed. This model accounted for the laser focus, reflection, absorption and transmission, laser energy distribution, and the aluminum melting and vaporization processes. Finally, this model was validated by comparing the actual melt depth of the aluminum substrate with the one predicted by the model.

The impact of social pressures, locus of control, and professional commitment on auditors’ judgment

PurposeThe purpose of this paper is to investigate the impact of improper social pressures on auditors’ judgment in the setting of a high power distance and low individualism society. Auditors’ judgment in this paper is related to the case of auditors’ willingness to sign off on net equipment balance for assets in question. Second, the paper investigates the role of locus of control and the relationship of multidimensional professional commitment on auditors’ judgment under conditions of social pressure.Design/methodology/approachThe experimental method is used in this research. The paper uses a case that was developed by Lord and DeZoort to manipulate the interest variable, social pressures. The paper also uses locus of control and multidimensional professional commitment as the explanatory variables.FindingsThe research finds that social pressures affect auditors’ judgment in a high power distance and low individualism society. Auditors who contend with improper social pressures make judgments that violate their integrity and professionalism. The paper also finds that locus of control and multidimensionality of professional commitment might potentially affect auditors’ judgment.Originality/valueThe research takes into account cultural influence on auditors’ judgment. The paper uses subjects who are in a high power distance and low individualism society. As Public Accountant is a worldwide profession, it is important to understand the impact of cultural dimensions on the profession. Moreover, insights drawn from this paper may be of assistance to regulators and the public accountant profession in considering and developing a mechanism that can mitigate the impact of improper social pressures.

도시 우수관망 노선 최적화를 통한 침수량 저감효과 분석

It is general to design the sewer network in current urban basin to calculate the minimum construction cost depending on sewer route setting of the shortest distance, and precedent researches on optimal design of sewer network is focused on cost-benefit of sewer network. Also, regional torrential rains currently occurred frequently increase the risk of local heavy rainfall in the urban basin with increasing of impermeable areas due to urbanization while exceeding of discharge capacity in the urban basin sewer network, so limitations on existing sewer design have came to the fore. Thus, this study has control the flow changes in pipes as the function objective that can be controlled depending on configurations of sewer through controlling of superposition effects between runoff hydrograph to determine the minimum overflow volume optimal sewer network focusing on that optimal sewer network to maximize the flooding prevention effect, and through application of excessive rainfall events by design frequency 10 years, reduction effects of inundation have been analyzed. Resulting in that, in case of overflow volume minimum sewer network, among 33 nodes, 20 sewers were connected to other direction than current sewers, and overflow volumes for each point about excessive rainfalls show that reduction rate against current sewer network was between 24% and 46%.

On Selection of Optimal Physical Layer Parameters for Wireless Sensor Networks Over Rayleigh Fading Channels

This paper investigates the issue of energy efficient transmission of data in a wireless sensor network. The notion of energy per successfully received bit (ESB), which is defined as the ratio of total energy required to send a packet and expected amount of data per packet, is used to find the optimal setting of transmission energy and hop distance to achieve energy efficiency. Analytical solution for optimal hop distance, transmit energy, and packet size that minimize the ESB, for a given modulation scheme and a given channel model are determined. Numerical optimization and simulation results are also presented. The results are beneficial for selecting the optimal node density and transmit energy for a given modulation scheme, which gives minimum ESB. Alternately, the best modulation scheme can be chosen for a given hop distance and for a given channel model.